Asymptomatic and symptomatic microscopic Plasmodium falciparum and P.vivax parasitaemia in pregnancy is associated with adverse outcomes including maternal mortality, maternal anaemia and for the fetus miscarriage, preterm birth (PTB), stillbirth, small for gestational age (SGA), and neonatal death. Evidence showing significant adverse maternal and birth outcomes in women with sub-microscopic infection remains equivocal.
Among 15,000 women prospectively registered to antenatal care between 2012 and 2015, we selected a sub-cohort of 3,500 women from three groups: malaria, refractory anemia, and control. This included all the women who had confirmed microscopic malaria during pregnancy (N), a proportion of women who had had not responded to at least 6 weeks of haematinic treatment for anaemia (HCT <30%) (N), and a further random sample of women who did not have malaria or anaemia in pregnancy (N). Packed red blood cells from the first antenatal visit were used to extract DNA and to detect malaria parasites using ultrasensitive qPCR. The method used Pf 3D7 standard control by FACT system with a 5-fold serial dilution of 150,000 p/mL to 48 p/mL. This qPCR is targeted to all 5 plasmodium species (genus level detected).
Amongst the screened women the overall qPCR prevalence was 6.0% which decreased over time from 17.0% in 2012, 11.1% in 2013, 10.3% in 2014 and 5.0% in 2015. On speciation of qPCR positive cases P.vivax (51.5%) dominated followed by P.falciparum (10.9%), and mixed P.falciparum and P.vivax infection (3.0%) leaving nearly 1/3 (35.5%) of cases as Plasmodium not specified.
Further details on the impact on pregnancy outcomes including the relationship between submicroscopic and patent infection and maternal anaemia in pregnancy and at delivery, miscarriage, PTB, stillbirth, SGA, and neonatal death in women with and without submicroscopic infection will be presented.