Table.

Summary of currently used data sources for research of medication safety in pregnancy, with strengths, limitations, and possible improvements

Data source	Example	Strengths	Limitations	Ways to improve
Spontaneous case reports	Vigibase¹²	Early signal detection	Stimulated reporting bias; lack of data harmonization across systems; does not include non-cases	Standardize case report forms across reporting systems
Teratology Information Services	European Network of Teratology Information Services (ENTIS)¹⁴	Early signal detection	Stimulated reporting bias; small sample size	Pool data across Teratology Information Services centers
Case-control studies using primary data	National Birth Defects Prevention Study (NBDPS)¹⁹	Excellent detail on specific birth defects; often highly detailed exposure and confounder data, including genetic and other biological data	Retrospective exposure reporting may induce information bias; limited data on other pregnancy outcomes not used in the creation of the case-control studies	Nest case-control studies in larger population registries; verify exposure data from other sources
Birth cohort studies using primary data	Norwegian Mother and Child Cohort Study (MoBa)²²	Highly detailed data, including confounders, over-the-counter drugs, genetic and other biological data	Selection bias; small sample size	Link multiple cohorts; nest cohorts in larger population registries
Studies that repurpose existing data	Medicaid Analytic eXtract (MAX)⁴⁰	Sample size; representative sample of the population	Minimal measurement of some important confounders; short follow-up period for some data sources	Augment with linkage to other data sources, such as birth certificates or other population registries