Impact of Sub-patent Malaria During Pregnancy on Birth-Weight in Odisha, India: Time-to-Event Analysis of Prospective Longitudinal Follow-Up of a Survey

ObjectiveThe current study aimed to estimate prevalence of malaria infection, especially sub-patent infection, in pregnant women residing in high malaria-endemic, hard-to-reach pockets of the Indian state of Odisha; and also measure its impact on birth-weight of their new-borns.MethodA time-to-event analysis of prospective longitudinal follow-up study nested within a cross-sectional survey of people residing in high malaria-endemic six districts of Odisha was conducted during July-November 2019. Malaria status in pregnant mothers was categorized as malaria free; sub-patent, and patent. Hazards Ratio (HR) of low birth-weight (LBW; birth-weight < 2500 gms) was estimated in these three categories (n = 308) adjusted for residence (block), gravida, caste, age and gestational age at testing.Results50.3% pregnant women had sub-patent malaria infection, 3.9% had patent infection. In fully adjusted model, hazards ratio of LBW was 3.76 (95% CI 1.12, 12.64, p = 0.032) in pregnant women with patent infection and 1.82 (95% CI 0.87, 3.81, p = 0.109) in women with sub-patent infection when compared to no malaria group.ConclusionThe study showed that half of the pregnant women in high-endemic pockets had sub-patent infection which posed deleterious influence on birth-weight of their new-borns. The study thereby flags the prevalence of sub-patent infection as a public health concern, because sub-patent infection in pregnant mothers may persist as a silent reservoir, with the potential to derail the malaria control program, especially when the country plans malaria elimination by 2030.

Automated summary

The study aimed to estimate the prevalence of malaria infection in pregnant women in high malaria-endemic and hard-to-reach areas of Odisha, India, and its impact on birth weight. The results showed that half of the pregnant women in high-endemic areas had sub-patent malaria infection, which had a negative impact on the birth weight of their newborns. Therefore, the prevalence of sub-patent infection is considered a public health concern.