Women who have had bariatric surgery have higher risks for early delivery during pregnancy and having babies who were small for their gestational age, according to a new study published in BMJ. Bariatric surgery is currently the most effective weight loss method because it provides both substantial and sustaining results. This type of surgery has become increasingly important to overweight women who want to become pregnant, as obesity can pose problems during pregnancy and after delivery.

Researchers looked at the Swedish medical birth register, which includes information on 98 percent of the babies born in that country since 1973. For this study, scientists restricted their search to 1,742,702 babies born between 1992 and 2009 after excluding children from multiple births as these babies tend to have different gestation and fetal development rates than babies from single births. Of these babies, 2562 were born to mothers who had undergone bariatric surgery. The mothers had undergone various bariatric surgical procedures including gastric bypass, vertical banded gastroplasty, and gastric banding.

The study showed the annual number of births to women who had bariatric surgery increased between 1992 and 2009. The popularity of this weight loss procedure has grown dramatically in Sweden, the United States, and in many other countries. Bariatric surgery is especially popular among women of childbearing age.

Obesity can cause a variety of complications during pregnancy, including preterm births, excessive birth weight, and stillbirth. Other complications include high blood pressure and gestational diabetes, a condition marked by high blood sugar levels during pregnancy. Many women have the procedure in hopes of becoming pregnant and reducing the risk of complications during pregnancy.

The researchers observed preterm births in 9.7 percent of the women who had undergone bariatric surgery but only 6.1 percent in women who did not have the surgery. Furthermore, the women who had this weight loss procedure had a higher risk for having a moderately to severely premature delivery. Fortunately, there was not an increased risk for infant mortality associated with bariatric surgery.

Obstetricians should consider women who have had bariatric surgery at greater risk for preterm births and low birth weight babies.

Source: Perinatal outcomes after bariatric surgery: nationwide population based matched cohort study. BMJ 2013;347:f6460. Web. Retrieved 25 Nov 2013.