Tropical Health Matters

Reena Sethi, DrPH Candidate in International Health, The Johns Hopkins Bloomberg School of Public Health and Senior Monitoring and Evaluation Adviser, Jhpiego shares with us the challenges of malaria acquired from the pregnant mother by their newborn child.

Strategies and recommendations to prevent the transmission of HIV from a mother to her child are known but less information is available on the epidemiology and management of malaria transmitted from pregnant women to their newborns. As presented in a review of congenital infections, one of the lesser known effects of malaria in pregnancy is the maternal-fetal transmission of infected erythrocytes that can result in poor perinatal outcomes. While clinical malaria in newborns is rare, most likely due to the transplacental transfer of maternal antibodies and the inhibitory effect of fetal hemoglobin on the development of malaria parasites, it is unclear what the true incidence of this condition is in Africa and Asia.

Recently published studies in Burkina Faso estimated the incidence of congenital malaria to be 2.1% and the prevalence of mother-to-child transmission of asymptomatic malaria to be 18.5% in one health center in Ouagadougou; in one hospital in Papua, Indonesia, congenital malaria was said to occur in 8 out of 1000 live births from 2005 to 2010; and in a study in one hospital in Madhya Pradesh, India, the incidence of congenital malaria was 29 out of 1000 live births. In a study involving six hospitals in Nigeria, the overall incidence of congenital malaria was found to be 5.1%. Transmission has been associated with both Plasmodium falciparum and Plasmodium vivax. The uncertainty and variation in estimates are likely related to the source of the tested blood (umbilical cord blood or infant peripheral blood), presentation of symptoms that are similar to neonatal sepsis, as well as the lack of capacity to conduct high quality diagnostic tests.

Since congenital malaria results from the transmission of parasites from the mother to the baby (presumably through placental transmission), prevention of malaria through the use of IPTp when appropriate reduces maternal parasitemia, most likely resulting in a lower rate of transmission of malaria to the newborn. In a study in Côte d’Ivoire, factors that protected mothers from placental malaria parasitaemia were the use of IPTp (SP) or ITNs during pregnancy and multigravidity. A study in Ibadan, Nigeria found that IPT-SP was effective in preventing maternal and placental malaria as well as improving pregnancy outcomes among parturient women. Researchers in Southern Ghana reported that placental malaria decreased after the implementation of IPTp.

However, in settings where IPTp is ineffective, the effect of alternative strategies, such as intermittent screening and testing in pregnancy (ISTp) on placental malaria should be examined. Little evidence is currently available on the efficacy of ISTp on maternal and newborn outcomes.

Further research also needs to be conducted in diverse settings to develop a standardized definition for congenital malaria and to understand the short and long-term consequences of this condition in order to establish guidelines for diagnosis and treatment. In pre-elimination contexts, where acquired malaria immunity may be reduced, further evidence is needed on the feasibility of screening all febrile babies and following newborns born to women with malaria during pregnancy and of other possible strategies to improve infant outcomes.

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