Adenomyosis and risk of preterm delivery

Objectives To evaluate the risk of preterm delivery in patients with adenomyosis. Design A 1:2 nested case-control study. Setting Tertiary-care institution. Population A base cohort population of 2138 pregnant women who attended routine prenatal check-up between July 1999 and June 2005. Methods From this base cohort population, gravid women with singleton pregnancy who delivered prior to the completion of 37 weeks of gestation were identified and formed the study group. Singleton gravid women who had term delivery and who matched with age, body mass index, smoking, and status of previous preterm delivery were recruited concurrently and served as control group. Preterm delivery cases were further divided into spontaneous preterm delivery and preterm premature rupture of membranes (PPROM) cases. Main outcome measures Risk analysis of preterm delivery between gravid women with and without adenomyosis. Results One-hundred and four preterm delivery case subjects and 208 control subjects were assessed. Overall, gravid women with adenomyosis were associated with significantly increased risk of preterm delivery (adjusted odds ratio 1.96, 95% CI 1.23-4.47, P = 0.022). For subgroup analysis, gravid women with adenomyosis had an adjusted 1.84-fold risk of spontaneous preterm delivery (95% CI 1.32-4.31, P = 0.012) and an adjusted 1.98-fold risk of PPROM (95% CI 1.39-3.15, P = 0.017). Conclusions Gravid women with adenomyosis were associated with increased risk of both spontaneous preterm delivery and PPROM. A common pathophysiological pathway may exist in these two disorders. Further in-depth biochemical and molecular studies are necessary to explore this phenomenon.