Effect of chloroquine prophylaxis during pregnancy on maternal haematocrit

Two controlled trials of chloroquine prophylaxis during pregnancy were performed, one in Burkina Faso in 1987, on all pregnant women, and the other in Cameroon in 1992, on primigravidae only. Maternal haematocrit at delivery was found to be significantly higher in those women who had received chloroquine than in those who had not, both in Burkina Faso (37.4% v. 36.5%; P = 0.01) and in Cameroon (34.8% v. 32.8%; P = 0.02). Anaemia, defined as an haematocrit of < 30%, was also less common in those treated with chloroquine (6.3% v. 8.5% in Burkina Faso and 8.3% v. 18.4% in Cameroon) but this difference was not significant in either country. A slight improvement in haematological status when prophylaxis is given has also been observed in similar studies performed in other tropical countries. The present results confirm the usefulness of targeting antimalarial prophylaxis at pregnant women. Such prophylaxis during the first pregnancy also increases birthweight.