Context

The proportion of pregnancies after bariatric surgery has been increasing in the last few decades and in some countries they now constitute around 1% of annual deliveries.1 ,2 Maternal obesity is associated with several adverse pregnancy outcomes such as gestational diabetes, preterm birth, stillbirth and macrosomia. Theoretically, weight loss prior to pregnancy would reduce such risks. This appears to be the case in women with weight loss induced by bariatric surgery for the outcomes gestational diabetes and macrosomia,3 but not for the outcome preterm birth where risks instead are increased.4 There is concern that bariatric surgery may cause fetal growth restriction2 ,3 , …