Endometriosis, especially mild disease: a risk factor for miscarriages

The miscarriage rate in women with endometriosis is increased compared to control women. It is highest in women with milder forms of endometriosis (e.g. superficial peritoneal lesions).

Volume 108, Issue 5, Pages 806–814.e2


Alexandra Sabrina Kohl Schwartz, M.D., Monika Martina Wölfler, M.D., Vera Mitter, M.Sc., Martina Rauchfuss, M.D., Felix Haeberlin, M.D., Markus Eberhard, M.D., Stephanie von Orelli, M.D., Bruno Imthurn, M.D., Patrick Imesch, M.D., Daniel Fink, M.D., Brigitte Leeners, M.D.



To investigate the prevalence of miscarriage in women with endometriosis (WwE) compared with disease-free control women (CW).


Cross-sectional analysis nested in a retrospective observational study (n = 940).


Hospitals and associated private practices.


Previously pregnant women (n = 268) within reproductive age in matched pairs.


Retrospective analysis of surgical reports and self-administered questionnaires.

Main Outcome Measure(s)

Rate of miscarriage, subanalysis for fertility status (≤12 vs. >12 months' time to conception), endometriosis stages (revised American Society of Reproductive Medicine classification [rASRM] I/II vs. III/IV) and phenotypic localizations (superficial peritoneal, ovarian, and deep infiltrating endometriosis).


The miscarriage rate was higher in WwE (35.8% [95% confidence interval 29.6%–42.0%]) compared with CW (22.0% [16.7%–27.0%]); adjusted incidence risk ratio of 1.97 (95% CI 1.41–2.75). This remained significant in subfertile WwE (50.0% [40.7%–59.4%]) vs. CW (25.8% [8.5%–41.2%]) but not in fertile WwE (24.5% [16.3%–31.6%]) vs. CW (21.5% [15.9%–26.8%]). The miscarriage rate was higher in women with milder forms (rASRM I/II 42.1% [32.6%–51.4%] vs. rASRM III/IV 30.8% [22.6%–38.7%], compared with 22.0% [16.7%–27.0%] in CW), and in women with superficial peritoneal endometriosis (42.0% [32.0%–53.9%]) compared with ovarian endometriosis (28.6% [17.7%–38.7%]) and deep infiltrating endometriosis (33.9% [21.2%–46.0%]) compared with CW (22.0% [16.7%–27.0%]).


Mild endometriosis, as in superficial lesions, is related to a great extent of inflammatory disorder, possibly leading to defective folliculogenesis, fertilization, and/or implantation, presenting as increased risk of miscarriage.

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