Pregnancy Outcomes After Bariatric Surgery

Pregnancy in women after undergoing bariatric surgery are by no means uncommon. There is even some evidence from case series to suggest that babies born to mothers, who have undergone surgery may be less likely to become obese or experience the cardiometabolic complications of obesity.

This risk needs to be balanced against potential risks the known adverse effects of gastric bypass surgery on the metabolism of iron, vitamin B12, and folate,

Now a paper by Karl Johansson and colleagues, published in the New England Journal of Medicine, suggests that this may well be the case.

The researchers identified 627,693 singleton pregnancies in the Swedish Medical Birth Register from 2006 through 2011, of which 670 occurred in women who had previously undergone bariatric surgery and for whom presurgery weight was documented.

They found that pregnancies after bariatric surgery, as compared with matched control pregnancies, were associated with lower risks of gestational diabetes (1.9% vs. 6.8%; odds ratio, 0.25) and a lower incidence of large-for-gestational-age infants (8.6% vs. 22.4%; odds ratio, 0.33).

These potentially beneficial outcomes for the infant were counterbalanced by a two-fold increase in the likelihood of having a small-for-gestational-age infants (15.6% vs. 7.6%; odds ratio, 2.20) and a somewhat shorter gestation (mean difference -4.5 days)

Also, the risk of stillbirth or neonatal death was 1.7% versus 0.7% (odds ratio, 2.39).

No differences were found in the frequency of congenital malformations.

Bariatric surgery was associated with reduced risks of gestational diabetes and excessive fetal growth, shorter gestation, an increased risk of small-for-gestational-age infants, and possibly increased mortality.

Thus, the authors conclude that,

“…a history of bariatric surgery was associated with reduced risks of gestational diabetes and large-for-gestational-age infants.”

Nevertheless, they do recommend increased surveillance during pregnancy and the neonatal period, as bariatric surgery may also be associated with small-for-gestational-age infants, a shorter length of gestation, and potentially an increased risk of stillbirth or neonatal death.

@DrSharma
Edmonton, AB