Incidental Identification of Molar Pregnancy During Maternal Cell Contamination Testing

Abstract Maternal cell contamination (MCC) testing ensures accuracy in prenatal genetic diagnosis by comparing maternal and fetal short tandem repeat (STR) profiles. Occasionally, MCC patterns reveal rare abnormalities such as triploidy and molar pregnancy. We summarize cases where homozygous paternal-only STR alleles indicated a complete molar pregnancy, confirmed by chromosomal microarray analysis. This demonstrates the additional diagnostic potential of MCC testing beyond its routine purpose.