FETOPLACENTAL HISTOLOGY AS A PREDICTOR OF KARYOTYPE - A CONTROLLED-STUDY OF SPONTANEOUS FIRST-TRIMESTER ABORTIONS

It has been suggested that inferences about fetal karyotype can be mad e from examination of placental and decidual histology in early, spont aneous abortions (SABs). We assessed the reproducibility and predictiv e value of histologic features in 75 karyotyped, first trimester SABs; 32% (24 of 75) had normal male karyotypes (46,XY) and 68% (51 of 75) were cytogenetically abnormal (29 trisomy, 12 triploidy, eight monosom y X, and two tetraploidy). Three pathologists independently assessed 1 7 fetal, placental, and decidual histological findings and made predic tions about the karyotype (normal, abnormal, or uncertain). Good to ex cellent interobserver and intraobserver reproducibility (K > 0.58) was achieved for the identification of five histological features: villou s cavitation, anucleate fetal erythrocytes, amnion, umbilical cord, an d fetal tissue. When histology and karyotype were compared using Fishe r's exact test, no histological feature was associated with ''any abno rmal karyotype,'' two features (anucleate, fetal erythrocytes and umbi lical cord) were associated with a normal karyotype, two features (vil lous dysmorphism and cisterns) were associated with triploidy, and fou r features (villous hydrops, no umbilical cord, no fetal tissue, and n o anucleate erythrocytes) were associated with trisomy. Despite these significant histological-cytogenetic associations, the positive predic tive values of each of these histological features with their correspo nding karyotypes were low, ranging- from 0.41 to 0.73 (mean, 0.53). Ou r data suggest that certain histological features in first trimester S ABs are associated with the SAB's karyotype and are reproducible; howe ver, such histological features did not perform as well as diagnostic tests for predicting the likelihood of normal versus abnormal karyotyp e. Copyight (C) 1995 by W.B. Saunders Company