The authors of the research, published in BMJ, looked at roughly 15,000 births that took place in Sweden between 1992 and 2009, including about 2,500 among women who had had had weight loss surgery. On average, the women delivered about five years after the surgery.
After controlling for age, smoking and other factors that could influence pregnancy complications, the researchers found that 10 percent of children born to women who had undergone bariatric surgery were delivered prematurely, compared with 6 percent in the other group.
A similar pattern was found for low birth weight. Five percent of children born to mothers in the surgery group were small for their gestational age, compared with 3 percent in the other group.
The researchers speculate that the trends could be driven by deficiencies in vitamins and minerals, which occur after bariatric surgery and could affect fetal and placental growth.
Image: Pregnant belly, via Shutterstock