Gastric Bypass Does Not Elevate Risk of Stillbirths, Neonatal Deaths

November 9, 2019

By Louise Gagnon

LAS VEGAS -- November 8, 2019 -- Women who have undergone a gastric bypass are not at an increased risk of having a stillborn infant or having an infant that experiences neonatal death, according to a study presented here at Obesity Week 2019.

“In a previous study, we found a signal for increased risk of stillbirth and neonatal death in women with previous bariatric surgery,” explained Olof Stephansson, MD, Karolina Institute, Stockholm, Sweden. “We therefore performed this study using a larger updated cohort.”

The investigators looked at 5,110 singleton births from women who underwent gastric bypass surgery and 28,379 controls who did not between 2007 and 2016. Data came from the Swedish Medical Birth Registry. The investigators took into account factors like maternal age, parity, body mass index early in pregnancy, diabetes status, and smoking when determining matched controls.

Prior to gastric bypass, the mean body mass index was 43.1 and 9.6% had diabetes. The median surgery-to-conception interval was 2.6 years, and the mean weight loss between surgery and early pregnancy was 39 kg.

The investigators found that the risk of stillbirth after gastric bypass was 0.5% and was exactly the same in matched controls (adjusted risk ratio [aRR] = 1.02; P = .95. The risk of neonatal death was similar between the 2 groups, at 0.3% for women who underwent gastric bypass and 0.2% for controls (aRR = 1.39; P = .39).

For the combined outcome of stillbirths and neonatal death, investigators also saw no difference between women who underwent surgery and their matched controls (0.8% vs 0.7%; aRR = 1.13; P = .55).

“We did not find any increased risk of stillbirth or neonatal death,” said Dr. Stephansson. “This is reassuring for women who have previous bariatric surgery [and are contemplating pregnancy]. This is an important study as we could not observe any increased risk. These findings should be confirmed in other studies based on other populations.”

While the findings are limited because of the design of the study, Dr. Stephansson pointed out this type of investigation can only be observational and retrospective in nature.

Obesity Week is sponsored by the American Society for Metabolic & Bariatric Surgery and the Obesity Society.

[Presentation title: Risk of Stillbirth and Neonatal Death After Gastric Bypass: Nationwide Matched Cohort Study]