Does advanced maternal age confer a survival advantage to infants born at early gestation?

Table 1 Maternal and fetal/infant characteristics by maternal age among singleton births, Unites States, 2003–2005

Maternal age	20–29 years		≥35 years		P-value
	N	%	N	%
Total	5456260		1390435
Primiparity^a	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

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