Temporal Patterns in Tubal Ectopic Pregnancy Worldwide: A Scoping Review

BACKGROUND: Ectopic pregnancy has been observed to follow temporal patterns. Despite nearly a century of documented trends, no standardized approach has been established to define, understand, or investigate these patterns. Doing so could provide insights into possible environmental, biological, or sociocultural factors driving these patterns. OBJECTIVE: This scoping review aimed to synthesize the evidence of temporal patterns in tubal ectopic pregnancy rates worldwide, assess the methodologies, and identify research gaps possibly hindering causal factors inquiry. METHODS: Following Joanna Briggs Institute guidelines, we searched EMBASE, MEDLINE, CINAHL, The Cochrane Library, Scopus, and Google Scholar in June 2024. Peer-reviewed studies, gray literature, and editorial sources reporting seasonal, monthly, or quarterly fluctuations in tubal ectopic pregnancy incidence in humans were considered without limitation to publication year. Study characteristics, analytic approaches, noted limitations, temporal trends, and hypotheses to explain those trends were extracted and summarized descriptively. RESULTS: Thirty-two studies spanning 18 countries, published between 1932 and 2022, met eligibility criteria. Many studies reported seasonal or monthly peaks, though findings were inconsistent worldwide. Data sources, incidence denominators, and methods for analyzing ectopic pregnancy temporal patterns were heterogenous. Studies used either the estimated conception date or diagnosis date as the timepoint of interest for analysis, a methodological difference that limited cross-study comparisons. CONCLUSIONS: There are significant methodological gaps in the study of ectopic pregnancy temporal patterns. To improve temporal analysis and generalizability, future research should use data sets that include outpatient records and conduct conception date-based analysis with universal units of time like weeks or months.