Birth weight for gestational age norms for a large cohort of infants born to HIV-negative women in Botswana compared with norms for U.S.-born black infants

Table 1 Distribution of birth weights for gestational age for babies born to HIV-negative women in Botswana compared with median for babies born to black women in the U.S.

Gestational Age (weeks)	N	Minimum (grams)	Lower Quartile (grams)	Median (grams)	Upper Quartile (grams)	Maximum (grams)	U.S. median * (grams)	Δ Median (Botswana - U.S.)	p-value^†
26	9	700	880	930	1230	1680	857	73	.051
27	20	670	1013	1116	1610	2310	977	139	.004
28	29	790	1120	1260	1740	2700	1120	140	.003
29	54	750	1200	1375	1725	2950	1304	71	.015
30	62	860	1390	1660	2180	2990	1525	135	.002
31	71	810	1535	1815	2630	3300	1804	11	.032
32	119	800	1680	2085	2730	3440	2084	0.6	.099
33	162	1170	2055	2410	2790	3790	2358	52	.370
34	268	1380	2100	2510	2928	3850	2571	- 61	.095
35	394	1180	2320	2700	3060	4200	2733	- 33	.172
36	687	1470	2560	2850	3115	4335	2870	- 20	.164
37	1056	1790	2690	2960	3240	4680	3014	- 53	< .001
38	1758	1900	2820	3060	3330	4550	3158	- 98	< .001
39	2340	1890	2890	3130	3405	5150	3277	- 147	< .001
40	2482	1960	2970	3220	3500	4920	3356	- 135	< .001
41	1357	1980	3000	3290	3600	5000	3399	- 109	< .001
42	746	2000	3000	3300	3610	5080	3346	- 45	.016
43	125	2300	3000	3280	3540	4405	3316	- 35	.492
44	14	2680	3100	3345	3700	4785	3328	16	.583

* Oken E, Kleinman KP, Rich-Edwards J, Gillman MW. A nearly continuous measure of birth weight for gestational age using a United States national reference. BMC Pediatrics 2003;3:10.
^† Wilcoxon signed rank test.

ISSN: 1471-2431