Miriam E. Tucker

November 02, 2016

Washington, DC — Bariatric surgery before pregnancy in obese women can reduce their risks for cesarean delivery and adverse neonatal outcomes, new research shows.

Results from a systematic review and meta-analysis involving more than 350,000 women, including nearly 11,000 who had undergone bariatric surgery, were presented here at the American College of Surgeons Clinical Congress 2016 by fourth-year medical students Brittanie Young, MS, and Samantha Drew from the Philadelphia College of Osteopathic Medicine (PCOM), Pennsylvania, and colleagues.

"Bariatric surgery should be considered as a risk-mitigating step towards a achieving a healthy pregnancy and delivery," lead author A. Christopher Ibikunle, MD, assistant professor of surgery at PCOM and chief executive officer of Georgia SurgiCare, Loganville, told Medscape Medical News.

Bariatric surgery places the expectant mother at a lower risk for cesarean delivery as well as assisted vaginal delivery, which may be related to the increased risk for both large for gestational age and macrosomia in obese mothers, Young and Drew explain in their poster.

"This could [have] a potentially huge impact on clinical practice," Young told Medscape Medical News.

The primary safety concern would be adequate nutritional intake during the pregnancy, but that can be managed, she added. "There is a common theme of postsurgical patients being nutrient and calorie deficient, which could have an effect on the developing fetus. Careful monitoring and nutritional consultation could help to address these concerns."

Asked to comment on the findings, Richard D. Stahl, MD, medical director of bariatric surgery at the University of Alabama at Birmingham, told Medscape Medical News that because it's a meta-analysis and not new data, "I wouldn't say this is necessarily practice-changing, but I think it supports what our beliefs were and what our interpretation was of the data already."

Cesarean Delivery Rates Lower, Outcomes Improved

The meta-analysis included 5 (of 47 reviewed) studies from 2000 to 2016, in which 4329 cesarean deliveries in 10,811 postbariatric women and 133,533 cesarean deliveries in 223,573 obese women were recorded.

Cesarean delivery rates were significantly lower among the women who had undergone bariatric surgery than among the obese population (39% vs 60%; P = .0).

Also significantly lower were rates of macrosomia, defined as weighing more than 4000 g at birth (2% vs 7%), large for gestational age (>90th percentile, 4.6% vs 10%), small for gestational age (<10th percentile, 7.1% vs 3.2%), and assisted vaginal delivery (2.2% vs. 2.6%). All P values were .00 except for that seen with assisted vaginal delivery (.011).

The difference in preterm delivery rates did not achieve statistical significance; preterm delivery occurred in 8.2% of the postbariatric surgery and 8.6% of the obese groups (P = .51).

Dr Stahl pointed out that these data dovetail with prior studies that have suggested improved fertility in women after weight loss via bariatric surgery. http://www.medscape.com/viewarticle/852843 And, while he wouldn't advise counseling a woman to undergo bariatric surgery solely for reasons related to pregnancy, "There are lots of data that support doing bariatric surgery for all sorts of reasons….There is evidence that it improves fertility, and now this meta-analysis suggests it makes the pregnancy less risky."

However, he does counsel women to avoid getting pregnant during the period of active weight loss, usually the first 12 to 18 months after the surgery.

And, while he noted that there may be a theoretical concern about decreased absorption of vitamins and micronutrients that potentially could affect the fetus, "there is no evidence to my knowledge that that is true," Dr Stahl said, adding "The beneficial effects of weight loss surgery seem to far outweigh any detrimental effects of micronutrient absorption, to the extent that I'm aware. We do think women should be treated with their usual prenatal vitamins and routine OB [obstetric] care, but they don't seem to require anything special or above and beyond what another pregnant patient would need."

Ms Young, Ms Drew, Dr Ibikunle, and Dr Stahl have disclosed no relevant financial relationships.

American College of Surgeons (ACS) Clinical Congress 2016. Presented October 17, 2016.

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