Bariatric Surgery and Pregnancy

To follow on from the previous post on fertility and contraception, this post will cover the effects of bariatric surgery on the outcomes of mothers and babies.

Considering first the effect of bariatric surgery on women and their pregnancies, it is important to realise that many women after bariatric surgery will still have a body mass index of greater than 25 kg/m2.  This is important as comparing pregnancy outcomes of women after bariatric surgery to all pregnant women, or to women with an elevated BMI will lead to different conclusions.

When comparing women who become pregnant after having bariatric surgery to women with an elevated BMI (or pregnancies in the same women before bariatric surgery), we know that bariatric surgery reduces the risks of gestational diabetes, high blood pressure and pre-eclampsia.  However the risks of gestational diabetes and Caesarian birth are still higher than the base line population.

Looking at the outcomes for the babies of women who have had bariatric surgery we know that bariatric surgery does not increase rates of stillbirth or congenital abnormalities, but does increase the risk of pre-term birth and of small for gestational age babies.  Importantly, there is also some evidence that bariatric surgery reduces the risk of these children having weight problems as they grow up.

The American College of Obstetrics and Gynecology offers the following guidance:

  • Conception should be delayed for 12 months after bariatric surgery to allow weight and nutritional status to stabilise.
  • A comprehensive nutritional assessment should occur early in pregnancy to assess nutritional status.
  • Women should take a prenatal multivitamin in addition to a bariatric multivitamin, but the total daily dose of vitamin A should not exceed 5000 IU.
  • Regular review by a bariatric surgeon and dietitian is recommended.
  • Serial ultrasound growth monitoring should be considered especially if time to conception is short.
  • Women may not tolerate the standard screening test for gestational diabetes (oral glucose tolerance test) after a Roux-en-Y gastric bypass and alternative tests should be considered.
  • Any unusual abdominal pain or vomiting during pregnancy should be urgently investigated by a bariatric surgeon.
  • Bariatric surgery is not an indication for Caesarian delivery.