Menu Close

Relationship between 17-Alpha Hydroxyprogesterone Caproate Concentration and Spontaneous Preterm Birth


Caritis, Steve N.; Venkataramanan, Raman; Thom, Elizabeth A.; Harper, Margaret A.; Klebanoff, Mark A.; Sorokin, Yoram; Thorp, John M., Jr.; Varner, Michael W.; Wapner, Ronald J.; & Iams, Jay D., et al. (2014). Relationship between 17-Alpha Hydroxyprogesterone Caproate Concentration and Spontaneous Preterm Birth. American Journal of Obstetrics & Gynecology, 210(2), 128.e1-6. PMCID: PMC3926421


OBJECTIVE: 17-alpha hydroxyprogesterone caproate (17-OHPC) 250 mg weekly reduces recurrent spontaneous preterm birth (SPTB) in women with a prior SPTB by 33%. The dose is not based on pharmacological considerations. A therapeutic concentration has not been determined hampering any attempt to optimize treatment. This study evaluated the relationship between 17-OHPC plasma concentrations and the rate of SPTB in women with singleton gestation.
STUDY DESIGN: A single blood sample was obtained between 25 and 28 weeks gestation from 315 women with a SPTB who participated in a placebo-controlled, prospective, randomized clinical trial evaluating the benefit of omega-3 supplementation in reducing preterm birth. All women in the parent study received 17-OHPC and 434 received omega-3 supplementation and 418 received a placebo. Plasma from 315 consenting women was analyzed for 17-OHPC concentration.
RESULTS: There were no differences between placebo and omega-3 supplemented groups in demographic variables, outcomes or in mean 17-OHPC concentration. Plasma concentrations of 17-OHPC ranged from 3.7- 56 ng/ml. Women with plasma concentrations of 17-OHPC in the lowest quartile had a significantly higher risk of spontaneous preterm birth (p= 0.03) and delivered at significantly earlier gestational ages (p = 0.002) than did women in the 2nd to 4th quartiles. The lowest preterm birth rates were seen when median 17-OHPC concentrations exceeded 6.4 ng/ml.
CONCLUSIONS: Low plasma 17-OHPC concentration is associated with an increased risk of SPTB. This finding validates efficacy of this treatment but suggests that additional studies are needed to determine the optimal dosage.


Reference Type

Journal Article

Year Published


Journal Title

American Journal of Obstetrics & Gynecology


Caritis, Steve N.
Venkataramanan, Raman
Thom, Elizabeth A.
Harper, Margaret A.
Klebanoff, Mark A.
Sorokin, Yoram
Thorp, John M., Jr.
Varner, Michael W.
Wapner, Ronald J.
Iams, Jay D.
Carpenter, Marshall W.
Grobman, William A.
Mercer, Brian M.
Sciscione, Anthony C.
Rouse, Dwight J.
Ramin, Susan M., for the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network and Obstetrical-Fetal Pharmacology Research Units Network