Placental vascular pathology findings and pathways to preterm delivery

Abstract

The authors examined the associations between placental vascular findings and preterm delivery in 1,053 subcohort women (239 preterm, 814 term) from a Michigan pregnancy cohort study (1998-2004). Twenty-nine placental vascular variables from microscopic examinations were grouped into 5 constructs: 3 maternal constructs - obstructive lesions (MV-O), bleeding/vessel integrity (MV-I), and lack of physiologic conversion of maternal spiral arteries (MV-D) - and 2 fetal constructs - obstructive lesions (FV-O) and bleeding/vessel integrity (FV-I). Construct-specific scores were created by adding the number of positive findings and deriving a dichotomous variable to approximate the top quintile ("high") and bottom 4 quintiles ("not high") within each construct. In multivariate polytomous logistic regression models, medically indicated preterm delivery at <35 weeks was significantly associated with high scores for each of the vascular constructs; adjusted odds ratios ranged from 2.4 to 5.4. Spontaneous preterm delivery at 35-36 weeks was significantly associated with a high score on any 1 of 3 constructs: MV-I, MV-D, and FV-I. Spontaneous preterm delivery at <35 weeks was significantly associated with a high score on 2 or more of 3 constructs: MV-I, MV-D, and FV-I; adjusted odds ratios ranged from 4.1 to 7.4. These results support a role for various placental vascular lesions in medically indicated and spontaneous preterm delivery.