UTEROPLACENTAL PATHOLOGY AND MATERNAL ARTERIAL MEAN BLOOD-PRESSURE INSPONTANEOUS PREMATURITY

OBJECTIVE: To examine if maternal blood pressure is directly related t o the presence and severity of uteroplacental vascular pathology in no npreeclamptic preterm birth. METHODS: A set of consecutive nonanomalou s singleton live births delivered at 22-32 weeks (excluding maternal d iabetes mellitus and chronic hypertension) between 1989 and 1994 inclu ded 342 cases of spontaneous prematurity (spontaneous premature membra ne rupture [PROM], preterm labor with intact membranes [PTL], and nonh ypertensive abruption) with mean arterial blood pressure at admission available in the maternal record. Presence and extent of placental les ions were scored. RESULTS: Mean maternal arterial blood pressure on ad mission was significantly related to the presence/extent of uteroplace ntal vascular lesions (P = .01) and to lesions of intraplacental vaso- occlusion (P = .04). These associations were independent of maternal a ge and gestational age at delivery. Moreover, the summation of uteropl acental and intraplacental vascular lesions into a cumulative placenta l vascular pathology score was even more significantly correlated with increasing mean blood pressure at admission, suggestive of synergism between these two placental pathological processes. CONCLUSIONS: In no npreeclamptic prematurity, mean maternal admission blood pressure is d irectly related to the severity of placental vascular pathology. (C) 1 998 by the Society for Gynecologic Investigation.