Skip to main content
. 2019 Jun 1;149(9):1585–1595. doi: 10.1093/jn/nxz094

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.