Prepregnancy bariatric surgery tied to ‘overall downward shift’ in infant growth

Key takeaways:

• Prepregnancy bariatric surgery was associated with higher risk for preterm birth and infants born small for gestational age.
• Surgery was also tied to fewer obesity-related complications.

Prepregnancy bariatric surgery was linked to lower risks for gestational hypertension, large for gestational age infants and gestational diabetes but increased risks for preterm birth and small for gestational age infants, data show.

“Pregnancy following malabsorptive surgeries such as the Roux-en-Y gastric bypass is associated with an increased risk of small for gestational age and premature infants but a lower risk of gestational diabetes mellitus, large for gestational age infants and preeclampsia,” Jade Eccles-Smith, MD, from the department of obstetric medicine at the Royal Brisbane and Women’s Hospital and Mater Research at The University of Queensland in Australia, and colleagues wrote in the American Journal of Obstetrics and Gynecology. “There are few publications regarding the outcomes after restrictive surgeries such as the laparoscopic gastric sleeve. The laparoscopic gastric sleeve is the most performed bariatric surgery in Queensland.”

Eccles-Smith and colleagues conducted a cohort study using linked hospital and perinatal registry data from 1,282 women who underwent prepregnancy bariatric surgery between 2013 and 2018, as well as control women who did not undergo surgery matched by age range, parity, BMI and smoking status. Researchers evaluated the first singleton pregnancy after bariatric surgery for each woman and assessed pregnancy and neonatal outcomes compared with controls.

Overall, 93% of women underwent laparoscopic sleeve gastrectomy, 4.3% underwent laparoscopic adjustable gastric bands and 2.7% underwent Roux-en-Y gastric bypass.

Compared with matched women, those who underwent prepregnancy bariatric surgery had lower absolute infant birth weight (mean, 3,223 g vs. 3,418 g; P < .001) and fewer large for gestational age infants (8.6% vs. 14.1%; P< .001). However, women who underwent surgery had a higher risk for preterm birth (10.5% vs. 7.8%; P = .007) and small for gestational age infants (10.7% vs. 7.3%; P < .001).

Fewer women with prepregnancy bariatric surgery had a gestational diabetes diagnosis (15% vs. 20%; P < .001) or gestational hypertension (3.7% vs. 5.4%; P = .01) compared with women without bariatric surgery.

In addition, prepregnancy bariatric surgery was associated with a lower risk for large for gestational age infants (OR = 0.54; 95% CI, 0.44-0.66) and a higher risk for small for gestational age infants (OR = 1.78; 95% CI, 1.46-2.17) in the adjusted model.

“Offspring born to women with prepregnancy bariatric surgery were more likely to be born small for gestational age and less likely to be born large for gestational age, demonstrating a lower overall birth weight compared to matched women,” the researchers wrote. “This indicates an overall downward shift in infant growth. In adjusted and unadjusted models, the association of prepregnancy bariatric surgery with small for gestational age and large for gestational age outcomes remained highly significant and of a similar magnitude to that reported for smoking or preeclampsia.”