Unborn babies may well be susceptible to certain diseases the mother acquires during pregnancy. Some of theses diseases can do much more damage to a developing embryo or foetus than to the mother herself. This is due to the unborn child’s immature immune system. Such a disease is rubella (German measles). Mother’s who have rubella early in pregnancy can deliver babies who are blind. Blindness is not just the only defect caused by this disease, mothers with rubella have given birth to children with defects such as deafness, cardiac abnormalities and mental retardation. Rubella is most dangerous during the first trimester. Other common diseases that may affect an embryo, foetus or newborn are Herpes, Syphilis, chicken pox, diabetes, influenza, toxoplasmosis, cytomegalovirus and tuberculosis.
A mother who takes drugs during pregnancy may well give birth to a child with a number of defects. This is the case for mothers using both common and illicit drugs. Nowadays in our advanced medical society, a mother can be taking a dangerous common drug without even realising its affect on her unborn child. Such a drug is thalidomide. This is a drug that is present in a mild tranquilliser sold over the counter. It was said to alleviate the periodic nausea that many women experience during the first trimester of pregnancy. Thalidomide turned out to be a violent teratogen. Thousands of women who had used thalidomide during the first two months of pregnancy gave birth to babies with horrible birth defects. Thalidomide babies often have badly deformed eyes, ears, noses and hearts. Many display phocomelia, which is a structural abnormality in which all or parts of limbs are missing and the feet or hands may be attached directly to the torso, similar to flippers. The kinds of birth defects caused by thalidomide depend upon when the drug is taken during pregnancy.
Unfortunately some of the most commonly used drugs are responsible for certain defects on an unborn child. Heavy use of aspirin has been linked to foetal growth restriction, poor motor control and even infant death (Barr et al., 1990; Kelley-Buchanan, 1988). Use of ibuprofen during the third trimester increases the risk of prolonged delivery and pulmonary hypertension in newborns (Chomitz, Chung, & Lieberman, 2000). Even antidepressants containing lithium can produce heart defects when taken in the first trimester (Friedman & Polifka, 1996).
This brings us on to one of the most common drugs, alcohol. In 1973, Kenneth Jones and colleagues described a foetal alcohol syndrome (FAS) that affects many children of alcoholic mothers. The most noticeable defects of FAS are that of microcephaly (small head) and malformations of the heart, limbs, joints and face (Abel, 1998). FAS babies are likely to display excessive irritability, hyperactivity, seizures and tremors. They are also lighter and smaller than normal. The majority of the 3 in 1000 babies born with FAS score well below average in intelligence throughout childhood and adolescence.
So how much can a mother drink without harming her baby? The symptoms of FAS are most severe when the ‘dose’ of alcohol is highest (mother is an alcoholic). Yet moderate ‘social drinking’ (1 to 3 ounces a day) can lead to less serious problems, called foetal alcohol effects (FAE) in some babies. These effects include restricted physical growth, minor physical abnormalities, poor motor skills, difficulty paying attention and subnormal intellectual performance. Yet even a mother who drinks less than an ounce of alcohol a day is more likely than a non-drinker to have an infant whose mental development is slightly below average (Jacobson & Jacobson, 1996). There is no defined sensitive period for FAE. It is just as risky drinking late in pregnancy as drinking early on.
Another extremely common drug is that of cigarettes. Nowadays everyone clearly knows that cigarettes are unhealthy for you and regular use leads to a number of diseases including cancer. Therefore one would think that pregnant mothers might make the assumption that it would be unhealthy for their unborn baby! Having said this, there is little evidence that smoking causes physical defects. However one recent review of the literature concluded that smoking clearly increases the risk of spontaneous abortion or death shortly after birth in otherwise normal infants (Chomitz et al. 2000). Smoking is the leading contributor to foetal growth restriction and low-birth weight deliveries. Smoking introduces nicotine and carbon dioxide into both the mother’s and foetus’s bloodstreams. This impairs the functioning of the placenta and restricts the exchange of oxygen and nutrients to the foetus. The extremity at which the unborn child is affected is proportional to the amount of cigarettes smoked by the mother.
This brings us on to illicit drugs, such as marijuana, cocaine and heroin. These drugs do not appear to produce gross physical abnormalities. Women using heroin, methadone and other addictive narcotic agents are more likely than non users to miscarry, deliver prematurely or have babies who die soon after birth. Babies may be born addicted to the narcotic their mother has taken. When deprived of the drug at birth, they can experience withdrawal systems such as vomiting, dehydration, convulsions, extreme irritability, weak sucking and high pitched crying. Cocaine has been known to restrict blood vessels of both mother and foetus hindering the flow of oxygen and nutrients across the placenta.
A mother’s diet is very important during pregnancy. Inadequate prenatal nutrition can be harmful. During the first trimester, malnutrition can disrupt the formation of the spinal chord and induce miscarriages. During the third trimester, it is more likely to result in low-birth-weight babies with small heads. Therefore it is important that mothers have plenty to eat during pregnancy. However, that is not enough! They still may fail to ingest all of the vitamins and minerals for a healthy pregnancy. Adding a small amount of magnesium and zinc to a mother’s diet improves the functioning of the placenta and reduces birth complications. Diets rich in folic acid help prevent Down syndrome, spina bifida, anencephaly and other defects of the neural tube. Having said this, the ingestion of too much mineral supplement (e.g. vitamin A) can produce birth defects.
The mother’s emotional well being during pregnancy may well have an effect on the unborn child’ development. During times of stress, her glands secrete powerful activating hormones such as adrenaline. These hormones may cross the placental barrier, enter the foetus’s bloodstream and increase the foetus’s motor activity. Prolonged and severe emotional stress is associated with stunted prenatal growth, premature delivery, low birth weight and other birth complications (Lobel, 1994; Paarlberg et al., 1995).
Many factors have been discussed that affect a normal pregnancy. Therefore it is extremely important for all potential mothers to look after themselves during those nine months. Even constant exposure to an unfit environment may cause problems. For example being surrounded by smokers or even constant heavy air pollution. To ensure the likelihood of a normal pregnancy, mothers should stay well away from both common and illicit drugs or consult their doctor about over the counter prescriptions. This, combined with a healthy, plentiful diet, should reduce any risk of abnormalities and birth complications.
References
Developmental Psychology: Childhood and Adolescence
D.R. Shaffer (Brooks/Cole; 1999)
Exploring Developmental Psychology
D. Messer & S. Millar (London: Arnold, 1999)
Principles of Developmental Psychology
G. Butterworth and M. Harris (Hove: Earlbaum, 1994)
