By Abu Bakar Abdul Majeed
The Sun, September 19, 1995
THE PLACENTA IS LEAST discriminative in allowing the passage of drugs and chemicals, good or bad, from the mother to the unborn. This include drugs that induce foetal and embryonic abnormalities. These class of drugs is known as teratogens. The risk of embryopathies and fetopathies is greatest during the first trimester when the unborn is taking shape.
Thalidomide and diethylstisbestrol (DES) are two of the most infamous drugs that bear witness to these abnormalities. The former drug was introduced in Europe in the 1960's as a mild sedative to give peaceful sleep. However, within a year, it was discovered that a large number of malformed babies were born to mothers taking the drug. They mostly had flippers instead of well developed hands and feet.
In the early 1970's, the then adolescent daughters of mothers who had been previously prescribed with DES, an artificial steroid, during their pregnancies in the 1960's, were found to suffer from an unusual kind of cancer of the vagina and cervix. These DES "daughters" were also found to be less able to conceive.
Narcotic drugs such as heroin, methadone and phencyclidine (angel dust), and barbiturates like Phenobarbital can also induce addiction in the unborn. The infants born to addicts may suffer from acute drug withdrawal. Cocaine is another drug of abuse which can have serious effects on the foetus. Large doses of cocaine, taken via "snorting", subcutaneous or intravenous injection, or inhalation with ether, can lead to the separation of the placenta. This can lead to foetal distress, and consequently, premature labour.
Addicts with acquired immune deficiency syndrome (AIDS) can also pass on the disease through the placenta to the foetus. The newborn infants then manifest very frequent infections through infancy, slow growth, and markedly increased death rate.
Microorganisms associated with sexually transmitted diseases such as syphilis, herpes and gonorrhea can also cause injury to the fetus or newborn. The virus of rubella (German measles), formerly caused a great deal of foetal injury but the development of an effective and safe vaccine has almost eradicated the problem.
Despite the fact that animal studies have proven that moderate to high doses of the majority of the inhaled and ingested chemicals can induce severe birth defects, these chemicals are quite insignificant in producing human foetal disorders at the levels normally encountered in everyday life. In essence, there is no evidence that foetal abnormalities today is more common that a hundred years ago.
Nevertheless, one thing is clear. Chemicals acquired during smoking and drinking have persistently been associated with adverse effects on the foetus. The various detrimental effects of these habits have been highlighted, time and again. While smoking mothers are normally associated with underweight babies, alcoholic mothers tend to give birth to babies with a characteristic foetal alcohol syndrome (FAS). The most common abnormality of FAS is mental retardation (see also Healthtrack, August 29, 1995).
In general, the unborn needs as much protection against the onslaught of drugs and chemicals as anyone else. We all wish for a healthy and beautiful baby. Some may argue that mother nature should be left to care for the unborn.
However, looking at the causes of teratogenicity as described above and in the previous two articles of this column, one cannot deny the fact that we do have an important role to play. In a sense, foetal and embryonic abnormalities due to ingested or inhaled drugs and chemicals are avoidable because they are induced either via accidental or conscious consumption.
Thus, the onus is upon us to steer clear of, or prevent such mishaps. Most urgently, pregnant women should refrain from smoking and consuming alcoholic beverages. Also, for the sake of both the mother and her unborn child, stay away from addictive drugs, or for that matter, the use of medicines unnecessarily. Consumption of caffeine-containing drinks (coffee, tea, colas, and cocoa) should be limited, although the evidence for caffeine's injurious effect on the foetus is thus far available only in animal studies.
Potential fathers also should not take an entirely casual attitude toward their smoking, drinking, and drug-taking habits. Genetic damage to the sperm is possible and can be passed on to the baby. Men and women should always take precautions when indulging in sexual activities to preclude the possibility of contracting sexually-transmitted disease. All female children and young women must be made aware of the public health effort to vaccinate them against German measles.
And as far as drugs are concerned, the best general rule is not to medicate yourself during pregnancy. Always consult your doctor or pharmacist.
