TABLE 5.

Frequency of spontaneous preterm birth by quartile of 17-alpha hydroxyprogesterone caproate and race

	Self-reported race
	African American N ¼ 75		Caucasian N ¼ 174		Other N ¼ 19		Alla N ¼ 268
Quartile	SPTB
17OHP-C	nb	%c	nb	%c	nb	%c	nb	%c
1	5	27.8	19	44.2	1	25	25	38.5
2	6	31.6	12	27.3	0	0	18	26.5
3	6	31.6	12	27.3	1	20	19	27.9
4	3	15.8	11	25.6	0	0	14	20.9

SPTB, spontaneous preterm birth; 17 OHP-C, 17-alpha hydroxyprogesterone caproate.

^aCochran-Armitage trend test, P ¼ .04;

^bIn each quartile;

^cWith respect to total patients in that quartile.

Bustos et al. Association of CYP3A and PR SNPs and 17 OHP-C. Am J Obstet Gynecol 2017.