Transcervical fetoscopic diagnosis of structural defects in four first-trimester monochorionic twin intrauterine...

While chromosomal abnormalities are often the cause of early failed pregnancies, other mechanisms could be involved in monochorionic twin intrauterine deaths, that might be screened for careful morphological analysis.

Transcervical fetoscopy prior to instrumental evacuation of the uterus was performed in four first-trimester monochorionic twin intrauterine deaths.

We present fetoscopic and cytogenetic findings in four cases of monochorionic twin intrauterine deaths. In the first, generalized abnormal embryonic development observed in both twins was a manifestation of trisomy 20. The second (thoracophagus) and third (acardius) pair of twins had anomalies peculiar to multiple gestations. The fourth pair of twins was remarkable because of the concordance for the observed limb-reduction defects.

Malformations of first-trimester monochorionic twin intrauterine deaths might cover a wide spectrum of etiologies from abnormal chromosomes and single gene defects to rare duplication anomalies. Their detection by careful morphological analysis and the identification of a specific mechanism provides valuable information for genetic counseling and prenatal investigation in a future pregnancy.