Quantification of the burden and consequences of pregnancy-associated malaria in the Democratic Republic of the Congo

Abstract

Background: Pregnancy-associated malaria (PAM) produces poor birth outcomes, but its prevalence is commonly estimated in convenience samples.

Methods: We assessed the prevalence of malaria using real-time polymerase chain reaction (PCR) and estimated the consequences of infection on birth outcomes, using specimens from a nationally representative sample of 4570 women of childbearing age (WOCBA) responding to the 2007 Demographic and Health Survey in Democratic Republic of the Congo (DRC).

Results: Overall, 31.2% (95% confidence interval [CI], 29.2-33.1) of WOCBA were parasitemic, which was significantly more common in pregnant (37.2% [31.0-43.5]) than nonpregnant women (30.4% [CI, 28.4-32.5], prevalence ratio [PR] 1.22 [1.02-1.47]). Plasmodium falciparum was highest among pregnant women (36.6% vs 28.8%, PR 1.27 [1.05-1.53]). By contrast, P malariae was less common in pregnant (0.6%) compared with nonpregnant women (2.7%, PR 0.23 [0.09-0.56]). Extrapolation of the prevalence estimate to the population at risk of malaria in DRC suggests 1.015 million births are affected by P falciparum infection annually, and that adherence to preventive measures could prevent up to 549 000 episodes of pregnancy-associated malaria and 47 000 low-birth-weight births.

Conclusions: Pregnancy-associated malaria and its consequences are highly prevalent in the DRC. Increasing the uptake of malaria preventive measures represents a significant opportunity to improve birth outcomes and neonatal health.

Figure 1.

Geographic clusters in Democratic Republic of the Congo in which women of childbearing age were sampled for survey.

Figure 2.

Schematic approach to the extrapolation of survey results to PAM burden and control estimates. Abbreviations: PAM, pregnancy-associated malaria; DRC, Democratic Republic of the Congo; G1/2, primi- and secundigravidae; ITN, insecticide-treated bednet; IPTp-SP, intermittent preventive therapy with sulfadoxine-pyrimethamine; LBW: low birth weight. ^a References [9, 15, 18]. ^b Reference [16]. ^c Reference [9]. ^d Reference [7]. ^e Reference [4]. ^f Reference [17]. ^g References [4, 19]. ^h Reference [20].

Figure 3.

Infecting Plasmodium species among parasitemic pregnant and nonpregnant women.

Figure 4.

Parasite prevalence by gravidity and trimester among 520 pregnant women. Parasitemias include any malaria species. Values are percentages; those in parentheses are 95% confidence intervals. Gravidity and trimester determined by self-report. Overall differences in proportions were nonsignificant in a Poisson regression model. All analyses calculated using sampling weights.