Subclinical malaria among pregnant women living in refugee settlements in Northern Uganda.

Background: Malaria during pregnancy contributes to significant perinatal morbidity and mortality, accounting for almost 25% of global maternal mortality. However, the epidemiology and risk factors for subclinical malaria among pregnant women living in refugee settlements is poorly understood.

Objective: To determine the prevalence and predictors of subclinical malaria among pregnant women in refugee settlements in Northern Uganda.

Design: We conducted a multi-center, cross-sectional study.

Methods: The study was conducted between April and June 2023 and involved pregnant women aged 18-45 years attending routine antenatal care (ANC) at three health facilities serving refugee communities in Adjumani district, Uganda. We collected sociodemographic, environmental, maternal, and obstetric factors using a structured questionnaire. Both CareStart Malaria HRP-2/pLDH (Pf/Pan) combo rapid diagnostic test (RDT) and blood smear microscopy with 3% Giemsa staining were simultaneously performed on samples from each patient. Logistic regression analysis identified factors independently associated with subclinical malaria, reported as adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

Results: We enrolled 304 pregnant women, with a mean age of 25 years. In total, 68.8% (n = 209) had lived in the settlement for over 12 months, 25.7% (n = 78) were primigravida, and 1.0% (n = 3) were living with HIV. Malaria prevalence was 5.3% (n = 16) by RDT and 3.2% (n = 10; seven Plasmodium falciparum and three P. malariae) by microscopy. Only 4 (25.0%) of the RDT-positive cases were also positive by microscopy (Cohen's kappa: 0.278-Fair agreement). All participants were asymptomatic. Factors associated with higher odds of subclinical malaria included primiparity (aOR: 2.79, 95% CI: 1.25-6.25, p = 0.013), ⩾4 ANC visits (aOR: 2.41, 95% CI: 1.34-4.34, p = 0.003), and residence in the settlement for less than 12 months (aOR: 2.54, 95% CI: 2.0-3.22, p < 0.001). Living in the settlement for over 3 years, being primigravida, and being married were associated with 68%, 50%, and 68% lower odds of subclinical malaria, respectively (aOR: 0.32, 95% CI: 0.13-0.79, p = 0.014; aOR: 0.50, 95% CI: 1.22-5.52, p = 0.016; aOR: 0.32, 95% CI: 0.13-0.78, p = 0.012).

Conclusion: Our study reveals the high prevalence of subclinical malaria among pregnant women in refugee settlements, particularly among primiparous women and recent arrivals. The poor agreement between RDT and microscopy suggests the need for dual screening in asymptomatic pregnant women.