Question: A patient in my clinic, who is 10 weeks into her first pregnancy and is a known carrier of hemophilia B, is considering the advantages and disadvantages of antenatal tests and is especially worried about a vaginal delivery thatmight cause bleeding. How should I manage her pregnancy?
Answer: Many female carriers of hemophilia were found to have lower-than-expected levels of plasma factors, which are thought to be due to X chromosome inactivation. Chorionic villous sampling is the preferred test to determine the sex of the fetus and whether a male infant is affected with hemophilia. Vaginal delivery is not contraindicated and has been proven during the last two decades to be as safe as cesarean section. Vacuum extraction should be avoided to minimize risk of intracranial hemolysis and severe cephalhematoma.