. Author manuscript; available in PMC: 2013 Apr 11.

Published in final edited form as: Pediatrics. 2006 Dec;118(6):2488–2497. doi: 10.1542/peds.2006-1824

TABLE 5.

The Change in Risk of Infant Death According to Plurality and Gestation for Black Women, 1999–2001 vs 1989–1991

Variable	1989–1991			1999–2001			AOR^a			Comparison to Singleton AORs^b
Variable	Live Births	Infant Deaths	IMR^c	Live Births	Infant Deaths	IMR	AOR	95% CI	P	AOR/AOR	95% CI	P
All gestations
Singletons	1 800 819	24 191	13.43	1 649 176	16 943	10.27	0.717	0.700–0.734	<.0001	1.000
Twins	49 913	2726	54.62	56 805	2399	42.23	0.616	0.569–0.667	<.0001	0.859	0.790–0.934	<.0001
Triplets	801	101	126.09	1421	174	122.45	0.724	0.496–1.056	.101	1.009	0.691–1.475	.961
≤24 wk
Singletons	9773	7311	748.08	9555	6350	664.57	0.682	0.638–0.729	<.0001	1.000
Twins	1740	1404	806.90	1982	1431	722.00	0.604	0.513–0.710	<.0001	0.885	0.743–1.055	.173
Triplets	63	54	857.14	133	107	804.51	1.069	0.487–2.348	.877	1.568	0.712–3.453	.264
25–28 wk
Singletons	15 206	3394	223.20	14 338	2148	149.81	0.629	0.591–0.670	<.0001	1.000
Twins	2417	644	266.45	2846	429	150.74	0.503	0.435–0.583	<.0001	0.800	0.682–0.938	.006
Triplets	101	31	306.93	212	43	202.83	0.498	0.280–0.887	.019	0.792	0.443–1.414	.430
29–32 wk
Singletons	33 066	1648	49.84	27 456	947	34.49	0.699	0.642–0.762	<.0001	1.000
Twins	5481	224	40.87	6357	160	25.17	0.605	0.487–0.752	<.0001	0.865	0.685–1.094	.226
Triplets^d	212	7	33.02	422	14	33.18	0.961	0.358–2.574	.939	1.374	0.511–3.697	.529
33–36 wk
Singletons	209 736	2938	14.01	176 023	1753	9.96	0.759	0.713–0.807	<.0001	1.000
Twins	17 364	256	14.74	22 871	208	9.09	0.650	0.539–0.783	<.0001	0.856	0.704–1.042	.122
Triplets^d,^e	425	9	21.18	654	10	15.29	0.914	0.386–2.166	.843	1.205	0.507–2.861	.673
37–40 wk
Singletons	1 179 518	6814	5.78	1 165 282	4713	4.04	0.756	0.727–0.785	<.0001	1.000
Twins	20 339	164	8.06	21 087	159	7.54	1.051	0.829–1.333	.679	1.392	1.094–1.770	.007
41–43 wk
Singletons	353 520	2086	5.90	256 522	1032	4.02	0.722	0.668–0.780	<.0001	1.000
Twins^d	2572	34	13.22	1662	12	7.22	0.645	0.318–1.308	.230	0.893	0.439–1.819	.756

IMR indicates infant mortality rate.

Odds of infant death within each plurality group in 1999 –2001 vs 1989 –1991 adjusted for maternal age (<20, 20 –34, and >34 years), smoking (nonsmoker, smoker, and unknown), and parity (0, 1–3, ≥4, and unknown).

The plurality-specific change in risk of infant death between 1999 –2001 vs 1989 –1991 compared with the change for singletons.

Deaths per 1000 live births.

Rates are based on small numbers (<20 in the numerator) and should be interpreted with caution.

Includes triplets born 33 to 36 weeks and later.