Drug abuse during pregnancy is responsible for a surprising amount of birth defects and other adverse outcomes for the baby. The types of defects that can occur depend on which drug is used, how much is used and the timing during pregnancy when it is used. The most commonly abused drugs include alcohol, amphetamines and cocaine.
Alcohol
Alcohol is responsible for a larger number of and more severe birth defects than any other drug used during pregnancy. No specific amount of alcohol during pregnancy is considered to be safe, but small amounts of alcohol (less than one drink) on occasion are generally not thought to significantly increase the risk for adverse outcomes for the fetus. A study published in the journal "Epidemiology" in 1995 found that the babies of mothers who drank moderate amounts of alcohol (three or more drinks per week) had a higher rate of intrauterine growth restriction and low birth weight. Exposure to larger amounts of alcohol can lead to the fetal alcohol syndrome, which can consist of slow growth both before and after birth, central nervous system damage resulting in mental retardation and behavior problems, distinctive facial features including a smooth philtrum (area under the nose), small eye openings and organ malformations such as heart defects. Binge drinking may also increase the risk for birth defects and growth delay. The physical anomalies associated with alcohol abuse are most common with exposure occurring before 12 weeks; the growth delay and developmental delay generally occur with exposure after 24 weeks.
Amphetamines
Amphetamines and methamphetamines (also known as crystal meth, speed, ice and crank) are being used with increasing frequency among women. These drugs act as stimulants, increasing energy and attention in the short run. Studies are inconsistent regarding whether amphetamine use or abuse can cause birth defects. Part of the problem in clarifying the risks is that women who use amphetamines often also use other drugs, so that it is difficult to determine whether any birth defects are caused by amphetamines or other drugs. Amphetamine use can cause reduced birth weight and preterm delivery. Withdrawal symptoms can also be seen in newborns, such as jitteriness and drowsiness.
Cocaine
Cocaine abuse can cause devastating effects on a pregnancy; even one use can cause problems. Cocaine (also known as crack, coke, blow and snow) acts as a powerful stimulant and a vasoconstrictor, which, when used during pregnancy, can temporarily diminish blood flow to the placenta and fetus. The main risks from cocaine use are during the second and third trimesters, when it can cause hemorrhage inside the fetal brain and fetal death. As with amphetamines, it is difficult to determine whether cocaine can cause birth defects because of the compounding influence of other drugs in many cases. However, experts suspect that cocaine use contributes to growth restriction that affects weight, length and head circumference; brain malformations; limb reduction defects; and intestinal malformations. Cocaine use can also cause placental abruption, where the placenta separates from the wall of the placenta prematurely. This complication can cause premature birth and massive bleeding in the mother, jeopardizing the life of the mother and fetus. After birth, prenatal exposure to cocaine can contribute to learning disabilities and behavioral problems.
References
- "Epidemiology"; The Association of Moderate Maternal and Paternal Alcohol Consumption with Birthweight and Gestational Age; GC Windham et al; 1995
- March of Dimes; Professionals and Researchers Quick Reference Fact Sheet: Illicit Drug Use During Pregnancy; Accessed 03-05-10
