At recruitment, mean age was 29.3 ± 4.9 years, mean BMI 25.0 ± 5.4 kg/m and mean gestation at 14.3 ± 2.9 weeks.
Overall mean gestation at delivery in those women with a spontaneous onset of labour at term was 281.3 (SD 8.4) days with 6.8% of pregnancies delivering postdates.
Blood samples were collected by venipuncture from the mother at the time of the second pregnancy interview (n = 352; mean gestation ± SD = 26 ± 2.9 weeks) and in the hospital before delivery (n = 33).
We interviewed mothers twice during pregnancy (mean gestation, 14.0 and 26.6 weeks), after delivery, and when children were 6 months and 1, 2, 3.5, and 5 years of age.
Participants gained a mean of 15.6 kg (range -7.3 to 40.9) in pregnancy (mean gestation length 39.5 weeks, SD 1.9), and 823 (54%) gained excessively according to Institute of Medicine criteria [ 4].
Heredity also influences gestation; in cattle the mean gestation period for Holstein-Friesians is 279 days; for Brown Swiss, 290 days; other breeds fall between these extremes.
Mean gestation was 37.6 ± 2.9 weeks, and mean birth weight was 2882.4 ± 837 g.
Mean (±SD) birth weight in antiphospholipid syndrome group was 2867 ± 914 g (control, 3492 ± 527 g; P =.02), and the mean gestation at delivery was 36.5 ± 5.2 weeks (control, 40.3 ± 0.7 weeks; P =.002).
A cross-sectional design with women categorised by SOC was used and the sample was recruited from hospital maternity services in the U. K at their booking clinics with a mean gestation of 14 weeks.
The mean gestation week was 9.85 ± 2.21.
The mean gestation at birth was 29.3 weeks.
