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PRU-MHC: Policy Research Unit in Maternal Health & Care (2010 - 2018)

Surveillance of pregnancy after gastric bypass surgery

The prevalence of maternal obesity is dramatically rising in the UK, with approximately 5% of women having a BMI of 35 or over at any point in pregnancy. The adverse consequences of obesity on maternal and perinatal health are well established. Gastric bypass surgery is an effective procedure used to achieve weight loss in people with morbid obesity; the most commonly performed surgery is a Roux-en-Y gastric bypass, which can be an open or laparoscopic procedure. Several studies and reviews have analysed pregnancy outcomes following bariatric surgery. Studies demonstrate a reduction in obesity-related gestational complications such as gestational diabetes and maternal hypertension. There appear to be conflicting results regarding the incidence of intrauterine growth restriction and mode of delivery following bariatric surgery. Complications such as intestinal hernias, nutritional deficiencies and increase in birth defects in pregnancies following gastric bypass surgery have also been cited. Studies conducted thus far emphasise the importance of appropriate monitoring and effective nutritional control, although this is not currently defined.

There is a need for robust evidence regarding how long to delay pregnancy following bariatric surgery. Due to the potential nutritional deficiencies and concomitant complications associated with rapid weight loss, current advice is to delay pregnancy for 1 year after bypass surgery. However, studies have shown similar maternal and neonatal outcomes between patients who conceived during the first post-operative year, and those who conceived after. This study will use the UK Obstetric Surveillance System (UKOSS) to describe the epidemiology, management and outcomes of pregnancy following gastric bypass surgery in the UK and to assess current practice and develop further guidelines for optimal management.

NPEU Contact:
Marian Knight (