Cell-Free DNA as an Addition to Ultrasound for Screening of a Complete Hydatidiform Mole and Coexisting Normal Fetus Pregnancy: A Case Report

Background Complete hydatidiform mole and coexisting normal fetus pregnancies (CHMCF) are rare and can be life-threatening to the mother. Definitive diagnosis can be made with chorionic villus sampling or amniocentesis. However invasive procedures carry a risk of bleeding. We present the case of a twin molar pregnancy where a cell-free DNA screening test was utilized to evaluate for CHMCF pregnancy. Case A patient presented at 15-week gestational age with suspected CHMCF pregnancy. Ultrasound revealed a normal-appearing pregnancy abutting a multicystic lesion concerning for a complete mole. Cell-free DNA was obtained and was suggestive of complete paternal uniparental disomy. Pathological evaluation of the products of conception confirmed the diagnosis of CHMCF. Conclusion In atypical cases, cell-free DNA may be useful in evaluation of molar pregnancy.