Pregnancy and offspring outcomes after pre-pregnancy bariatric surgery.

Abstract

Background: Bariatric surgery is internationally performed as a treatment option in obesity to achieve significant and sustained weight loss. There is an increasing number of women having pregnancies after bariatric surgery with mixed maternal and fetal outcomes, with a limited number of large, matched studies.

Objective: This study aimed to describe the type of pre-pregnancy bariatric surgery, to analyse maternal, pregnancy and offspring outcomes compared to matched women and to assess the impact of pre-pregnancy bariatric surgery on fetal growth, particularly proportions of small for gestational (SGA) and large for gestational age (LGA).

Study design: A statewide hospital and perinatal data register linked cross-sectional matched study was performed. In total, n=2,018 births in n=1,677 women with pre-pregnancy bariatric surgery were registered between 2013 and 2018, of those n=1,282 were included and analysed with 1:10 to age, parity, smoking status and Body Mass Index (BMI) matched women without bariatric surgery. The first singleton pregnancy following bariatric surgery for each woman was used for analysis. Pregnancy and neonatal outcomes from International Statistical Classification of Diseases Tenth revision codes (ICD-10AM) and neonatal birth records for outcomes of interest were analysed. Multivariable logistic regression was used to estimate the association between SGA and LGA and pre-pregnancy bariatric surgery.

Results: Of the n=1,282 women, 93% had undergone laparoscopic sleeve gastrectomy. Offspring had lower absolute birthweight (3223g ± 605g vs 3418g ± 595g; p<0.001), fewer LGA (8.6% vs 14.1%; p<0.001) and more SGA infants (10.7% vs 7.3%; p<0.001) than offspring born to matched women. Offspring were more likely to be born preterm (10.5% vs 7.8%; p=0.007) to mothers with pre-pregnancy bariatric surgery. Fewer women with previous bariatric surgery were diagnosed with GDM (15% vs 20%; p<0.001) or pregnancy induced hypertension (3.7% vs 5.4%; p=0.01). In the adjusted model, pre-pregnancy bariatric surgery was associated with a lower risk of LGA (OR 0.54, 95% CI 0.44-0.66) and higher risk of SGA (OR 1.78, 95% CI 1.46-2.17).

Conclusions: These data suggest that pre-pregnancy bariatric surgery was associated with a reduction in several obesity related pregnancy complications at the expense of more pre-term births and SGA offspring.