Assisted Reproduction: No Birth Defect Risk

Nov. 2, 2005 -- Women who conceive with the help of assisted reproductive technology (ART) are more likely to have problems during their pregnancy, but their babies do not have a higher than normal risk for birth defects, a new study shows.

Researchers compared pregnancy outcomes among women who conceived with and without in vitro fertilization or other forms of assisted reproduction in a study published in the Nov. 1 issue of the journal Obstetrics and Gynecology.

Treatment for infertility was associated with a higher risk of complications prior to birth, including pregnancy-related high blood pressure and diabetes, placental problems, and even stillbirth.

Babies born as a result of assisted reproduction, however, were no more likely to have chromosomal abnormalities or birth defects than babies conceived without the help of medical science.

"Overall, this should be seen as a very reassuring finding," says researcher Tracy Shevell, MD, who specializes in treating high-risk pregnancies. "For the most part, the complications we found are easily identified and managed."

40,000 Babies a Year

In 2001, more than 40,000 babies -- roughly 1% of all births -- resulted from assisted reproductive technology (ART) procedures such as in vitro fertilization (IVF) and ovulation induction.

There has long been concern that children born via ART are at greater risk for complications that can follow them through life.

Past research has been mixed, but most earlier studies included twin and multiple-birth pregnancies, which have a higher risk of problems regardless of conception method.

In the study, researchers analyzed outcomes from roughly 36,000, single-birth pregnancies. Ninety-five percent were conceived without ART, 3.4% involved ovulation induction, and 1.5% involved IVF.

The women were followed closely throughout their pregnancies, and no evidence of an increase in low birth weight, chromosomal abnormalities, or birth defects was seen in babies born via ART.

ART and Pregnancy Complications

Pregnancy complications that were found to be associated with assisted reproduction included:

• Placenta previa. Women who underwent IVF were six times more likely to develop the condition, in which the placenta is implanted either too near the cervix or may partially or completely cover it. The cervix is the opening to the womb. Heavy cervical bleeding is a common complication, and surgical delivery is generally required.
• IVF patients were 2.7 times more likely to develop preeclampsia, a sharp, potentially dangerous increase in the mother's blood pressure.
• Women who had IVF or ovulation induction were 2.4 times more likely to experience premature separation of the placenta from the uterine wall, a condition known as placental abruption.
• IVF patients were 2.3 times more likely to require cesarean deliveries.

Though each of these complications carries risks for both mother and baby, they are all highly treatable with careful monitoring, Shevell tells WebMD.

The one exception is fetal loss after 24 weeks' gestation, which was seen twice as often among women who had ovulation induction as among women who conceived naturally.

Is Treatment the Cause?

It is not known why women treated with ART are at higher risk, but there is a high suspicion that the same medical issues that contribute to infertility contribute to pregnancy complications.

"It should not be surprising that women who had a medical problem that made it difficult for them to get pregnant also had problems once they became pregnant," says William Gibbons, MD, who is president of the Society for Assisted Reproductive Technology.

ART procedures are commonly performed on women who have no identified cause for their infertility, University of Vermont gynecology professor Julia Johnson, MD, tells WebMD.

"Since we don't have a good understanding of what causes their infertility, the fact that these women may have complications in pregnancy is not too surprising," she says.

The experts agreed that women considering ART should be counseled about the risk of pregnancy complications. But Shevell tells WebMD that pregnancies that result from treatment should not automatically be considered high risk.

"These are patients who need to be treated with a little more scrutiny during pregnancy," she says. "But most general ob-gyns are comfortable treating these conditions, and outcomes are generally good."

SOURCES: Shevell, T. Obstetrics and Gynecology, Nov. 1, 2005; vol 106: pp 1039-1045. ACOG Committee Opinion, Obstetrics and Gynecology, Nov. 1, 2005; vol 106: pp 1143-1146. Tracy Shevell, MD, division of maternal fetal medicine, Stamford Hospital, Stamford, Conn. William Gibbons, MD, president, Society for Assisted Reproductive Technology. Julia Johnson, MD, professor and vice chairman, department of gynecology, University of Vermont, Burlington.