Heterogeneity in the prevalence of subclinical malaria, other co-infections and anemia among pregnant women in rural areas of Myanmar: A community-based longitudinal study

Abstract Background: Due to the low prevalence of clinical malaria of 1-2 % among pregnant women in Myanmar, little is known about its impact on mothers and newborns. Helminth and HIV co-infections may cause anaemia and other adverse health outcomes for both mother and child. This study assessed the prevalence of subclinical malaria and co-infections among pregnant women, and their association with adverse outcomes of pregnancy in the presence of infection. Methods: A prospective longitudinal study was conducted in 12 villages in two townships in Myanmar between 2013 to 2015. A total of 752 pregnant women, with mean age of 27 years, were enrolled and followed up once a month, until six weeks after the delivery. Results: About 84% of women were asymptomatic and 40% were primigravid at the time of enrolment. The prevalence of subclinical malaria as measured by nested PCR was 5.7% for either P. falciparum or P. vivax , with 2.7% prevalence of P. falciparum and 2.8% prevalence of P. vivax. Helminth infections were prevalent in 17% of women, and one woman with a HIV infection was found in our study. The burden of anemia was high, with an overall prevalence of 37% with or without helminth infection, 42% of the women were malaria positive and 43% had dual infections (both malaria and helminth). Only 11 abnormal pregnancy outcomes (7 stillbirth, 2 premature, 2 twins) were identified. Poisson regression showed that women in their first trimester had a 2.9 times higher rate of subclinical malaria compared to women in the third trimester (PR:2.9, 95%CI: 1.19, 7.31, p=0.019), women who were enrolled during the wet season were 2.5 times more likely to be malaria positive than the women enrolled in the dry season (PR: 2.5, 95%CI: 1.27, 4.88, p=0.008), and the malaria positivity rate decreased by 5% when increased in one year of woman’s age (PR:0.95, 95%CI: 0.91, 0.99, p=0.02). In the multivariable regression, the age of respondents was the only significant factor associated with subclinical malaria in pregnancy. Conclusions: The low prevalence of heterogenous subclinical malaria among pregnant women should not be neglected when targeting malaria elimination.