Timing of pregnancy in obese women after bariatric surgery

There is an increased risk of preterm and small-for-gestational-age births associated with bariatric surgery, especially if maternal early pregnancy body mass index (BMI) is <30.0kg/m(2). However, the relationship between timing of pregnancy post-bariatric surgery and effects on pregnancy outcome are unknown. The aim of this study was to investigate the timing of pregnancy post-bariatric surgery and compare early pregnancy BMI between women who became pregnant before or after the recommended 12month postoperative window.

Women who underwent either sleeve gastrectomy or gastric bypass and subsequently became pregnant were offered antenatal care in a multidisciplinary high-risk clinic. There were 50 such pregnancies in women who attended our high-risk clinic (n=26 <12months and n=24 >12months postoperatively, mean estimated times to conception 31.9±12.6weeks and 102.8±37.7weeks respectively). There was no significant difference in early pregnancy BMI between groups (33.2±6.8kg/m(2) and 32.5+2.1kg/m(2) respectively, p=0.78). There were 6 miscarriages in each group, however more women in the <12month (n=8) than in the >12months group (n=2) were lost-to-follow-up (likelihood ratio 4.2, p=0.04).

Women who became pregnant <12months post-bariatric surgery were, for unknown reasons, less likely to attend follow-up in a specialist antenatal clinic than those who became pregnant >12months postoperatively. Further research is required to explore the relationship between timing of pregnancy post-bariatric surgery and pregnancy outcome and to identify predictors more clinically useful than early pregnancy BMI, in this high-risk pregnancy group.