O-218 Symptoms and signs of adenomyosis according to the revised MUSA criteria in 375 women with pregnancy loss and known ploidy of the pregnancy loss

Abstract Study question • Does adenomyosis increase risk of euploid pregnancy loss (PL)? • Is there a correlation of euploid PL and direct and/or indirect features of adenomyosis? Summary answer No increased risk of euploid PL was observed in women with ultrasonographic signs of adenomyosis according to the revised MUSA (Morphological Uterus Sonographic Assessment) criteria. What is known already Adenomyosis is defined by benign invasion of the endometrium into the myometrium and disruption of the uterine anatomy. Diagnosis by histology is the gold standard, usually after hysterectomy. Recently, focus on non-invasive diagnostics has increased with the revised MUSA criteria for using transvaginal ultrasound for the diagnosis of adenomyosis. The impact of adenomyosis on fertility is conflicting as current literature range from showing no effect to lower live birth rates after in vitro fertilization and increased risk of PL in women with adenomyosis. Study design, size, duration The included patients are from an ongoing prospective cohort study in Denmark focused on PL from year 2020-2025, n = 2800. In a random sample of 375 women, two trained sonographers conducted a retrospective analysis of 3D ultrasound uterine volumes without Doppler. A questionnaire on physical health symptoms was answered 14 days after the pregnancy loss including questions on menstrual pain Participants/materials, setting, methods Women were included at the time of PL diagnosis. The ploidy status of the fetus, aneuploid or euploid, was determined using cell free fetal DNA analysis or direct sequencing of fetal tissue. 3D ultrasound uterine volumes without Doppler were performed four to eight weeks post-pregnancy loss. The revised MUSA-criteria were applied to describe adenomyosis by 3D ultrasonography by two sonographers. Main results and the role of chance Women in the cohort were aged 20-45 years, with a mean BMI of 23.7 and with a mean gestational age of 9.3 weeks at time of the PL. In the evaluated 375 3D ultrasonographic scans, we did not observe any significant difference in the amount of direct and indirect MUSA features between women with euploid and aneuploid PL. Women with two or more PLs had a higher prevalence of irregular (OR = 1.57, p = 0.04) and disrupted junction zones (OR = 1.63, p = 0.03), compared to women with only one PL. Globular uterus tended to be more frequent in women with more than one PL (OR 1.7, p = 0.09), however insignificantly. Higher cumulative number of MUSA features was associated with higher age of the women, r-value 0.16 (p = 0.001). Women with severe menstrual pain more often experienced euploid PL, OR 1.44 (p = 0.03). Limitations, reasons for caution The 3D-volumes were without Doppler, resulting in unassessed translesional vascularity, risking underestimating the effect of adenomyosis. Wider implications of the findings Junctional-zone changes are more frequent in women with more than two PLs, indicating that changes in the junctional zone could be involved in the pathogenesis of some PL increasing the recurrence risk. The amount of direct and indirect MUSA features were comparable in women with euploid vs. aneuploid PL. Trial registration number No