Drugs during Pregnancy

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“Drugs during Pregnancy,” Ensign, Jan. 1976, 72–73

Drugs during Pregnancy

A mother concerned about her newborn child asks, “Is he all right?” The answer, fortunately, is usually affirmative. But at an alarming frequency of 1 to 10 percent or greater (the figures varying considerably due to the number of malformations that go undetected until later in life), children are born with major defects of body, limb, and mind.

Birth defects are defined as metabolic, structural, or functional disorders that originate in the womb, usually very early in gestation. The greatest period of sensitivity of the embryo to malforming influences is from one week to two months after conception.

As the embryonic vessel develops in the mother’s body, mutations, abnormal chromosomal constitutions, factors in the environment, and combinations of these can alter the developmental processes both physically and mentally.

Hereditary defects are caused by dominant and recessive mutations. Hemophilia and sickle-cell anemia are examples of gene-induced disorders of the blood. Phenylketonuria is an inherited metabolic disease that can lead to mental retardation if dietary measures are not taken. Although these diseases may take their toll later in life, they are regarded as birth defects because the genetic determinants of these diseases are present at birth.

Under abnormal chromosomal constitution one would find the “syndromes,” which range in effect from mental retardation to impaired reproduction. An example of this class of disorders would be Down’s Syndrome or mongolism. In the cells of individuals with this particular anomaly, one of the “pages of blueprints” (chromosomes) is present in triplicate rather than duplicate.

Defects classified as environmental would be those induced by influences external to the embryo: radiation from natural and therapeutic sources; infections caused by microorganisms such as rubella virus, cytomegalovirus, toxoplasma, and syphilis; nutritional factors such as vitamin, mineral, and amino acid imbalances; and chemicals found in certain drugs, hormones, and industrial wastes.

It is estimated that 20 percent of all birth defects are hereditary, involving single gene mutations; 5 percent arise from abnormal chromosomal constitution; and approximately 10 percent are of known environmental origin. Simple arithmetic reveals that causative factors for the remaining 65 percent have not been identified. Certainly a host of genetic and environmental factors interact to produce the majority of congenital malformations, the “multifactorial group.” Thus we face the problem of identifying high-risk mothers and of searching for malformation-producing agents.

The precise impact on the fetus of medicines and other chemicals found in the environment unfortunately remains unknown. It is still being debated whether or not alcohol; aspirin, antacids, antihistamines, antibiotics, antiemetics, barbiturates, contraceptives (both hormonal anovulatory and foam and jelly spermicidal), insecticides, LSD, marijuana, nicotine, and tranquilizers, to mention only a few, pose a threat to the embryo.

One investigator reports a positive correlation between ingestion of aspirin during the first trimester of pregnancy and a higher incidence of nervous system defects.1 To support his findings, he draws upon laboratory experiments that demonstrate that aspirin induces abnormalities in the rat fetus, particularly under extreme fasting conditions. Another investigator reports no such association in humans and rejects the rat study on the basis that placental transfer of drugs and nutrients in rats differs considerably from that in humans. “Furthermore,” contends the second investigator, “the per-kilogram dosage required to produce malformations in rats exceeds many times the usual therapeutic dose in man.”

Similarly, a recent report suggests that women who unknowingly became pregnant while taking contraceptive measures, and who continued taking synthetic progesterone, may have unwittingly induced the anomalies that subsequently occurred in their children.2 The report is reinforced by studies demonstrating that hormonal contraceptives given in large doses to laboratory animals have adverse effects on their fetuses. Another study surveying human populations reports no evidence implicating the “pill” in increasing the incidence of congenital malformations, but suggests that spermicidal foams and jellies must be regarded with suspicion.3

The hallucinogen LSD has been suspected of causing birth defects, possibly by breaking chromosomes; but more recently it has been suggested that the real culprit might not be LSD, but marijuana.4

Nicotine from cigarettes has been associated with lowered birth weight, prematurity, and stillbirth, but with regard to birth defects per se, the evidence is less convincing. Needless to say, with recent findings from a British study that “children whose mothers (during pregnancy) had smoked 10 cigarettes or more a day tended to be stunted physically and behind their peers in school scholastically, especially in reading and mathematics,”5 smoking mothers are certainly not exercising wisdom.

It has recently been established that children born of chronic alcoholic mothers are at greater risk of having central nervous system, heart, and other disorders (the fetal alcohol syndrome). The effect of “social drinking” on the unborn is unknown.6

And although aerosols have recently been caught in the “consumer-government crossfire,” because the chemicals contained quickly cross the respiratory membranes and enter the circulatory system, their impact on fetal health, at present, is equivocal.

Despite the fact that drug consumption during pregnancy has been associated with birth defects, it is not uncommon for women during the critical first trimester of pregnancy to consume several drug compounds, both over-the-counter and prescribed. The example frequently cited concerns a woman who, upon delivery of a malformed child, was asked if she had taken any drugs during the first eight or twelve weeks of pregnancy. Her immediate recollection suggested not, but further probing revealed that she had taken tranquilizers, pep-up pills, left-over antibiotics, weight-reducing pills, nasal sprays; she had used insecticide sprays in her kitchen, and hair and deodorant sprays in a small, unventilated bathroom.

Because we are a drug and chemical-oriented society, and because the origins of the majority of birth defects are unknown, mothers during pregnancy, and perhaps even during child-bearing years, would be prudent to avoid, as far as possible, any of the previously mentioned “environmental factors” suspected of causing malformations.

And if medical treatment is deemed necessary during pregnancy, it should be administered by one in the medical profession who has knowledge of the pregnancy, who is aware of the sensitivity of the human embryo to environmental agents, and who weighs carefully the benefit of desired therapy to mother against its potential hazard to the embryo.

With these precautions, the inevitable question regarding the welfare of the newborn child can be answered affirmatively with an additional degree of certainty.

The following general references are provided for those desiring further information:

Apgar, V. and J. Beck, Is My Baby All Right? New York: Trident Press, 1972.

Bergsma, D. (ed.) The Infant at Risk, New York: Intercontinental Medical Book Corp., 1974.

Nelson M. and J. Forfar, “Associations between drugs administered during pregnancy and congenital abnormalities of the fetus,” British Medical Journal 1 (1971) 523:27.

Shepard, T., Catalog of Teratogenic Agents, Baltimore: Johns Hopkins Press, 1973.

Warkany, J., Congenital Malformations, Notes and Comments, Chicago: Yearbook Publishers, 1971.

Wilson, J., Environment and Birth Defects, New York: Academic Press, 1973.