Prevalence of developmental and inflammatory lesions in nonmolar first-trimester spontaneous abortions

The management of patients with first-trimester spontaneous abortions is ha ndicapped by two problems: difficulty in recognizing conceptions that abort because of abnormal karyotypes and an incomplete understanding of what cau ses abortions with normal karyotypes, Our goals in this study were to defin e features useful in distinguishing normal from abnormal karyotype and to i dentify pathological processes contributing to abortions with a normal kary otype. The study population consisted of 668 well-characterized first-trime ster spontaneous abortions derived from a larger study of 1,054 consecutive ly karyotyped spontaneous abortions. Clinical factors increased in specimen s with normal karyotype were maternal age younger than 20 years (P=.0003) a nd autoimmune markers (P=.0474). Developmental features associated with abn ormal karyotype were developmental stage less than 6 weeks (P=.0017), hydro pic villi greater than 1 mm (P=.0004), and villi with two or more dysmorphi c features (P=.0001), Developmental stage greater than 11.5 weeks was incre ased with normal karyotype (P=.0001), Histological features increased in sp ecimens with a normal karyotype were chronic intervillositis (P=.0003), inc reased perivillous fibrin deposition with intermediate trophoblast (P=.0006 ), decidual plasma cells (P=.0040), deciduitis without plasma cells (P=.066 0), and chronic villitis (P=.1581). Overall, 19% of samples with a normal k aryotype versus 8% with abnormal karyotype had one or more of these finding s (P<.0001), Autoimmune markers, chronic intervillositis, and increased per ivillous fibrin with intermediate trophoblast all had positive predictive v alues greater than 85% for normal karyotype, whereas dysmorphic villi had a positive predictive value of 90% for abnormal karyotype, Patients with rec urrent spontaneous abortion and normal karyotype were more likely to have o ne or more of the histological features listed above (31%) than patients wi th normal karyotype and no prior abortions (13%) and patients with recurren t abortion and abnormal karyotype (11%), HUM PATHOL 30:93-100, Copyright (C ) 1999 by W.B. Saunders Company.