Sickle cell disease in pregnancy.

S-Homozygotes, SC heterozygotes, and S-beta-thalassaemia heterozygotes are the haemoglobinopathies which make up sickle cell disease. Although their clinical features are similar, as regards complications during pregnancy, Hb S-beta-thalassaemia most dangerous, the main causes of mortality being severe anemia, acute sequestration crisis, bacterial infections, painful episodes, and pulmonary bone marrow fat embolism. Folic acid and antimalarials (where these are indicated) are often successful in preventing severe anaemia. It is best to reserve blood transfusion to replace moderate loss or to correct gross anaemia quickly when this is considered severe enough to threaten life. Painful crises are particularly common towards the end of pregnancy and in treating these episodes, analgesics, antibiotics, and sometimes heparin are used. S-homozygote carries additional hazards. Because of the prevalence of pelvic contraction, fetopelvic disproportion is common and so the incidence of operative deliveries is high. Many fetuses are lost through an increased incidence of abortion and perinatal mortality. In the survivors, there is evidence of intrauterine growth retardation brought about by continuous maternal anaemia throughout pregnancy.