Table 2.
Summary of study results by BMI adjustment method.a
| Comparison characteristics | Procedure(s) | OR or RR (95% CI) | Variable used in Matching (MV) and Adjustment (AV) |
|---|---|---|---|
| Unmatched/unadjusted for BMI | |||
| Sheiner et al. 200431 | Any bariatric surgery | uOR 1.28 (0.76, 2.15)b | MV: None AV: None |
| Marceau et al. 200438 | Biliopancreatic diversion | uOR 1.62 (0.71, 3.73)b | MV: None AV: None |
| Weintraub et al. 200832 | Any bariatric surgery | aOR 1.90 (0.88, 4.12) | MV: None AV: Age; Preterm delivery |
| Normal BMI | |||
| Berlac et al. 201433,c | Gastric bypass (RYGB) | uOR 1.39 (0.86, 2.25)b | MV: Age; Parity; Plurality; Year of delivery AV: None |
| Adjusted/matched BMI | |||
| Josefsson et al. 201344 | Any bariatric surgery (gastroplasty, gastric banding, and gastric bypass) | aOR 1.09 (0.63, 1.91) | MV: None AV: Early pregnancy BMI; Age; Diabetes; HTN/Preeclampsia; Marital status; Smoking |
| Berlac et al. 201433,c | Gastric bypass (RYGB) | uOR 1.16 (0.73, 1.85)b | MV: Prepregnancy BMI; Age; Parity; Plurality; Year of delivery AV: None |
| Parent et al. 201736 | Any bariatric surgery (gastroplasty, gastric banding, sleeve gastrectomy, and RYGB) | aRR 1.12 (0.99, 1.26) | MV: None AV: Prepregnancy BMI; Age; Birth year; Diabetes; Education; Household income; HTN; Parity; Race/Ethnicity |
| Obese (BMI>40 kg/m2) at delivery | |||
| Abenhaim et al. 201635 | Any bariatric surgery (specific procedures not provided) | aOR 0.74 (0.52, 1.04) | MV: None AV: Age; Cardiovascular disease; Diabetes; Hospital type; HTN; Income; Insurance type; Pulmonary disease; Race; Renal disease |
| Matched pre-surgery BMI/prepregnancy BMI | |||
| Johansson et al. 201534 All pregnancies Restricted to one pregnancy per women |
Gastric bypass (Predominantly RYGB) | aOR 0.63 (0.34, 1.18) aOR 0.68 (0.35, 1.31) |
MV: Pre-surgery BMI/Early pregnancy BMI; Age; Education; Parity; Smoking; Year of delivery AV: History of coexisting conditions; History of substance abuse; Mother’s country of birth |
BMI, body mass index; CI, confidence interval; OR, odds ratio; RR, risk ratio; RYGB, Roux-en-Y gastric bypass; uOR/aOR, unadjusted/adjusted odds ratio; uRR/aRR, unadjusted/adjusted rate ratio
a
Studies without association estimates30,37,39,40-42 were not included in this table and results from Adams et al.43 were not presented because the authors did not provide a clear description of their comparison group.
b
uOR calculated from data provided in the article.
c
Berlac et al.33 included two comparison groups: women with normal prepregnancy BMI and women matched on prepregnancy BMI.