['To determine the effects of CP-154, 526, a corticotropin releasing hormone (CRH) receptor antagonist, on the length of normal rat gestation.', 'Twenty-four timed-pregnant Sprague-Dawley rats were purchased for this study. The drug and placebo were administered to the animals using an osmotic pump surgically inserted in the dorsal subcutaneous space. Six animals received 6 mg/kg/day of the drug, six animals received 12 mg/kg/day of the drug and twelve animals received the placebo. The gestational period, weight of each pup and number of pups in each litter were recorded and compared in the drug group versus placebo group.', 'No difference was noted in the gestational period of the drug and placebo rats. The mean weight of pups in both the drug and placebo groups was 6.18 g. The number of pups per litter were similar in the drug and placebo groups.'] Does a corticotropin releasing hormone receptor antagonist delay parturition in rats?