Table 3.
Female age and fecundability, stratified by gravidity, PRESTO, 2013–2017.
| Exposure | Nulligravid (n=1,664)
|
Gravid (n=1,298)
|
||||
|---|---|---|---|---|---|---|
| Pregnancies N | Cycles N | Adjusted FRa (95% CI) | Pregnancies N | Cycles N | Adjusted FRa (95% CI) | |
| Female age (y) | ||||||
| 21–24 | 75 | 568 | 1.00 (Reference) | 63 | 363 | 1.00 (Reference) |
| 25–27 | 218 | 1462 | 0.88 (0.66, 1.16) | 138 | 722 | 0.92 (0.68, 1.24) |
| 28–30 | 352 | 2441 | 0.80 (0.59, 1.07) | 254 | 1218 | 0.95 (0.70, 1.30) |
| 31–33 | 243 | 1617 | 0.84 (0.62, 1.14) | 217 | 1241 | 0.88 (0.64, 1.22) |
| 34–36 | 87 | 736 | 0.68 (0.48, 0.96) | 114 | 607 | 0.96 (0.67, 1.40) |
| 37–39 | 21 | 263 | 0.51 (0.30, 0.85) | 53 | 401 | 0.70 (0.46, 1.08) |
| 40–45 | 1 | 49 | 0.20 (0.03, 1.44) | 12 | 152 | 0.48 (0.24, 0.94) |
a
Adjusted for female education, female smoking, female alcohol use, female BMI, female vigorous physical activity, male education, male BMI, male smoking, household income, using methods to improve chances of conception, intercourse frequency, last method of contraception, and partner age.