Malaria during pregnancy is thought to affect both uterine and umbilical artery blood flow, leading to decreased oxygen and nutrient exchange between the mother and fetus, and ultimately to intrauterine growth restriction.

We examined the effect of concurrent malaria on changes in uterine artery and umbilical artery resistance indices over gestational age. We used data from 177 pregnant women enrolled in a longitudinal Doppler ultrasound study. Women with high uterine artery and umbilical artery resistance had neonates that weighed less and were smaller. Compared to multigravidae with no malaria, primigravidae with concurrent malaria had an 11–13% increase in uterine artery resistance. Compared to women with no concurrent malaria and a male fetus, concurrent malaria caused an acute 10-14% increase in umbilical artery resistance among women female fetus, while women with a male fetus and concurrent malaria had a 2–3% increase in umbilical artery resistance.

We also examined the effect of early pregnancy malaria parasitemia (≤20 weeks' gestation) on subsequent changes in uteroplacental blood flow and fetal growth among a subset of 128 women with early pregnancy malaria exposure data. Early pregnancy malaria infection affected placentation, reflected by changes in uterine artery blood flow. Among nourished women, early pregnancy malaria decreased uterine artery resistance (-0.036; 95% CI: -0.065, -0.0058), but among undernourished women, early pregnancy malaria increased uterine artery resistance (+0.022; 95% CI: -0.031, 0.074). Among primigravidae, early pregnancy malaria decreased umbilical artery resistance, reflecting adaptive villous angiogenesis with early pregnancy malaria. Primigravidae with early pregnancy malaria had 3.6 times the risk of subsequent IUGR (95% CI: 2.1, 6.2) compared to multigravidae with no early pregnancy malaria.

Our findings point to both the acute effects of concurrent parasitemia and the effects of early pregnancy malaria on placental development. The acute effects of malaria on placental blood flow indicate the need for management and control strategies during pregnancy. Early pregnancy malaria infection leads to changes in placentation, villous angiogenesis, and intrauterine growth restriction. Our findings support the initiation of malaria prevention and control efforts earlier in pregnancy.