Prevalence of congenital malaria in an urban and a semirural area in Lagos: a two-centre cross-sectional study

Congenital malaria is an important cause of morbidity and mortality in newborns. Signs and symptoms of congenital malaria are non-specific and could be confused with Neonatal sepsis. There has been a recent decline in malaria burden worldwide attributed to a new strategy recommended by the WHO including the use of intermittent preventive treatment of malaria in pregnancy using Sulfadoxine-Pyrimethamine (IPT-SP) during pregnancy, long lasting insecticide treated nets, malaria case management with Artemisinin-based combination therapy etc. This study sets out to determine the effect of these changes on the prevalence of congenital malaria in two centres in Lagos, Nigeria. Using a cross-sectional observational descriptive design, a total of 291 mother and newborn pairs were enrolled from an urban area and a semi-rural area in Lagos between April and October 2014. About three-fifths of the total study population was derived from the urban centre. A pre-designed questionnaire was used to extract basic physical and demographic information such as the use of IPT-SP during pregnancy. Malaria microscopy was carried out on the maternal blood samples, and the corresponding newborns' heel prick and cord blood samples while the placenta tissues were examined for malaria pigments. Malaria parasitaemia, cord blood and congenital malaria were 0.34%, 0% and 0% respectively while that of placental malaria pigmentation was 18.9%. Placental malaria incidence was less in mothers who received IPT-SP in pregnancy (p = 0.016). Placental malaria incidence was higher in mothers ≤ 24 years (p = 0.044) and the less educated women had a higher prevalence of placental malaria (p = 0.001). The incidence of placental malaria was higher in the semi-rural area (92.7% vs. 7.3%, p ≤ 0.0001). Newborns of mothers with placental malaria had lower birth weight (2881.8 vs. 3100.7 g, p = 0.020) and smaller head circumference (34.3 vs. 35.1 cm, p = 0.006). This study demonstrated a significant decline in the prevalence of congenital malaria reflecting the recently reported decline in the burden of malaria in the general population in Africa. Use of IPT-SP during pregnancy, urban area residence and higher educational status appear to have been protective against malaria. A regular surveillance is however necessary considering the dynamics involved in malaria drug resistance.