The Prevalence and Clinical Impact of Adenomyosis in Pregnancy-Related Hysterectomy

Background: The epidemiology of adenomyosis has been traditionally based on patients undergoing hysterectomy for gynecological indications, while its prevalence among hysterectomies performed for obstetric complications is unknown. The aim of this study was to assess the prevalence and clinical impact of adenomyosis diagnosed through histology among women undergoing pregnancy-related hysterectomy (PH). Methods: This was a retrospective cohort study. Women who delivered at a tertiary care regional obstetric hub in Milan between 2009 and 2020 were reviewed to identify cases of PH. Histopathological reports of surgical specimens were examined. Cases with adenomyosis were compared to those without adenomyosis for baseline characteristics, obstetric history and outcomes. Results: During the study period there were 71,061 births and a total of 130 PH, giving a PH incidence of 1.83 per 1000 deliveries. Adenomyosis cases were 18, giving a prevalence of 13.8%. Adenomyosis was associated with placenta previa (77.8 vs. 45.5%, p = 0.01), chorionamnionitis (27.8 vs. 5.4%, p = 0.008), lower gestational age at birth (32 ± 4.6 vs. 35.5 ± 3.6 weeks’ gestation, p = 0.0004), and intrauterine fetal demise among twin pregnancies (50 vs. 4.5%, p = 0.048). Conclusion: Adenomyosis entails a relevant impact on obstetric and perinatal outcomes related to PH. More evidence is needed on the clinical relevance of an ultrasonographic diagnosis of adenomyosis before conception.