Over 46% of African pregnant women are anemic. Oral iron is recommended but often suboptimal, particularly late in pregnancy. Intravenous ferric carboxymaltose (FCM) could treat anemia in women in the third trimester in sub-Saharan Africa. In an open-label, individually randomized trial in antenatal clinics in southern Malawi, we randomized 590 women at 27-35 weeks of gestation with capillary hemoglobin <10.0 g dl-1 to FCM (20 mg kg-1 up to 1,000 mg, once at enrollment) or standard of care (60 mg elemental iron, twice daily for 90 days). Participants and their infants were followed to 4 weeks postpartum. Primary outcomes were maternal anemia at 36 weeks' gestation or delivery (whichever occurred first) and neonatal birthweight. At the primary timepoint, 126 of 270 (46.7%) of women in the FCM group were anemic, compared to 170 of 271 (67.3%) women in the standard-of-care group (PR, 0.74 (95% CI 0.64, 0.87); P = 0.0002). There was no difference between groups in birthweight (mean difference 10.9 g (-65.7, 87.5 g); P = 0.78). No serious infusion-related reactions occurred, and there were no differences in adverse events between groups. In Malawian women in late pregnancy, FCM effectively and safely reduced anemia before childbirth. Australia New Zealand Clinical Trial registration: ANZCTR12621001239853.

BackgroundDetection of anaemia is crucial for clinical medicine and public health. Current WHO anaemia definitions are based on statistical thresholds (fifth centiles) set more than 50 years ago. We sought to establish evidence for the statistical haemoglobin thresholds for anaemia that can be applied globally and inform WHO and clinical guidelines.MethodsIn this analysis we identified international data sources from populations in the USA, England, Australia, China, the Netherlands, Canada, Ecuador, and Bangladesh with sufficient clinical and laboratory information collected between 1998 and 2020 to obtain a healthy reference sample. Individuals with clinical or biochemical evidence of a condition that could reduce haemoglobin concentrations were excluded. We estimated haemoglobin thresholds (ie, 5th centiles) for children aged 6–23 months, 24–59 months, 5–11 years, and 12–17 years, and adults aged 18–65 years (including during pregnancy) for individual datasets and pooled across data sources. We also collated findings from three large-scale genetic studies to summarise genetic variants affecting haemoglobin concentrations in different ancestral populations.FindingsWe identified eight data sources comprising 18 individual datasets that were eligible for inclusion in the analysis. In pooled analyses, the haemoglobin fifth centile was 104·4 g/L (90% CI 103·5–105·3) in 924 children aged 6–23 months, 110·2 g/L (109·5–110·9) in 1874 children aged 24–59 months, and 114·4 g/L (113·6–115·2) in 1839 children aged 5–11 years. Values diverged by sex in adolescents and adults. In pooled analyses, the fifth centile was 122·2 g/L (90% CI 121·3–123·1) in 1741 female adolescents aged 12–17 years and 128·2 g/L (126·4–130·0) in 1103 male adolescents aged 12–17 years. In pooled analyses of adults aged 18–65 years, the fifth centile was 119·7 g/L (90% CI 119·1–120·3) in 3640 non-pregnant females and 134·9 g/L (134·2–135·6) in 2377 males. Fifth centiles in pregnancy were 110·3 g/L (90% CI 109·5–111·0) in the first trimester (n=772) and 105·9 g/L (104·0–107·7) in the second trimester (n=111), with insufficient data for analysis in the third trimester. There were insufficient data for adults older than 65 years. We did not identify ancestry-specific high prevalence of non-clinically relevant genetic variants that influence haemoglobin concentrations.InterpretationOur results enable global harmonisation of clinical and public health haemoglobin thresholds for diagnosis of anaemia. Haemoglobin thresholds are similar between sexes until adolescence, after which males have higher thresholds than females. We did not find any evidence that thresholds should differ between people of differering ancestries.FundingWorld Health Organization and the Bill & Melinda Gates Foundation.

Detection of anaemia is critical for clinical medicine and public health. Current WHO values that define anaemia are statistical thresholds (5 th centile) set over 50 years ago, and are presently <110g/L in children 6-59 months, <115g/L in children 5-11 years, <110g/L in pregnant women, <120g/L in children 12-14 years of age, <120g/L in non-pregnant women, and <130g/L in men. Haemoglobin is sensitive to iron and other nutrient deficiencies, medical illness and inflammation, and is impacted by genetic conditions; thus, careful exclusion of these conditions is crucial to obtain a healthy reference population. We identified data sources from which sufficient clinical and laboratory information was available to determine an apparently healthy reference sample. Individuals were excluded if they had any clinical or biochemical evidence of a condition that may diminish haemoglobin concentration. Discrete 5 th centiles were estimated along with two-sided 90% confidence intervals and estimates combined using a fixed-effect approach. Estimates for the 5 th centile of the healthy reference population in children were similar between sexes. Thresholds in children 6-23 months were 104.4g/L [90% CI 103.5, 105.3]; in children 24-59 months were 110.2g/L [109.5, 110.9]; and in children 5-11 years were 114.1g/L [113.2, 115.0]. Thresholds diverged by sex in adolescents and adults. In females and males 12-17 years, thresholds were 122.2g/L [121.3, 123.1] and 128.2 [126.4, 130.0], respectively. In adults 18-65 years, thresholds were 119.7g/L [119.1, 120.3] in non-pregnant females and 134.9g/L [134.2, 135.6] in males. Limited analyses indicated 5 th centiles in first-trimester pregnancy of 110.3g/L [109.5, 111.0] and 105.9g/L [104.0, 107.7] in the second trimester. All thresholds were robust to variations in definitions and analysis models. Using multiple datasets comprising Asian, African, and European ancestries, we did not identify novel high prevalence genetic variants that influence haemoglobin concentration, other than variants in genes known to cause important clinical disease, suggesting non-clinical genetic factors do not influence the 5 th centile between ancestries. Our results directly inform WHO guideline development and provide a platform for global harmonisation of laboratory, clinical and public health haemoglobin thresholds.

Hepcidin is known to be suppressed in human pregnancy; and while it's known that intravenous iron infusion increases hepcidin levels, it is unknown to what degree this occurs during pregnancy. The REVAMP trial was an open label, individually randomised controlled trial, in 862 Malawian pregnant women in the second trimester, with moderate to severe anaemia (haemoglobin<10.0g/dL). Participants were randomised equally to either intravenous Ferric Carboxymaltose (FCM), or standard of care (Oral iron), and followed up to 28 days post partum. To evaluate hepcidin and erythroferrone levels, a total of 250 participants were randomly selected. This sample was balanced with the main trial with regards to trial arm (FCM 50%, Oral iron 50%), baseline iron deficiency (42.2%), anaemia (96.4%), parity (nulliparous 55.6%), and HIV status (HIV positive 15.3%). Hepcidin and erythroferrone levels were measured by ELISA, on serum samples collected longitudinally across 3 pregnancy timepoints (baseline, 28-days post randomisation, 36-weeks gestation), delivery, and 28-days postpartum. Serum hepcidin levels (reported as: median [IQR]) were not different between the trial arms at baseline (FCM: 11.91ng/ml [5.56-20.53], Oral iron: 12.79ng/ml [6.65-20.40]). At 28 days post randomisation, hepcidin was higher in those treated with FCM (31.92ng/ml [14.80-59.84]) than oral iron (5.85ng/ml [2.50-15.12]), p<0.001. Hepcidin remained significantly increased at 36 weeks gestation (FCM: 21.14ng/ml [11.84-41.62], Oral iron: 10.86ng/ml [8.34-18.03], p<0.001). At delivery levels were higher overall, remaining higher in those who received FCM treatment (80.56ng/ml [25.11-149.6]) than Oral iron (37.39ng/ml [16.35-91.85], p=0.001). At 28days postpartum, hepcidin remained higher in the FCM arm 39.29ng/ml [19.52-76.37] than the Oral arm 17.67ng/ml [11.05-38.21], p<0.001. Erythroferrone levels were not statistically different between arms at any timepoint; values were highest at baseline (FCM median 0.92ng/ml [0.42-1.45], Oral iron 1.06ng/ml [0.52-2.04]). This is the first study examining the effects of modern intravenous iron infusions on hepcidin levels during pregnancy, and demonstrates that there is a statistically significant increase in hepcidin levels after ferric carboxymaltose, throughout pregnancy, persisting to four weeks post partum.

Aim: Hepcidin levels are suppressed during human and murine pregnancy. It is unknown whether hepcidin levels are primarily the result of iron deficiency/utilisation or whether there is a pregnancy-specific mechanism for hepcidin suppression. We reasoned that Tmprss6 inhibition would cause constitutive BMP-SMAD signalling and help determine the mechanism of antenatal hepcidin suppression. Method: Female wildtype C57BL/6 mice were treated subcutaneously every 21 days with a GalNAc-siRNA conjugate targeting Tmprss6 (Silence Therapeutics GmbH, Berlin, Germany) or a non-targeting control (NTC) siRNA conjugate. Mice were mated and monitored for pregnancy. Samples were collected from pregnant mice humanely euthanised at E8.5 or E14.5, and unmated controls. Results: Treatment with Tmprss6 siRNA inhibited hepatic Tmprss6 mRNA expression (unmated fold change 0.077, p<0.0001). qPCR Hamp expression was significantly increased in Tmprss6 siRNA-treated mice, compared to NTC-treated mice, at all timepoints. Serum hepcidin, by ELISA, was higher in Tmprss6 siRNA-treated mice than in NTC-treated mice at E14.5 (1126ng/ml vs 178.5, p<0.0001). In unmated mice, serum hepcidin was not significantly elevated (640.9 vs 980.1ng/ml, p=0.224). Across NTC treated pregnancy, Hamp expression and serum hepcidin were reduced at E14.5 compared to unmated ( Hamp fold change E14.5 0.293, p=0.0367; serum hepcidin E14.5 178.5 vs 640.9, p=0.0247). In contrast, Tmprss6 siRNA treatment caused elevated hepcidin through pregnancy (E14.5 1126 vs unmated 980ng/ml, p=0.99); Fig 1a. Maternal liver iron was unchanged between groups. Tmprss6 siRNA reduced placental iron, fetal liver iron, and fetal weight (0.189 vs 0.226g, p<0.0001), Fig 1b. At E8.5/E14.5, Tmprss6 siRNA reduced Mean Cell Volume (E14.5: 41.42 vs 51.72fL, p<0.0001) and Mean Cell Haemoglobin (E14.5: 11.20 vs 15.68pg, p<0.0001); at E14.5 only, maternal anaemia was seen with Tmprss6 siRNA (haemoglobin 9.4 vs 13.85g/L, p=0.0004). Conclusion: Disruption of Tmprss6 increased hepcidin and ablated the hepcidin fall over pregnancy. This may suggest that any pregnancy-related factor which directly suppresses hepcidin cannot overcome Tmprss6 knockdown. Tmprss6 siRNA treatment resulted in iron-restricted erythropoiesis, reduced placental iron and impacted fetal development, despite unchanged liver iron stores.

Placental infection remains a significant health burden for mothers and their babies in low-income countries, especially in sub-Saharan Africa, where malaria transmission is intense. An increase in inflammatory biomarkers and poor vascularisation are characteristics of placentas infected with malaria. Hofbauer cells (HBCs) – placental villous macrophages of fetal origin – are one of the most abundant immune cells in the placenta. HBCs are thought to have roles in angiogenic processes and have been linked with the pathophysiology of several infections and inflammatory conditions during pregnancy, including malaria (caused by Plasmodium falciparum ). However, there is limited in situ data on the transcriptional, proteomic or morphologic profile of these cells either during or following clearance of P. falciparum infection. We leveraged placental samples prospectively collected at delivery from 610 Malawian women enduring a high burden of malaria and other infections and nutritional deficiencies. We profiled placentas through spatial transcriptomic and proteomic platforms to discern in situ HBC features that could distinguish placentas with or without evidence of past malaria. In this cohort, past placental infection was common and was associated with lower birth weight babies (adjusted effect [95% confidence interval], −80.9 [−165.9, −3.7] g, P= 0.040). However, at term, HBC numbers, abundance, and transcriptional profiles from placentas with evidence of past infection were similar to those of placentas without malaria. HBCs may recover post-infection back to a basal state or may be replaced in the tissue over the course of pregnancy. Placentas with evidence of past malaria did show evidence of reduced fetal vessel development (mean area difference: −22.8% [−37.6, −7.9], P=0.003). Reduced vascular development following infection early in pregnancy may reflect disturbances to the normal vasculogenic and angiogenic processes, of which HBCs are an integral part.

Polycythemia Vera (PV) is a myeloproliferative neoplasm driven by activating mutations in JAK2 that result in unrestrained erythrocyte production, increasing patients' hematocrit and hemoglobin concentration, placing them at risk of life-threatening thrombotic events. Our GWAS of 440 PV cases and 403,351 controls utilizing UK Biobank data found that SNPs in HFE known to cause hemochromatosis are highly associated with PV diagnosis, linking iron regulation to PV. Analysis of the FinnGen dataset independently confirmed over-representation of homozygous HFE variants in PV patients. HFE influences the expression of hepcidin, the master regulator of systemic iron homeostasis. Through genetic dissection of PV mouse models, we show that the PV erythroid phenotype is directly linked to hepcidin expression: endogenous hepcidin upregulation alleviates erythroid disease whereas hepcidin ablation worsens it. Further, we demonstrate that in PV, hepcidin is not regulated by expanded erythropoiesis but is likely governed by inflammatory cytokines signaling via GP130 coupled receptors. These findings have important implications for understanding the pathophysiology of PV and offer new therapeutic strategies for this disease.

Anemia affects 36% of pregnant women worldwide. Of those affected, around 40% is due to iron deficiency (ID). Iron is an essential micronutrient involved in vital processes such as erythropoiesis, immune responses, and importantly-during pregnancy-placental and fetal development. Although menstrual bleeding can impact the incidence of ID even before the onset of pregnancy, this narrative review is pregnancy focused and will explore the impact of ID on placental development and iron uptake, fetal development and immunity, and maternal and infant susceptibility to infection. Although there have been advances in this area of research, much is needed to understand the regulation of iron and the effects of ID during pregnancy. Notably, more human studies are essential to generate the best evidence to advance strategies to reduce the incidence of ID during pregnancy to improve maternal, neonatal, and infant health.

Background Detection of anaemia is critical for clinical medicine and public health in high and low income settings, but anaemia definitions are uncertain, causing discordance across different laboratories and guidelines. Current WHO anaemia definitions, set in 1968 using limited data, reflect the 5th centile of the haemoglobin distribution in apparently healthy populations. WHO is now reviewing these definitions. Haemoglobin concentration is sensitive to iron and other nutrient deficiencies, inflammation, renal impairment, and genetic conditions, and thus conservative criteria to obtain a healthy reference population is crucial in estimating the 5th centile. To support WHO definitions, this study estimated the 5th centile for haemoglobin in healthy reference populations derived from a secondary analysis of large cohorts. Methods We identified data sources from which sufficient clinical and laboratory data were available to identify an apparently healthy reference sample. These comprised the National Health and Nutrition Examination Survey (NHANES, USA, 8 survey years); Health Survey for England (HSE, England, 4 survey years); the Australian Health Survey (AHS), comprising 2 separate surveys: National Health Survey (NHS, Australia) and National Nutrition and Physical Activity Survey (NNPAS, Australia); TARGetKids! (prospective longitudinal cohort of children, Canada); BRISC (trial of oral iron in infants, Bangladesh); Generation R (prospective cohort of pregnant women, Netherlands). Markers or iron status and inflammation were available in all surveys, with exclusions for ferritin<15ug/L (or <12ug/L in children <5 years), or C-Reactive Protein (CRP) >5mg/L. Where possible, exclusions were applied based on renal function, folate, and active B12. Clinical data from all surveys (except Generation R) excluded individuals with pre-existing health conditions, use of medication (other than contraception), recent illness or hospital admission. In the pregnant Generation R group, those with pregnancy complications were excluded. In all groups, current smokers and those who consumed excess alcohol were excluded. Adults with BMI <18.5 or >30kg/m2 were excluded; children were excluded if growth z-scores were <-2 or >+2. In children <24months, those with birth complications or prematurity were excluded. Thresholds were defined in adult men (18-65 years), adult non-pregnant women (18-65 years), pregnant women (18-45 years, by trimester), and children (6-23 months, 24-59 months, 5-11 years, 12-17 years). Discrete 2.5th and 5th centiles were estimated along with two-sided 90% confidence intervals for each data set and estimates were combined across all data sources using a fixed-effect meta-analysis approach. Results In non pregnant adult men and women (total n=57,896 individuals), exclusions resulted in an apparently healthy group of 15-20% of each survey (less where survey years were missing required biochemistry). A broad range of self-reported ethnicities/ancestries were represented. For example in healthy adults: NHANES 17-33% of participants identified as White; HSE >90% identified as White; AHS 50-60% reported European ancestry. 5th centiles of the distribution of haemoglobin values in the derived reference samples were obtained (see Figure 1 for example in non-pregnant women). Pooled estimates for each sample are shown in Table 1. The results generally align with current WHO thresholds, other than adult men, where a 5th centile of 135.1g/L (90% CI 134.4-135.7) is above the WHO threshold of 130g/L, and in children 6-23 months where the 5th centile of 104.5g/L (90% CI 103.6-105.4) is lower than the current value of 110g/L. Our data support the current threshold in non-pregnant adult women of 120g/L. Sensitivity analyses suggest persons of Black race or ethnicity may have 5th centiles lower than values of White persons (predominantly within the US surveys), but presence of haemoglobinopathy as well as other contributing factors cannot be excluded. Conclusion In this analysis using stringent criteria to define healthy reference group at low risk of iron/ other nutrient deficiency, or inflammation, we have estimated statistical thresholds to define anaemia across the lifecycle. These data contribute to WHO guideline development, and provide a platform for harmonisation of thresholds across different laboratories and clinical guidelines. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal