Table 3.
Adjusted Odds Ratios for the Relation Between Maternal Body Mass Index and Postpartum Hemorrhage Outcomes, Stratified by Mode of Delivery
| PPH | Atonic PPH | Severe PPH | ||||
|---|---|---|---|---|---|---|
| Vaginal Delivery* | ||||||
| BMI | N (%) | Adjusted OR (99% CI) | N (%) | Adjusted OR (99% CI) | N (%) | Adjusted OR (99% CI) |
| <18.5 | 1504 (2.4%) | 0.92 (0.86 – 0.99) | 1164 (1.9%) | 0.90 (0.83 – 0.97) | 203 (0.3%) | 1.1 (0.91 – 1.33) |
| 18.5 – 24.9 | 20,432 (2.8%) | Reference | 16,036 (2.2%) | Reference | 2173 (0.3%) | Reference |
| 25 – 29.9 | 11,090 (3.1%) | 1.09 (1.06 – 1.13) | 8720 (2.4%) | 1.1 (1.06 – 1.14) | 1050 (0.3%) | 0.97 (0.88 – 1.08) |
| 30 – 34.9 | 5325 (3.3%) | 1.16 (1.12 – 1.21) | 4233 (2.6%) | 1.19 (1.14 – 1.25) | 479 (0.3%) | 0.97 (0.85 – 1.11) |
| 35 – 39.9 | 1953 (3.3%) | 1.12 (1.05 – 1.19) | 1524 (2.5%) | 1.13 (1.05 – 1.21) | 151 (0.2%) | 0.81 (0.65 – 1.01) |
| ≥ 40 | 1042 (3.5%) | 1.15 (1.06 – 1.25) | 805 (2.7%) | 1.15 (1.05 – 1.27) | 99 (0.3%) | 1.02 (0.78 – 1.34) |
| Instrumental Delivery* | ||||||
| BMI | N (%) | Adjusted OR (99% CI) | N (%) | Adjusted OR (99% CI) | N (%) | Adjusted OR (99% CI) |
| <18.5 | 177 (3.6%) | 0.96 (0.81 – 1.12) | 134 (2.7%) | 0.85 (0.67 – 1.08) | 36 (0.8%) | 1.23 (0.78 – 1.97) |
| 18.5 – 24.9 | 1913 (4.1%) | Reference | 1585 (3.4%) | Reference | 291 (0.6%) | Reference |
| 25 – 29.9 | 743 (4.4%) | 1.09 (0.99 – 1.19) | 617 (3.7%) | 1.1 (0.97 – 1.25) | 100 (0.6%) | 0.91 (0.67 – 1.23) |
| 30 – 34.9 | 274 (4.4%) | 1.13 (0.99 – 1.3) | 223 (3.6%) | 1.12 (0.92 – 1.37) | 38 (0.6%) | 0.91 (0.58 – 1.44) |
| 35 – 39.9 | 80 (3.8%) | 0.97 (0.77 – 1.23) | 70 (3.3%) | 1.05 (0.75 – 1.45) | 12 (0.6%) | 0.84 (0.39 – 1.82) |
| ≥ 40 | 54 (5.2%) | 1.29 (0.96 – 1.72) | 42 (4.0%) | 1.22 (0.79 – 1.86) | 9 (0.9%) | 1.32 (0.54 – 3.24) |
| Caesarean Delivery* | ||||||
| BMI | N (%) | Adjusted OR (99% CI) | N (%) | Adjusted OR (99% CI) | N (%) | Adjusted OR (99% CI) |
| <18.5 | 333 (1.7%) | 0.96 (0.78 – 1.18) | 127 (0.6%) | 0.88 (0.76 – 1.02) | 98 (0.5%) | 0.94 (0.74 – 1.19) |
| 18.5 – 24.9 | 5910 (2.0%) | Reference | 2048 (0.7%) | Reference | 1605 (0.5%) | Reference |
| 25 – 29.9 | 3427 (1.8%) | 1.09 (0.97 – 1.23) | 1186 (0.6%) | 0.99 (0.93 – 1.05) | 902 (0.5%) | 0.91 (0.83 – 1.00) |
| 30 – 34.9 | 1782 (1.6%) | 1.13 (0.95 – 1.36) | 553 (0.5%) | 0.95 (0.88 – 1.02) | 415 (0.4%) | 0.77 (0.67 – 0.87) |
| 35 – 39.9 | 809 (1.6%) | 0.97 (0.71 – 1.32) | 257 (0.5%) | 0.91 (0.82 – 1.00) | 200 (0.4%) | 0.76 (0.64 – 0.91) |
| ≥ 40 | 543 (1.5%) | 1.28 (0.88 – 1.88) | 180 (0.5%) | 0.87 (0.79 – 0.98) | 134 (0.4%) | 0.76 (0.62 – 0.94) |
BMI = body mass index; PPH = postpartum hemorrhage; aOR = adjusted odds ratios
Rates of PPH were row percentages with the denominator based on the number of women in each body mass index class. Models adjusted for maternal age, race/ethnicity, insurance, education, chronic hypertension, trimester when prenatal care was initiated, gestational age at delivery, parity, plurality, previous cesarean delivery, prolonged labor, induction of labor, chorioamnionitis, placental abruption, polyhydramnios, fibroids, stillbirth. Hospital site was considered as a random effect, to account for patient clustering within site. Labor and placenta previa were also adjusted for in the models for cesarean delivery.