Am. Burgess et Gm. Hutchins, INFLAMMATION OF THE LUNGS, UMBILICAL-CORD AND PLACENTA ASSOCIATED WITH MECONIUM PASSAGE IN-UTERO - REVIEW OF 123 AUTOPSIED CASES, Pathology research and practice, 192(11), 1996, pp. 1121-1128
It is uncertain how often the passage of meconium in utero is a respon
se to some event causing fetal distress as opposed to being simply the
physiologic functioning of a maturing intestinal tract. The extent to
which meconium may produce injury or inflammation in pulmonary and pl
acental tissues after intrauterine exposure is also unclear. This stud
y was a retrospective review of 123 cases, 79 stillborn and 44 livebor
n less than one month of age, autopsied at The Johns Hopkins Hospital,
and showing histologic evidence of intrauterine meconium exposure by
aspirated meconium or meconium macrophages in placental tissues. Of 55
cases with pulmonary inflammation, 13 (24%) had fetal pneumonia, 5 (9
%) had postnatal bronchopneumonia, and 37 (67%) had inflammation secon
dary to meconium aspiration. There was inflammation of the umbilical c
ord in 31 (41%) of the 75 cases with available slides, 11 (15%) had fu
nisitis associated with chorioamnionitis and 18 (58%) were secondary t
o meconium exposure. There were 19 cases with focal injury of cord ves
sels from meconium, two of which had cord ulceration. Inflammation of
the membranes and chorionic plate was present in 24 (33%) of the 72 ca
ses where it could be assessed, and was due to chorioamnionitis in 11
(46%) and to meconium in 13 (54%). In general, meconium-related inflam
mation was much less severe in the membranes than in the cord. There w
ere 67 (54%) cases with definite or probable evidence of fetal distres
s. In 38 (48%) stillborns no cause of fetal death in utero was identif
ied and in 18 (41%) liveborns there was no known prenatal problem. The
results support the concept that meconium passage in utero may occur
either as a response to fetal distress or as a physiologic process. In
flammation in the lung and placental tissues, and vascular injury in t
he umbilical cord may arise secondary to in utero exposure to meconium
.