Women who abuse drugs during pregnancy face increased risks for many different problems for both themselves and their babies. Four of the most common complications associated with substance abuse are miscarriage, fetal growth restriction, preterm delivery and birth defects. With adequate education about the devastating risks of substance abuse, pregnant women can make appropriate choices to maximize their chances for a healthy pregnancy.
Miscarriage and Stillbirth
Miscarriage is defined as death of the fetus before approximately 20 weeks gestation; stillbirth is the term for fetal death after about 20 weeks gestation. Both miscarriage and stillbirth occur at increased rates in pregnancies exposed to many different substances, including alcohol, cigarettes, amphetamines and cocaine. Because the fetus receives all of its oxygen and nutrients through the mother's bloodstream, toxins in cigarette smoke, alcohol and other drugs can directly damage the fetus. In addition, constricted blood vessels caused by cigarette smoke and cocaine can reduce blood flow to the fetus, leading to fetal death.
Fetal Growth Restriction
The same mechanisms that can lead to miscarriage and stillbirth can restrict the growth of the fetus. Women who abuse drugs also tend to eat a poor diet, so that the fetus does not receive adequate vitamins and nutrients to grow properly. Babies who are growth-restricted tend to be born underweight. Small, underweight babies face increased risks for many complications in the newborn period and beyond, including breathing problems, behavior problems and learning disabilities. Megan McCoy, M.S., a prenatal genetic counselor, sometimes counsels drug-abusing clients about the problems their babies might face. "Babies who are born small for their gestational age and/or preterm are disadvantaged from the get-go. I try to help women understand the risky situation they are creating and help them find assistance to stop using drugs, but unfortunately for many of the babies the damage has already been done."
Preterm Delivery
In addition to being born small and underweight, babies of drug abusers are also likely to be born preterm, or before 37 weeks gestation. According to a study published in the journal "Pediatrics," a baby's brain at 35 weeks gestation weighs only two-thirds what it will weigh at 40 weeks gestation. Clearly, those last few weeks in the womb are important for continuing brain development; babies born early have higher rates of learning disabilities and behavioral problems than those born at term. Other complications of preterm birth include infections, bleeding in the brain, jaundice and anemia.
Birth Defects
Many different substances when abused during pregnancy can cause birth defects. The riskiest time frame for exposures to cause birth defects is during the first trimester of pregnancy, when the fetal organs are forming. Alcohol abuse increases the risk for heart defects, facial malformations such as clefts, openings in the spine or head, which are called neural tube defects, and other birth defects. According to the Royal Women's Hospital, amphetamines may be responsible for some cases of facial clefts, heart defects and limb malformations. Cocaine use can lead to brain malformations and reduction defects of the limbs, where an arm, leg, hand or foot may fail to develop completely.
References
- Megan McCoy, M.S., CGC; Genzyme Genetics; Los Angeles
- March of Dimes: Premature Birth
- "Pediatrics"; Late-Preterm Infants: A Population at Risk; WA Engle et al; Dec. 2007
- Royal Women's Hospital: Amphetamines
