TABLE 1.

Birthweight percentiles by gestational age at birth

Sex	Birthweight percentile
	5th	10th	90th	95th
	Birthweight, g
Male
Gestational age
23	539	569	1147	1302
24	543	599	1138	1289
25	587	648	1236	1447
26	633	712	1431	1655
27	695	779	1622	1892
28	774	875	1886	2168
29	865	967	2262	2505
30	963	1105	2642	2828
31	1118	1278	2960	3107
32	1319	1502	3208	3346
33	1532	1735	3412	3557
34	1765	1964	3585	3747
35	1994	2188	3722	3931
36	2193	2380	3755	3977
37	2411	2602	3844	4055
38	2630	2797	3962	4157
39	2772	2934	4080	4267
40	2853	3021	4174	4360
41	2888	3060	4249	4438
42	2838	3016	4240	4433
43	2807	2984	4180	4376
Female
Gestational age
23	491	520	1130	1253
24	523	547	1110	1263
25	558	600	1181	1405
26	596	656	1325	1593
27	652	723	1600	1915
28	687	795	1908	2189
29	800	913	2322	2534
30	933	1063	2679	2849
31	1065	1221	2987	3124
32	1219	1411	3186	3339
33	1451	1643	3373	3526
34	1677	1873	3521	3697
35	1891	2089	3627	3837
36	2091	2287	3655	3871
37	2320	2500	3725	3928
38	2530	2700	3827	4017
39	2681	2829	3925	4111
40	2762	2913	4015	4194
41	2790	2951	4084	4267
42	2758	2918	4081	4269
43	2724	2883	4041	4233

For each year within the 1991–2001 birth cohort, annual birthweight percentiles were calculated and used to determine birthweight appropriateness for children born within that year. The analysis included children who survived to 1 year of age. Gestational age refers to completed gestational age at birth (23w1d = 23 weeks).

Moore. Autism risk by birthweight percentile. Am J Obstet Gynecol 2012.