How adenomyosis changes throughout pregnancy: A retrospective cohort study

OBJECTIVE: To study how adenomyosis changes during pregnancy and to possibly correlate these changes to maternal and fetal outcomes. METHODS: Retrospective exploratory cohort study including 254 women with a pre‐conceptional/first‐trimester scan to document adenomyosis and known obstetric outcome. If visible, adenomyosis signs were documented in each trimester and postpartum. Mann–Whitney U tests or χ(2) tests were used for continuous and categorical variables, respectively. RESULTS: A globular uterus was reported in 79% (n = 52) of women with adenomyosis in the first trimester, in 38% (n = 20) and 2% (n = 1) of women in the second and third trimesters, respectively, and postpartum in 77% (n = 34) of women. Asymmetrical thickening (n = 20, 30%) and cysts (n = 15, 23%) were only visible in 1st trimester. Adenomyosis was associated with miscarriage (odds ratio [OR] 5.9, 95% confidence interval [CI] 2.4–14.9, P < 0.001) also in normal conception only (OR 5.1, 95% CI 1.8–14.2, P = 0.002) or adjusting for maternal age (adjusted OR 5.9, 95% CI 2.3–15.2, P < 0.001). Gestational age at delivery was lower in adenomyosis (P = 0.004); the cesarean section rate was higher than in controls (OR 2.5, 95% CI 1.3–4.8, P = 0.007) also adjusting for age (adjusted OR 2.07, 95% CI 1.06–4.08, P = 0.035). CONCLUSIONS: Signs of adenomyosis were visible but progressively disappeared in pregnancy; adenomyosis was associated with an increased risk of early miscarriage. Prospective studies are needed to confirm our results.