Women Who Recently Had Weight Loss Surgery Face Increased Preterm and Low Weight Birth Risks

New research raises additional concerns about the risks associated with weight loss surgery, indicating that women who undergo bariatric surgery also may have a higher risk of giving birth to infants prematurely and with low birth weights, leading to potential health complications for their children.

Newborns born to women who recently underwent weight loss surgery often weigh less and were born earlier compared to infants born to women who underwent weight-loss surgery, but waited at least a year to get pregnant, according to Dutch researchers.

Researchers studied 196 women who underwent bariatric surgery, including gastric banding, gastric bypass, and sleeve gastrectomy. These surgeries use various techniques to decrease the size of the stomach to help patients lose weight.

The study compared three groups: patients who conceived within 12 months of weight-loss surgery were considered the early group, those who got pregnant between 12 and 24 months after bariatric surgery were considered the middle group, and those who conceived more than 24 months after surgery were considered the late group.

According to the findings, women who conceived a child shortly after undergoing bariatric surgery had a higher rate of preterm pregnancies and conceived smaller children more often than women in the middle to late groups.

Overall, 23.5% of women in the early group had shorter pregnancies by five to seven days. Women in the early group also lost an average of nearly two pounds during pregnancy compared to the women in other groups who gained between 22 and 23 pounds during their pregnancies.

Newborns born to women in the early groups weighed less than newborns born to women in the other groups. On average, early group newborns weighed 6.56 pounds compared to 6.97 and 7.08 pounds.

Women who conceived shortly after undergoing bariatric surgery also had more preterm births than the other two groups. Lower weight gain during pregnancy was linked to both early delivery and infants with lower birth weight.

In fact, women who gained less weight during pregnancy gave birth to infants that weighed one-third a pound less than other infants born to women who gained more weight. Women who gained less weight also had a higher risk of giving birth to infants preterm. The risk was nearly 16% compared to 6% among women who gained adequate weight during pregnancy.

The researchers determined women who get pregnant within a year of having bariatric surgery are more likely to have preterm births and give birth to smaller than normal infants. This result is similar to prior research which also indicated women who undergo bariatric surgery face an increased risk of preterm delivery during pregnancy.

Women who have weight-loss surgery also face other risks, including increased risk of digestive tract problems which may lead to increased risk of poor nutrition. Studies have also suggested women who undergo bariatric surgery may face an increased risk of committing suicide.

The researchers recommend women avoid pregnancy for 12 to 24 months after undergoing weight-loss surgery to avoid side effects to the infant. By waiting to get pregnant, women can avoid problems linked to ongoing weight loss, including increased risk of malnutrition due to significantly lower calorie intake.

The findings are being presented at the European Congress on Obesity virtual annual meeting held this week. Research presented at medical conferences are considered preliminary until published in a peer-reviewed journal.