Table 2.
Relationships between body mass index at age 20 and the likelihood of having experienced a miscarriage, irregular periods or failing to become pregnant even if trying for one straight year
| Body mass index (kg/m2) | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | <18.5 | 18.5–19.9 | 20–24.9 | 25–29.9 | 30–32.4 | ≥32.5 | p value | |
| Dependent variable | ||||||||
| Ever experienced miscarriage | ||||||||
| Miscarriage | 46,334 | 1.06 (1.00, 1.12) | 1.02 (0.97, 1.07) | 1.00 | 1.11 (1.03, 1.20) | 1.11 (0.92, 1.35) | 0.97 (0.80, 1.16) | 0.06 |
| Miscarriagea | 44,975 | 1.04 (0.98, 1.10) | 1.02 (0.97, 1.07) | 1.00 | 1.07 (0.99, 1.16) | 1.04 (0.85, 1.27) | 0.92 (0.76, 1.11) | 0.46 |
| Miscarriageb | 42,979 | 1.04 (0.98, 1.11) | 1.02 (0.97, 1.08) | 1.00 | 1.05 (0.97, 1.14) | 1.01 (0.82, 1.24) | 0.87 (0.72, 1.06) | 0.40 |
| Menstrual irregularities | ||||||||
| Menstrual irregularities | 45,701 | 1.03 (0.95, 1.12) | 0.98 (0.91, 1.04) | 1.00 | 1.18 (1.07, 1.31) | 1.89 (1.53, 2.33) | 1.98 (1.64, 2.39) | <0.0001 |
| Menstrual irregularitiesa | 44,429 | 1.03 (0.95, 1.12) | 0.97 (0.90, 1.04) | 1.00 | 1.16 (1.05, 1.28) | 1.84 (1.49, 2.28) | 1.91 (1.58, 2.31) | <0.0001 |
| Menstrual irregularitiesc | 42,979 | 1.04 (0.96, 1.13) | 0.97 (0.90, 1.04) | 1.00 | 1.16 (1.04, 1.29) | 1.79 (1.44, 2.23) | 1.87 (1.54, 2.27) | <0.0001 |
| Problems with becoming pregnant | ||||||||
| Problems with becoming pregnant | 46,582 | 1.16 (1.08, 1.25) | 1.13 (1.06, 1.20) | 1.00 | 1.11 (1.01, 1.22) | 1.46 (1.17, 1.82) | 1.55 (1.26, 1.90) | <0.0001 |
| Problems with becoming pregnanta | 45,246 | 1.14 (1.06, 1.23) | 1.12 (1.05, 1.20) | 1.00 | 1.11 (1.00, 1.22) | 1.49 (1.19, 1.87) | 1.53 (1.25, 1.89) | <0.0001 |
| Problems with becoming pregnantd | 42,979 | 1.13 (1.04, 1.22) | 1.13 (1.06, 1.21) | 1.00 | 1.07 (0.97, 1.19) | 1.36 (1.08, 1.72) | 1.36 (1.10, 1.69) | <0.0001 |
Odds ratio (95 % CI). Adjusted for age when filling in the questionnaire and marital status
aAlso adjusted for ever smoking, ever use of alcohol, ethnic background (blacks vs. other) and level of education
bAlso adjusted for ever smoking, ever use of alcohol, ethnic background (blacks vs. other), level of education as well as problems with becoming pregnant, menstrual irregularities and age at menarche
cAlso adjusted for ever smoking, ever use of alcohol, ethnic background (blacks vs. other), level of education as well as experienced a miscarriage, problems with becoming pregnant and age at menarche
dAlso adjusted for ever smoking, ever use of alcohol, ethnic background (blacks vs. other), level of education as well as experienced a miscarriage, menstrual irregularities and age at menarche