A Rhesus negative woman may experience stillbirth of the second child that is Rhesus positive because

Step 1: Analyze the question The question is about Rhesus incompatibility (Rh factor) between a Rh-negative mother and a Rh-positive baby, and why this can cause stillbirth in a second pregnancy.

Step 2: The concept

• The Rh factor is an antigen on the surface of red blood cells. Rh-positive people have it; Rh-negative people don't.
• First pregnancy: During childbirth, some of the Rh-positive baby's blood can enter the Rh-negative mother's bloodstream. Her immune system sees the Rh antigen as foreign and makes anti-Rh antibodies.
• Second pregnancy: If the next baby is also Rh-positive, the mother's anti-Rh antibodies cross the placenta into the foetus's blood. They attack the foetal red blood cells, causing agglutination (clumping) and destruction of the cells (haemolysis). This is called haemolytic disease of the newborn (erythroblastosis fetalis). The foetus becomes severely anaemic and can die, which results in stillbirth.

Step 3: Check the options

• A. Nourishment is not the issue. The placenta still functions. ✗
• B. Poor circulation is not the cause. ✗
• C. The foetal blood clumps because of the mother's antibodies. ✓
• D. The problem isn't general susceptibility to disease. It is a specific antigen-antibody reaction. ✗

Step 4: Answer The correct option is C: the blood of the foetus might clump.

Tip: Remember "Rh- mother, Rh+ baby, second child is at risk." The first baby sensitises the mother (antibodies form), and the second baby faces the attack. Link the keyword antibodies → agglutination (clumping). Today, doctors give Rh-negative mothers an anti-D injection after the first birth to prevent this.