TABLE 7.
Supplementary iron intake and fecundability among women planning a pregnancy in the Snart Foraeldre and PRESTO cohorts, stratified by heavy menses/short cycles1
| Heavy menses or short cycles | Not heavy menses or short cycles | |||||
|---|---|---|---|---|---|---|
| Pregnancies, n | Cycles at risk, n | Adjusted2 FR (95% CI) | Pregnancies, n | Cycles at risk, n | Adjusted2 FR (95% CI) | |
| Snart Foraeldre, n = 1693 | ||||||
| Nonuser | 113 | 551 | 1.00 (Ref.) | 344 | 1947 | 1.00 (Ref.) |
| Any iron-containing supplement user | 204 | 1017 | 1.09 (0.87, 1.36) | 490 | 2663 | 1.01 (0.89, 1.15) |
| Supplement type | ||||||
| Nonuser | 113 | 551 | 1.00 (Ref.) | 344 | 1947 | 1.00 (Ref.) |
| Multivitamin user | 182 | 930 | 1.10 (0.88, 1.39) | 441 | 2423 | 1.01 (0.89, 1.14) |
| Iron-only supplement user | 22 | 87 | 1.01 (0.67, 1.52) | 49 | 240 | 1.06 (0.80, 1.40) |
| PRESTO, n = 2969 | ||||||
| Iron-containing supplements | ||||||
| Nonuser | 46 | 512 | 1.00 (Ref.) | 139 | 1047 | 1.00 (Ref.) |
| Any iron-containing supplement user | 383 | 2846 | 1.58 (1.17, 2.13) | 1248 | 7995 | 1.09 (0.93, 1.29) |
| Supplement type | ||||||
| Nonuser | 46 | 512 | 1.00 (Ref.) | 139 | 1047 | 1.00 (Ref.) |
| Multivitamin user | 328 | 2416 | 1.57 (1.16, 2.12) | 1108 | 7093 | 1.09 (0.93, 1.29) |
| Iron-only supplement user | 55 | 430 | 1.62 (1.10, 2.37) | 140 | 902 | 1.09 (0.88, 1.36) |
1
FR, fecundability ratio.
2
Adjusted for age, vocational training/education, BMI, physical activity, smoking, alcohol consumption, use of oral contraceptives, parity, cycle regularity and length, doing something to improve chances of conception, use of iron and vitamin C supplements, multivitamin use, dietary vitamin C (continuous), and total energy (continuous). The PRESTO models are also adjusted for race/ethnicity. Heme and nonheme iron models are mutually adjusted for each other.