Influence of the number and timing of malaria episodes during pregnancy on prematurity and small-for-gestational-age in an area of low transmission

Abstract

BackgroundMost evidence on the association between malaria in pregnancy and adverse pregnancy outcomes focuses on falciparum malaria detected at birth. We assessed the association between the number and timing of falciparum and vivax malaria episodes during pregnancy on small-for-gestational-age (SGA) and preterm birth.MethodsWe analysed observational data collected from antenatal clinics on the Thailand-Myanmar border (1986–2015). We assessed the effects of the total number of malaria episodes in pregnancy on SGA and the effects of malaria in pregnancy on SGA, very preterm birth, and late preterm birth, by the gestational age at malaria detection and treatment using logistic regression models with time-dependent malaria variables (monthly intervals). World Health Organisation definitions of very preterm birth (≥28 and <32 weeks) and late preterm birth (≥32 and <37 weeks) and international SGA standards were used.ResultsOf 50,060 pregnant women followed, 8221 (16%) had malaria during their pregnancy. Of the 50,060 newborns, 10,005 (21%) were SGA, 540 (1%) were very preterm, and 4331 (9%) were late preterm. The rates of falciparum and vivax malaria were highest at 6 and 5 weeks’ gestation, respectively. The odds of SGA increased linearly by 1.13-fold (95% confidence interval: 1.09, 1.17) and 1.27-fold (1.21, 1.33) per episode of falciparum and vivax malaria, respectively. Falciparum malaria at any gestation period after 12–16 weeks and vivax malaria after 20–24 weeks were associated with SGA (falciparum odds ratio, OR range: 1.15–1.63 [p range: <0.001–0.094]; vivax OR range: 1.12–1.54 [p range: <0.001–0.138]). Falciparum malaria at any gestation period after 24–28 weeks was associated with either very or late preterm birth (OR range: 1.44–2.53; p range: <0.001–0.001). Vivax malaria at 24–28 weeks was associated with very preterm birth (OR: 1.79 [1.11, 2.90]), and vivax malaria at 28–32 weeks was associated with late preterm birth (OR: 1.23 [1.01, 1.50]). Many of these associations held for asymptomatic malaria.ConclusionsProtection against malaria should be started as early as possible in pregnancy. Malaria control and elimination efforts in the general population can avert the adverse consequences associated with treated asymptomatic malaria in pregnancy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-017-0877-6) contains supplementary material, which is available to authorized users.

Malaria during pregnancy and newborns outcome in an unstable transmission area in Brazil: a population-based record linkage study

“…The absence of the association between P. falciparum infections and the occurrence of SGA or LBW newborns can be related with the restricted pool of variant genes of the Amazonian parasite, which can explain the mild outcomes observed in the Americas, substantially different from other endemic regions in the world 36 . Nevertheless, our data corroborate some findings in Southeast Asia from Moore et al that show that P. vivax infection is associated with SGA and P. falciparum infection with late preterm, although we could not correlate with time of infection 34 .…”

“…Newborns reduced weight at birth either classified as LBW or SGA, is an important predictive marker of neonatal and child survival, and can result from two basic factors: intrauterine growth restriction and preterm births 33,31 . In gestational malaria, birth weight reduction is the main adverse outcome observed in studies involving P. falciparum infections 2,30,34,35 . In our observations, malaria infection during pregnancy represents a critical morbidity that impacts newborns’ weight.…”

Malaria prevalence in pregnant women receiving antenatal care at the health centre of University of Uyo, Nigeria

“…The IPT with sulphadoxine-pyrimethamine, thus, contributed to a reduction in the prevalence of the disease in the study population. This clearly shows the need to start protection against malaria as early as possible in pregnancy [16]. The significant difference in the prevalence of malaria in relation to age reported in this study is a reflection of the age-related state of anti-malarial immunity that is developed as a result of repeated malaria infections under established malaria endemicity.…”

Genesis of placental sequestration in malaria and possible targets for drugs for placental malaria

“…Women in endemic areas likely have immunity to the common form of malaria caused by infected RBCs that bind to CD36 receptors but primigravidae do not have immunity to VAR2CSA‐binding infected RBCs that bind in the placenta and cause placental malaria. Infected pregnant women eventually form antibodies that block the binding of infected RBCs to chondroitin sulfate A proteoglycans and infections during subsequent pregnancies are not as severe (Desai et al, ; Duffy & Fried, ; Ezebialu et al, ; McLean, Ataide, Simpson, Beeson, & Fowkes, ; Moore et al, ; Rogerson, ; Rogerson, Hviid, Duffy, Leke, & Taylor, ; Sharma & Shukla, ; Uneke, , ).…”

“…Pregnant women are more susceptible to malaria and more severely affected (Beaudet et al, ; Huynh, Cottrell, Cot, & Briand, ; Kourtis, Read, & Jamieson, ; Menendez, ; Moore et al, ). This is particularly true for pregnant women infected with Plasmodium falciparum due to inflammation and cell sequestration in the placenta (referred to as placental malaria).…”