Endometriosis and Ectopic Pregnancy: A Meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational (cohort and case-control) studies
PubMed 31546066 · doi:10.1016/j.jmig.2019.09.778
What was done
A systematic review and random-effects meta-analysis was conducted across MEDLINE, Embase, CINAHL, and Cochrane Library (through April 1, 2019) for cohort and case-control studies evaluating endometriosis and ectopic pregnancy risk. Quality was evaluated using the Newcastle-Ottawa Scale (cutoff >= 7 for higher quality). Random-effects models calculated weighted estimated average odds ratios (OR), and heterogeneity was evaluated using the I2 metric.
What was found
Fifteen studies were analyzed: - 10 case-control studies (17,972 ectopic cases; 485,266 controls) showed an increased risk of ectopic pregnancy associated with endometriosis: OR 2.66 (95% CI 1.14–6.21, p = .02). - 5 cohort studies (30,609 women with endometriosis; 107,321 without) showed an overall OR of 0.95 (95% CI 0.29–3.11, p = .94). - In a post hoc analysis of cohort studies with Newcastle-Ottawa score >= 7, the association was significant: OR 2.16 (95% CI 1.67–2.79, p < .001). - Heterogeneity was high across case-control (I2 = 93.9%) and cohort studies (I2 = 96.6%, p < .001). Egger's test showed no significant publication bias (p = .35 and p = .70).
Why it matters
This review synthesizes observational evidence indicating that endometriosis may double the risk of ectopic pregnancy, supporting heightened clinical awareness during early gestation.
Limits
Between-study heterogeneity was extremely high (>93%). The primary pooled cohort estimate was null and only reached significance in a post hoc subgroup. Data were insufficient to analyze risk according to anatomical stage of endometriosis or conception method (spontaneous vs assisted reproductive technology).
Cited by
- supports Endometriosis and associated pelvic inflammation increase the risk of ectopic pregnancy and miscarriage.