“False Positive” Noninvasive Prenatal Testing Result? Consider Maternal Malignancy

Not long after the introduction of noninvasive prenatal testing (NIPT) for fetal aneuploidy, case reports emerged of women with false-positive NIPT results (positive aneuploidy screens but normal fetal karyotypes) in whom malignancies were diagnosed during or after pregnancy; presumably, circulating apoptotic maternal cancer cells contributed to these abnormal chromosome proportions. In an industry-funded study, investigators examined >125,000 NIPT samples for incidental malignancy diagnoses.

Among 3757 samples (3%) that screened positive for aneuploidies (involving chromosome 13, 18, 21, X, or Y), 10 maternal cancers were diagnosed (including lymphoma, uterine sarcoma, and colorectal cancer) in asymptomatic women a mean of 16 weeks after th…