From: Validation of a model for optimal birth weight: a prospective study using serial ultrasounds
Characteristic | N | % |
---|---|---|
All births | 691 | 100 |
All scans | 2,848 | 100 |
Infant sex | ||
Male | 354 | 51 |
Female | 337 | 49 |
Maternal age (years) | ||
Less than 20 | 58 | 8 |
20–24 | 132 | 19 |
25–29 | 210 | 30 |
30–34 | 201 | 29 |
35 or over | 90 | 13 |
Birth order | ||
First birth | 308 | 45 |
Second birth | 215 | 31 |
Third birth | 108 | 16 |
Fourth birth or more | 60 | 9 |
Scans per gestation period | ||
14–17 weeks | 147 | 5 |
18–22 weeks | 578 | 20 |
23–27 weeks | 561 | 20 |
28–32 weeks | 550 | 19 |
33–39 weeks | 991 | 34 |
40–42 weeks | 21 | 1 |
Scans per individual | ||
2–3 scans | 190 | 28 |
4–5 scans | 459 | 66 |
6–8 scans | 42 | 6 |