Preterm labor leads to preterm delivery in over 50% of cases.  Current treatment for preterm labor is inadequate and relies on findings in other smooth muscles. No treatment can prevent labor to allow a fetus to remain in the womb until term.  Regulation of contraction/relaxation of the uterine smooth muscle is poorly understood.  Recent work in our laboratory has revealed major disparity between term and preterm human uterine smooth muscle that suggests new approach to drug discovery.