Pregnancy Weight Gain After Gastric Bypass or Sleeve Gastrectomy

Key Points Question Does pregnancy weight gain differ by history of bariatric surgery, surgical procedure, surgery-to-conception interval, and/or surgery-to-conception weight loss? Findings This cohort study of 12 776 pregnancies (6388 postsurgery vs 6388 controls) in Sweden found that women with history of bariatric surgery gained less weight during pregnancy than women without such a history but with otherwise similar early-pregnancy characteristics. Pregnancy weight gain did not differ between gastric bypass and sleeve gastrectomy, but pregnancy weight gain was lower in women with a shorter surgery-to-conception interval or lower surgery-to-conception weight loss. Meaning Pregnancy weight gain is lower in women with a history of bariatric surgery compared with those without, particularly when the surgery-to-conception interval is shorter.


eFigure 1 .
Inclusion Criteria and Final Sample Size for Pregnancies in Sweden Between 2014-2021 eFigure 2. The Association Between Surgery-to-Conception Interval and Pregnancy Weight Gain Among Pregnancies With a History of Gastric Bypass (N=5486) a Z-score refers to the mean pregnancy weight gain z-score observed in the data, not predicted from the regression model.b Corresponding weight gain z-score in kilograms at 40 weeks.c Mean difference in z score estimated from the multivariable linear regression model with a robust sandwich estimator, adjusted for maternal age and parity.eFigure 3. The Association Between Surgery-to-Conception Interval and Pregnancy Weight Gain Among Pregnancies With a History of Sleeve Gastrectomy (N=905) a Z-score refers to the mean of pregnancy weight gain z-score observed in the data, not predicted from the regression model.b Corresponding weight gain z-score in kilograms at 40 weeks.c Mean difference in z score was estimated from the multivariable linear regression model with a robust sandwich estimator, adjusted for maternal age and parity.eFigure 4. The Association Between Surgery-to-Conception Interval and Pregnancy Weight Gain Among Nulliparous Women With a History of Bariatric Surgery (N=2245) a Z-score refers to the mean pregnancy weight gain z-score exactly observed in the data, not predict from the regression model.b Corresponding weight gain z-score in kilogram at 40 weeks.c Mean difference in z score was estimated from the multivariable linear regression model with a robust sandwich estimator, adjusted for maternal age.eFigure 5.The Association Between Surgery-to-Conception Interval and Pregnancy Weight Gain Among Parous Women With a History of Bariatric Surgery (N=4146) a Z-score referred to the mean of pregnancy weight gain z-score exactly observed in the data, but not predict from the regression model.b Corresponding weight gain z-score in kilogram at 40 weeks.c Mean difference in z score was estimated from the multivariable linear regression model with robust sandwich estimators with adjustments for maternal age.

eTable 1 .
Maternal Characteristics of Included Versus Excluded Singleton Pregnancies With and Without a History of Bariatric Surgery (Gastric Bypass or Sleeve Gastrectomy) in Sweden Between 2014 and 2021 Before Matching Specific Additional Adjustments Based on Early-Pregnancy Weight Status for Women With and Without a History of Bariatric Surgery, and Based on Surgical Procedure Note: The exact numbers were not reported for case number <5 per cell.Missing data was indicated by NA. a Within 12 months before pregnancy.eTable 2.

Pregnancies with a history of bariatric surgery vs those without Surgery types among within the bariatric surgery group Bariatric surgery General population pregnancies P value Sleeve gastrectomy Gastric bypass P value
Maternal Characteristics of Matched Versus Unmatched Singleton Pregnancies With a History of Bariatric Surgery (Gastric Bypass or Sleeve Gastrectomy) in Sweden Between 2014 and 2021 Note: The exact numbers were not reported for case number <5 per cell.Missing data was indicated by NA. a Within 12 months before pregnancy eTable 4. Note: The exact numbers were not reported for case number <5 per cell.Missing data was indicated by NA. a Within 12 months before pregnancy Pregnancy

with a history of bariatric surgery Surgery type among pregnancies with a history of bariatric surgery
Overview of Adherence to the Institute of Medicine (IOM) Guidelines for Surgery Group, Matched Controls, and Pregnancies Conceived at Different Years After Surgery per Early-Pregnancy BMI Category Adjusted Predicted Means of Pregnancy Weight Gain z Scores According to Surgery-to-Conception Interval and Stratified by Early-Pregnancy BMI Weight Status Note: The exact numbers were not reported for case number <5 per cell.Missing data was indicated by NA. eTable 6. a Adjusted Means of Pregnancy Weight Gain z Scores According to Surgery-Conception Weight Change and Stratified by Early-Pregnancy BMI Weight Status We selected the weight change interval based on the turning point in our predicted curve, which was around -40 to -20 kg.As -120 and 20 kg were not present in our data, we used -126 and 23 kg instead.Means of Pregnancy Weight Gain z Scores According to Surgery-to-Conception Interval and Surgery-to-Conception Weight Change, Stratified by Early-Pregnancy BMI Weight Status b Predicted mean pregnancy weight gain z-scores were adjusted for maternal age and parity.©2023Xu H et al.JAMA Network Open.eTable 7. a b Predicted mean pregnancy weight gain z-scores were adjusted for maternal age and parity.eTable8.
Pregnancy Outcomes by Surgery-to-Conception Interval and Pregnancy Weight Gain z Score Categories eTable 9.