Why a Special Intervention for Pregnant Women?

Adults living in areas of high malaria transmission become partially immune to malaria. However, because of the changes in women’s immune systems when they become pregnant, pregnant women lose some of their immunity to malaria infection.

Malaria-infected human placenta examined under the microscope. The intervillous spaces (central area of the picture) are filled with red blood cells, most of which are infected with Plasmodium falciparum malaria parasites. The parasites appear here as black dots. A malaria-infected placenta is unable to carry out normally its main function: to provide nutrients to the fetus.

Malaria infection during pregnancy can have adverse effects on both mother and fetus, including maternal anemia, fetal loss, premature delivery, intrauterine growth retardation, and delivery of low birth-weight infants (<2500 g or <5.5 pounds), a risk factor for death.

It is a particular problem for women in their first and second pregnancies and for women who are HIV-positive.

Effects Vary by Transmission

The problems that malaria infection causes differ somewhat by the type of malaria transmission area: stable (high) or unstable (low) transmission.

• In high transmission areas, women have gained a level of immunity to malaria that wanes somewhat during pregnancy. Malaria infection is more likely to contribute to maternal anemia and delivery of low birth-weight infants (<2500 g or <5.5 pounds). It is a particular problem for women in their first and second pregnancies, for younger women, and for women who are HIV-positive.
• In low transmission areas, women generally have developed no immunity to malaria. Malaria infection is more likely to result in severe malaria disease, maternal anemia, premature delivery, or fetal loss.

A pregnant woman during a prenatal consultation in Malawi receives sulfadoxine-pyrimethamine for intermittent preventive treatment of malaria (IPTp). The plastic bag on the table holds an insecticide-treated bed net, another method for protecting her against malaria.

Recommended Interventions

The currently recommended interventions for pregnant women are

• effective case management (diagnosis and treatment of illness)
• use of insecticide-treated bed nets
• intermittent preventive treatment (IPTp) (for women in high transmission areas).

Women should also receive iron/folate supplementation to protect them against anemia, a common occurrence among all pregnant women.

IPTp

IPTp entails administration of a curative dose of an effective antimalarial drug (currently sulfadoxine-pyrimethamine) at least twice during pregnancy to all pregnant women whether or not they are infected with the malaria parasite. IPTp is given at routine prenatal care visits, starting in the second trimester. Each dose should be at least 1 month apart.