A novel test could enable the diagnosis of hemolytic disease of the fetus and newborn (HDFN) without blood extraction through the fetal umbilical cord, thus preventing the complications associated with this procedure, according to a recently published study in Nature’s Journal of Perinatology.
Currently, the method of choice to diagnose HDFN during pregnancy is blood sampling through cordocentesis, an invasive procedure that involves inserting a needle in the mother’s abdominal area to reach the umbilical cord.
Due to adverse effects associated with cordocentesis, such as infections and early delivery, there is an interest in developing risk-free alternatives with high diagnostic accuracy. Based on the fact that an increased carbon monoxide (CO) level measured in exhaled breath is used to diagnose hemolysis in infants, the authors attempted to assess whether CO measured in maternal breath could diagnose fetal HDFN.
The method was tested in five women in the third trimester of pregnancy with a confirmed HDFN diagnosis. Researchers found that exhaled CO levels increased in all five women and decreased shortly after delivery.
The sampling was performed with a nasal cannula, a lightweight elastic tube with two small prongs inserted into the nostrils. The procedure lasted less than two minutes, and none of the women reported feeling any discomfort during the procedure.
Although the results of this study appear promising, more studies with larger samples should be made to assess the accuracy of the method before its widespread use is recommended, the authors wrote.
“Considerably more work remains to be done before we know if this technology could inform perinatal care,” the authors wrote. “However, at this early point we are convinced it is highly feasible and very acceptable to pregnant patients.”
HDFN occurs when the fetal red blood cells responsible for oxygen transport break down before birth, which leads to anemia and the elevation of a toxic byproduct of hemoglobin production called bilirubin, which is extremely dangerous for the newborn.
