Preterm labor: placental pathology and clinical correlation.

Abstract

To determine the relevance of ischemia in the incidence of preterm labor. A second objective was to document perinatal outcomes for patients with preterm labor classified according to its clinical, functional, and pathologic characteristics (infectious, ischemic, mixed, or idiopathic). Perinatal outcomes were evaluated for 145 consecutive patients with preterm labor, subdivided into etiologic categories according to clinical, functional (Doppler), and morphologic (placental pathology) characteristics. A group of 44 normal pregnancies delivered at term served as controls. Of the preterm labor group, 28.3% were classified as ischemic, compared with 4.5% of the control group (odds ratio and 95% confidence interval = 8.28 [1.8, 51.8]; P < .05). Compared with the control group, the preterm labor patients who delivered preterm had higher rates of ischemia (31.4% compared with 4.5%; P < .05) and infection (16.1% compared with 2.3%; P < .05). Among the preterm labor group, patients classified in the infectious or ischemic subgroups had a higher rate of preterm delivery (95.0% and 90.2% compared with 73.2%; P < .05), admission to the neonatal intensive care unit (75.0% and 61.0% compared with 40.0%; P < .05), and newborn weight under 1500 g (35.0% and 19.5% compared with 3.7%; P < .05) than the idiopathic subgroup. Preterm labor resulting from infection or ischemia is associated with a higher perinatal complication rate than idiopathic preterm labor.