17 alpha-hydroxyprogesterone caproate to prevent prematurity in nulliparas with cervical length less than 30 mm - Grobman, W A; Thom, E A; Spong, C Y (Am J Obstet Gynecol, 2012)
, et al; Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units (MFMU) Network.