title: Studies on the effects of altered timing of parturition in the rat.
abstract: Manipulation of the length of gestation with two different agents has been compared and contrasted in the rat. Single subcutaneous injection of 1 mg/rat of PGF 2 alpha on day 19 of gestation caused premature parturition of at least 24 hours in 55% of treated rats. Premature parturition was associated with perinatal death and cannibalism of delivered pups. Subcutaneous implantation of pellets of naproxen over days 20-23 of gestation prolonged gestation to 24 days and synchronized onset of parturition compared to placebo-treated controls. Post-mature onset of delivery, in contrast, was associated with increased birth weight of pups and a survival rate of 90%. Post-mature pup deaths were restricted to the last pups delivered, i.e. longest gestation. The potential utility of naproxen for manipulation of time of parturition in domestic animals is suggested.
mesh_terms: D000818:Animals; D001724:Birth Weight; D005260:Female; D005328:Fetal Viability / Q000187:drug effects; D005865:Gestational Age; D007751:Labor, Induced; D007743:Labor, Obstetric / Q000187:drug effects*; D009288:Naproxen / Q000494:pharmacology*; D011247:Pregnancy; D011460:Prostaglandins F / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
chemical_list: D011460:Prostaglandins F; D009288:Naproxen