PURPOSE OF REVIEW: The purpose of this review is to critically evaluate the strengths and limitations of different data sources for pregnancy-related research in patients with rheumatic diseases. We describe challenges in studying adverse pregnancy outcomes in the setting of observational research, with a particular focus on the studies of maternal drug exposures. RECENT FINDINGS: We discuss potential threats to validity in the assessment of exposure and outcomes and controlling for confounding; present findings from selected pregnancy-related observational studies conducted using data from registries and health plans; and highlight future research opportunities for pregnancy research. SUMMARY: Registry and health plan data contribute complementary information to each other. Used together, linked data sources may allow clinicians, researchers, and patients to obtain a more complete understanding of the risk and benefits associated with maternal drug exposure and of the risk factors associated with adverse birth outcomes in women with rheumatic disease. © 2014 Wolters Kluwer Health.