Gynaecology & Obstetrics Rh incompatibility does not produce serious complications in the first pregnancy. Which of the following explains this phenomenon? A Antibodies are not able to cross placenta B Antibody titer is very low during secondary immune response C IgG generated is ineffective against fetal red cells. D Massive hemolysis is compensated by increased erythropoesis. 💡 Explanation Rh incompatibility does not produce serious complications in the first pregnancy. Which of the following explains this phenomenon? ✓ Correct Answer: A. Antibodies are not able to cross placenta