A study out this week should bring some peace of mind to women who need medical help to become pregnant. Previous reports have suggested that women who use assisted reproductive technology, including fertility-enhancing drugs and in vitro fertilization, are more likely to have a baby with birth defects, Down syndrome, or low birth weight. But a study of more than 36,000 women published in the journal Obstetrics and Gynecology finds that babies conceived with an assist from science are at no greater risk than those made the old-fashioned way.

Women in the study who used assisted reproductive technology were, however, more likely to have complicated pregnancies than other women. In particular, women who conceived using in vitro fertilization had more instances of placenta previa, in which the placenta covers the opening of the cervix, and preeclampsia, a potentially life-threatening condition characterized by a sudden rise in blood pressure during pregnancy. Women who used fertility drugs to help conceive were about twice as likely to lose the fetus after the 24th week of pregnancy and 2.4 times more likely to have a placenta that separated from the uterine wall before birth. In addition, though this study looked only at single births, couples who use assisted reproductive technology are 30 times more likely to have multiple births, and that in itself carries a greater risk of complications.

"For the most part, these risks are more on the minor side, and they're risks that we can control and mediate as providers," says lead author Tracy Shevell, a perinatologist at Stamford Hospital in Connecticut. "I would not use these results to discourage patients from doing IVF." Shevell says that mothers who use help to conceive should be on the lookout for potential signs of complications. For example, spotting or bleeding could be a symptom of placenta previa. A headache, blurry vision, or chest pain could signal preeclampsia. Doctors and patients need to be vigilant so that complications can be treated and don't harm the mother or the baby.