What increases the risk of Rh incompatibility in subsequent pregnancies?

• A. Increased maternal age
• B. Higher birth weights
• C. Severity increases with each subsequent pregnancy
• D. Presence of congenital anomalies

Answer: (C)

The risk of Rh incompatibility in subsequent pregnancies is significantly influenced by the sensitization process that occurs after a first pregnancy involving an Rh-positive fetus in an Rh-negative mother. When an Rh-negative mother carries an Rh-positive baby, the fetal Rh-positive red blood cells can enter the maternal circulation during pregnancy or delivery. This exposure can lead to the development of antibodies against the Rh factor.

In subsequent pregnancies, if the mother is again pregnant with an Rh-positive fetus, these pre-existing antibodies can cross the placenta. Their presence can lead to hemolytic disease of the newborn (HDN), which can become more severe with each subsequent pregnancy as the maternal immune response becomes increasingly aggressive due to the sensitization that has occurred.

This progressive risk is linked to the body's immune memory; each exposure to the Rh-positive blood can heighten the maternal immune response. Therefore, as the number of pregnancies increases and more sensitization occurs, the chances of severe Rh incompatibility complications also increase correspondingly.

Other options do not directly heighten the risk of Rh incompatibility in the same manner. Maternal age, birth weight of the infant, and congenital anomalies while having their own significance in prenatal care and outcomes, do not inherently increase the risk of developing antibodies or the