Pregnancy After Bariatric Surgery Linked to Adverse Perinatal Outcomes

By Will Boggs MD

August 22, 2019

NEW YORK (Reuters Health) - Pregnancy after bariatric surgery is associated with increases in some adverse perinatal outcomes, according to a new systematic review and meta-analysis.

"Bariatric surgery improves many obesity-related comorbidities for the mother, such as gestational diabetes and hypertension, which have severe implications for both mother and baby," said Dr. Zainab Akhter of Newcastle University, in Newcastle upon Tyne, U.K.

"However, this is still a high-risk pregnancy group, and additional monitoring and support need to be provided to these women as it would be for women with the above comorbidities. We recommend monitoring nutrition preconception and in pregnancy and extra fetal growth monitoring," he told Reuters Health by email.

Previous assessments of pregnancy after bariatric surgery have focused on maternal outcomes, and there is limited evidence on perinatal outcomes other than size for gestational age and preterm birth.

Dr. Akhter and colleagues compared adverse perinatal outcomes among women who underwent bariatric surgery prior to pregnancy with those who did not in 33 studies that reported original data on perinatal outcomes. Overall, the studies included 14,880 pregnancies after bariatric surgery and more than 3.9 million without.

The pooled odds of perinatal mortality or stillbirth were 38% higher (P=0.031) and the odds of congenital anomalies were 29% higher (P=0.019) with prior bariatric surgery than without, according to results from 10 studies.

The overall odds of preterm birth were 35% higher among women who had bariatric surgery than among those without (P=0.001), whereas the odds of post-term birth were 54% lower among women who had bariatric surgery, the researchers report in PLOS Medicine, online August 6.

Mean gestational age, however, did not differ significantly between the groups.

The odds of a small-for-gestational-age (SGA) baby with prior bariatric surgery were 2.13-fold higher than without (P<0.001), but this increase seemed to be limited to women who had undergone Roux-en-Y gastric bypass (RYGB) or biliopancreatic diversion (BPD).

The odds of a large-for-gestational-age (LGA) baby with prior bariatric surgery were 58% lower, and in subgroup analyses, this decrease was significant only in the subgroup that underwent RYGB or BPD.

Mean birth weights were also significantly lower after bariatric surgery, again limited to the RYGB group in subgroup analyses.

Babies born post-bariatric surgery were 41% more likely than those born to other mothers to be admitted to the neonatal intensive-care unit (NICU).

"Based on where we were able to subgroup results by surgery type, it was clear that malabsorptive procedures, particularly RYGB, were more likely to increase the risk of an adverse perinatal outcome than restrictive surgery types," Dr. Akhter said. "This suggests a link with nutrition, and, therefore, health professionals involved in the care of these women need to provide additional nutritional support during preconception and pregnancy after bariatric surgery."

"The current evidence base could be used to inform risk communication about potential future pregnancies with women of reproductive age prior to surgery," the authors conclude.


PLoS Med 2019.