What is it about the uterus anyway?

More fetuses die or are left damaged by preterm delivery than any other cause. This is not only a devastating problem for the family, but a very expensive problem as well. The drugs physicians currently have available to treat women in labor are largely ineffective and in some cases, given their toxicity, may violate the sacred goal of treatment, "Primum Non Nocere". At the present time, we do not understand the regulation of the uterine smooth muscle that leads to birth. If we knew more, particularly how best to induce relaxation of a uterus undergoing preterm labor, we could revolutionize the treatment of this problem and potentially save thousands of lives and reduce morbidity greatly. The ability of nitric oxide to relax smooth muscle has led to an interest in employing nitric oxide-donors in the treatment of preterm labor. However, fundamental differences exist in the regulation of uterine and other smooth muscles. While some are treating preterm labor using nitric oxide, this approach exposes mother and fetus to unwanted effects of nitrovasodilators. With more detailed knowledge of uterine smooth muscle signaling, an opportunity exists to develop new therapeutics. We discuss the current treatment for preterm labor and consider the evidence that nitric oxide-mediated relaxation of myometrial smooth muscle is cyclic nucleotide-independent. Knowledge of the regulation of myometrium that is disparate from that of other smooth muscles may reveal molecular targets that are unique to the myometrium and can there for be pursued as tocolytic targets.