Pregnancy-associated malaria

Pregnancy-associated malaria (PAM) refers to malaria infection in pregnant women, particularly infections caused by the parasite Plasmodium falciparum. This condition is a significant public health problem in malaria-endemic areas, predominantly in sub-Saharan Africa. It poses a high risk not only to the pregnant woman but also to the fetus, leading to poor outcomes such as preterm birth, low birth weight, and increased infant mortality.

Etiology

Pregnancy-associated malaria is caused by the sequestration of Plasmodium falciparum-infected erythrocytes in the placenta. The parasites express a unique variant of the erythrocyte membrane protein 1 (PfEMP1), which mediates adhesion to chondroitin sulfate A (CSA) in the placental tissue. This specific interaction is crucial for the pathogenesis of PAM and distinguishes it from non-pregnancy-associated malaria.

Pathophysiology

The accumulation of infected erythrocytes in the placental intervillous spaces leads to inflammation, reduced blood flow, and hypoxia. This environment can impair nutrient and gas exchange between the mother and fetus, contributing to adverse pregnancy outcomes. The immune response to PAM is also altered, with pregnant women having reduced immunity to malaria, making them more susceptible to infection and increasing the severity of the disease.

Clinical Manifestations

Pregnancy-associated malaria can present with a wide range of symptoms, from asymptomatic infections to severe malaria. Common symptoms include fever, anemia, and in severe cases, respiratory distress. The condition is particularly dangerous because it can lead to maternal anemia, which is associated with increased maternal mortality, and placental malaria, which can cause fetal growth restriction, low birth weight, preterm birth, and stillbirth.

Diagnosis

Diagnosis of PAM is similar to that of malaria in the general population and includes the use of rapid diagnostic tests (RDTs) and microscopy. However, the sensitivity of these tests may be lower in pregnant women due to the sequestration of parasites in the placenta. Therefore, a high index of suspicion is necessary in endemic areas, even when initial tests are negative.

Prevention and Control

Prevention of pregnancy-associated malaria focuses on the use of insecticide-treated nets (ITNs), indoor residual spraying (IRS), and the administration of intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP). IPTp-SP is recommended by the World Health Organization (WHO) in areas with moderate to high malaria transmission. It involves the administration of at least three doses of SP during the second and third trimesters of pregnancy.

Treatment

The treatment of PAM involves the use of antimalarial drugs that are safe in pregnancy. The choice of medication depends on the severity of the disease and the local drug resistance patterns. For uncomplicated malaria, the WHO recommends the use of quinine plus clindamycin in the first trimester, and artemisinin-based combination therapies (ACTs) in the second and third trimesters. For severe malaria, intravenous artesunate is preferred.

Epidemiology

Pregnancy-associated malaria is most prevalent in sub-Saharan Africa, where high transmission rates of Plasmodium falciparum coincide with a large number of pregnancies at risk. It is estimated that each year, PAM is responsible for approximately 10,000 maternal deaths and up to 200,000 infant deaths.

Conclusion

Pregnancy-associated malaria is a complex condition with significant implications for maternal and child health. Effective prevention, timely diagnosis, and appropriate treatment are crucial to mitigate its impact. Ongoing research and improved implementation of control measures are needed to reduce the burden of PAM in endemic regions.