Table 1.
Pregnancy and offspring characteristics of 412 randomly selected amniotic fluid samples, by availability, Denmark, 1980–1996.
| Amniotic fluid samples (n = 412) | ||||||
|---|---|---|---|---|---|---|
| Characteristic | Available (n = 300) | Unavailable (n = 112) | p-Valuea | |||
| Maternal age at birth [years (%)] | 0.02 | |||||
| < 30 | 30 | 21 | ||||
| 30–34 | 24 | 17 | ||||
| ≥ 35 | 46 | 62 | ||||
| Primiparous (%) | 35 | 28 | 0.14 | |||
| Year of amniocentesis (%) | < 0.001 | |||||
| 1980–1984 | 33 | 20 | ||||
| 1985–1990 | 34 | 60 | ||||
| 1991–1996 | 33 | 20 | ||||
| Gestational week of amniocentesis (%) | 0.78 | |||||
| < 15 | 27 | 23 | ||||
| 15–17 | 57 | 60 | ||||
| ≥ 17 | 16 | 17 | ||||
| Congenital malformations in boysb (%) | 6 | 11 | 0.13 | |||
| Apgar score ≥ 9 (%) | 85 | 84 | 0.88 | |||
| Gestational age at birth [weeks (mean ± SD)] | 39.6 ± 1.5 | 39.5 ± 1.8 | 0.79 | |||
| Birth weight [g (mean ± SD)] | 3,535 ± 561 | 3,544 ± 664 | 0.89 | |||
| aCategorical variables were tested with Pearson’s chi-square test, and continuous variables with the t-test. bCryptorchidism and hypospadias were not included. | ||||||