New blood test predicts dangerous condition in pregnant women
In a new blood test, scientists examine "chemical tags" on top of DNA to predict the likelihood of developing pre-eclampsia.The blood test, done at the end of the first trimester of pregnancy, helps identify patients at the highest risk of pre-eclampsia. This is a potentially life-threatening condition associated with high blood pressure during pregnancy.
The test helps "look at" the DNA floating in the blood during pregnancy. Doctors are already collecting it to perform non-invasive prenatal screenings, tests used to check if a fetus has extra or missing chromosomes.
This free-floating DNA emerges from dying cells in the body. If a woman is pregnant, the fraction comes from the placenta, so it is useful. Scientists developed the new blood test given the previously proven link between it and the condition of the placenta.
"We do not see the test as something that should be used independently of all others, but rather as a complement," the scientists wrote of the new blood test, which was described in a report published in Nature Medicine.
The scientists analyzed cell-free DNA previously collected from nearly 500 pregnant women. About one-third of the women in the study developed early-onset preeclampsia, which develops before the 34th week of pregnancy. Both at the time of diagnosis and several weeks before, women with preeclampsia had different DNA methylation patterns than controls. These differences were attributed to cell-free placental DNA rather than other cell types.