Embryoscopic and cytogenetic analysis of 233 missed abortions: factors involved in the pathogenesis of developmental defects of early failed pregnancies

TLDR

Missed abortions are frequently caused by chromosomal abnormalities, but other developmental defects may also play a role and can be detected by transcervical embryoscopy. The study aims to correlate morphological and cytogenetic findings in spontaneous abortion specimens to improve genetic counseling and prenatal care for couples with recurrent pregnancy loss. In 272 patients, transcervical embryoscopy was performed before curettage, followed by cytogenetic analysis of chorionic villi using G‑banding or comparative genomic hybridization with flow cytometry; successful embryo visualization occurred in 233 cases and karyotyping in 221. Among 233 examined cases, 75 % had abnormal karyotypes, 18 % displayed morphological defects despite normal karyotypes, and 7 % showed no detectable abnormalities, with a spectrum of defects including holoprosencephaly, anencephaly, spina bifida, and limb anomalies.

Abstract

While chromosomal abnormalities are often the cause of missed abortions, other defects could be involved, which might be screened for by transcervical embryoscopy.A total of 272 patients with missed abortion underwent transcervical embryoscopy prior to dilatation and curettage, together with cytogenetic analysis of chorionic villi, using either standard G-banding cytogenetic techniques or comparative genomic hybridization in combination with flow cytometry analysis.Visualization of the embryo or early fetus (12 cases) was successful in 233 patients, and karyotyping in 221. Among 233 examined cases, 33 had normal external features, 71 were classified as growth-disorganized and 129 had either isolated or multiple defects, including holoprosencephaly, anencephaly, encephalocele, spina bifida, microcephaly, facial dysplasia, limb reduction defect, cleft hand, syndactyly, pseudosyndactly, polydactyly, various forms of cleft lip and an amniotic adhesion. Of the 165 cases with an abnormal karyotype, there were 46 grossly disorganized embryos, 98 multiple defects, six single defects and 15 morphologically normal cases. Of the 56 cases with a normal karyotype, there were 20 grossly disorganized embryos, 16 multiple defects, four single defects and 16 morphologically normal cases.A total of 75% of the cases with missed abortion had an abnormal karyotype, 18% had a morphological defect with a normal karyotype, while no embryonic or chromosomal abnormality could be diagnosed in 7% of the cases. Correlation of morphological and cytogenetic findings in spontaneous abortion specimens could provide valuable information for genetic counselling and prenatal care in future pregnancies in couples with a history of repeated pregnancy loss.