WAEC Biology 2023 Objective — Question 42
Question 42 of 50 from the West African Examinations Council (WAEC) Biology 2023 Objective paper, with the correct answer and a full explanation.
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A Rhesus negative woman may experience stillbirth of the second child that is Rhesus positive because
- A. the woman is susceptible to diseases during pregnancy
- B. the blood of the foetus might clump, as they have a poor circulatory systemCorrect
- C. the foetus is deprived of nourishment
- D. (option D not clearly legible in the source scan)
Explanation
Rh-antibodies are not harmful until the second or later pregnancy. If the baby is Rh-negative just like the mother, there is no issue. However, if the baby (foetus) is Rh-positive, the mother's Rh-antibodies will recognize the Rh-proteins on the surface of the baby's blood cells as foreign, causing them to attack those cells (agglutination/clumping) — a risk that grows from the second Rh-positive pregnancy onward.
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