Table 2. Association Between Mode of Delivery With Obesity in Offspring Among 33 226 Women.
| Mode of delivery | Obese participants, No./total No. (%)a | Offspring obesity | |
|---|---|---|---|
| RR (95% CI) | P value | ||
| Overall | 12 156/33 226 (36.6) | NA | NA |
| Vaginal | 11 722/32 137 (36.5) | 1 [Reference] | NA |
| Cesarean | 434/1089 (39.9) | ||
| Crude | 1.09 (1.01-1.18) | .02 | |
| Adjustedb | 1.11 (1.03-1.19) | .005 | |
| Additional analysis | |||
| Marginal structural model estimate | 434/1089 (39.9) | 1.11 (1.03-1.19) | <.001 |
| Maternal BMI as continuous variablec | 434/1089 (39.9) | 1.11 (1.03-1.19) | .006 |
| Allowing obesity status to change over time | 434/1089 (39.9) | 1.18 (1.08-1.29) | <.001 |
| Women who remained obese during follow-up (n = 31 867) | 391/1046 (37.4) | 1.13 (1.05-1.22) | .002 |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); NA, not applicable; RR, relative risk.
Body mass index of 30 or higher.
Adjusted models included terms for maternal age at delivery, race/ethnicity (white or other), maternal educational level (≥high school or ≥college), maternal prepregnancy BMI group (<18.5, 18.5-24.99, 25-29.99, or ≥30), gestational weight gain (<9.1 kg or ≥9.1 kg), maternal height, gestational diabetes (yes or no), preeclampsia (yes or no), pregnancy-induced hypertension (yes or no), year of birth (1946-1951, 1952-1961, or 1962-1964), gestational age at delivery (<37, 37-39, 40-42, or ≥43 weeks), birth weight group (<2.3, 2.3-3.1, 3.2-3.8, 3.9-4.4, or ≥4.5 kg), smoking during pregnancy (no, first trimester, second and third trimesters, or current), and region of residence at birth (Northeast, Midwest, West, or South).
Adjusted model modeling prepregnancy BMI as a continuous variable with a linear term and a quadratic term.