Cancer clue in prenatal blood tests for expecting moms

New Delhi (The Uttam Hindu): Many expectant mothers opt for blood tests during pregnancy to screen for fetal conditions like Down syndrome, but a surprising discovery has emerged — these tests can sometimes uncover hidden cancers in the woman. A study of 107 pregnant women with unusual test results revealed that 52 were eventually diagnosed with cancer. Most of them were treated and are now in remission, although seven with advanced cancer unfortunately passed away. Dr. Diana Bianchi, senior author of the study, emphasized that these women appeared healthy and reported no symptoms.

Lymphoma, a blood cancer, was the most common, followed by colon and breast cancers. The blood test in question, called cell-free DNA sequencing, checks for fetal abnormalities by analyzing DNA fragments from the placenta that enter the mother's bloodstream. But it can also detect DNA from cancer cells. Each year, millions of pregnant women take this test, and about 1 in 10,000 may receive an inconclusive result—neither positive nor negative for fetal abnormalities. This small group, potentially only 250 women in the U.S. annually, faces a 48% risk of having cancer. “They must take the results seriously and undergo further testing,” Bianchi warns. The study recommends that these women undergo a whole-body MRI to detect cancer, as physical exams or family history alone are insufficient. While the test is widely used to screen for Down syndrome and other disorders, the finding raises new concerns. Experts like Dr. Neeta Vora highlight the need for doctors to understand this rare DNA result and emphasize that the costly whole-body MRI, which ranges from $1,000 to $2,000, may not be covered by insurance. This new revelation could reshape how doctors approach prenatal testing and cancer detection.