In Vitro Myometrial Contractions in Laboring and Non-laboring Women

The purpose of this study is to compare the ability of an isolated sample of uterine muscle tissue (in a tissue bath) to contract in the presence of various drugs. The drugs studied--uterotonics--are typically used to contract the uterus when a pregnant patient continues to bleed after delivery. Amongst common uterotonic drugs, namely oxytocin, ergonovine, prostaglandin F2alpha, and misoprostol, the most effective one to use is unknown. The investigators will be testing isolated uterine muscle samples to increasing concentrations of these four drugs in three patient populations: non-laboring, laboring without exogenous oxytocin augmentation, and laboring with oxytocin augmentation. Contractile measures will be measured and compared between all groups. The investigators hypothesize that oxytocin alone will have a weaker uterotonic effect in oxytocin-augmented laboring patients, and all four drugs will induce different patterns of contractions.