From: Does advanced maternal age confer a survival advantage to infants born at early gestation?
Maternal age | 20–29 years | ≥35 years | P-value | ||
---|---|---|---|---|---|
N | % | N | % | ||
Total | 5456260 | 1390435 | |||
Primiparitya | 1872836 | 34.5 | 220523 | 15.9 | <0.001 |
Maternal race | <0.001 | ||||
Non-Hispanic white | 3148757 | 57.7 | 938771 | 67.5 | |
African American | 894564 | 16.4 | 158429 | 11.4 | |
Hispanic | 1122755 | 20.6 | 192012 | 13.8 | |
Other | 59252 | 1.1 | 192012 | 0.6 | |
Missing race | 230932 | 4.2 | 93055 | 6.7 | |
Unmarried | 2233258 | 41.0 | 218518 | 15.7 | <0.001 |
Education (any college) | 2360637 | 43.7 | 966218 | 70.4 | <0.001 |
Smoking during pregnancy | 699909 | 12.8 | 92929 | 6.7 | <0.001 |
Missing | 231952 | 4.3 | 63329 | 4.6 | |
Gestational age (weeks) | <0.001 | ||||
22–27 | 27605 | 0.5 | 7854 | 0.6 | |
28–33 | 90464 | 1.7 | 28120 | 2.0 | |
34–36 | 351685 | 6.4 | 98114 | 7.1 | |
37–40 | 4528206 | 83.0 | 1159833 | 83.4 | |
41–43 | 458300 | 8.4 | 96514 | 6.9 | |
Birth weight (g) | <0.001 | ||||
500–999 | 28536 | 0.5 | 8528 | 0.6 | |
1000–2499 | 322682 | 5.9 | 85676 | 6.2 | |
2500–3499 | 3177955 | 58.2 | 720293 | 51.8 | |
3500–4499 | 1869180 | 34.3 | 550843 | 39.6 | |
≥4500 | 57907 | 1.1 | 25095 | 1.8 | |
Any congenital anomaly | 63746 | 1.2 | 19276 | 1.4 | <0.001 |
Infant's gender (male) | 2793711 | 51.2 | 713245 | 51.3 | 0.046 |
Fetal death | 16645 | 0.31 | 5583 | 0.40 | <0.001 |
Neonatal death | 13742 | 0.25 | 3900 | 0.28 | <0.001 |
Perinatal death | 30387 | 0.56 | 9483 | 0.68 | <0.001 |