Hairdressers | Sisters | |
Observational unit = woman | ||
Year of birth (mean, 95% range) | 1965 (1951 to 1975) | 1965 (1948 to 1978) |
Height (mean, 95% range) | 166 (155 to 177) | 166 (154 to 178) |
Non-smoker at all pregnancies (n, %)* | 1975 (79) | 2193 (76) |
Changed smoking habits between pregnancies (n, %)* | 263 (8) | 380 (10) |
Observational unit = pregnancy | ||
Gestational length (mean, 95% range) | 39 (23 to 45) | 39 (22 to 44) |
Maternal age (mean, 95% range) | 28 (15 to 46) | 28 (16 to 44) |
First parity (n, %) | 2987 (48) | 3690 (44) |
Maternal weight (kg; mean, 95% range) | 66 (50 to 95) | 66 (49 to 97) |
Maternal weight increase since last pregnancy (n, %) | 681 (21) | 805 (23) |
Body mass index (BMI) | ||
<20 | 319 (10) | 365 (10) |
20–25 | 1976 (61) | 2066 (59) |
25–30 | 682 (21) | 781 (22) |
>30 | 237 (7) | 279 (8) |
Maternal BMI increase since last pregnancy (n, %)*† | 199 (6) | 257 (7) |
Boy (n, %) | 3222 (52) | 4358 (52) |
Non-smoking mother (n, %)* | 4244 (82) | 5233 (78) |
Note that because of missing data all numbers do not add up to 100%.
*Based on pregnancies from 1982 and onwards.
†BMI categorised as low, normal, overweight and obese.