Alyssa Kahane1, Alison L Park2, Joel G Ray3. 1. St Michael's Hospital, University of Toronto, Toronto, and Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada. 2. Institute for Clinical Evaluative Science, Toronto, Ontario, Canada. 3. Departments of Medicine, Health Policy Management and Evaluation, and Obstetrics and Gynecology, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. Electronic address: rayj@smh.ca.
Abstract
BACKGROUND: There exist structural and physiological commonalities between myometrial and myocardial tissue, and each can become dysfunctional, such as in the presence of cardiometabolic factors. METHODS: This population-based cohort study was comprised of 1,608,720 women with ≥ 1 singleton hospital live birth at 24-41 weeks' gestation in Ontario, from 1992 to 2016. The main exposure was prolonged first stage of labour; secondary exposure was prolonged second stage of labour. The main outcome was a composite of heart failure, cardiomyopathy or dysrhythmia ≥ 1 day after the index delivery. Cox proportional hazard regression was used to generate a hazard ratio (HR), adjusted for maternal age, parity, obstructed labour or fetal malposition, preeclampsia, income quintile, rural residence, preterm birth, and infant birth weight-each at the time of delivery; time-varying drug/tobacco use, obesity, diabetes mellitus, chronic hypertension, kidney disease, dyslipidemia-each diagnosed before or at time of delivery; as well as newly diagnosed coronary artery disease or congenital heart disease arising ≥ 1 day after the index delivery. RESULTS: After a median follow-up of 10.5 and 14.0 years, respectively, there were 78 composite cardiac events (2.33 per 10,000 person-years) among women with prolonged first stage of labour vs 4114 events (2.30 per 10,000 person-years) among those without prolonged labour-a crude HR of 1.07 (95% confidence interval [CI], 0.86-1.34) and an adjusted HR of 1.09 (95% CI, 0.87-1.36). Women with prolonged second stage of labour had an adjusted HR of 0.86 (95% CI, 0.75-0.99) for the composite outcome. CONCLUSIONS: Women with prolonged labour do not appear to be at a higher short-term risk of cardiac outcomes.
BACKGROUND: There exist structural and physiological commonalities between myometrial and myocardial tissue, and each can become dysfunctional, such as in the presence of cardiometabolic factors. METHODS: This population-based cohort study was comprised of 1,608,720 women with ≥ 1 singleton hospital live birth at 24-41 weeks' gestation in Ontario, from 1992 to 2016. The main exposure was prolonged first stage of labour; secondary exposure was prolonged second stage of labour. The main outcome was a composite of heart failure, cardiomyopathy or dysrhythmia ≥ 1 day after the index delivery. Cox proportional hazard regression was used to generate a hazard ratio (HR), adjusted for maternal age, parity, obstructed labour or fetal malposition, preeclampsia, income quintile, rural residence, preterm birth, and infant birth weight-each at the time of delivery; time-varying drug/tobacco use, obesity, diabetes mellitus, chronic hypertension, kidney disease, dyslipidemia-each diagnosed before or at time of delivery; as well as newly diagnosed coronary artery disease or congenital heart disease arising ≥ 1 day after the index delivery. RESULTS: After a median follow-up of 10.5 and 14.0 years, respectively, there were 78 composite cardiac events (2.33 per 10,000 person-years) among women with prolonged first stage of labour vs 4114 events (2.30 per 10,000 person-years) among those without prolonged labour-a crude HR of 1.07 (95% confidence interval [CI], 0.86-1.34) and an adjusted HR of 1.09 (95% CI, 0.87-1.36). Women with prolonged second stage of labour had an adjusted HR of 0.86 (95% CI, 0.75-0.99) for the composite outcome. CONCLUSIONS:Women with prolonged labour do not appear to be at a higher short-term risk of cardiac outcomes.