Plasmodium falciparum parasitaemia in the first half of pregnancy, uterine and umbilical artery blood flow, and foetal growth: a longitudinal Doppler ultrasound study

Jennifer B Griffin,Amy H Herring,John M Thorp,Stephen J Rogerson,Victor Lokomba,Sarah H Landis,Antoinette K Tshefu,Steven R Meshnick

doi:10.1186/1475-2875-11-319

Abstract

BackgroundDuring early pregnancy, the placenta develops to meet the metabolic demands of the foetus. The objective of this analysis was to examine the effect of malaria parasitaemia prior to 20 weeks’ gestation on subsequent changes in uterine and umbilical artery blood flow and intrauterine growth restriction.MethodsData were analysed from 548 antenatal visits after 20 weeks’ gestation of 128 women, which included foetal biometric measures and interrogation of uterine and umbilical artery blood flow. Linear mixed effect models estimated the effect of early pregnancy malaria parasitaemia on uterine and umbilical artery resistance indices. Log-binomial models with generalized estimating equations estimated the effect of early pregnancy malaria parasitaemia on the risk of intrauterine growth restriction.ResultsThere were differential effects of early pregnancy malaria parasitaemia on uterine artery resistance by nutritional status, with decreased uterine artery resistance among nourished women with early pregnancy malaria and increased uterine artery resistance among undernourished women with early pregnancy malaria. Among primigravidae, early pregnancy malaria parasitaemia decreased umbilical artery resistance in the late third trimester, likely reflecting adaptive villous angiogenesis. In fully adjusted models, primigravidae with early pregnancy malaria parasitaemia had 3.6 times the risk of subsequent intrauterine growth restriction (95% CI: 2.1, 6.2) compared to the referent group of multigravidae with no early pregnancy malaria parasitaemia.ConclusionsEarly pregnancy malaria parasitaemia affects uterine and umbilical artery blood flow, possibly due to alterations in placentation and angiogenesis, respectively. Among primigravidae, early pregnancy malaria parasitaemia increases the risk of intrauterine growth restriction. The findings support the initiation of malaria parasitaemia prevention and control efforts earlier in pregnancy.

Highlights

During early pregnancy, the placenta develops to meet the metabolic demands of the foetus
Abnormal uterine artery resistance is associated with pre-eclampsia, intrauterine growth restriction (IUGR) and adverse pregnancy outcomes [6], while increased umbilical artery resistance is associated with foetal distress and IUGR [7,8]
No primigravidae were found to have sub microscopic parasitaemia, while in 30% of multigravida parasitaemia was submicroscopic. These semi-quantitative findings indicate that while the frequency of malaria infection was similar in primigravidae and multigravidae (Table 1), primigravidae had a higher parasite burden compared to multigravidae

Summary

Introduction

The placenta develops to meet the metabolic demands of the foetus. The World Health Organization recommends prevention and control strategies for malaria parasitaemia in pregnancy, including case management of malaria parasitaemia and anaemia; insecticide-treated nets (ITNs); and, at least two doses of intermittent preventive treatment in pregnancy (IPTp) with sulphadoxine-pyrimethamine after the awareness of foetal movement [1] (from approximately 17–19 weeks’ gestation [2]).The peak prevalence of malaria parasitaemia in pregnancy occurs from 13 to 20 weeks’ gestation [3], mostly prior to the first dose of IPTp [1] During this critical period of early pregnancy, the placenta develops to meet the growing metabolic demands of the foetus. Ultrasound can assess foetal biometry measurements, which can be used to identify IUGR foetuses by comparing estimated foetal weights to established foetal growth standards

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Conclusion