TABLE 3.
Association between BMI at 18 y and weight change since 18 y and probability of implantation, clinical pregnancy, and live birth in the Environment and Reproductive Health Study
| Adjusted probability (95% CI)1 | |||||
|---|---|---|---|---|---|
| Characteristic | Women | Cycles | Successful implantation | Clinical pregnancy | Live birth |
| BMI at 18 y, kg/m2 | |||||
| <18.5 | 92 | 150 | 58.7 (50.1, 66.8) | 52.2 (44.0, 60.3) | 43.4 (35.2, 51.9) |
| 18.5–19.9 | 89 | 153 | 54.0 (45.7, 62.0) | 48.3 (40.5, 56.2) | 40.7 (32.9, 48.9) |
| 20–22.4 (reference) | 197 | 358 | 56.1 (50.7, 61.4) | 46.8 (41.6, 52.0) | 36.6 (31.6, 42.0) |
| 22.5–24.9 | 68 | 129 | 51.1 (42.1, 60.0) | 41.5 (33.3, 50.2) | 32.5 (24.7, 41.4) |
| ≥25 | 40 | 73 | 50.1 (38.4, 61.8) | 47.1 (36.1, 58.5) | 38.9 (28.1, 50.8) |
| P-trend2 | 0.20 | 0.20 | 0.20 | ||
| Weight change since 18 y | |||||
| Lost (<0 kg) | 58 | 104 | 57.7 (47.5, 67.3) | 46.2 (36.8, 56.0) | 38.7 (29.4, 48.9) |
| Stable (gained 0–4.9 kg) (reference) | 129 | 222 | 55.1 (48.2, 61.8) | 47.4 (40.9, 54.1) | 40.1 (33.6, 47.0) |
| Gained 5–9.9 kg | 117 | 213 | 58.9 (51.9, 65.7) | 50.1 (43.3, 56.8) | 37.1 (30.6, 44.1) |
| Gained 10–14.9 kg | 75 | 131 | 57.6 (48.7, 66.1) | 51.3 (42.7, 59.8) | 45.4 (36.6, 54.4) |
| Gained ≥15 kg | 107 | 193 | 47.0 (39.6, 54.5) | 41.9 (34.9, 49.1) | 31.6 (25.1, 38.9) |
| P-trend for weight change | 0.07 | 0.35 | 0.19 | ||
| P-trend for weight gain3 | 0.07 | 0.24 | 0.17 | ||
1Adjusted for age, smoking status, race, education, and height. Weight change models were further adjusted for BMI at 18 y.
2Test for trend was performed using the median level of BMI at 18 y or weight change since 18 y in each category as a continuous variable in the model.
3Test for trend using median value for each weight change category among women who remained weight stable or gained weight (excludes women who lost weight).