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doi: 10.1111/ppe.12180
97
Commentary
Infertility and Preterm Delivery: What Do We Know and Where Do We Go from Here? Lauren A. Wise Department of Epidemiology, Boston University School of Public Health Slone Epidemiology Center, Boston University, Boston, MA
In this issue of Paediatric and Perinatal Epidemiology, Messerlian and colleagues1 examine the association between infertility and risk of preterm delivery in a Canadian hospital-based cohort study. The study was unique in applying advanced analytic methods to separate total and direct effects of various causes of infertility on preterm delivery, not mediated through fertility treatment. This research question is of clinical importance because if infertility is indeed a cause of adverse birth outcomes such as preterm delivery, a simple assessment of attempt time among couples that are planning a pregnancy could help identify those at higher risk. Messerlian et al. found little evidence of a direct effect of the diagnosed causes of infertility (e.g. ovulatory disorder) on the risk of preterm delivery. They concluded that most of the excess risk of preterm delivery observed in the study population was explained by maternal characteristics and by the effects of fertility treatment, and not by infertility itself. They did, however, report some evidence of direct effects of ovulatory dysfunction, endotubal factor, and uterine abnormalities on preterm delivery, but data on these associations were too sparse for firm conclusions. This report is important because it is the only study to evaluate underlying causes of infertility in relation to preterm delivery. Earlier studies consistently documented a positive association between assisted reproductive technologies (ART) and risk of preterm delivery,2,3 but subsequent studies showed that infertility itself, independent of ART, was also associated with preterm delivery risk.4–10 In a 2012 meta-analysis of eight studies by Messerlian et al.,6 the pooled odds ratios for infertility [time-to-pregnancy (TTP) ≥12 vs.
doi: 10.1111/ppe.12180
97
Commentary
Infertility and Preterm Delivery: What Do We Know and Where Do We Go from Here? Lauren A. Wise Department of Epidemiology, Boston University School of Public Health Slone Epidemiology Center, Boston University, Boston, MA
In this issue of Paediatric and Perinatal Epidemiology, Messerlian and colleagues1 examine the association between infertility and risk of preterm delivery in a Canadian hospital-based cohort study. The study was unique in applying advanced analytic methods to separate total and direct effects of various causes of infertility on preterm delivery, not mediated through fertility treatment. This research question is of clinical importance because if infertility is indeed a cause of adverse birth outcomes such as preterm delivery, a simple assessment of attempt time among couples that are planning a pregnancy could help identify those at higher risk. Messerlian et al. found little evidence of a direct effect of the diagnosed causes of infertility (e.g. ovulatory disorder) on the risk of preterm delivery. They concluded that most of the excess risk of preterm delivery observed in the study population was explained by maternal characteristics and by the effects of fertility treatment, and not by infertility itself. They did, however, report some evidence of direct effects of ovulatory dysfunction, endotubal factor, and uterine abnormalities on preterm delivery, but data on these associations were too sparse for firm conclusions. This report is important because it is the only study to evaluate underlying causes of infertility in relation to preterm delivery. Earlier studies consistently documented a positive association between assisted reproductive technologies (ART) and risk of preterm delivery,2,3 but subsequent studies showed that infertility itself, independent of ART, was also associated with preterm delivery risk.4–10 In a 2012 meta-analysis of eight studies by Messerlian et al.,6 the pooled odds ratios for infertility [time-to-pregnancy (TTP) ≥12 vs.
