incidence of and maternal-fetal risk factors associated with therapeutic abortion: a nested case-control design based on a population-based historical cohort

Background: therapeutic abortion (ta) has been defined as termination of pregnancy before the 20th week of gestation in order to save the mother’s life and prevent birth defects. the present study aimed to investigate the incidence of ta and its related maternal-fetal risk factors. methods: this historical cohort study reviewed 11000 birth records. among these reviewed records, 83 cases of ta were identified. then, for each case, three controls of live infants born in the same hospital on the same day were selected and matched for gestational age. we used a researcher-made questionnaire for data collection. results: the cumulative incidence of ta was computed 7.54 per 1000 live births. the results of multiple cox regression model revealed that four risk factors including male gender; parental consanguinity; maternal diseases including gestational hypertension, gestational diabetes mellitus, hypothyroidism, infertility, the use of in vitro fertilization (ivf) and urinary tract infection; and maternal medication consumption increased the risk of ta (all hazard ratios > 1: p<0.05). conclusion: for the first time, we assessed the incidence of ta through this population-based cohort study in iran. importantly, parental consanguinity was one of the predictors of ta revealed in this study. identification of the causes of ta would prevent the birth of infants with congenital anomalies.