Is Pregnancy Safe After Weight Loss Surgery?

Is it OK to get pregnant after having a weight loss operation? This is a worrying question for many young women who want to lose weight. The benefits of weight loss surgery are now well known. But, how do weight loss operations affect the mother and baby during pregnancy? This blog post explains up to date medical evidence on this topic.

Let’s consider Jane, a 29 year-old women who weighs 21 stones (133 kg). Her height is 5 feet and 6 inches (167 cm). Her BMI works out to be 48. She has been told that she could lose 7-8 stones with a gastric bypass operation. Jane and her husband are keen to start a family. They have been told that Jane’s obesity increases risks for both her and her baby.(1) Obese mothers have higher risk for getting diabetes and high blood pressure during pregnancy. The risk for diabetes and high blood pressure is about 3 times higher in obese mothers. Also, obese mothers are more likely to need caesarean section instead of normal delivery. Babies of obese mothers have higher risk for premature birth, miscarriage, large size, birth injuries, stillbirth and death after delivery.

Jane is worried about the effect of a gastric bypass on her own safety and the safety of her baby during pregnancy? Basically, her question is whether the pregnancy-risks after gastric bypass are any different from her risks now with a BMI of 48? Will pregnancy be safer or will it be more risky if she has a weight loss operation?

Medical studies have compared the risks of pregnancy in women after gastric bypass surgery with obese women who have not had weight loss surgery. These studies matched gastric bypass mothers with obese mothers who have the same pre-bypass BMI. Let’s say Jane gets down to a BMI of 31 after gastric bypass and then become pregnant. Her risks during pregnancy are compared with the risks for a woman who has BMI of 48 (the same as Jane before the bypass).

The risk for diabetes and high blood pressure during pregnancy was significantly lower in mothers who had gastric bypass. Diabetes was seen in about 2% of gastric bypass mothers versus 7% of obese mothers.(2) High blood pressure was seen in about 3% of gastric bypass mothers versus 15% of obese mothers.(3) Also, significantly fewer gastric bypass mothers need caesarean sections than obese mothers.(4) On all counts, gastric bypass makes pregnancy safer for mothers.

But, the studies bring up some worries for the safety of the baby. On the positive side, babies of gastric bypass mothers are less likely to be large for gestational age. About 8% of gastric bypass mothers had large babies versus 22% of obese mothers. But, babies of gastric bypass mother are more likely to be small for gestational age. About 15% of gastric bypass mothers had small babies versus 7% of obese mothers.(2) Also, there seems to be increased risk for premature births and stillbirths for gastric bypass mothers, although these differences were not statistically significant. In a nutshell, there is a trade-off. Before bypass, the baby is at higher risk of being too large. After bypass, the baby is at higher risk of being too small.

What should Jane do? Overall, it is very clear that weight loss surgery will improve Jane’s health and quality of life. Also, pregnancy will be safer for Jane after weight loss surgery. The risk that her baby is too large is less after weight loss surgery. But, there is greater risk that her baby could be too small or prematurely born.

For detailed and accurate advice on the pros and cons of weight loss surgery, make an appointment to see Mr Sarela, consultant surgeon in Leeds. Call 0113 388 2127



  1. Gonzalez I, Lecube A, Rubio MA, Garcia-Luna PP. Pregnancy after bariatric surgery: improving outcomes for mother and child. International Journal of Womens Health. 2016;8:721-9.
  2. Johansson K, Cnattingius S, Naslund I, Roos N, Trolle Lagerros Y, Granath F, et al. Outcomes of Pregnancy After Bariatric Surgery. New England Journal of Medicine. 2015;372(9):814-24.
  3. Bennett WL, Gilson MM, Jamshidi R, Burke AE, Segal JB, Steele KE, et al. Impact of Bariatric Surgery on Hypertensive Disorders in Pregnancy: Retrospective Analysis of Insurance Claims Data. British Medical Journal. 2010;340:c1662.
  4. Drew S, Ibikunle C, Sanni A. Women Who Undergo Weight-Loss Operations Have a Lower Risk for Cesarean Section Later On 2016 [Available from: