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Background: Malaria infection during pregnancy can cause significant morbidity and mortality to a pregnant woman, her fetus and newborn. In areas of high endemic transmission, gravidity is an important risk factor for infection, but there is a complex relationship with other exposure-related factors, and use of protective measures. This study investigated the association between gravidity and placental malaria (PM), among pregnant women aged 14–49 in Kintampo, a high transmission area of Ghana. Methods: Between 2008 and 2011, as part of a study investigating the association between PM and malaria in infancy, pregnant women attending antenatal care (ANC) clinics in the study area were enrolled and followed up until delivery. The outcome of PM was assessed at delivery by placental histopathology. Multivariable logistic regression analyses were used to investigate the association between gravidity and PM, identify other key risk factors, and control for potential confounders. Pre-specified effect modifiers including area of residence, socio-economic score (SES), ITN use and IPTp-SP use were explored. Results: The prevalence of PM was 65.9% in primigravidae, and 26.5% in multigravidae. After adjusting for age, SES and relationship status, primigravidae were shown to have over three times the odds of PM compared to multigravidae, defined as women with 2 or more previous pregnancies [adjusted OR = 3.36 (95% CI 2.39–4.71), N = 1808, P < 0.001]. The association appeared stronger in rural areas [OR for PG vs. MG was 3.79 (95% CI 3.61–5.51) in rural areas; 2.09 (95% CI 1.17–3.71) in urban areas; P for interaction = 0.07], and among women with lower socio-economic scores [OR for PG vs. MG was 4.73 (95% CI 3.08–7.25) amongst women with lower SES; OR = 2.14 (95% CI 1.38–3.35) among women with higher SES; P for interaction = 0.008]. There was also evidence of lower risk among primigravidae with better use of the current preventive measures IPTp and LLIN. Conclusions: The burden of PM is most heavily focused on primigravidae of low SES living in rural areas of high transmission. Programmes should prioritize primigravidae and young women of child-bearing age for interventions such as LLIN distribution, educational initiatives and treatment to reduce the burden of malaria in first pregnancy. [ABSTRACT FROM AUTHOR]

Parasitemia among pregnant women with protective immunity to Plasmodium falciparum malaria is often dominated by VAR2CSA-positive infected erythrocytes (IEs). VAR2CSA mediates sequestration of IEs in the placenta. We hypothesized that the previously observed spontaneous postpartum clearance of parasitemia in such women is related to the expulsion of the placenta, which removes the sequestration focus of VAR2CSA-positive IEs. We assessed parasitemias and gene transcription before and shortly after delivery in 17 Ghanaian women. The precipitous decline in parasitemia postpartum was accompanied by selective reduction in transcription of the gene encoding VAR2CSA. Our findings provide a mechanistic explanation for the earlier observation., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background. Whether the risk of malaria is increased in infants born to mothers who experience malaria during pregnancy is uncertain.Methods. We investigated malaria incidence among an infant cohort born to 355 primigravidae and 1500 multigravidae with or without placental malaria (PM) in a high malaria transmission area of Ghana. PM was assessed using placental histology.Results. The incidence of all episodes of malaria parasitemia or clinical malaria was very similar among 3 groups of infants: those born to multigravidae without PM, multigravidae with PM, and primigravidae with PM. Infants born to primigravidae without PM experienced a lower incidence of malaria parasitemia or clinical malaria than the other 3 groups: adjusted hazard ratio, 0.64 (95% confidence interval [CI], .48–.86, P < .01) and 0.60 (95% CI, .43–.84, P < .01), respectively. The incidence of malaria parasitemia or clinical malaria was about 2 times higher in most poor infants compared to least poor infants.Conclusions. There was no suggestion that exposure to PM directly increased incidence of malaria among infants of multigravidae. In our study area, absence of placental malaria in primigravidae is a marker of low exposure, and this probably explains the lower incidence of malaria-related outcomes among infants of PM-negative primigravidae. [ABSTRACT FROM PUBLISHER]

• Household air pollution exposure during pregnancy affects birth outcomes in Ghana. • Effects are strongest in pregnancies unaffected by placental malaria. • Carbon monoxide during pregnancy is associated with reduced fetal growth. • Carbon monoxide during pregnancy is also associated with shorter gestational age. • Malaria during pregnancy may obscure the effects of air pollution on fetal growth. Low birth weight and prematurity are important risk factors for death and disability, and may be affected by prenatal exposure to household air pollution (HAP). We investigate associations between maternal exposure to carbon monoxide (CO) during pregnancy and birth outcomes (birth weight, birth length, head circumference, gestational age, low birth weight, small for gestational age, and preterm birth) among 1288 live-born infants in the Ghana Randomized Air Pollution and Health Study (GRAPHS). We evaluate whether evidence of malaria during pregnancy, as determined by placental histopathology, modifies these associations. We observed effects of CO on birth weight, birth length, and gestational age that were modified by placental malarial status. Among infants from pregnancies without evidence of placental malaria, each 1 ppm increase in CO was associated with reduced birth weight (−53.4 g [95% CI: −84.8, −21.9 g]), birth length (−0.3 cm [−0.6, −0.1 cm]), gestational age (−1.0 days [−1.8, −0.2 days]), and weight-for-age Z score (−0.08 standard deviations [−0.16, −0.01 standard deviations]). These associations were not observed in pregnancies with evidence of placental malaria. Each 1 ppm increase in maternal exposure to CO was associated with elevated odds of low birth weight (LBW, OR 1.14 [0.97, 1.33]) and small for gestational age (SGA, OR 1.14 [0.98, 1.32]) among all infants. Even modest reductions in exposure to HAP among pregnant women could yield substantial public health benefits, underscoring a need for interventions to effectively reduce exposure. Adverse associations with HAP were discernible only among those without evidence of placental malaria, a key driver of impaired fetal growth in this malaria-endemic area. [ABSTRACT FROM AUTHOR]

Background: Placental malaria (PM) poses life-threatening complications to pregnant women as they are at increased risk of maternal and perinatal morbidity and mortality associated with malaria. This study examined the factors associated with placental malaria in the Upper West Regional Hospital (UWR)., Methods: A cross-sectional hospital-based study was carried out among pregnant women delivering at Upper West Regional Hospital. A cross-sectional screening survey was conducted from January 2019 to April 2019. Three hundred eligible mothers were consecutively recruited. A record review of their maternal and child history was assessed using a checklist. Placental blood samples were taken for microscopy to determine placental malaria parasitemia. Logistic regression analysis was done to determine the factors associated with placental malaria at 95 % confidence level., Results: The proportion of mothers with placental malaria was 7 % (21/300), (95 % CI, 4.3-10.5 %). Plasmodium falciparum was the only species identified in those with PM. Majority of the women 66.7 % (14/21) with placental malaria had parasite density in the range 501 to 5,000 parasites/µL. Obstetric and health service factors that were significantly associated with placental malaria were gravidity and antenatal care (ANC) attendance. Primigravida (aOR = 3.48, 95 %CI = 1.01-12.01) and having less than 4 ANC attendance (aOR = 9.78, 95 %CI = 2.89-33.11) were found to be significantly associated with placental malaria., Conclusions: The proportion of women with PM was relatively low. Primigravid mothers reporting less than 4 ANC visits had the highest risk of placental malaria. Expectant mothers should be encouraged to attend at least 4 ANC visits prior to delivery.