Lower back pain in pregnancy. This study is therefore designed to determine the prevalence of low back pain in pregnant women, and also find out the predisposing factors and the impact of low back pain on daily living in pregnant women in Lagos.

University Degree Medicine and Dentistry

CHAPTER ONE

INTRODUCTION

1.1 Introduction

Low back pain (LBP) is the most common and currently one of the most widespread musculoskeletal problems affecting the human population (Walsh, 1990). It has been estimated that a quarter to half of the patients seen in physiotherapy outpatient departments suffer from back pain. The severity of this musculoskeletal condition ranges from mild back muscle strain to the gruesome pain that may incapacitate man from working as well as living a healthy life (Owoeye, 1999).

Disability reported as a result of LBP and loss of manpower with huge amounts of revenue loss has increased dramatically recently (Akinbo, 1998). Annually, over $50 billion is spent on the diagnosis and treatment of back pain in the United States (Jameel et al, 1996). The time off work due to LBP has increased by 40% for all other complaints (Helen, 1992). These figures are of great concern to all professionals dealing with the problem of LBP, especially the physiotherapist.

Back pain is a common symptom in women of childbearing age, with as many as half of these women reporting back pain at some stage during pregnancy (Fast et al, 1987; Berg, 1988; Ostgaard, 1991). Ostgaard et al (1991) have shown that there seems to be little difference in the prevalence of LBP between pregnant and non-pregnant women. Although non-specific low back pain is experienced by both pregnant and non-pregnant women, however, studies have shown that more severe pain which may result in sacroiliac dysfunction is a common feature in pregnancy (Berg et al, 1988; Ostgaard et al, 1991). LBP experienced during pregnancy is more severe and disabling and is present for a greater proportion of the time (Fast et al, 1987). About 10% of pregnant women may be prevented from working as a result of LBP (Berg, 1988), and over a third report that it interferes with daily life (Ostgaard et al, 1991).

The anatomical origins of back pain in pregnancy vary and are difficult to determine and diagnose (Nilsson-Wikmar and Harms-Ringdahl, 1999). Women describe pain variously as occurring in the low back, sacral, posterior thigh and leg, pubic groin and hip areas. These may occur simultaneously or separately antenatally, during delivery or postnatally (Heiberg and Aarseth, 1997).

Lockstadt (2000) stated that back pain in pregnancy usually presents itself most commonly in the following areas: sacroiliac joints at the posterior superior iliac spine (42%), the groin areas (53%), coccyx (33%), pubic symphysis anteriorly (77%), and occasionally other areas of the pelvic and upper legs. Rarely does pain occur below the knee. Pain tends to be influenced by posture and is associated with a waddling gait (Lockstadt, 2000).

Interestingly, despite the growing recognition of the importance of LBP during pregnancy, there is paucity of data regarding the prevalence and severity of this problem in this country. This study is therefore designed to determine the prevalence of low back pain in pregnant women, and also find out the predisposing factors and the impact of low back pain on daily living in pregnant women in Lagos.

1.2 Statement of Problem

It has been estimated that between 50% and 80% of women experience some form of back pain during their pregnancy (Lockstadt, 2000), ranging from mild pain associated with specific activities to acute back pain that can become chronic. About 10% of the time, the pain becomes so severe that it can interfere with the ability to work or carry out normal activities during pregnancy (Berg, 1988).

Studies have shown that LBP occurs at various times within the course of the pregnancy, but can begin as early as eight to twelve weeks into pregnancy; and that women with pre-existing low back problems are more likely to develop low back pain, and their back pain can occur earlier in the pregnancy (Brynhildsen, 1998, Wang et al, 2004).

This study therefore aimed at providing answers to the following questions:

What is the prevalence of low back pain in pregnancy?
What are the predisposing (risk) factors for low back pain in pregnancy?
What is the impact of low back pain in pregnancy on activities of daily living?

1.3 Aims of Study

To ascertain the prevalence of back pain in pregnancy
To determine which period (trimester) of pregnancy it is that back pain starts
To determine the relationship between previous low back pain and the occurrence of back pain in pregnant women
To identify the risk factors associated with developing low back pain in pregnancy.
To determine the impact of LBP in pregnancy on daily living

1.4 Hypotheses

There would be no significant relationship between age and the occurrence of low back pain in pregnancy.
There would be no relationship between weight gain in pregnancy and the occurrence of low back pain in pregnancy.
There would be no significant relationship between body mass index (BMI) before pregnancy and the occurrence of low back pain in pregnancy.
There would be no significant difference in the prevalence of LBP in the different trimesters of pregnancy.
There would be no significant relationship between previous low back pain and the occurrence of low back pain in pregnancy.
There would be no significant relationship between LBP in previous pregnancies and the occurrence of LBP in current pregnancy.
There would be no significant relationship between LBP during menstruation and the occurrence of LBP in Pregnancy.
There would be no significant relationship between multiparity and the occurrence of LBP in pregnancy
There would be no significant relationship between previous participation in exercise and occurrence of LBP in pregnancy.

1.5 Significance of Study

The outcome of this study would provide important information on the predisposing factors to the development of low back pain in pregnancy. In addition, knowledge about the possible relationship between physical activity and LBP during pregnancy may assist antenatal care providers in improving health during pregnancy.

Collectively, these results would help widen the scope of antenatal physiotherapy, incorporating back care as a preventive measure, and also to prevent recurrence and persistence of LBP.

It may further provide more evidence for physiotherapy in the prevention and management of low back pain in pregnancy, which has previously received little attention, as back pain was thought to be a normal part of pregnancy.

1.6 Scope of Study

This study involved 882 pregnant women, who were receiving ante-natal care at various teaching hospitals, primary health centres, general hospitals and private hospitals in Lagos State,

1.7 Limitations

This study was limited by the level of compliance of the participants.

1.8 Assumptions

It was assumed that the questionnaires used in carrying out this study were answered honestly and accurately.

1.9 Definition of Terms

Antenatal Occurring or existing before birth (Gould Medical Dictionary, 1979)

Low back pain A condition in which a patient feels an incapacitating pain at the lower part of the back (Owoeye, 1999).

Post natal Subsequent to childbirth

Pregnancy A physiological phenomenon, which is preceded by sexual intercourse. The condition where a growing foetus is within the body, lasting 40 weeks, or 280 days.

Pueperium The period following delivery, during which the remaining changes of pregnancy revert.

Relaxin A water soluble hormone having diverse effects on the musculoskeletal system, found in human serum during pregnancy

CHAPTER TWO

LITERATURE REVIEW

2.1 Epidemiology of Low Back Pain in Pregnancy

Back pain is the most common soft tissue complaint generally encountered by pregnant women (Colliton, 2004). It has been estimated that between 50% and 80% of women experience some form of back pain during their pregnancy and many describe pubic, pelvic, hip, knee, and various other joint discomforts (Mantle 1981; Lockstadt, 2000; Marnach et al, 2003). LBP often persists after delivery and may last up to 1 year (Berg et al, 1988). Data from other countries (e.g. Sweden, the United Kingdom, Scandinavia and Australia) indicate that LBP is a common problem during pregnancy (Ostgaard 1991; Noren et al, 1997; Foti et al, 2000).

2.2 Aetiology of Back Pain in Pregnancy

The aetiology of LBP in pregnancy is probably related to a combination of mechanical, metabolic, circulatory, and psychosocial contributing factors. One-third of patients experience pain starting during the first trimester, when mechanical forces are not a significant force. This is highly suggestive that the most probable cause is due to a change in hormonal influence. It is believed that hormones cause changes at the insertion point of ligaments into bone. A higher concentration of ligaments in the lower spine may suggest the cause for a higher incidence of back pain in the multiparous mother who has had more exposure to hormonal influences. Overall pain may arise from the muscles and ligaments combined with some alteration in blood flow to the pelvic musculature and ligaments (Lockstadt, 2000).

Postural adaptations, fatigue, increased joint mobility, increased collagen volume causing pressure on pain sensitive structures, weight gain, and pressure from the growing foetus may all contribute to low back pain in pregnancy (Polden and Mantle, 1990). In addition, poor passive stability from lax joints plus poor active stability from altered muscle recruitment and stretched pelvic and abdominal muscles probably contribute to back pain (Watkins, 1998; Coldron and Vits 2001). Other musculoskeletal factors include physically strenuous work and work involving bending, twisting, lifting and sitting, large abdominal sagittal and transverse diameters and a naturally large lumbar lordosis, pre-pregnancy low back pain, and decreased fitness level before pregnancy (Ostgaard et al, 1993; Heckman and Sassard, 1994; Heiberg and Aarseth, 1997)

For many mothers backache resolves in the first few weeks after delivery, but for some it may continue for months, and for a few it first presents postpartum. When backache develops postpartum, it is rarely severe and usually related to poor posture (Russell et al, 1993).

The most likely cause of postnatal back pain is simply that it is a continuation of antenatal problems (Russell et al, 1996), especially since, like antenatal back pain, it is more often reported by younger mothers (Breen et al, 1994). In a Swedish survey, pain persisted 18 months after delivery in over a third of the women who had backache during pregnancy. Chronic postnatal backache was again associated with an increased frequency of previous backache and heavy monotonous work, and more severe discomfort during pregnancy was associated with a longer postnatal course (Ostgaard et al, 1992).

Various factors are believed to aggravate LBP in pregnancy. They include prolonged periods of standing or walking, standing on one leg, climbing stairs, turning over in bed, intercourse, bending forward, stepping in or out of bed, and driving.

2.3 Anatomy of the Back

The back is described as the posterior aspect of the trunk, inferior to the neck and superior to the buttocks. It is the region to which the head, neck and limbs are attached (Moore and Dalley, 1999). The back comprises the skin, subcutaneous tissue, ligaments and vertebral column, spinal cord and meninges, ribs (in the thoracic region) and various nerves and vessels (Moore and Dalley, 1999).

Located also at the back are the ligaments and paraspinal muscles. Hence, the structure and plasticity of the spinal column are maintained by the interplay of vertebrae, ligaments and the tightening effects of paraspinal muscles (McMinn, 1998).

2.3.1 The Vertebral Column

The vertebral column is the central core of the back (Owoeye, 1998). The vertebral or spinal column is literally called the backbone (McMinn, 1998). It is composed of bones called vertebrae stacked one on top of the other with the intervertebral discs interposed between the bodies of each pair of vertebrae. The vertebral column extends from the skull to the tip of the coccyx. The vertebral column forms the skeleton of the neck, back, and the main part of the axial skeleton. The vertebral column consists of 33 vertebrae arranged in five regions: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal vertebrae. The five sacral vertebrae are fused to form the sacrum and the four coccygeal vertebrae to form the coccyx (Moore and Dalley, 1999).

A typical vertebra consists of a vertebral body, vertebral arch and seven processes (Moore and Dalley, 1999). Vertebrae vary in size and other characteristics from one region of the vertebral column to another, and also within each region. The vertebrae gradually become longer as the vertebral column descends to the sacrum and then they become progressively smaller towards the apex of the coccyx.

These structural differences relate to the fact that successive vertebrae bear increasing amounts of the body’s weight as the column descends until it is transferred to the pelvic girdle at the sacroiliac joint. The vertebral column is relatively flexible because it consists of the many relatively small vertebrae separated by the intervertebral discs and articulates at synovial joints. The greatest movements occur at the cervical and lumbar regions and they are the most frequent sites of disabling pain (Moore and Dalley, 1999).

The vertebral column in adults has four curvatures namely the cervical, thoracic lumbar and sacral curvatures. They provide a flexible support for the body. The cervical and lumbar curvatures are concave posteriorly. The thoracic and sacral curvatures are concave anteriorly. The lumbar curvature is generally more pronounced in females and ends at the lumbosacral angle formed at the junction of L5 vertebra with the sacrum (Moore and Dalley 1999).

The lumbar vertebrae are in the lower back between the thorax and sacrum. They account for much of the thickness of the lower trunk in the median plane. Lumbar vertebrae ...

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The lumbar vertebrae are in the lower back between the thorax and sacrum. They account for much of the thickness of the lower trunk in the median plane. Lumbar vertebrae have massive bodies because the weight they support increases towards the inferior end of the vertebral column (Moore and Dalley, 1999).

The fifth lumbar vertebra is the largest of all movable vertebrae; it carries the weight of the whole upper body. L5 is characterised by its massive body and transverse process. It is largely responsible for the lumbosacral angle between the long axis of the body of the sacrum. Body weight is transmitted from the L5 vertebra to the base of the sacrum, formed by the superior surface of the S1 vertebra (Moore and Dalley, 1999).

2.3.2 The Intervertebral Disc

Approximately one fourth of the length of the adult vertebral column is formed by the fibrocartilagenous intervertebral disc (Moore and Dalley, 1999). The discs act as shock absorbers. They are thinnest in the thoracic region and are thickest in the lumbar region. The lumbar discs are thicker anteriorly (Sinaki and Mokri, 2000).

Each vertebral disc consists of an outer fibrous part composed of connective lamella of fibrocartilage called annulus fibrosus and gelatinous central mass called nucleus pulposus. The annulus fibrosus is thicker anteriorly than posteriorly. The nucleus pulposus in early years of life consists of 88% water, which decreases with age (Sinaki and Mokri, 2000).

Plate 1: The Vertebral column (Netter,1998)

Plate 2: The Intervertebral Disc (Netter, 1998)

2.3.3 Muscles of the Back

The Quadratus Lumborum is a large muscle on the posterior abdominal wall between the psoas major and the erector spinae. The muscle attaches to the crest of the ilium lateral to the attachment of the erector spinae and sends attachments to the 12th rib and transverse processes of L1 to L3. It is innervated by the dorsal root of spinal nerves (Smith et al, 1996).

Erector Spinae Muscle is the chief extensor of the spine. It is divided into three columns namely: iliocostalis, longissmus and the spinalis. The common origin of the erector spinae is the posterior surface of the iliac crest and sacrum. It inserts in the occipital portion of the skull. It is innervated by the dorsal rami of spinal nerves (Netter, 1998).

Multifidus Muscle extends from the sacrum to the cervical vertebrae but is most developed in the lumbar spine. It is innervated by the dorsal rami of the spinal nerves (Netter, 1998).

External Oblique Muscle extends from the lower eight ribs and inserts into the linea alba.
Psoas Major Muscle originates from C5 and the transverse process of the lumbar vertebrae and inserts into the lesser trochanter of the femur. It is innervated by the ventral rami of L1-L3 nerves.

Psoas Minor Muscle lies anterior to the psoas major. It originates from the twelfth thoracic and first lumbar vertebrae and inserts into the illiopectineal eminence. It is innervated by the ventral rami of L1-L3 (Moore and Dalley, 1999).

Plate 3: Muscles of the Back (Netter. 1998)

2.3.4 Ligaments of the Back

The anterior longitudinal ligament is a strong, broad fibrous band that covers and connects the anterolateral aspects of the vertebral bodies and intervertebral discs (Moore and Dalley 1999). The ligament extends from the pelvic surface of the sacrum to the anterior tubercule of C1 and the occipital bone anterior to the foramen magnum. This ligament maintains stability of the joints between the vertebral bodies and helps prevent hyperextension of the vertebral column (Moore and Dalley 1999).

The posterior longitudinal ligament is a much narrower, somewhat weaker band than the anterior longitudinal ligament. The posterior longitudinal ligament runs within the vertebral canal along the posterior aspects of the vertebral bodies (Moore and Dalley 1999). It is attached to the intervertebral discs and the posterior edges of the vertebral bodies from C2 to the sacrum. This ligament helps prevent hyperflexion of the vertebral column and herniation or posterior protrusion of the discs. It is well provided with nociceptive (pain) nerve endings (Moore and Dalley, 1999)

Plate 4: Ligaments of the Back

2.4 Pregnancy and Pregnancy Related Changes

A human pregnancy is calculated as usually lasting about 40 weeks or 280 days. It is divided for the purpose of description and discussion into 3 periods or trimesters (Kisner et al, 1992). It culminates in labour and the delivery of the foetus and placenta.

Pregnancy is followed by pueperium, a period of 6 – 8weeks during which time the remaining changes of pregnancy revert. For the first eight weeks, it is usual to call the developing baby an embryo, thereafter; up until delivery, it is called the foetus (Chamberlain, 1997). The foetus grows within a thin, semi-transparent sac (the amnion). It is bathed in amniotic fluid and is attached to the placenta by the umbilical cord. The placenta, amnion and cord secrete the amniotic fluid. The foetus drinks it and excretes it as urine, it is said to be replaced every three hours. The volume of fluid normally increases throughout pregnancy to its maximum of about a litre at around 38 weeks of gestation (Mantle, 1997).

A baby is said to be full term at gestational age of 37 or more weeks, providing it weighs more than 2500g. Survival is good over 34 weeks and is poor under 28weeks, although survival following birth at 23 weeks has now been achieved (Mantle, 1997).

2.4.1 Anatomical and Physiological Changes in Pregnancy

The changes of pregnancy are chiefly the direct result of the interaction of four factors: the hormonally mediated changes in collagen and involuntary muscle; the increased total blood volume with increased blood flow to the uterus and kidneys; the growth of the foetus resulting in consequent enlargement and displacement of the uterus and finally the increase in body weight and adaptive changes in the centre of gravity and posture. The demands that these changes make upon a woman should never be underestimated (Polden et al, 1997).

A 25% increase in total weight is normal during pregnancy. This is necessary to nourish the foetus. It is about 10 – 12.5 kg (22 – 28 lbs) (American Academy of Paediatrics, 1983). The Institute of Medicine (1990) recommends a 28 to 40 lb increase in weight in underweight women, 25 to 35 lb weight gain in women in the normal weight range, 15 to 25 lb in the overweight, and 15 to 25 lb in the obese. A mother’s height, her weight per height at the start of the pregnancy and her weight gain can all influence the size of her foetus (Trusswel, 1985).

The effects of pregnancy on the musculoskeletal system are the ones that involve the physiotherapist most directly. First, to attempt to prevent disorders that may arise as a result of changes that may occur, and then when problems do arise, to treat them (Polden et al, 1997).

There is a generalised increase in joint laxity, and also in joint range, which is hormonally mediated. Research has shown a greater increase in joint range and therefore in the degree of laxity (Calguineri et al 1982).

During pregnancy, it is usually necessary for a woman to adopt her posture to compensate for her changing centre of gravity, as for most women the lumbar and thoracic curves are increased. Work done by Bullock et al, (1987) confirms this.

The changing centre of gravity is directly made necessary by the distending abdomen; the muscle fibres permit stretch, but the collagen components, (the aponeurosis, fibrous sheaths and the linea alba) probably undergo hormonally mediated structural changes to provide the necessary temporary extra extensibility. The distance between the two rectus abdominis muscles can be seen to wide throughout pregnancy, and the linea alba may even split under strain (diastasis recti). Range of motion could be reduced as a result of increased water retention, which may result in varying degrees of oedema of ankles and feet in most women (Polden et al 1997).

Pathophysiology of Low Back Pain in Pregnancy

Back pain is the most common soft tissue complaint pregnant women generally encounter (Colliton, 2004). There are a number of reasons for this, including:

increased ligament laxity due to the release of the hormone relaxin
increase in weight gain and forward weight bearing
poor body mechanics and postural habits
ribcage enlargement increasing rib subluxations
nerve and vascular impingement from mechanical pressure

The above factors increase the frequency of vertebral subluxations, muscular spasms, soft tissue pain and altered spinal biomechanics (Colliton, 2004).

Posture changes that occur during pregnancy help the woman maintain balance in the upright position as the foetus grows. The increasing weight is distributed primarily in the abdominal girth. After 12 weeks of pregnancy, the uterus expands out of the pelvis and moves superiorly, anteriorly, and laterally. The abdominal muscles become less effective at maintaining neutral posture (shoulders back, avoiding hyperlordosis) because the growing uterus stretches the muscles, reducing their tone. Initially, however, studies have shown that lumbar lordosis remains the same or increases only slightly (Colliton, 2004). The centre of gravity as a whole, though, shifts more posteriorly and inferiorly as the spine moves posterior to the centre of gravity.

As pregnancy progresses, production of the hormone relaxin, which allows pelvic expansion to accommodate the enlarging uterus, increases tenfold, reaching its peak at the 14th week (Colliton, 2004). Joint laxity is more pronounced in multiparous women than it is during the first pregnancy. In the lumbar spine, joint laxity is most notable in the anterior and posterior longitudinal ligaments, both of which are pain-sensitive structures. As these static supports in the lumbar spine become more lax, they cannot as effectively withstand shear forces, and discogenic symptoms and/or pain from the facet joints may increase.

As the abdominal muscles stretch to accommodate the growing foetus, their ability to help stabilize the pelvis decreases. The burden shifts to the paraspinal muscles, which become strained at a time when they may be shortened from the increased lordosis of the lumbar spine.

Treatment of Low Back Pain in Pregnancy

Many treatment options are available including a pelvic belt or brace (by prescription), exercise, appropriate rest, medication, ice and heat, massage, and standard back exercises. Patients are instructed to avoid excessive weight gain, exercise to strengthen the back muscles, maintain correct posture, and to wear sensible shoes (not high heels). However, no strong evidence exists concerning the effect of physical therapy interventions on the prevention and treatment of back and pelvic pain related to pregnancy (Stuge et al, 2003).

Currently, physicians and physiotherapists usually prescribe a pain contingent treatment regimen of relative (bed) rest and avoiding several day-to-day activities such as using the stairs, bending, twisting, lifting and cycling. Additionally, the usual treatment approach of a physiotherapist more often includes an exercise program to guide rectification of the muscle imbalance and alignment of the pelvic girdle (Hides et al, 2001, Bastiaenen et al, 2004).

CHAPTER THREE

MATERIALS AND METHODS

3.1 Materials

3.1.1 Subject Selection

Eight hundred and eighty two pregnant women participated in this study after informed consent had been obtained. They were recruited from various teaching hospitals, primary health centres, general hospitals and private hospitals in Lagos State, where they were receiving antenatal care. Data was collected between March and June 2007.

3.1.2 Instrumentation/Apparatus

The instruments that were used during this study are:

Weighing scale
Height meter
Questionnaire

3.1.3 Description of Apparatus

Weighing Scale: This is graduated in kilograms (kg) and pounds, with maximum weighing capacity of 120kg and 260 pounds. It measures to the nearest 0.1kg. It was used to measure the weight of the subjects

Height Meter: It is made of steel and calibrated in inches and centimetres. The height meter measures to the nearest 1cm and was used to get the exact height of the subjects.

Questionnaire: A 45-item closed-ended questionnaire was used to collect information about the respondents. It collected information regarding demographic and baseline characteristics of respondents, recreational habits, history of LBP before and during pregnancy, and the effect of LBP on daily living.

3.2 Methods

3.2.1 Sampling Methods

The subjects were selected using sample of convenience, as only subjects who volunteered took part in this study.

3.2.2 Research Design

A survey design was used in this study.

3.2.3 Questionnaire Design

The questionnaire was titled “SURVEY: LOW BACK PAIN IN PREGNANCY”. It was adopted from a previous survey by Wang et al (2004), which was done in the United States. It was developed based on the objectives of this study, which were to determine the prevalence, risk factors and impact of LBP on pregnant women in Lagos State.

The questionnaire consisted of 45 items regarding demographic and baseline characteristics of respondents, recreational habits, history of LBP before and during pregnancy, and the effect of LBP on daily living. The questionnaire comprised of four sections as follows:

Section A: Demographic and Bio Data regarding the participant’s age, weight, height, marital status, education and occupation

Section B: About your Pregnancy. This section enquired about how long the participant had been pregnant, number of previous pregnancies, pre-existing medical conditions, medications taken and assessment of potential risk factors for LBP in pregnancy

Section C: History of Low Back Pain before Pregnancy. This section sought to ascertain the existence of low back pain before pregnancy, low back pain in previous pregnancies and measures taken to relieve the pain then.

Section D: History of Low Back Pain in Pregnancy. This section sought to ascertain the presence of low back pain in pregnancy, areas of the body where pain was being experienced, measures taken to relieve low back pain and activities/positions that relieve/aggravate the LBP and the impact of the pain on activities of daily living.

During the pilot phase of the study, the questionnaire was pre-tested by 14 pregnant women and found to be suitable for the target population (Appendix I).

3.2.4 Ethical Issues

Prior to the commencement of the survey, ethical approval was sought and obtained from the Research and Ethics Committee of the Lagos University Teaching Hospital and Lagos State University Teaching Hospital (Appendix III).

3.2.5 Procedure for Data Collection

Prior to distribution of the questionnaire, the subjects were enlightened on the aims of the study, thereby seeking their consent, after which the questionnaire was administered to obtain their responses. They were also assured that the prior knowledge and approval of the management of the health institutions they were recruited from had been sought.

Sections of the questionnaire not understood were explained to the respondents. The respondents were assured of the utmost confidentiality of their responses.

3.3. Data Analysis

Data collected was analyzed using SPSS version 13.0 for windows. Descriptive statistics of mean, standard deviation and percentages and inferential statistics of Chi Square were also used in analysing the data. The level of significance was set at P<0.05.

The results were represented using tables, pie charts and bar charts.

CHAPTER FOUR

RESULTS

4.1 Results

4.1.1 Socio-Demographic Characteristics of Respondents

A total of 1,000 questionnaires were distributed and 882 copies were returned, giving a total response rate of 88.2%.

The age range of respondents was between 15 and 50 years, with the majority 575 (65.2%) of the respondents in the third decade of life (Table 1). Chi-square analysis showed that there was no statistically significant relationship (x²=1.084; P=0.78) between age and the occurrence of Low Back Pain (LBP) in the respondents (Table 2).

The majority 838 (95.0%) of the respondents were married, 39 (4.4%) respondents were single, 2 (0.2%) were separated and 3 (0.3%) were widowed (Table 1).

The majority of the respondents 646 (73.2%) had post secondary education, 217 (24.6%) had secondary education, and 19 (2.2%) respondents had only primary education. Thirty-nine (4.4%) respondents were single, 838 (95.0%) were married, 2 (0.2%) were separated and 3 (0.3%) were widowed (Table1).

In 394 (54.4%) and 194 (27.0%) respondents, their job activities involved sitting and standing for more than 75% of the day respectively, while 107 (14.9%) involved lifting and walking for more than 75% of the day (Table 1). Chi-square test showed no significant relationship (P=0.65) between job activities and the occurrence of LBP pregnancy (Table 2).

According to the WHO (2000) classification of BMI, 77 (8.7%) respondents were underweight before pregnancy, 469 (53.2%) were in the normal weight range, 254 (28.8%) were overweight and 82 (9.3%) respondents were obese (Figure 2). Chi-square test showed that there was no significant difference (x²=1.843; P=0.61) in the occurrence of LBP in pregnancy among the four categories of BMI in the respondents (Table 2).

Most of the respondents 732 (83.0%) were in good health without any pre-existing medical condition, while 150 (17%) had been diagnosed with a previous medical condition. Seventy-nine (9.0%) respondents were on prescribed medications.

The majority of respondents 571 (64.7%) were in the third trimester of pregnancy, and 54 (6.1%) and 257 (29.1%) respondents were in the first and second trimester of pregnancy respectively (Figure 1).

Table1: Socio-Demographic Data of Respondents.

Table 2: Chi-Square Analysis for Relationship between Age, Job Activities and BMI and the Occurrence of LBP in Pregnancy

Figure 1: Distribution of Duration of Pregnancy among Respondents

Figure 2: BMI classification of respondents before pregnancy

4.1.2 Predisposing Factors to LBP in Pregnancy

The number of previous pregnancies in respondents ranged from 0 to 12 pregnancies. . Figure 3 compares the incidence of LBP in pregnancy in with parity. However, the Chi-square test for showed no statistically significance between multiparity and the occurrence of LBP in pregnancy P=0.97 (Table 3).

The total weight gain in pregnancy ranged from 0.5kg to 51.0kg. Using the Institute of Medicine (1990) guidelines, 682 (77.13) of the respondents gained weight normally within the expected normal range of weight gain in pregnancy, while 200 (22.7%) respondents gained weight abnormally. Figure 4 shows the distribution of weight gain observed in respondents during pregnancy. Of the respondents that gained weight abnormally, 6 (3%) were in the first trimester, 44 (22%) were in the second trimester and 150 (75%) were in the third trimester. Chi-square analysis showed no significant relationship between abnormal weight gain and the occurrence of LBP in Pregnancy (x²=0.001; P=0.98) (Table 4).

Figure 3: Comparison of Parity with Incidence of LBP in Pregnancy

Table 3: Chi-square analysis for relationship between multiparity and occurrence of LBP in pregnancy

Table 4: Weight Gain Observed in Respondents during Pregnancy

Figure 4: Weight Gain Observed in Respondents during Pregnancy

Seventy-seven (8.7%) respondents had previously been on Birth Control Pills (BCP). The Chi-square analysis for significant relationship between BCP use and LBP showed that there was no statistically significant relationship between BCP use and the occurrence of LBP in pregnancy (P=0.63). Forty-five (5.1%) respondents had also received hormone replacement therapy for infertility prior to the current pregnancy. The Chi-square analysis for significant relationship between hormone replacement therapy and LBP showed that there was no statistically significant relationship between hormone replacement therapy and the occurrence of LBP in pregnancy (P=0.66) (Table 5).

Three hundred and one (34.1%) respondents reported experiencing major life changes within a 12-month period, while 581 (65.8%) had not experienced any such changes. Chi square analysis showed a significant relationship between having these major life changes and the occurrence of LBP in pregnancy (P=0.03) (Table 5).

Six hundred and ninety (78.2%) of the respondents reported that they consumed caffeinated drinks regularly while 192 (21.8%) reported that they did not. Chi-square analysis for significant relationship between consumption of caffeinated drinks and the occurrence of LBP showed that there was no statistically significant relationship between the consumption of caffeinated drinks and the occurrence of LBP in pregnancy (P=0.47) (Table 5).

Six (0.7%) respondents reported that they smoke cigarettes, while 63 (7.1%) respondents also reported that their husbands smoked cigarettes. The Chi-square analysis for significant relationship between cigarette smoking and LBP showed that there was no statistically significant relationship between cigarette smoking and the occurrence of LBP in pregnancy (P=0.35) (Table 5).

Twenty-three (3.2%) respondents had undergone spinal tap/epidural anaesthesia previously, while 859 (96.8%) respondents had never undergone spinal tap. Chi-square analysis showed no significant relationship between a previous spinal tap and the occurrence of LBP in pregnancy (P=0.24) (Table 5).

Table 5: Chi-square analysis for risk factors for developing LBP in pregnancy

Table 6 shows the frequency of exercise participation by respondents before Pregnancy. Two hundred and eighty five (32.3%) respondents reported that they participated in physical exercise before getting pregnant, while 597 (67.7%) did not participate in any form of exercise at all. One hundred and eighty five (64.9%) of these respondents reported that they exercised regularly, while 100 (35.0%) exercised occasionally (Table 6). Chi-square analysis however showed no significant relationship between previous exercise participation and the occurrence of LBP in pregnancy (P=0.30). (Table 5).

Figure 5 shows the nature of exercise participated in by respondents. Brisk walking was the most common form of physical exercise that respondents practiced before getting pregnant 117 (38.2%) respondents, 82 (26.8%) respondents were involved in jogging, 33 (10.8%) respondents were involved in running, 43 (14.1%) respondents engaged in aerobics, 12 (3.9%) respondents engaged in swimming, and 19 (6.2%) respondents played tennis. Figure 3 shows the nature of exercises respondents engaged in before getting pregnant.

Table 7 shows the frequency of exercise participation by respondents during pregnancy. Three hundred and ninety eight (45.1%) respondents did not engage in any form of physical exercise at all during pregnancy, 367 (41.6%) respondents reported that they exercised occasionally, while 117 (13.3%) respondents reported that they exercised regularly (Table 7).

Table 6: Frequency of Participation in Exercise before Pregnancy

Figure 5: Nature of Exercises Participated In By Respondents

Table 7: Frequency of Practice of Physical Exercises amongst Respondents during Pregnancy

4.1.3 History of LBP before Pregnancy

Majority of the respondents 609 (69.0%) had not experienced any back pain prior to getting pregnant (Table 9), 151 (17.1%) had experienced LBP, but required no treatment, 67 (7.6%) had experienced LBP which they treated at home, while 25 (2.8%) had experienced LBP serious enough to require them going to the hospital. Chi Square analysis of revealed a significant relationship between previous LBP and the occurrence of LBP in pregnancy (P=0.00) (Table 9).

Majority of the respondents 535 (60.6%) respondents did not have LBP associated with their menstrual periods, while 347 (39.3%) respondents reported that they experienced LBP just before/during their menstrual periods (Table 8). One hundred and sixty four of the respondents that experienced LBP reported that their LBP worsened with their menstrual periods. Chi square analysis showed a significant relationship between LBP during menstrual periods and the occurrence of LBP in Pregnancy (P=0.00) (Table 9).

Two hundred and thirty five (26.6%) respondents reported that they had experienced LBP with previous pregnancies (Table 8). Two hundred and thirty five (27.1%) respondents also reported that LBP experienced previously increased with pregnancy. Chi-square analysis is as shown in Table 9. There was a statistically significant relationship between LBP experience with previous pregnancies and the occurrence of LBP in current pregnancy (P=0.00) (Table 9).

Of those that had had LBP prior to getting pregnant, majority 111 (19.9%) respondents required no treatment, 10.2% practiced self medication and 3.9% required a visit to the hospital

Two hundred and twenty (39.4%) of the respondents that had LBP in the current pregnancy reported that their LBP increased with pregnancy, while 203 (36.3%) respondents reported that their LBP did not increase with pregnancy.

Figure 6 shows the measures taken by respondents to Relieve LBP before Pregnancy. Of the respondents that reported that they had experienced LBP prior to the current pregnancy, 185 (52.0%) reported that they had visited a doctor, 8 (2.2%) reported that they had visited a physiotherapist, 147 (41.3%) indulged in self-medication/use of analgesics, while 16 (4.5%) resorted to alternate medicine(Figure 4). The mean effectiveness of measures taken to relieve pain was 5.53±2.51.

Table 8: Occurrence of LBP before Pregnancy

Tale 9: Relationship between Previous LBP and LBP in Pregnancy

Figure 6: Measures Taken to Relieve LBP before Pregnancy

4.1.4 Prevalence of LBP in Current Pregnancy

Three hundred and twenty three (36.6%) respondents did not have LBP at all in this pregnancy while 559 (63.4%) respondents reported that they experienced LBP in the current pregnancy (Figure 7).

Report of LBP to Antenatal Care Providers

Two hundred and sixty (43.4%) of the respondents that experienced LBP in the current pregnancy had reported the LBP to their antenatal health care providers. Of those that reported the pain, 46 (21.5%) were told the LBP was normal in pregnancy, the majority, 80 (37.4%), were told to rest, 18 (8.4%) were advised to exercise because of the LBP and 70 (32.7%) were told to take drugs (analgesics) for the pain (Table 10).

Nature of Pain Described by Respondents

Twenty (2.3%) of the respondents described the nature of their pain as numbness, 13 (1.5%) described it as tingling, 311(35.3%) described it as aching, 13 (1.5%) described it as burning, 12 (1.4%) described it as electrical shock sensation, 79 (9.0%) described it as muscle pulling sensation, 28 (3.2%) described it as shooting pain (Figure 8).

Period of onset of LBP among Respondents

Of the 559 respondents that experienced LBP in the current pregnancy, majority 211 (37.7%) started experiencing LBP from the third trimester of pregnancy. One hundred and forty three (25.5%) respondents reported that they started experiencing LBP in the first trimester of pregnancy, while 206 (36.8%) respondents started experiencing it in the second trimester (Table 11). Chi square analysis showed no statistically significant relationship between the occurrence of LBP in the various trimesters of pregnancy (x²=2.090; P=0.352).

Location of Pain in the Respondents

Most respondents 347 (30.1%), felt pain in the lower back. Eighty one (7.0%) respondents felt pain in the upper back, 161 (14.0%) respondents felt pain in the lower back and back of one or both legs, 88 (7.6%) respondents felt pain in the buttocks, 129 (11.2%) felt pain in the groin, 164 (14.2%) felt pain in the hip, 31 (2.7%) felt pain in the upper legs, 67 (5.8%) felt pain in the front of the upper thigh, 53 (4.6%) felt pain at the back of the upper thigh 31 (2.7%) felt pain in the back of the legs (Figure 9).

Measures Taken to Relieve LBP in Pregnancy

Two hundred and ninety five (54.1%) of the respondents that had LBP in the current pregnancy reported that they had visited a doctor, 11 (2.1%) visited physiotherapists, 151 (29.3.0%) indulged in self-medication/use of analgesics, 22 (4.3%) resorted to alternate medicine, while 53 (10.3%) employed other measures to relieve the pain. The mean effectiveness of measures taken to relieve pain was 5.44±2.60 (Figure 10.

Figure 7: Prevalence of LBP among Respondents

Table 10: Frequency of Report of LBP to Antenatal Care Providers

Figure 8: Nature of Pain Reported By Respondents

Table 11: Period of Onset of LBP in Pregnancy

Table 12: Chi-Square Analysis for Period of Onset of LBP

Figure 9: Location of Pain in Respondents

Figure 10: Measures taken to relieve LBP in Pregnancy

4.1.5 Impact of LBP on Respondents

One hundred and ninety seven (35.2%) respondents reported that their LBP affected their sleep while 326 (58.3%) reported that their LBP did not affect their sleep. 248 (44.4%) respondents also reported that the LBP affects their daily activities, while 278 (49.7%) reported that the LBP did not affect daily activities, such as sweeping, cooking and bathing (Table 13).

One hundred and forty three (31.2%) respondents needed to take time off work because of the LBP, 242 (52.2%) respondents needed to change their footwear to manage the LBP, while 222 (39.7%), and 64 (13.9%) respondents considered their LBP a threat to having further pregnancies (Table 13).

Activities that Bring on the LBP

Two hundred and twenty one (22.1%) of the respondents that had LBP in the current pregnancy reported that standing brings on the LBP, 206 (20.6%) respondents reported that sitting brings on the LBP, 115 (11.5%) respondents reported that bending over a sink brings on LBP, 25 (2.5%) respondents reported that exercise brings on the pain, 115 (11.5%) reported that lifting objects brings on the LBP, 78 (7.8%) respondents reported that lying down brings on the LBP. 84 (8.4%) respondents reported that walking brings the LBP, 127 (12.7%) respondents reported that climbing stairs brings on the LBP, while 25 (2.5%) reported that driving brings on the LBP (Figure 11).

Activities that Relieve the LBP

Eighty seven (12.9%) respondents reported that standing relieves their LBP, 165 (24.4%) respondents reported that sitting relieves the pain, 22 (3.3%) reported that kneeling relieves the pain, while 390 (57.7%) respondents reported that lying down relieves the pain (Figure 12).

Actions that Make the Pain Worse

Forty five (5.1%) respondents stated that coughing made the pain worse, 35 (4.0%) respondents stated that sneezing made the pain worse, 151 (17.1%) respondents reported that straining during bowel movement worsened the pain. 64 (7.3%) respondents attributed other actions to making the LBP worse. (Figure 13)

Table 13: Impact of LBP on Respondents

Figure 11: Activities that bring on LBP in Respondents

Figure 12: Activities that Relieve LBP

Figure 13: Actions that Make the Pain Worse

Difficulty in Carrying out ADLs Due to LBP

The mean difficulty in dressing due to LBP was 1.68±2.47. The mean difficulty in outdoor walks was 2.64±2.74. The mean difficulty in sitting for long was 5.43±3.15. The mean difficulty in climbing stairs was 4.69±3.17. The mean difficulty in standing bent over a sink was 4.13±3.11. The mean difficulty in carrying a bag due to LBP was 2.79±5.24. The mean difficulty in making a bed due to LBP was 2.99±3.05. The mean difficulty in running due to LBP was 5.30±3.74. The mean difficulty in light work due to LBP was 1.90±2.47. The mean difficulty in heavy work due to LBP was 5.79±3.44. The mean difficulty in lifting heavy objects due to LBP was 6.53±3.39. The mean difficulty in dressing due to LBP was 4.74±3.48. The overall disability index was 4.05±3.29. Figure 14 shows the mean difficulty in carrying out various activities of daily living (ADLs).

Figure 14: Mean Difficulty in carrying out Various ADLs.

4.2 Hypothesis Testing

There would be no significant relationship between age and occurrence of low back pain in pregnancy. The Chi-square test showed that was no statistically significant relationship between age and LBP in pregnancy (P=0.78). Hence, the hypothesis is accepted.

There would be no significant relationship between weight gain in pregnancy and occurrence of low back pain in pregnancy. In Table 8 the Chi-square analysis shows there was no statistically significant relationship between weight gain in pregnancy and LBP in pregnancy (P=0.98). Hence, the hypothesis is accepted.

There would be no significant relationship between body mass index (BMI) before pregnancy and occurrence of low back pain in pregnancy. As shown in Table 8, the Chi-square analysis revealed no statistically significant relationship between BMI and LBP, with a P-value of 0.61. Thus, the hypothesis is accepted.

There would be no significant difference in the prevalence of LBP in the different trimesters of pregnancy. The Chi-square analysis showed no significant difference in the prevalence of LBP among the three trimesters of pregnancy (P=0.35). thus the hypothesis is accepted

There would be no significant relationship between previous low back pain and occurrence of low back pain in pregnancy. Chi Square analysis of relationship between previous LBP and current LBP in pregnancy revealed a significant relationship between previous LBP and current LBP in pregnancy (P=0.00). Therefore, null hypothesis is rejected.

There would be no significant relationship between low back pain in previous pregnancies and present low back pain in pregnant women. From Table 8, the results of the Chi-square analysis showed a statistically significant relationship between LBP experience with previous pregnancies and present LBP (P=0.00). Thus, the null hypothesis is rejected

There would be no significant relationship between LBP during menstruation and occurrence of low back pain in pregnancy. From Table 8, the Chi square analysis revealed a significant relationship (P=0.00). Thus, null hypothesis rejected

There would be no significant relationship between multiparty and occurrence of LBP in pregnancy. The Chi-square test for number of pregnancies showed no statistically significance between number of pregnancies and LBP in pregnancy (P=0.97). Hence, the hypothesis is accepted.

There would be no significant relationship between previous participation in exercise and occurrence of LBP in pregnancy. Chi square test showed no significant relationship between previous exercise participation and occurrence of LBP in pregnancy (P=0.30). Hence, the hypothesis is accepted.

CHAPTER FIVE

DISCUSSION, CONCLUSION AND RECOMMENDATIONS

5.1 Discussion

This study was carried out to ascertain the prevalence of Low Back Pain (LBP) in pregnancy and the risk factors associated with it.

It was observed that a large number of respondents experienced LBP during the current pregnancy. This implies that LBP is a common phenomenon in pregnancy. The prevalence of LBP found in this study (63.4%) is similar to that reported by Wang et al (2004), who reported a prevalence of 68.8%. It was also found that LBP may be present at any time during pregnancy. However, it was found to be more common in the last two trimesters of pregnancy. This is in contrast to the report by Fast et al (1987), which indicates that LBP mainly occurs primarily during the first 5–7 months of pregnancy. This is probably because the increasing weight of the baby helps to further stretch the already lax ligaments of the back, as the majority of the respondents gained weight normally in this study.

The results of this study also suggest that variables like maternal age, nature of job, use of birth control pills, history of infertility accompanied by hormone therapy, caffeine use, smoking, previous spinal or epidural anesthesia and BMI before pregnancy do not contribute to the development of LBP during pregnancy. This finding agrees with the report of Leboeuf-Yde (2000), whose study titled Body weight and Low back Pain confirmed that these variables do not contribute to LBP in pregnancy. Multiparity was also not found to be a significant risk factor to developing LBP in pregnancy, as was similarly reported by Fast et al (1987). On the contrary, a large portion of those who experienced LBP in the current pregnancy were in their first pregnancy. This is in disagreement with Hanneke et al (2006), who stated that previous pregnancy was associated with developing chronic LBP.

In addition, history of previous LBP and LBP during menstruation were found to be significant risk factors for the development of LBP in the current pregnancy. This concurs with the findings of Ostgaard et al (1991), who reported that back problems before pregnancy increased the risk of back pain in pregnancy. A history of LBP in previous pregnancies was also found to be a predictive factor for LBP in pregnancy. This may not be unconnected with increased ligamentous laxity that may be observed in multiparous mothers who have had more exposure to hormonal influences, as suggested by Lockstatdt (2000), who reported that repeated exposure to relaxin increases ligamentous laxity. A report by Brynhildsen et al (1998), also confirms that previous LBP may be a significant predictive factor for developing LBP in pregnancy.

Respondents reported the greatest difficulty in lifting heavy objects, running, participating in exercise and sitting for prolonged periods due to their LBP. This was particularly observed in respondents in the third trimester or pregnancy. Of the respondents that experienced LBP in the current pregnancy 44.4% reported that it affected their activities of daily living, and 35.2% reported that it disturbed their sleep. This is comparable with the study carried out by Wang et al (2004), where 58% of respondents reported that LBP experienced in pregnancy disturbed their sleep, while 57% reported that it affected their daily activities.

The findings show that of the 559 respondents who reported having LBP during pregnancy, only 43.4% revealed the existence of LBP to their antenatal care providers These antenatal care providers provided recommendations to these women ranging from prescribing analgesics to advising them to rest and exercise. Most of the antenatal care clinicians instructed the women to accept LBP as a normal part of pregnancy and rest. In the United Kingdom and Scandinavia on the other hand, treatment for LBP during pregnancy frequently includes patient education about LBP, education regarding posture and body mechanics from the first trimester, information about mechanical supports such as type of pillow to use while sleeping, and physiotherapy (MacEvilly and Buggy, 1996).

5.2 Conclusion

Based on the findings of this study, the following conclusions were made:

LBP during pregnancy is a common problem that should not be ignored due to its socio-economic effects and impact on daily living.
The results of this survey underscore the fact that many pregnant women suffer significant pain that is left untreated. This pain impacts not only the individual woman, but also adversely affects those she cares for by limiting her daily activities, as well as adversely impacting her work productivity.
Most pregnant women fail to report LBP to their antenatal care providers.
Most antenatal care providers do not provide appropriate treatment for LBP in pregnancy.
Appropriate treatment measures are yet to be developed for LBP in pregnancy.

5.3 Recommendations

Based on the findings of this study, it is recommended that:

Antenatal care providers should address the problem of LBP in pregnancy by adopting appropriate treatment measures, and referring women who experience this LBP for appropriate treatment, including physiotherapy, where necessary.
Back care education in Antenatal Physiotherapy should be offered to pregnant women, particularly those who are at risk of developing LBP during pregnancy as early in their pregnancy as possible. This may prevent or result in less troublesome and severe LBP in pregnancy.

Implications for Further Studies

Future studies to examine the Knowledge and attitudes of Antenatal care providers to LBP in pregnancy may provide insight as to why antenatal care providers do not refer such patients for physiotherapy.

Further studies may also look into examining physiotherapy modalities and techniques may help in relieving LBP in pregnancy

It is therefore very important that researchers contribute to improving women’s health through research focused on the prevention and treatment of LBP in pregnancy.

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