In high-transmission settings, where levels of acquired immunity tend to be high, P. falciparum infection is usually asymptomatic in pregnancy. Yet, parasites may be present in the placenta and contribute to maternal anaemia even in the absence of documented peripheral parasitaemia. Both maternal anaemia and placental parasitaemia can lead to low birth weight, which is an important contributor to infant mortality. In high-transmission settings, the adverse effects of P. falciparum infection in pregnancy are most pronounced for women in their first pregnancy.
In low-transmission settings, where women of reproductive age have relatively little acquired immunity to malaria, malaria in pregnancy is associated with anaemia, an increased risk of severe malaria, and it may lead to spontaneous abortion, stillbirth, prematurity and low birth weight. In such settings, malaria affects all pregnant women, regardless of the number of times they have been pregnant.
Infection with P. vivax, as with P. falciparum, leads to chronic anaemia and placental malaria infection, reducing the birth weight and increasing the risk of neonatal death. For women in their first pregnancy, the reduction in birth weight is approximately two thirds of what is associated with P. falciparum, but with P. vivax the effect appears to increase with successive pregnancies.
WHO recommends the following package of interventions for the prevention and treatment of malaria during pregnancy:
- Use of Long-lasting Insecticidal Nets (LLINs);
- In areas of stable malaria transmission of sub-Saharan Africa, Intermittent Preventive Treatment in Pregnancy (IPTp) with Sulfadoxine-Pyrimethamine (SP);
- Prompt diagnosis and effective treatment of malaria infections.
IPTp reduces maternal malaria episodes, maternal anaemia, placental parasitaemia, low birth weight, and neonatal mortality.
Furthermore, all pregnant women should receive iron and folic acid supplementation as a part of routine antenatal care.