An increasing number of pregnant women are undergoing noninvasive prenatal testing to help identify fetal genetic abnormalities. This is done using a blood test that looks at the DNA of both the mother and fetus. In a small percentage of these tests, the results appear abnormal, but the baby's genetics are later shown to be normal. A new study examined if the rare diagnosis of maternal cancer could be one cause of such discrepancies. The study is being released to coincide with its presentation at the 19th International Conference on Prenatal Diagnosis and Therapy in Washington, D.C.
Researchers at Tufts Medical Center in Boston examined more than 125,000 noninvasive prenatal test results over the course of a two year period. Approximately 3,800 women had abnormal test results, and ten of those women were subsequently diagnosed with cancer. Medical records and additional genetic information were examined in eight of those women to look for patterns suggestive of underlying cancer.
Based on the results of the study, researchers estimate there is between a twenty and forty-four percent risk of maternal cancer if an abnormal number of chromosomes are detected. Further studies are needed to fully understand the clinical implications of these discordant results.