Evaluating the Safety of Medication Exposures During Pregnancy: A Case Study of Study Designs and Data Sources in Multiple Sclerosis

BACKGROUND Regulatory agencies often request prospective, product-specific post-authorization pregnancy exposure registries to monitor safety during pregnancy, even though studies using existing health databases could also be employed. OBJECTIVES Using multiple sclerosis (MS) as a case study, we evaluated various study designs and data sources previously used to study medication exposure in pregnancy. METHODS We examined (1) strengths and limitations of study designs used for pregnancy safety studies in women exposed to MS-specific medications during pregnancy and (2) existing data sources used to conduct such studies in other disease areas. For the data sources identified, we contacted data custodians to determine the feasibility of assessing the risk of adverse outcomes in women with MS exposed to disease-modifying therapies (DMTs) during pregnancy. RESULTS Of 43 MS-specific studies identified, most of which were prospective registries, very few, regardless of design and study population, produced timely and robust results for spontaneous abortions and major congenital malformations, considering study duration, achievement of target enrollment numbers, inclusion of internal comparators, and publication of results. Building on the successful use of existing healthcare databases to investigate drug safety during pregnancy in other disease areas, we identified 13 data sources that could be used to study intravenous DMT exposures in women with MS. CONCLUSIONS Prospective, treatment-specific registries have generally failed to deliver robust information. For this reason, other study approaches, in particular cohort studies using existing healthcare databases, should be considered for evaluating the safety of drug exposure in pregnancy, including in MS.