Adults who have survived repeated malaria infections throughout their lifetimes may become partially immune to severe or fatal malaria. However, because of the changes in women’s immune systems during pregnancy and the presence of a new organ (the placenta) with new places for parasites to bind, pregnant women lose some of their immunity to malaria infection.
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.
Adverse Effects Vary by Transmission Level
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 developed immunity that generally prevents severe disease, however, parasite specifically target the placenta, leading in an increased risk during pregnancygained 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.