Identification of disproportionate reporting signals for ectopic pregnancy in the FAERS database from 2004 to 2024: A...

Ectopic pregnancy (EP) is a serious obstetric complication with a rising global incidence, partly related to the increasing use of hormonal therapies and assisted reproductive technologies. Although structural abnormalities and infectious factors have been extensively studied, the reporting patterns of EP involving specific drugs remain insufficiently characterized in large spontaneous reporting systems. Previous studies have been limited by small sample sizes and heterogeneous designs, and potential drug-related EP reporting signals have not been comprehensively evaluated.

This retrospective real-world pharmacovigilance study used data from the FDA Adverse Event Reporting System (FAERS), covering reports submitted from the first quarter of 2004 (2004Q1) to the fourth quarter of 2024 (2024Q4). After deduplication, drug names were standardized using RxNorm and adverse event terms were standardized using MedDRA version 27.1. Reports involving EP-related coded terms were extracted. Disproportionality analysis using the reporting odds ratio and 95% confidence intervals was performed to evaluate drug-event reporting associations. Subgroup analyses were conducted according to drug class, indication, body weight, and time to onset. Weibull distribution modeling was applied to explore report-based temporal patterns of frequently reported drugs.

A total of 4924 EP reports were identified, predominantly among women of reproductive age, with 46.6% aged 24-35 years. Levonorgestrel, etonogestrel, and clomifene showed the strongest disproportionate reporting signals for EP. Sixteen drugs, including interferon beta-1a, mifepristone, and lamivudine, were identified as potential novel safety signals not described in product labeling. The distribution of signal-positive drugs varied across body weight strata, with montelukast and medroxyprogesterone showing notable reporting signals in higher-weight subgroups. Time-to-onset analysis identified both early failure and random failure reporting patterns, supporting the need for temporally tailored pharmacovigilance strategies.

This study identified disproportionate reporting signals for EP in a large spontaneous reporting database. These findings should be interpreted as hypothesis-generating pharmacovigilance observations rather than evidence of incidence, causal effects, or clinically confirmed risk differences. The results might help prioritize drug-event pairs for further evaluation and warrant validation in well-designed epidemiologic and clinical studies.