(131) Database profile: EPI-MERES, a nationwide mother-child register built from the French National Health Data System (SNDS) for pregnancy and paediatric pharmacoepidemiological research
Background: Risks associated with exposure to medications during pregnancy, barely measurable during clinical trials, are of public health concern. Observational studies are crucial for pregnancy research and the secondary use of large healthcare databases is of growing interest.
Objectives: We describe the French national mother-child register EPI-MERES, set-up as a permanent tool facilitating the evaluation of medication use during pregnancy and its impact on both mother and child health outcomes.
Methods: Using data from the National Health Data System (SNDS), we established an unselected register of all pregnancies among females aged 12-55 ended from 2010 onwards in France, identified by diagnosis and procedures codes and linked to their offspring using deterministic algorithm. EPI-MERES is enriched through yearly updates with additional pregnancies, new-borns and child’s observation time. Data are currently available up to 2021. EPI-MERES contains a wide set of information on maternal (medical history, sociodemographic characteristics), pregnancies (start and end dates, pregnancy outcome, assisted reproduction, ultrasound scans, gestational diabetes and hypertension), and offspring (birth weight, outpatient and inpatient healthcare use, hospital and long-term diseases diagnosis) characteristics. Comprehensive information on medication exposure by gestation period is available based on reimbursement data.
Results: As of today, EPI-MERES includes a total of 12,170,915 pregnancies (median maternal age: 30 years). Of them, 8,848,645 (73%) ended in a delivery: 8,802,659 with a live birth (accounting for 98% of all live births recorded in France since 2010) and 45,986 with a stillbirth; and 2,336,652 (19%) were terminated (elective/therapeutic abortion). Among all live births, 94% were successfully linked to an identified child for a total of 8,529,397 infants included (median birth weight 3.3 kg, 6.3% born prematurely). Median follow-up from birth is 6.2 [IQR 3.2- 9.1] years. Among pregnancies ended in 2018-2019, 96% had at least one medication dispensed during pregnancy. The most common therapeutic classes dispensed were alimentary tract and metabolism (84%), blood and blood forming organs (72%), and nervous system (64%). Compared to 2010-2011, the share of exposed pregnancies was unchanged, though the total number of drugs dispensed decreased (6 versus 7, in median) and exposure to preventive drugs increased (doubled for iron and folic acid, quadrupled for vaccines).
Conclusions: EPI-MERES register is a large and powerful tool for drug safety research during pregnancy, notably regarding teratogenic risk and other serious adverse events among children exposed to medications in utero.