Identifying women with indicators of subfertility in a statewide population database: operationalizing the missing link in assisted reproductive technology research

ObjectiveTo identify a group of deliveries to mothers with indicators of subfertility (SUBFERTILITY).DesignLongitudinal cohort study.SettingHospital.Patient(s)A total of 334,152 deliveries to Massachusetts mothers in a Massachusetts hospital between July 1, 2004, and December 31, 2008.Intervention(s)None.Main Outcome Measure(s)Subfertility was defined by an indication on a current or past birth certificate or hospital utilization data of infertility or assisted reproductive technology (ART) cycle before index delivery and no indication of ART use with index delivery.Result(s)Initially, 12,367 deliveries met the inclusion criteria for SUBFERTILITY (8,019 from birth certificates, 2,777 from hospital data, 1,571 from prior ART treatment). Removing deliveries from more than one data source resulted in 10,764 unique deliveries. Removing deliveries resulting from ART treatments left 6,238 deliveries in the SUBFERTILITY category. Demographic analysis indicated that deliveries in SUBFERTILITY were more similar to those in the ART population than to those in the fertile population.Conclusion(s)We have demonstrated the feasibility of using existing population-based linked public health data sets to identify SUBFERTILITY deliveries, and we have used ART data to distinguish ART and SUBFERTILITY births. The SUBFERTILITY category can serve as a comparison group of subfertile patients for studies of ART delivery and longitudinal health outcomes.