What blood test is essential to determine a pregnant individual's blood group or rhesus factor?

The essential blood test to determine a pregnant individual's blood group and Rhesus factor is antibody screening. This test is crucial during pregnancy because it helps identify any potential Rh incompatibility between the mother and fetus. If a mother is Rh-negative and the fetus is Rh-positive, this can lead to hemolytic disease of the newborn, which can be serious or even life-threatening. The antibody screening looks for the presence of specific antibodies in the mother’s blood, helping healthcare providers manage and monitor potential risks and complications effectively.

The other tests mentioned, while important for different aspects of maternal and fetal health, do not specifically assess blood group or Rhesus factor. A haemoglobin test focuses on the oxygen-carrying capacity of blood and diagnosing anemia, a blood glucose test monitors levels to assess for gestational diabetes, and a Hepatitis B test screens for the presence of the virus, which can affect both the mother’s and baby’s health, but none provide information about blood type or Rhesus factor.