Maternal Hb Concentrations Research Articles

Association between maternal haemoglobin status during pregnancy and children’s mental and psychomotor development at 18 months of age: Evidence from rural Bangladesh

ABSTRACT Background Anaemia is commonly caused by iron deficiency and screened by haemoglobin (Hb) concentration in blood. There is a scarcity of longitudinal data on the relationship between maternal Hb levels during pregnancy and neurodevelopment in children. Objective To measure the relationship of maternal Hb concentrations during pregnancy on early child development. Methods This prospective cohort study included 1,720 mother-child dyads in rural Bangladesh. Maternal Hb concentrations were measured at 14 and 30 weeks of gestation. The child’s Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI) at 18 months of age were measured using Bayley Scales of Infant and Toddler Development (BSID-II). Data on socio-demographic characteristics, anthropometrics, mothers’ IQ and children’s home stimulation were also collected. Bivariate and multivariable-adjusted linear regression analyses were used to explore associations of maternal Hb with child development. Results Mean Hb concentrations at 14 and 30 weeks of gestation were 116.6 g/L (±12.7) and 114.7 g/L (±12.7), respectively. Mean MDI and PDI scores among 18-month-old children were 78.9 (±12.4) and 93.8 (±13.7), respectively. Maternal 14-week Hb concentration was correlated with PDI (r = 0.06; p < 0.05) and 30-week Hb concentrations was correlated with MDI (r = 0.05; p < 0.05). Multivariable adjusted linear regression analysis showed that an increase in 14-week Hb concentrations increased the PDI scores among boys (β = 0.09; 95% CI: 0.02, 0.16). Hb concentrations at 30 weeks of gestation were not associated with MDI or PDI scores. Conclusion Higher maternal Hb concentrations at 14 weeks of gestation were associated with higher PDI among 18-month-old boys in Bangladesh.

Association between maternal hemoglobin concentration and educational attainment in mid-childhood in a high-resource obstetric setting: a prospective cohort study

BackgroundAlthough maternal Hb levels during pregnancy are commonly associated with perinatal outcomes, their link to childhood neurodevelopment remains uncertain. ObjectiveThis study aimed to examine the associations between maternal hemoglobin (Hb) in early and late pregnancy with offspring mid-childhood educational attainment in a high-resource obstetric setting. Study DesignPregnancy data from a prospective birth cohort (Pregnancy Outcome Prediction Study, Cambridge, UK, 2008-2012, N=3285) were linked to mid-childhood educational outcomes (Department for Education, UK). Regression models adjusted for maternal, child, and socioeconomic factors were used to determine associations between maternal Hb, pregnancy complications, and offspring educational outcomes (ages 5-7). ResultsNo association was observed between maternal Hb at 12 weeks and the likelihood of either adverse pregnancy outcomes or children meeting expected educational standards between ages 5-7. Higher maternal Hb at 28 weeks was associated with an increased risk of small-for-gestational age infants (aOR1.26, 95%CI 1.11-1.59; p=0.002) and preterm birth (aOR1.38, 95%CI 1.11-1.81; p=0.005). There were no adverse birth outcomes associated with anemia. However children of mothers who were anaemic at 28 weeks had ∼40% increased risk of not attaining expected educational standards at age 5 (aOR1.42, 95%CI 1.03-1.95; p=0.03). There was no association between maternal anemia at 28 weeks and educational performance at ages 6-7. No associations were found between high maternal Hb concentrations (top decile) or change Hb concentrations between 12-28 weeks and childhood educational attainment. ConclusionsMaternal anemia at 28 weeks of pregnancy is associated with reduced educational attainment aged 5, but not at older ages (6-7 years). A proactive approach to increasing maternal hemoglobin in high-resource settings is unlikely to impact on long-term childhood educational attainment.

Intra-uterine exposure to lower maternal haemoglobin concentration is associated with impaired cognitive function in stunted adolescents: results from a 17-year longitudinal cohort study in Indonesia

The long-term impact of maternal anaemia on cognitive performance remains unknown. Indonesian longitudinal cohort data of 363 paired pregnant mothers and their 10–14-year-old offspring were used to investigate the association between maternal haemoglobin (Hb) concentration and their offspring’s cognitive function (assessed by Raven’s Progressive Matrices test) during adolescence. The weighted anaemia prevalence was 49.3% in pregnant mothers and 22.2% in adolescents. Adolescents who were stunted, anaemic, or living in a rural area had significantly lower cognitive scores than their counterparts. Maternal Hb was not associated with adolescent cognitive function (β: 0.14; 95%CI: −0.052–0.340). However, the effect of maternal Hb concentration on offspring’s cognitive function was modified by stunting status (β, stunted: 0.44; 95%CI: 0.05–0.82; non-stunted: 0.01; 95%CI: −0.02–0.24). This study shows adverse cognitive outcomes at adolescent age are likely multi-causal and can be partially explained by intra-uterine exposure to low maternal Hb concentrations.

Maternal low and high hemoglobin concentrations and associations with adverse maternal and infant health outcomes: an updated global systematic review and meta-analysis

BackgroundGrowing evidence suggests low and high maternal hemoglobin (Hb) concentrations may have adverse consequences for maternal and child health. There remain questions on specific Hb thresholds to define anemia and high Hb as well as how cutoffs may vary by anemia etiology and timing of assessment.MethodsWe conducted an updated systematic review (using PubMed and Cochrane Review) on low (< 110 g/L) and high (≥ 130 g/L) maternal Hb concentrations and associations with a range of maternal and infant health outcomes. We examined associations by timing of Hb assessment (preconception; first, second, and third trimesters, as well as at any time point in pregnancy), varying cutoffs used for defining low and high hemoglobin concentrations and performed stratified analyses by iron-deficiency anemia. We conducted meta-analyses to obtain odds ratios (OR) and 95% confidence intervals.ResultsThe updated systematic review included 148 studies. Low maternal Hb at any time point in pregnancy was associated with: low birthweight, LBW (OR (95% CI) 1.28 (1.22–1.35)), very low birthweight, VLBW (2.15 (1.47–3.13)), preterm birth, PTB (1.35 (1.29–1.42)), small-for-gestational age, SGA (1.11 (1.02–1.19)), stillbirth 1.43 (1.24–1.65)), perinatal mortality (1.75 (1.28–2.39)), neonatal mortality (1.25 (1.16–1.34), postpartum hemorrhage (1.69 (1.45–1.97)), transfusion (3.68 (2.58–5.26)), pre-eclampsia (1.57 (1.23–2.01)), and prenatal depression (1.44 (1.24–1.68)). For maternal mortality, the OR was higher for Hb < 90 (4.83 (2.17–10.74)) than for Hb < 100 (2.87 (1.08–7.67)). High maternal Hb was associated with: VLBW (1.35 (1.16–1.57)), PTB (1.12 (1.00-1.25)), SGA (1.17 (1.09–1.25)), stillbirth (1.32 (1.09–1.60)), maternal mortality (2.01 (1.12–3.61)), gestational diabetes (1.71 (1.19–2.46)), and pre-eclampsia (1.34 (1.16–1.56)). Stronger associations were noted earlier in pregnancy for low Hb and adverse birth outcomes while the role of timing of high Hb was inconsistent. Lower Hb cutoffs were associated with greater odds of poor outcomes; for high Hb, data were too limited to identify patterns. Information on anemia etiology was limited; relationships did not vary by iron-deficiency anemia.ConclusionBoth low and high maternal Hb concentrations during pregnancy are strong predictors of adverse maternal and infant health outcomes. Additional research is needed to establish healthy reference ranges and design effective interventions to optimize maternal Hb during pregnancy.

Long-Term Association Between Maternal Preconception Hemoglobin Concentration, Anemia, and Child Health and Development in Vietnam

BackgroundThe long-term association between preconception maternal hemoglobin (Hb) concentrations and child health and development is unclear. ObjectivesWe examined associations between maternal preconception Hb concentrations and anemia with 1) birth outcomes (weight, length, preterm, gestational age, small for gestational age); 2) child Hb at 3 mo, 6 mo, 12 mo, and 24 mo; and 3) motor and mental development at 12 mo and 24 mo (Bayley scales for infant development) and cognitive functioning at 6–7 y (Wechsler Intelligence Scale for Children). MethodsWe used data from a randomized controlled trial (PRECONCEPT) conducted in Vietnam. Over 5000 women who were intending to conceive were recruited, and offspring were prospectively followed from birth (n = 1599) through 6–7 y (n = 1318). Multivariable linear and logistic regressions were used to assess the association between preconception Hb or anemia (Hb < 12g/dL) on child health and development outcomes, adjusted by supplementation group (tested for interactions) and confounding at maternal, child, and household levels. ResultsAt preconception enrollment, 20% of the women were anemic. Maternal preconception Hb was positively associated with child Hb at 3 mo (0.06; 95% CI: 0.01, 0.12), 6 mo (0.08; 95% CI: 0.03, 0.13), 12 mo (0.10; 95% CI: 0.04, 0.15), and 24 mo (0.07; 95% CI: 0.02, 0.12). Likewise, maternal preconception Hb was associated with reduced risk of child anemia at 6 mo (0.89; 95% CI: 0.81, 0.98), 12 mo (0.81; 95% CI: 0.74, 0.89), and 24 mo (0.87; 95% CI: 0.79, 0.95). Maternal preconception anemia was negatively associated with cognition (−1.64; 95% CI: −3.09, −0.19) and language development (−1.61; 95% CI: −3.20, −0.03) at 24 mo. Preconception Hb was not associated with birth outcomes or cognitive outcomes at 6–7 y. ConclusionsMaternal preconception Hb was associated with child Hb across the first 1000 d of life. However, preconception Hb was not a significant predictor of birth outcomes or cognitive outcomes at 6–7 y in this cohort from Vietnam. Clinical Trial RegistrationPRECONCEPT study (NCT: 01665378).

Maternal anaemia and birth weight: a cross-sectional study from Jiangxi Province, China.

Association between maternal haemoglobin (Hb) and low birth weight (LBW) remains a controversial topic, and data in China were sparse. We aimed to investigate the association between maternal Hb and LBW among pregnant women in Jiangxi Province, China. In this cross-sectional study, 1,029 participants were enrolled. Anaemia was classified according to World Health Organization's definition of anaemia in pregnancy. Logistic regression analysis was performed to evaluate the association between maternal Hb and LBW. Generalized additive model and smooth curve fitting (penalized spline method) were conducted to explore the exact shape of curve between them. The overall prevalence of anaemia was 58.2% in our study. A significantly higher risk of LBW was found in moderate anaemia subjects (odds ratio [OR] = 2.93; 95% confidence interval [CI]: 1.16-5.31) and severe anaemia subjects (OR = 63.86; 95% CI: 25.66-158.90) compared with maternal Hb concentration >100 g/L. The fully adjusted smooth curve fitting presented an L-shaped association between the maternal Hb and LBW, with a turning point at about 110 g/L. Subgroup analyses showed that stronger associations between maternal Hb and LBW were detected in pregnant women with high education, long duration of gestation and multiple antenatal visits (all P for interaction <0.05). Anaemia in delivering women was associated with an elevated risk of LBW and the risk increased with the severity of anaemia, especially among pregnant women with high education, long duration of gestation and multiple antenatal visits from Jiangxi Province, China.

Association of Maternal Longitudinal Hemoglobin with Small for Gestational Age during Pregnancy: A Prospective Cohort Study.

Background: Few studies have investigated the association of maternal longitudinal hemoglobin (Hb) with small for gestational age during pregnancy. The current study examined the associations of maternal Hb concentrations and Hb changes throughout the middle and late stages of pregnancy with small for gestational age (SGA) in a large prospective cohort study. Methods: This was a prospective cohort study, which enrolled pregnant women at 8–16 weeks of gestation and followed up regularly. Maternal Hb concentrations were measured at the middle (14–27 weeks) and late (28–42 weeks) stages of pregnancy, and the Hb change from the middle to late stage of pregnancy was assessed. The Log-Poisson regression model was used to identify the association of maternal Hb with SGA, including the implications of Hb during specific pregnancy periods and Hb change across the middle to late stages of pregnancy. Of the total 3233 singleton live births, 208 (6.4%) were SGA. After adjusting for potential confounders, compared with Hb 110–119 g/L, Hb ≥ 130 g/L at late pregnancy was significantly associated with a higher risk of SGA (adjusted RR: 2.16; 95% CI: 1.49, 3.13). When Hb changes from the middle to late stages of pregnancy were classified by tertiles, the greatest change in the Hb group (<−6.0 g/L) was significantly associated with a lower risk of SGA (adjusted RR: 0.56; 95% CI: 0.37, 0.85) compared with the intermediate group (−6.0~1.9 g/L). In conclusion, for women at low risk of iron deficiency, both higher Hb concentrations in late pregnancy and less Hb reduction during pregnancy were associated with an increased risk of SGA.

Preconception Hemoglobin Concentration and Risk of Low Birth Weight and Small-for-Gestational-Age: A Large Prospective Cohort Study in China.

Less is known about the impact of maternal preconception anemia on birth outcomes. We aimed to examine associations between preconception hemoglobin (Hb) concentrations with risk of low birth weight (LBW) and small-for-gestational-age (SGA). This study was from a large population-based prospective cohort in China and included 124,725 women with singleton live births delivered at gestational ages of 28–45 weeks who were registered before pregnancy. Maternal Hb concentrations were measured during registration, and other health-related information was recorded prospectively. Logistic regression was used to evaluate the associations between preconception Hb concentrations with risk of LBW and SGA, adjusting for potential confounders. The results showed women with preconception anemia accounted for 22.28%. The incidences of LBW/SGA were 2.37%/6.30% among anemic women, and 2.01%/5.48% among non-anemic women, respectively. Preconception mild anemia increased by 17% (95% confidence interval (CI): 1.06, 1.28) and 14% (95% CI: 1.07, 1.21) the risk for LBW and SGA, while moderate-to-severe anemia had no significant association with LBW and SGA. Compared with the 120–129 g/L group, a U-shaped association was observed between preconception Hb concentrations with LBW and SGA. In conclusion, not only maternal anemia but also elevated Hb concentrations before pregnancy contribute to an increased risk of LBW and SGA.

Placental EPO mRNA Expression Is Measurable in Very Preterm to Term Placentae

ObjectivesOur objective was to evaluate placental EPO mRNA expression in term and preterm placentae and explore maternal/neonatal/placental determinants of EPO expression. MethodsPlacental tissue was collected from pregnant adolescents (n = 82, < 19 y of age) and from women (n = 62) carrying multiple fetuses (twins = 23, triplets = 39). Placental mRNA expression was evaluated using qPCR. Hemoglobin and iron status biomarkers (SF, TBI, sTfR, Hepcidin) were measured in maternal blood at delivery and in cord blood. ResultsIn this population, women delivered between 30–42 weeks of gestation. Of the 144 women, 30% delivered prematurely (< 37 weeks, n = 44) and 69% delivered at term (≥37 weeks, n = 100). As expected, preterm placentae weighed significantly less than term placenta (293 ± 93 g vs. 544 ± 143 g, p < 0.0001). Placental EPO mRNA expression was detected in all samples collected. Placental EPO mRNA expression did not significantly differ between anemic (Hb < 13 g/dL) (n = 23) and non-anemic (n = 84) neonates (p = 0.69), nor was it significantly associated with maternal anemia at delivery (p = 0.44). Placental EPO mRNA expression was also not significantly associated with maternal (p = 0.56) or neonatal (p = 0.61) Hb concentrations, placental weight (p = 0.46) or gestational age at delivery (p = 0.39). ConclusionsWhile placental EPO mRNA was detected in all placental tissue collected between 30–42 weeks of gestation none of the iron biomarkers evaluated were significantly related to placental EPO mRNA expression. Further studies are needed to understand determinants of placental EPO mRNA and protein expression. Funding SourcesThe U.S. National Institutes of Health (NIH) National Institute of Child Health and Development (NICHD) Grant 1R21HD098864, The Gerber Foundation and USDA grants 2005–35,200-15,218 and 2009–35,200-05,171.

Hemoglobin concentrations and adverse birth outcomes in South Asian pregnant women: findings from a prospective Maternal and Neonatal Health Registry

BackgroundWhile the relationship between hemoglobin (Hb) concentrations and pregnancy outcomes has been studied often, most reports have focused on a specific Hb cutoff used to define anemia. Fewer studies have evaluated pregnancy outcomes across the entire range of Hb values. Moreover, to date, most studies of the relationship of Hb concentrations to pregnancy outcomes have been done in high-income countries. Thus, we have sought to determine the relationship between the range of maternal Hb concentrations and adverse birth outcomes among South Asian pregnant women.MethodsFor this study, we used data collected from two South Asian countries (Pakistan – Sindh Province and two sites in India - Belagavi and Nagpur) in a prospective maternal and newborn health registry study. To assess the association between Hb concentrations and various maternal and fetal outcomes, we classified the Hb concentrations into seven categories. Regression analyses adjusting for multiple potential confounders were performed to assess adverse pregnancy outcomes across the range of Hb concentrations.FindingsBetween January 2012 and December 2018, 130,888 pregnant women were enrolled in the South Asian sites had a Hb measurement available, delivered and were included in the analyses. Overall, the mean Hb concentration of pregnant women from the sites was 9.9 g/dL, 10.0 g/dL in the Indian sites and 9.5 g/dL in the Pakistan site. Hb concentrations < 7 g/dL were observed in 6.9% of the pregnant Pakistani women and 0.2% of the Indian women. In both the Pakistani and Indian sites, women with higher parity and women with no formal education had lower Hb concentrations. In the Pakistani site, women > 35 years of age, women with ≥4 children and those who enrolled in the third trimester were more likely to have Hb concentrations of < 7 g/dL but these associations were not found for the Indian sites. When adjusting for potential confounders, for both India and Pakistan, lower Hb concentrations were associated with stillbirth, preterm birth, lower mean birthweight, and increased risk of low birthweight. In the Pakistani site, there was evidence of a U-shaped relationship between Hb concentrations and low birth weight, and neonatal mortality, and in India with hypertensive disease.InterpretationThis study documented the relationship between maternal Hb concentrations and adverse pregnancy outcomes in women from the Pakistani and Indian sites across the range of Hb values. Both low and high Hb concentrations were associated with risk of at least some adverse outcomes. Hence, both low and high values of Hb should be considered risk factors for the mother and fetus.

Preconception Hb concentration with risk of spontaneous abortion: a population-based cohort study in over 3·9 million women across rural China.

Evidence on the relationship between maternal Hb concentration and spontaneous abortion (SA) risk is limited and conflicting. The purpose of the study was to evaluate whether maternal preconception anaemia or high Hb concentration is associated with risk of SA. A population-based cohort study established between 2013 and 2017. Local maternal and child care service centres in each county. In total, 3 971 428 women aged 20-49 years, who participated in National Free Pre-Pregnancy Checkups Project from 2013 to 2016 and successfully got pregnant before 2017 in rural China. A total of 101 700 (2·56 %) women were recorded having SA, with highest SA rate in women with severe anaemia (4·58 %). Compared with women with Hb of 110-149 g/l, the multivariable-adjusted OR for SA was 1·52 (95 % CI: 1·25, 1·86) for women with Hb < 70 g/l, 0·92 (0·84, 1·01) for 70-99 g/l, 0·80 (0·77, 0·83) for 100-109 g/l, 1·11 (1·08, 1·15) for 150-159 g/l, 1·12 (1·04, 1·20) for 160-169 g/l and 1·02 (0·93, 1·12) for ≥ 170 g/l, respectively. An approximate U-shaped curve for the risk of SA with Hb concentrations was observed when Hb concentrations less than 145 g/l, above which the association plateaued (Pnon-linear < 0·001). Severe anaemia and high Hb concentration before pregnancy were associated with an increased risk of SA. Women with mild anaemia prior to pregnancy had lower risk of SA. Underlying mechanisms need to be further studied.

Iron intake and iron status during pregnancy and risk of congenital heart defects: A case-control study

BackgroundThe relationships between iron nutritional status and congenital heart defects (CHDs) among humans are still unclear. This study aimed to explore the associations of maternal iron intake during pregnancy and maternal and neonatal iron status with CHDs. MethodsThis hospital-based case-control study analyzed 474 cases and 948 controls in Shaanxi China. Eligible women waiting for delivery in the hospital were interviewed to report their diets and characteristics during pregnancy. We conveniently collected maternal blood before delivery and neonatal cord blood to get a subgroup of 50 cases and 100 controls. Mixed logistic regression models were used to estimate ORs (95%CIs) for CHDs associated with iron intake. Mixed linear regression models were used to assess the relationships between CHDs and iron status. ResultsMothers whose fetuses have CHDs were less likely to have higher intakes of total iron and heme iron during pregnancy, and the tests for linear trend were significant (all P < 0.05). Mothers whose fetuses have CHDs were less likely to take iron supplements during pregnancy (OR = 0.28, 95%CI: 0.21, 0.36) and during the first trimester (OR = 0.32, 95%CI: 0.12, 0.84). Maternal SF and Hb concentrations before delivery were lower and maternal sTfR/SF before delivery was higher among the cases than the controls. ConclusionsMothers whose fetuses have CHDs are less likely to have higher intakes of total iron and heme iron and take iron supplements during pregnancy compared to their counterparts. Maternal iron status before delivery is low among mothers whose fetuses have CHDs.

Anaemia and iron deficiency in pregnancy and adverse perinatal outcomes in Southern India.

We examined the prevalence of anaemia, iron deficiency, and inflammation during pregnancy and their associations with adverse pregnancy and infant outcomes in India. Three hundred and sixty-six women participating in a randomised trial of vitamin B12 supplementation were monitored to assess haemoglobin (Hb), serum ferritin (SF), hepcidin, C-reactive protein (CRP), and alpha-1-acid glycoprotein (AGP) during pregnancy. Women received vitamin B12 supplementation (50 µg per day) or placebo daily; all women received daily prenatal iron-folic acid supplementation. Binomial and linear regression models were used to examine the associations of maternal iron biomarkers with pregnancy and infant outcomes. Thirty percent of women were anaemic (Hb < 11.0 g/dl), 48% were iron deficient (SF < 15.0 µg/l), and 23% had iron deficiency anaemia at their first prenatal visit. The prevalence of inflammation (CRP > 5.0 mg/l: 17%; AGP > 1.0 g/l: 11%) and anaemia of inflammation (Hb < 11.0 g/dl, SF > 15.0 µg/l, plus CRP > 5.0 mg/l or AGP > 1.0 g/l: 2%) were low. Infants born to anaemic women had a twofold higher risk of low birth weight (<2500 g; risk ratio [RR]: 2.15, 95%CI: 1.20-3.84, p = 0.01), preterm delivery (RR: 2.67 (1.43-5.00); p = 0.002), underweight (WAZ < -2; RR: 2.20, 95%CI: 1.16-4.15, p = 0.02), and lower MUAC (β(SE): -0.94 (0.45)cm, p = 0.03). Similarly, maternal Hb concentrations predicted higher infant birth weight (p = 0.02) and greater gestational age at delivery (β(SE): 0.28 (0.08) weeks, p = 0.001), lower risk of preterm delivery (<37 weeks; RR: 0.76, 95%CI: 0.66-86, p < 0.0001); and higher infant MUAC (β(SE): 0.36 (0.13) cm, p = 0.006). Maternal SF concentrations were associated with greater birth length (β(SE): 0.44 (0.20) cm, p < 0.03). Findings were similar after adjusting SF concentrations for inflammation. IDA was associated with higher risk of low birth weight (RR: 1.99 (1.08-3.68); p = 0.03) and preterm birth (RR: 3.46 (1.81-6.61); p = 0.0002); and lower birth weight (p = 0.02), gestational age at birth (p = 0.0002), and infant WAZ scores (p = 0.02). The prevalence of anaemia and iron deficiency was high early in pregnancy and associated with increased risk of adverse pregnancy and infant outcomes. A comprehensive approach to prevent anaemia is needed in women of reproductive age, to enhance haematological status and improve maternal and child health outcomes.

Maternal hemoglobin concentrations across pregnancy and maternal and child health: a systematic review and meta-analysis.

Maternal anemia is a well‐recognized global health problem; however, there remain questions on specific hemoglobin (Hb) thresholds that predict health risk or protection for mother and child. We conducted a systematic review and meta‐analysis to examine the associations of maternal Hb concentrations with a range of maternal and infant health outcomes, accounting for the timing of measurement (preconception, and first, second, and third trimesters), etiology of anemia, and cutoff category. The systematic review included 272 studies and the meta‐analysis included 95 studies. Low maternal Hb (<110 g/L) was associated with poor birth outcomes (low birth weight, preterm birth, small‐for‐gestational‐age (SGA), stillbirth, and perinatal and neonatal mortality) and adverse maternal outcomes (postpartum hemorrhage, preeclampsia, and blood transfusion). High maternal Hb (>130 g/L) was associated with increased odds of SGA, stillbirth, preeclampsia, and gestational diabetes. Relationships varied by the timing of measurement and cutoff category (stronger associations with lower cutoffs); limited data were available on anemia etiology. There were insufficient data for other maternal outcomes and long‐term child health outcomes. Current data are insufficient for determining if revisions to current Hb cutoffs are required. Pooled high‐quality individual‐level data analyses, as well as prospective cohort studies, would be valuable to inform the reevaluation of Hb cutoffs.

Maternal haemoglobin concentrations before and during pregnancy as determinants of the concentrations of children at 3–5 years of age: A large follow-up study

To examine the association between haemoglobin (Hb) concentrations in mothers before and during pregnancy and those in children at 3-5 years of age. The study included 78,923 women who conceived during 1993-1996 and delivered a singleton live infant. Maternal Hb concentrations were measured at pre-pregnancy health check-up and first prenatal visit, and during the second and third trimester. Hb concentrations of children born to these women were measured at 3-5 years of age. Associations between Hb levels in mothers and children were examined. Unconditional logistic regression was used to explore the association between maternal Hb levels and risk for anaemia in children. Maternal Hb levels before and during pregnancy were positively associated with children's Hb levels. Using maternal Hb ≥ 130 g/L as the referent, the risk for anaemia in children at 3-5 years of age was higher when maternal second trimester Hb concentrations were 70-99 g/L (odds ratio [OR] = 1.76, 95% confidence interval [CI] = 1.56-1.99), 100-109 g/L (OR = 1.45, 95% CI = 1.29-1.64), and 110-119 g/L (OR = 1.18, 95% CI = 1.04-1.33). Children were 1.52 and 1.23-times more likely to suffer from anaemia when maternal third trimester Hb concentrations were 70-99 and 100-109 g/L, respectively. A pre-pregnancy Hb concentration of 80-109 g/L and first prenatal visit Hb concentrations of 80-109 and 100-119 g/L were also associated with increased risks for childhood anaemia. Low maternal Hb concentrations before or during pregnancy increase the risk for anaemia in children at 3-5 years of age.

Preconception Hb concentration and risk of preterm birth in over 2·7 million Chinese women aged 20-49 years: a population-based cohort study.

Evidence on the association between maternal Hb concentration and preterm birth (PTB) risk is inconclusive. This paper aimed to explore whether women with anaemia or high Hb level before pregnancy would be at higher risk of PTB. We conducted a population-based cohort study with 2 722 274 women aged 20-49 years, who participated in National Free Pre-Pregnancy Checkups Project between 2013 and 2015 and delivered a singleton before 2016 in rural China. Logistic models were used to estimate OR and 95 % CI after adjusting for confounding variables. Restricted cubic spline models were applied to evaluate the dose-response relationships. A total of 192 819 (7·08 %) women had preterm deliveries. Compared with women with Hb of 110-149 g/l, the multivariable-adjusted OR for PTB was 1·19 (95 % CI 0·98, 1·44) for women with Hb<70 g/l, 1·01 (95 % CI 0·97, 1·03) for 70-99 g/l, 0·96 (95 % CI 0·95, 0·98) for 100-109 g/l, 1·04 (95 % CI 1·01, 1·06) for 150-159 g/l, 1·11 (95 % CI 1·05, 1·17) for 160-169 g/l and 1·19 (95 % CI 1·11, 1·27) for ≥170 g/l, respectively. The multivariable-adjusted OR for very PTB (VPTB) was 1·07 (95 % CI 1·03, 1·12) and 1·06 (95 % CI 1·01, 1·12) for women with Hb <110 and ≥150 g/l, compared with those with Hb of 110-149 g/l, respectively. Our study identified a U-shaped relationship between maternal preconception Hb concentration and PTB risk. Both preconception anaemia and high Hb level can significantly increase VPTB risk. Appropriate intervention for women with abnormal Hb levels before pregnancy is very necessary.

Pregnancy Induced Hypertension Accompanied With Anemia: Potential Stunting of Newborns

INTRODUCTION: Pregnancy induced hypertension (PIH) of anemia pregnant women is a major contributor to adverse birth outcomes of newborns. This research aims to assess the association between pregnancy induced hypertension of anemia pregnant women and poor birth outcomes of newborns, especially body length of newborns at delivery.MATERIAL &amp;amp; METHODS: One hundred and eight pregnant women are enrolled according to the inclusion criteria. Sociodemographic data, anthropometric measurements, obstetric profiles (gravida), and data of systolic and diastolic blood pressure were collected in this study. Trained midwives drew blood samples from pregnant women as the study samples to measure their hemoglobin (Hb) concentrations and to assess their anemia. Gestational age (GA), types of delivery, anthropometric measurements of newborns (length, weight, head circumference, abdominal circumference and chest circumference) were conducted at delivery. Univariate and bivariate linear analyses were conducted to compare birth outcomes of newborns for each groupRESULTS: Of the total 108 pregnant women as the study samples, 25 pregnant women had blood pressures at normal level and normal Hb concentrations, 36 pregnant women had pregnancy induced hypertension (PIH), 29 pregnant women had anemia and 18 pregnant women had pregnancy induced hypertension (PIH) of anemia pregnant women respectively. All groups showed significantly different characteristics of pregnant women in terms of age (p = 0,027), height (p = 0,019), weight (p = 0.000), body mass index (BMI) (p = 0,001), Hb concentration (p = 0.000), systolic blood pressure (p = 0.000), diastolic blood pressure (p = 0.000). Mean length of newborns was significantly lower in pregnancy induced hypertension (PIH) with anemia pregnant women (p = 0.001). Statistical tests showed that there were negative correlations between maternal Hb concentrations and birth length (p = 0.024) as well as blood pressure and birth length (p = 0.000).CONCLUSION: The average length of newborns in pregnancy induced hypertension (PIH) and pregnancy induced hypertension (PIH) of anemia pregnant women was statistically significant shorter length (stunting) than the normal group. Thus, it is suggested that women who give birth with these conditions should pay more attention to the intake of good nutrition in the first 5 years of their children (the gold period) to prevent long-term adverse effects.

Maternal haemoglobin concentration and risk of preterm birth in a Chinese population

The aim was to examine the relationship between maternal haemoglobin (Hb) concentrations and risk of preterm birth by secondary analysis of data from a randomised controlled trial. This analysis included 10,430 women who were at least 20 years old and no more than 20 weeks of gestation. Results revealed neither first- nor second-trimester Hb concentrations were associated with the risk of preterm births. However, the risk of preterm birth increased when the Hb level was low (<130 g/L) in the first but high (≥130 g/L) in the second trimester, regardless of supplement type (iron-containing: AOR: 2.26, 95% CI: 1.37–3.73; non-iron-containing: AOR: 2.16, 95% CI: 1.11–4.21). In conclusion, maternal Hb concentrations were not associated with the risk of preterm birth. A low-Hb level in the first trimester but coupled with a high Hb level in the second was associated with an elevated risk of preterm birth.Impact statementWhat is already known on this subject: The relationship between maternal Hb concentration and preterm birth remains inconclusive. Some studies have shown an association between a low- or a high-Hb level and an increased risk of preterm birth. Others have not found such an association. Yet others have shown a U-shaped relationship.What do the results of this study add: Overall, maternal Hb concentrations in first or second trimester were not statistically associated with the risk of preterm birth. However, women with a low Hb concentration in the first trimester together with a high Hb concentration in the second trimester had an increased risk of preterm birth, compared to women who had a higher Hb concentration in the first trimester that remained similar during the second trimester.What are the implications are of these findings for clinical practice and/or further research: Our finding helps identify mothers who are at risk of having a preterm delivery. Investigating the underlying clinical causes of the unfavourable change in Hb levels and close follow-up to these women may help improve birth outcomes.

Maternal Hemoglobin Concentration during Gestation and Risk of Anemia in Infancy: Secondary Analysis of a Randomized Controlled Trial

This study examined the relationship between maternal hemoglobin (Hb) concentration and the risk of anemia in infancy. This analysis included 17 193 women who entered the trial when they were ≥20years of age, no more than 20weeks of gestation, had mild or no anemia, and delivered singleton live births. Maternal Hb concentrations were measured in the first trimester and during 24-28weeks of gestation; infant Hb concentrations were measured at 5-7months and 11-13months of life. The associations between maternal Hb concentrations and infant Hb concentrations were examined. Maternal Hb concentrations measured during 24-28weeks of gestation, but not in the first trimester, were correlated with infant Hb concentrations measured at either of the 2 post-partum periods. The risk of infant anemia at 5-7months of age increased when maternal Hb concentration was ≤109g/L during 24-28weeks of gestation (aOR, 1.95; 95% CI, 1.59-2.40) and 11-13months of age (aOR, 1.72; 95% CI, 1.36-2.18), whereas the risk of anemia during 5-7months of age as well as 11-13months in infancy decreased when maternal Hb level at 24-28weeks of gestation was 120-129g/L (aOR for 5-7months, 0.74 [95% CI, 0.64-0.85]; aOR for 11-13months, 0.72 [95% CI, 0.61-0.85]), or ≥130g/L (aOR for 5-7months, 0.75 [95% CI, 0.63-0.90]; aOR for 11-13months, 0.89 [95% CI, 0.73-1.08]). Low maternal Hb concentration during 24-28weeks of gestation was associated with an increased risk of anemia in infancy, whereas high maternal Hb concentration was associated with a reduced risk of anemia. Clinicaltrials.gov: NCT00133744.

Maternal hemoglobin concentration and hematocrit values may affect fetus development by influencing placental angiogenesis

Objective: Vasculogenesis and angiogenesis are crucial for maintaining proper placental perfusion and optimal fetal development. Among other physical and chemical factors, hypoxia is known to stimulate angiogenic processes. Preplacental type of hypoxia is often associated with maternal anemia and is thought to enhance vascularization within the fetoplacental unit. The goal of this study was to establish the correlation between the local expression of vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) receptors (flt-1, flk-1) with maternal hemoglobin (Hb) concentration, hematocrit (Ht) values and the infant birthweight.Methods: In total, 43 specimens of term placentas obtained from normal course pregnancies delivered at term were included in the study. The expression of flt-1 and flk-1 receptors was analyzed by immunohistochemical staining. Vascular/extravascular tissular index (V/EVTI) was measured by assessing a total vascular area. Nonparametric Mann–Whitney U-test and Spearman’s rank correlation were used to compare the various parameters and their differences between the groups.Results: Among the patients with low Hb concentration, nearly 2-fold greater expression of the flt-1 receptor was positively correlated with infants birthweight (p = 0.028).Conclusions: Increased placental vascular density (increased flt-1 expression), during a physiological course of gestation, may be an adaptive response to lowered maternal Hb concentration and Ht values encountered during pregnancy.