PLACENTAL AND DECIDUAL HISTOLOGY IN SPONTANEOUS-ABORTION - DETAILED DESCRIPTION AND CORRELATIONS WITH CHROMOSOME-NUMBER

Objectives: To determine the histopathology of failed pregnancy in cli nically symptomatic women with no more than one prior pregnancy loss i n order to provide baseline data, and to determine whether the histolo gy of the conceptus in spontaneous abortions could predict a normal or abnormal chromosome number. Methods: A review of all spontaneous abor tions from which karyotypes were obtained between 1984-1991 yielded 22 4 cases in which maternal history indicated no more than one prior spo ntaneous abortion, a reliable date of last menstrual period (LMP), and available villous (221) and/or decidual/implantation site (175) patho logy. Molar pregnancies were excluded. Results: Multivariate logistic regression analysis showed a significant relationship between chromoso me number and gestational age at loss as calculated from the LMP. Cons idering this confounder, a villous circulation indicating fetal life t o 11 or more weeks, chronic intervillositis and villous infarcts (each P < .01), and decidual vasculitis (P < .05) were more frequent in chr omosomally normal conceptions. Substituting possible variables into th e logistic regression equation yielded predictions ranging from 88% li kelihood of chromosomal abnormality to 97% likelihood of normal chromo some number. Conclusions: Histology can assist in assessing whether a spontaneous abortion is chromosomally normal or abnormal. There are ma ny pathologic findings seen in spontaneous abortions regardless of kar yotype; however, certain findings are more common in chromosomally nor mal abortions. These data provide a baseline for study of the histopat hology of habitual abortion.