Meconium-induced umbilical cord vascular necrosis and ulceration: a potential link between the placenta and poor pregnancy outcome

Abstract

The literature lacks epidemiologic study of pregnancy outcome with light-microscopic meconium-related lesions. We recently described previously unreported meconium-induced necrosis of placental and umbilical cord vessels and hypothesized that the lesions represent preceding vasocontraction and fetal hypoperfusion. Preliminary experiments then confirmed that meconium produces vasocontraction in isolated umbilical venous tissue. In the present study, we examined whether clinically meaningful abnormalities occur with these vascular signs of remote fetal meconium discharge. In a light-microscopic review of 1100 meconium-stained placentas, we found ten with meconium-induced vascular necrosis. In six of these ten cases, fetal distress necessitated cesarean delivery. Seven newborns had Apgar scores of 3 or less at 1 minute, and each of the seven cases tested had umbilical arterial pH less than 7.19. Because seven of the ten infants were born after December 1, 1989, clinical follow-up was limited. One died, another has neurodevelopmental deficiency, and a third has experienced enlargement of head circumference from the 50th percentile at birth to the 95th percentile at 10 months of age. Two placentas had umbilical cord ulceration, a lesion that has rarely been reported in the literature. We conclude that meconium-induced vascular necrosis seems to be a meaningful, detrimental lesion.