Causal Relationship Between Abortion and Endometriosis: A Bidirectional Two-Sample Mendelian Randomization Study

Yan Huang, Deyu Zhang, Yingfang Zhou, Chufang Peng
American journal of reproductive immunology (New York, N.Y. : 1989) · 2025 · vol. 93(3) , pp. e70064 · doi:10.1111/aji.70064 · PMID:40028715 · W4408161632
article OA: bronze CC0 ⤵ 1 in-corpus citation
🔓 Open OA copy View on OpenAlex View on PubMed View at publisher
⚙ AI-generated summary by claude@2026-06, 2026-06-07 ⓘ

This Mendelian randomization study found no causal relationship between medical, spontaneous, or other types of abortion and endometriosis, nor a causal effect of endometriosis on abortion likelihood.

One-sentence paraphrase of the abstract; not a substitute for reading it. No clinical advice. How this works

Abstract

PROBLEM: The relationship between abortion and endometriosis (EMS) has been inconsistent in previous observational studies and remains controversial. We intended to examine the causal relationship between abortion and EMS. METHODS OF STUDY: We conducted a Mendelian randomization (MR) analysis using genome-wide association study (GWAS) summary statistics, drawing data from the FinnGen database and the UK Biobank. The primary analysis utilized the random-effects inverse variance weighted (IVW) approach, complemented by weighted median, weighted mode, and MR-Egger methods. Comprehensive sensitivity analyses were conducted, encompassing the Cochran's Q statistic for assessing heterogeneity and MR-PRESSO to detect pleiotropy. Additionally, Leave-One-Out (LOO) analysis was conducted to confirm the stability of our results. RESULTS: The IVW method revealed no statistically significant causal association between various types of abortion and EMS. Specifically, the odds ratios (ORs) were as follows: medical abortion (OR 0.96, 95% CI: 0.78-1.18, p = 0.72), spontaneous abortion (OR 0.99, 95% CI: 0.81-1.21, p = 0.92), and other types of abortions (OR 1.01, 95% CI: 0.99-1.03, p = 0.36), indicating no significant effects on the risk of EMS. Similarly, analysis in the reverse direction showed no significant causal effects of EMS on the likelihood of experiencing any type of abortion, with ORs for medical abortion (0.97, 95% CI: 0.91-1.03, p = 0.33), spontaneous abortion (0.98, 95% CI: 0.92-1.04, p = 0.50), and other abortions (1.30, 95% CI: 0.76-2.23, p = 0.34). Sensitivity analyses supported these findings, demonstrating no evidence of horizontal pleiotropy or significant heterogeneity. CONCLUSION: Our MR results do not support a causal relationship between abortion and EMS.

My notes (saved in your browser only)

Condition tags

endometriosis

MeSH descriptors

Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous Abortion, Spontaneous

Citation neighborhood

Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. [ expand to 2 hops ] — adds papers reached through this work's immediate citers/citees. Heavier; up to 60 extra dots.

References (31)

Cited by (1)

Source provenance

europepmc
last seen: 2026-06-17T06:13:18.893374+00:00
openalex
last seen: 2026-06-10T17:14:06.276822+00:00
pubmed
last seen: 2026-06-17T06:10:18.838665+00:00
License: CC0 · commercial use OK