Newborn body composition after maternal bariatric surgery
Emma Malchau Carlsen1, Kristina Martha Renault2,3, Bertha Kanijo Møller1
1Department of Pediatrics, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.
Insights
Pregnancy after Roux-en-Y gastric bypass (RYGB) surgery impacts offspring body composition. Babies born after RYGB had lower birthweight, fat-free mass, and fat percentage, with surgery itself being the primary factor, not pre-pregnancy weight loss.
Area of Science:
- Reproductive Medicine
- Pediatric Endocrinology
- Bariatric Surgery Outcomes
Background:
- Pregnancy following Roux-en-Y gastric bypass (RYGB) is associated with an increased risk of low birthweight in offspring.
- Understanding the impact of RYGB on neonatal body composition is crucial for optimizing maternal and infant health outcomes.
Purpose of the Study:
- To investigate the effects of RYGB on the body composition of newborns.
- To differentiate the impact of maternal pre-pregnancy weight loss versus other surgical effects on fetal growth.
Main Methods:
- A cohort study comparing 25 mother-newborn dyads post-RYGB with 311 control dyads.
- Neonatal body composition assessed via dual-energy X-ray absorptiometry (DXA) within 48 hours of birth.
- Statistical models analyzed the influence of maternal pre-pregnancy BMI, gestational weight gain, parity, gestational age, and newborn sex.
Main Results:
- Offspring born after RYGB exhibited significantly lower birthweight (335g), fat-free mass (268g), and fat percentage (2.8%) compared to controls.
- Maternal pre-pregnancy weight loss accounted for only 2% of the reduction in neonatal fat-free mass.
- RYGB surgical effects, rather than weight loss, were responsible for 98% of the fat-free mass reduction and 47% of the fat mass reduction.
Conclusions:
- Neonatal body composition, including birthweight, fat-free mass, and fat percentage, is reduced in offspring born after maternal RYGB.
- The RYGB procedure itself, independent of pre-pregnancy weight loss, appears to be the primary determinant of altered fetal growth patterns.
Introduction:
In pregnancy after Roux-en-Y gastric bypass (RYGB), there is increased risk of low birthweight in the offspring. The present study examined how offspring body composition was affected by RYGB.
Material And Methods:
Mother-newborn dyads, where the mothers had undergone RYGB were included. Main outcome measure was neonatal body composition. Neonatal body composition was assessed by dual-energy X-ray absorptiometry scanning (DXA) within 48 hours after birth. In a statistical model offspring born after RYGB were compared with a reference material of offspring and analyses were made to estimate the effect of maternal pre-pregnancy body mass index (BMI), gestational weight gain, parity, gestational age at birth and newborn sex on newborn body composition. Analyses were made to estimate the impact of maternal weight loss before pregnancy and of other effects of bariatric surgery respectively. The study was performed at a university hospital between October 2012 and December 2013.
Results:
We included 25 mother-newborn dyads where the mothers had undergone RYGB and compared them to a reference material of 311 mother-newborn dyads with comparable pre-pregnancy BMI. Offspring born by mothers after RYGB had lower birthweight (335g, p<0.001), fat-free mass (268g, p<0.001) and fat% (2.8%, p<0.001) compared with reference material. Only 2% of the average reduction in newborn fat free mass could be attributed to maternal pre-pregnancy weight loss whereas other effects of RYGB accounted for 98%. Regarding reduction in fat mass 52% was attributed to weight loss and 47% to other effects of surgery.
Conclusion:
Offspring born after maternal bariatric surgery, had lower birthweight, fat-free mass and fat percentage when compared with a reference material. RYGB itself and not the pre-pregnancy weight loss seems to have had the greatest impact on fetal growth.
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