"After undergoing weightloss surgery women are significantly less prone to diabetes during pregnancy but twice as likely to deliver smallerthannormal infants a new study suggests. Swedish scientists found that weightloss or bariatric surgery before pregnancy lowers the chances of certain complications for mothers and babies but raises the odds for others. They recommended any pregnancy after weightloss surgery be considered highrisk and receive stricter monitoring. The number of women who are obese in early pregnancy has increased dramatically over the last decades said study author Kari Johansson a postdoctoral researcher and nutritionist at Karolinska Institute in Stockholm. Consequently there has been a dramatic rise in the number of women becoming pregnant after bariatric surgery she added. The positive effects of bariatric surgery on health outcomes  such as diabetes and cardiovascular disease  are reasonably wellstudied but less is known about the effects on pregnancy and postdelivery outcomes Johansson pointed out. The study was published online Feb.  in the New England Journal of Medicine. U.S. health officials say more than onethird of American adults are obese with a body mass index BMI a heightweight calculation of  or higher. Nearly  obese people underwent weightloss surgery in the United States in  according to the American Society for Metabolic and Bariatric Surgery. While various techniques may be used the surgery restricts the amount of food the stomach can hold andor reduces the intestines absorption of calories and nutrients from food. Johansson and her colleagues used data from nationwide Swedish health registries to compare pregnancies between nearly  women who had given birth after bariatric surgery and more than  women who hadnt had the surgery but had the same BMI.  Only  percent of women who had weightloss surgery developed gestational diabetes compared to  percent of the other group the researchers said. The surgical group was also much less likely to give birth to largerthannormal babies. However the weightloss surgery group was twice as likely to give birth to babies considered small for their gestational age and their pregnancies were also of slightly shorter duration. Additionally the surgical group experienced a slight bump in the rate of stillbirths the study found. The investigators didnt examine what might have caused smaller babies among bariatric surgery recipients or higher stillbirths. But Johannson said those outcomes might be due to reduced nutrient absorption resulting from the surgery with a fetus not receiving sufficient nutrition. It has been reported that gastric bypass a form of bariatric surgery increases the risk of protein iron vitamin B vitamin D and calcium deficiencies she said. Also many women in our study may have been continuing to lose weight when they became pregnant. Continued weight loss may affect fetal nutrition and could influence growth. Because obesity is linked to poor outcomes for expectant mothers and babies  including birth defects gestational diabetes high blood pressure premature birth and even childhood obesity  efforts to lose weight before pregnancy are important said Dr. Aaron Caughey chair of the department of obstetrics and gynecology at Oregon Health and Science Universitys School of Medicine. But Caughey who wrote an editorial accompanying the new research said women considering weightloss surgery should make the decision based on the longterm health benefits of the procedure  not on potential pregnancyrelated benefits. I dont think pregnancy should be the thing that tips the scale said Caughey. I dont think the evidence from this study is enough to say now that you should absolutely get this surgery so you have a better pregnancy outcome. Caughey agreed with the researchers that any pregnancy occurring after weightloss surgery merits a higher level of monitoring and should be considered highrisk. He also noted that some experts advise women who undergo weightloss surgery before pregnancy to delay conceiving until  to  months after the procedure the period when the most rapid weight loss occurs. I think a conversation with someone who takes care of complicated pregnancies a maternalfetal medicine doctor is a good idea Caughey said. More information The American Society for Metabolic and Bariatric Surgery offers more about weightloss surgery httpasmbs.orgpatientsbariatricsurgeryprocedures. SOURCES Kari Johansson Ph.D. postdoctoral researcher and nutritionist Karolinska Institute Stockholm Sweden Aaron B. Caughey M.D. Ph.D. chair department of obstetrics and gynecology and associate dean Womens Health Research and Policy Oregon Health and Science University School of Medicine Portland Ore. Feb.   New England Journal of Medicine online"