Prevalence of asymptomatic Plasmodium falciparum infection in pregnant women in Nigeria: a systematic review and meta-analysis.

Asymptomatic Plasmodium falciparum infection during pregnancy is a major cause of foetal and maternal morbidity and mortality. The current study estimated the prevalence of asymptomatic P. falciparum infection among pregnant women in Nigeria. We systematically searched the PubMed, Web of Science, Google Scholar and AJOL databases for studies that estimated the prevalence of asymptomatic P. falciparum infection in pregnant women up to December, 2019, and identified additional studies from reference lists. Twenty-seven studies which fulfilled eligibility criteria were included in final systematic review and meta-analysis. The prevalence of asymptomatic P. falciparum infection of individual study varied from 2.1% to 95.4%. Most surveys were performed in the southern parts of Nigeria. We observed a high degree of heterogeneity in most pooled estimates (I2 > 75%; p < 0.01). The pooled estimate of asymptomatic P. falciparum infection prevalence across studies for the entire period was 34.3% (95% CI: 24.0-46.3), ranging from 34.7% (95% CI: 22.8-48.9) in primigravida to 28.5% (95% CI: 15.8-45.8%) in the first trimester. Studies conducted from 2000-2009 (51.3%; 95% CI: 29.1-73.0), southern Nigeria (41.8%; 95% CI: 28.2-56.7), rural areas (52.1%; 95% CI: 19.4-83.0), and median sample size ≥ 246 (41.5; 95% CI: 25.9-58.9), had the highest pooled prevalence. Asymptomatic P. falciparum infection is considered high in pregnant women in Nigeria. This results, therefore, emphasize the need to actively diagnose and treat asymptomatic malaria infection during all antenatal care visits.