Histologic placental lesions in women with recurrent preterm delivery

Background. The aim of this study was to evaluate whether particular placental histopathology lesions are associated with recurrent preterm birth. Methods. We analyzed a database of 413 consecutive singleton pregnancies delivered at < 32 weeks with past reproductive history available. After the exclusion of nulliparous women, the pregnancies were divided according to the obstetrical history into group 1 (n = 328), women without prior preterm delivery (PTD); group 2 (n = 49), women with one prior preterm childbirth; and group 3 (n = 36), women with >= 2 prior preterm deliveries. Demographic and clinical variables were compared among the three groups by using Kruskal-Wallis test and chi-square test for trend. Finally, the individual placental lesions (i.e. 42 lesions of acute or chronic inflammation, uteroplacental vascular pathology, and intraplacental villous lesions) were correlated with the number of prior preterm deliveries by using regression analysis. A two-tailed P < 0.05 was considered significant. Results. No differences were found among the three groups in demographic or clinical variables. Regression analysis of scored placental lesions corrected for gestational age at delivery showed that the number of prior preterm deliveries was correlated only with chronic marginating choriodeciduitis (correlation coefficient = 0.13; P = 0.01) and acute choriodeciduitis (correlation coefficient = 0.14; P = 0.008). Conclusions. Among women delivered at < 32 weeks, those with prior preterm birth have histologic findings compatible with acute or chronic inflammatory involvement of the uterine cavity, suggesting that a prepregnancy endometrial infection rather than an ascending intrapregnancy pathway may be responsible for some recurrences of PTD.