Sept. 26, 2016 -- Infants born to women who've had a Roux-en-Y gastric bypass are more likely to be small for their gestational age and have nutritional deficiencies at birth, even if the mother takes supplements during pregnancy, a study suggests.
"We'd previously shown that there are nutrient deficiencies because of malabsorption in women who've undergone bariatric surgery," says Maxime Gerard, MD, of Ambroise Pare University Hospital in Boulogne-Billancourt, France.
"But this is the first time we've shown that there are nutrient deficiencies in infants born to these women, especially in vitamin A, calcium, and zinc, although these deficiencies might be prevented if mothers have very good supplementation during pregnancy."
The research was presented during the recent European Society for Paediatric Endocrinology annual meeting in Paris.
Fifty-six women who had previously undergone Roux-en-Y gastric bypass gave birth to single babies at the Angers University Hospital in Angers, France. They were matched for age and smoking status with 56 other women who gave birth over the same time.
Women who had undergone the bypass procedure waited, on average, 32 months before becoming pregnant to establish a stable, healthy weight.
Study subjects did not have diabetes, preeclampsia, or hypertension and experienced no complications during pregnancy. Before they got pregnant, the average body mass index (BMI) among women who had undergone bariatric surgery was 30.1, compared with 23.3 for the other women.
Women were told to take daily supplements after the gastric bypass surgery and throughout their pregnancy.
During pregnancy, women in the bariatric surgery group gained, on average, 9.8 kilograms (about 22 pounds). The other women gained about 12.7 kilograms, or 28 pounds. Interestingly, 29% of infants born to the bariatric surgery group were delivered by cesarean section, compared with only 4% of infants born to the other women.
Investigators noted that 23% of infants born to the bariatric surgery group were small for their gestational age, vs. only 3.6% of infants born to the other women.
Infants born to mothers who had undergone gastric bypass surgery weighed, on average, 3 kilograms (about 6.6 pounds) at birth, compared with an average of 3.35 kg (7.4 pounds) for those born to women who hadn’t had the surgery.
They were also significantly more likely to be deficient in a number of nutrients.
Nutrient Levels at Birth
Gerard says he didn't think the nutritional deficiencies caused restricted growth in the infants. He thinks it shows that the nutrients weren't absorbed well in the mothers.
On the other hand, other types of bariatric surgery, such as gastric banding and sleeve gastrectomy, are less likely to cause nutrients not to be absorbed well and might be considered as an alternative to the Roux-en-Y procedure, even if they are less effective at promoting weight loss, he noted.
That said, no type of bariatric surgery is "risk-free for infants," he added.
Doctors should evaluate babies born to women who have had weight loss surgery and measure their nutrient levels at birth, giving them supplements if needed, Gerard says.
"Doctors must have a discussion with obese future mothers about the benefits of surgery, and after surgery, they have to work with the mothers to ensure they are not nutrient-deprived."
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data before publication in a medical journal.