Mechanism And Clinical Effect Of Nitroglycerin Patch On Arresting Preterm Labor

Abstract To explore the new methods for the treatment of premature birth, we surveyed the fluctuation of the maternal plasma cortictrophin-releasing hormone (CRH) level during pregnancy, and chose nitroglycerin patch as the NO donor and evaluated the prospect that nitroglycerin patch act as tocolytic agent. Three models were utilized to evaluate the effect of nitroglycerin patch on arresting preterm labor, which included the measure of spontaneous delivery time between the first and second pups in term pregnancy rats, the delay in the onset of labor in pregnancy rabbits and the arrest of 15-methyl-prostaglandin F_2α induced abortion in mice. The results showed that CRH is involved in the pregnant process and parturition. The spontaneous delivery time between the first and second pups in term pregnancy rats in nitroglycerin patch group was 5 times longer than that in negative control. The onset of labor in rabbits was delayed 1² days in nitroglycerin patch group. The abortion rate of mice reduced from 93.3% to 53.3% by nitroglycerin patch, In women diagnosed as being in preterm labor, the mean prolongation of pregnancy was 25 days in the nitroglycerin patch group, and the CRH concentration at the women dropped sharply from 250 ng/L to 37.9 ng/L after treatment by nitroglycerin patch. These results suggested that maternal plasma CRH level is correlated to parturition significantly, and nitroglycerin patch appear to suppress uterine contraction in preterm labor animal models and women diagnosed as being in preterm labor through reducing CRH secretion, and may act as an effective and non-invasive treatment for preterm labor.