Epidemiological Study On The Effect Of Transderal Nitroglycerin Use For Preterm Labor

Background:Preterm labor is a complicated and frequent complication during pregnancy. Despite advances in perinatal medicine, the incidence of preterm birth has increased since the early1980. These babies are at increased risk of death and significant short and long term morbidity. Given the high burden of caring these babies imposed to the health care system and society, preterm birth and its sequelae are a major globe health problem in developed countries. The Canadian Preterm Labor Nitroglycerin Trial demonstrated that transdermal nitroglycerin (GTN), compared with placebo patches, significantly decreased the risk of severe neonatal morbidity and mortality. However, given this analysis in the oringial tial about50%subjects who were not true preterm labor there was about50%subjects were not true preterm births. We therefore conducted a secondary analysis with the support from Dr Graeme Smith and Canadian Institutes for Health Research (CIHR,(MCT41550).Objectives:This study is based on the previous randomized double-blind placebo controlled GTN trial. The objectives of the secondary analysis of data were to determine the possible mechanism for the improved neonatal outcomes with the use of GTN for preterm labor by examining only the women in the trial who delivered preterm, to evaluate developmental performance in the children born to women who participated in the GTN trial by using Ages and Stages Questionnaire (ASQ), after one year and two year of follow up, to determine the cost-effectiveness of GTN for preterm labor from a hospital perspective.Methods:Pregnant women who were clinically in preterm labour between24and32weeks were randomly allocated to either GTN or a placebo patch. Randomization is stratified by centre and gestational age (240wks to280ks,281wks to320wks). After first patches placement in the abdomen for 1hour, if there was ongoing uterine activity, an additional study patch was placed. Twenty-four hours after initiation of treatment, the patches were replaced with the same number of patches for further24hours of treatment. At the completion of treatment (48hours total), all patches were removed. The Ages and Stages Questionnaire (ASQ) were used for the children developmental assessments at one-year and two-year follow up study.For the secondary analysis, women in the original trial who delivered at term were excluded. A composite of severe neonatal outcomes, gestational age at delivery, and corticosteriod use, in additional to Kaplan-Meier survial analysis to assess time from randomization to delivery were examined. Then, the ASQ were used for the children developmental follow-up study. We compared the baseline characteristics between follow-up participants and those who did not in mothers and children, respectively. Total score and five domain scores of child development (communication, gross motor skills, fine motor skills, problem-solving, and personal social skill) were evaluated. Supplementary analyses were performed after stratifying study subjects by gestational age at birth (...