Reza Omani-Samani1, Mohammad A Mansournia2, Mahdi Sepidarkish1, Amir Almasi-Hashiani1, Saeid Safiri3, Samira Vesali1, Payam Amini1, Saman Maroufizadeh1. 1. Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran. 2. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. 3. Managerial Epidemiology Research Center, Department of Public Health, School of Nursing and Midwifery, Maragheh University of Medical Sciences, Maragheh, Iran.
Abstract
OBJECTIVE: To evaluate associations between a history of spontaneous abortion and preterm delivery during subsequent pregnancies. METHODS: The present secondary analysis included cross-sectional survey data related to all deliveries at 103 hospitals in Tehran, Iran, between July 6 and 21, 2015. Trained midwives interviewed patients within 24 hours of delivery. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to investigate associations between spontaneous abortion and preterm delivery. RESULTS: Data were included from 4991 deliveries. A history of spontaneous abortion (OR 1.50, 95% CI 1.21-1.87; P=0.001) and history of recurrent spontaneous abortion (OR 3.74, 95% CI 1.90-7.37; P=0.001) were associated with increased odds of preterm delivery in comparison with no such history. Similarly, one (OR 1.33, 95% CI 1.04-1.70; P=0.023), two (OR 1.78, 95% CI 1.15-2.74; P=0.009), or at least three prior spontaneous abortions (OR 4.10, 95% CI 2.08-8.08; P=0.001) were associated with increased odds of preterm delivery compared with none. Population attributable fractions of 9.49% (95% CI 3.36-15.12) and 2.00% (95% CI 0.57-3.56) were calculated for histories of spontaneous abortion and recurrent pregnancy loss, respectively. CONCLUSION: History of spontaneous abortion and history of recurrent pregnancy loss were associated with increased odds of preterm delivery. A greater number of spontaneous abortions corresponded to greater odds of preterm delivery.
OBJECTIVE: To evaluate associations between a history of spontaneous abortion and preterm delivery during subsequent pregnancies. METHODS: The present secondary analysis included cross-sectional survey data related to all deliveries at 103 hospitals in Tehran, Iran, between July 6 and 21, 2015. Trained midwives interviewed patients within 24 hours of delivery. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to investigate associations between spontaneous abortion and preterm delivery. RESULTS: Data were included from 4991 deliveries. A history of spontaneous abortion (OR 1.50, 95% CI 1.21-1.87; P=0.001) and history of recurrent spontaneous abortion (OR 3.74, 95% CI 1.90-7.37; P=0.001) were associated with increased odds of preterm delivery in comparison with no such history. Similarly, one (OR 1.33, 95% CI 1.04-1.70; P=0.023), two (OR 1.78, 95% CI 1.15-2.74; P=0.009), or at least three prior spontaneous abortions (OR 4.10, 95% CI 2.08-8.08; P=0.001) were associated with increased odds of preterm delivery compared with none. Population attributable fractions of 9.49% (95% CI 3.36-15.12) and 2.00% (95% CI 0.57-3.56) were calculated for histories of spontaneous abortion and recurrent pregnancy loss, respectively. CONCLUSION: History of spontaneous abortion and history of recurrent pregnancy loss were associated with increased odds of preterm delivery. A greater number of spontaneous abortions corresponded to greater odds of preterm delivery.