Smoking and Birth Defects
by Rallie McAllister, MD, MPH
Doctors and scientists have long assumed that smoking causes serious harm to babies and pregnant women, but the results of a new study* removed any lingering doubt.
The first-ever comprehensive systematic review of all studies conducted over the past 50 years clearly demonstrates that maternal smoking causes a range of serious birth defects including heart defects, missing or deformed limbs, gastrointestinal disorders, and facial disorders such as cleft lip and palate.
When a mom-to-be smokes during pregnancy, her unborn baby is exposed to carbon monoxide, tar, and nicotine, which can deprive the baby of the oxygen that is necessary for normal growth and development.
Smoking during pregnancy is also a risk factor for premature birth. Babies who survive being born prematurely and at low birth weight are at risk of other serious health problems, such as cerebral palsy and learning disorders. Smoking also can make it harder for a woman to get pregnant, and increases the chance that she’ll have a baby that is stillborn.
During pregnancy, smoking can cause problems for the mom-to-be as well. Smoking-related complications can include ectopic pregnancy or vaginal bleeding. Smoking during pregnancy can also lead to placental abruption, a condition in which the placenta peels away, partially or almost completely, from the uterine wall before delivery, and placenta previa, a low-lying placenta that covers part or all of the opening of the uterus.
Smoking is never good, but it’s especially bad when you’re expecting. If you’ve decided that you want to kick the habit, there’s no better time—or reason—than when you become pregnant.
*The new study, “Maternal smoking in pregnancy and birth defects: a systematic review based on 173,687 malformed cases and 11.7 million controls,” is published online in Human Reproduction Update from the European Society of Human Reproduction and Embryology.