Perinatal pharmacoepidemiology: How often are key methodological elements reported in publications?

Purpose: Publications provide important information for clinicians, researchers, and patients. Key methodological elements must be reported for maximum transparency. We identified key methodological elements necessary for fully understanding perinatal pharmacoepidemiology research and quantified the proportion of studies that reported these elements in a sample of publications.

Methods: Key methodological elements were identified from guidelines from regulatory agencies, literature, and subject-matter knowledge: source of information to determine pregnancy start; mother- or father-infant linkages (process, success rate); unit of analysis; and whether non-live births and fetuses with various anomalies were included in the study population. We conducted a literature review for recent observational studies on medical product utilization or safety during pregnancy and estimated the prevalence of reporting these elements.

Results: Data were extracted from a random sample of 100 publications; 8% were published in epidemiology/pharmacoepidemiology journals; 85% were medical product-safety studies. Of publications for which each element was applicable, 43% reported the source for determining pregnancy start; 57%, whether the study population included multifetal pregnancies; 39%, whether it included more than one pregnancy per woman; 27%, whether it included fetuses with chromosomal abnormalities; 60%, fetuses with major congenital malformations; and 93%, non-live births. Of the 20 studies with mother-infant linkage, 35% described the process; 21% reported the linkage success rate. Among studies with more than one pregnancy/offspring per woman, 22% reported methods addressing sibling correlation.

Conclusions: In this sample of pregnancy-related pharmacoepidemiology publications, completeness of reporting could have been improved. A pregnancy-specific checklist would increase transparency in the dissemination of study results.