Maternal Hemoglobin Concentrations and Birth Weight, Low Birth Weight (LBW), and Small for Gestational Age (SGA): Findings from a Prospective Study in Northwest China

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

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 gestational arsenic exposure and infant physical development: a prospective cohort study

BACKGROUND

Arsenic pollution is widespread worldwide. The association between gestational arsenic exposure and adverse birth outcomes has been demonstrated in previous studies; however, few investigations have examined whether gestational arsenic exposure has adverse effects on infant growth and development after birth.

OBJECTIVE

Our study was designed to evaluate particular associations between gestational arsenic exposure during pregnancy and newborn birth size and to investigate whether these associations continue to affect infants after birth.

METHODS

An ongoing prospective cohort study of 1100 pregnant women was conducted at the Wuxi Maternity and Child Health Care Hospital. The total urinary arsenic concentrations in the 2nd and 3rd trimester were determined using atomic fluorescence spectrometry. The relationships between urinary arsenic concentration and foetal growth parameters (birth weight, head circumference, length, and ponderal index), SGA (Small for gestational age), and physical growth of infants within one year after birth were analysed.

RESULTS

Urinary arsenic concentration in the 3rd trimester was associated with an increased incidence of SGA [adjusted model: OR = 2.860 (95% CI: 1.168, 7.020), P = 0.021)]. Arsenic exposure in late pregnancy had an adverse effect on the physical development of infants before the age of 1 year, and there was an interaction effect with the sex of infants. The weight and length of boys at 6 and 12 months negatively correlated with maternal urinary arsenic levels during late pregnancy.

CONCLUSIONS

In addition to affecting foetal growth, exposure to arsenic in the 3rd trimester also negatively affected the growth of offspring within the first year of life.

Daily oral iron supplementation during pregnancy

BACKGROUND

Iron and folic acid supplementation have been recommended in pregnancy for anaemia prevention, and may improve other maternal, pregnancy, and infant outcomes.

OBJECTIVES

To examine the effects of daily oral iron supplementation during pregnancy, either alone or in combination with folic acid or with other vitamins and minerals, as an intervention in antenatal care.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Registry on 18 January 2024 (including CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, WHO's International Clinical Trials Registry Platform, conference proceedings), and searched reference lists of retrieved studies.

SELECTION CRITERIA

Randomised or quasi-randomised trials that evaluated the effects of oral supplementation with daily iron, iron + folic acid, or iron + other vitamins and minerals during pregnancy were included.

DATA COLLECTION AND ANALYSIS

Review authors independently assessed trial eligibility, ascertained trustworthiness based on pre-defined criteria, assessed risk of bias, extracted data, and conducted checks for accuracy. We used the GRADE approach to assess the certainty of the evidence for primary outcomes. We anticipated high heterogeneity amongst trials; we pooled trial results using a random-effects model (average treatment effect).

MAIN RESULTS

We included 57 trials involving 48,971 women. A total of 40 trials compared the effects of daily oral supplements with iron to placebo or no iron; eight trials evaluated the effects of iron + folic acid compared to placebo or no iron + folic acid. Iron supplementation compared to placebo or no iron Maternal outcomes: Iron supplementation during pregnancy may reduce maternal anaemia (4.0% versus 7.4%; risk ratio (RR) 0.30, 95% confidence interval (CI) 0.20 to 0.47; 14 trials, 13,543 women; low-certainty evidence) and iron deficiency at term (44.0% versus 66.0%; RR 0.51, 95% CI 0.38 to 0.68; 8 trials, 2873 women; low-certainty evidence), and probably reduces maternal iron-deficiency anaemia at term (5.0% versus 18.4%; RR 0.41, 95% CI 0.26 to 0.63; 7 trials, 2704 women; moderate-certainty evidence), compared to placebo or no iron supplementation. There is probably little to no difference in maternal death (2 versus 4 events, RR 0.57, 95% CI 0.12 to 2.69; 3 trials, 14,060 women; moderate-certainty evidence). The evidence is very uncertain for adverse effects (21.6% versus 18.0%; RR 1.29, 95% CI 0.83 to 2.02; 12 trials, 2423 women; very low-certainty evidence) and severe anaemia (Hb < 70 g/L) in the second/third trimester (< 1% versus 3.6%; RR 0.22, 95% CI 0.01 to 3.20; 8 trials, 1398 women; very low-certainty evidence). No trials reported clinical malaria or infection during pregnancy. Infant outcomes: Women taking iron supplements are probably less likely to have infants with low birthweight (5.2% versus 6.1%; RR 0.84, 95% CI 0.72 to 0.99; 12 trials, 18,290 infants; moderate-certainty evidence), compared to placebo or no iron supplementation. However, the evidence is very uncertain for infant birthweight (MD 24.9 g, 95% CI -125.81 to 175.60; 16 trials, 18,554 infants; very low-certainty evidence). There is probably little to no difference in preterm birth (7.6% versus 8.2%; RR 0.93, 95% CI 0.84 to 1.02; 11 trials, 18,827 infants; moderate-certainty evidence) and there may be little to no difference in neonatal death (1.4% versus 1.5%, RR 0.98, 95% CI 0.77 to 1.24; 4 trials, 17,243 infants; low-certainty evidence) or congenital anomalies, including neural tube defects (41 versus 48 events; RR 0.88, 95% CI 0.58 to 1.33; 4 trials, 14,377 infants; low-certainty evidence). Iron + folic supplementation compared to placebo or no iron + folic acid Maternal outcomes: Daily oral supplementation with iron + folic acid probably reduces maternal anaemia at term (12.1% versus 25.5%; RR 0.44, 95% CI 0.30 to 0.64; 4 trials, 1962 women; moderate-certainty evidence), and may reduce maternal iron deficiency at term (3.6% versus 15%; RR 0.24, 95% CI 0.06 to 0.99; 1 trial, 131 women; low-certainty evidence), compared to placebo or no iron + folic acid. The evidence is very uncertain about the effects of iron + folic acid on maternal iron-deficiency anaemia (10.8% versus 25%; RR 0.43, 95% CI 0.17 to 1.09; 1 trial, 131 women; very low-certainty evidence), or maternal deaths (no events; 1 trial; very low-certainty evidence). The evidence is uncertain for adverse effects (21.0% versus 0.0%; RR 44.32, 95% CI 2.77 to 709.09; 1 trial, 456 women; low-certainty evidence), and the evidence is very uncertain for severe anaemia in the second or third trimester (< 1% versus 5.6%; RR 0.12, 95% CI 0.02 to 0.63; 4 trials, 506 women; very low-certainty evidence), compared to placebo or no iron + folic acid. Infant outcomes: There may be little to no difference in infant low birthweight (33.4% versus 40.2%; RR 1.07, 95% CI 0.31 to 3.74; 2 trials, 1311 infants; low-certainty evidence), comparing iron + folic acid supplementation to placebo or no iron + folic acid. Infants born to women who received iron + folic acid during pregnancy probably had higher birthweight (MD 57.73 g, 95% CI 7.66 to 107.79; 2 trials, 1365 infants; moderate-certainty evidence), compared to placebo or no iron + folic acid. There may be little to no difference in other infant outcomes, including preterm birth (19.4% versus 19.2%; RR 1.55, 95% CI 0.40 to 6.00; 3 trials, 1497 infants; low-certainty evidence), neonatal death (3.4% versus 4.2%; RR 0.81, 95% CI 0.51 to 1.30; 1 trial, 1793 infants; low-certainty evidence), or congenital anomalies (1.7% versus 2.4; RR 0.70, 95% CI 0.35 to 1.40; 1 trial, 1652 infants; low-certainty evidence), comparing iron + folic acid supplementation to placebo or no iron + folic acid. A total of 19 trials were conducted in malaria-endemic countries, or in settings with some malaria risk. No studies reported maternal clinical malaria; one study reported data on placental malaria.

AUTHORS' CONCLUSIONS

Daily oral iron supplementation during pregnancy may reduce maternal anaemia and iron deficiency at term. For other maternal and infant outcomes, there was little to no difference between groups or the evidence was uncertain. Future research is needed to examine the effects of iron supplementation on other maternal and infant health outcomes, including infant iron status, growth, and development.

Efficacy and Safety of Microsomal Ferric Pyrophosphate Supplement for Iron Deficiency Anemia in Pregnancy

Introduction Anemia during pregnancy is characterized by decreased hemoglobin levels. Iron deficiency poses a significant global health concern, especially in pregnant women, where increased iron demands are crucial for both maternal and fetal well-being. Method In the current study, we investigated the effectiveness and safety of 30 mg SunActiveTM Fe (Taiyo GmbH, Yokkaichi, Japan), emulsified microsomalTM ferric pyrophosphate (EMFP) tablets in treating iron deficiency anemia in 27 second-trimester singleton pregnant women. Results Our study results demonstrated that hemoglobin levels increased significantly within 30 days of treatment and continued to remain higher than baseline throughout the study. Serum ferritin levels exhibited a 6.61-fold increase, maintaining elevated levels consistently. Serum iron also increased significantly by 46.9%. Additionally, symptoms such as nausea, breathlessness, dizziness, irritability, and heartburn were notably reduced, leading to improved quality of life. Subjects reported decreased overall fatigue, indicating an enhanced quality of life. Babies born during the study showed healthy birth weights, with uncomplicated deliveries. High treatment compliance of 99.5% underscored patient commitment to the study. Furthermore, the investigational product demonstrated a favorable safety profile, with only two mild adverse events observed, unrelated to the treatment. Conclusion These findings suggest that EMFP could be a valuable therapeutic option for managing iron deficiency anemia in pregnant women, promoting better maternal and fetal outcomes. Further research with an increased sample size is warranted to delve into the underlying mechanisms behind these positive outcomes, nonetheless, our study provides a promising foundation for addressing this critical health issue.

Maternal anaemia during early pregnancy and the risk of neonatal outcomes: a prospective cohort study in Central China

BACKGROUND

The purpose of this study was to explore the association between anaemia during early pregnancy and the risk of neonatal outcomes.

METHODS

We collected clinical data from pregnant women (≥18 years) who received their first antenatal care between 8 and 14 weeks of gestation in Hunan Provincial Maternal and Child Health Care Hospital. Multiple logistic regression models and restricted cubic spline regression models were used to analyse the association between anaemia during early pregnancy and the risk of neonatal outcomes. In addition, sensitivity analysis was further performed to assess the robustness of the results.

RESULTS

The prospective cohort study ultimately included 34 087 singleton pregnancies. In this study, the rate of anaemia during early pregnancy was 16.3%. Our data showed that there was a positive relationship between the rate of preterm birth, low birth weight as well as small for gestational age (SGA) and the severity of maternal anaemia (Ptrend<0.05). After adjustment, the association of early pregnancy anaemia and haemoglobin (Hb) levels with the risk of preterm birth (mild anaemia adjusted OR (aOR) 1.37 (95% CI 1.25 to 1.52), moderate anaemia aOR 1.54 (95% CI 1.35 to 1.76) and severe anaemia aOR 4.03 (95% CI 2.67 to 6.08), respectively), low birth weight (mild anaemia aOR 1.61 (95% CI 1.44 to 1.79), moderate anaemia aOR 2.01 (95% CI 1.75 to 2.30) and severe anaemia aOR 6.11 (95% CI 3.99 to 9.36), respectively) and SGA (mild anaemia aOR 1.37 (95% CI 1.25 to 1.52), moderate anaemia aOR 1.54 (95% CI 1.35 to 1.76) and severe anaemia aOR 2.61 (95% CI 1.74 to 4.50), respectively; Pnon-linear<0.05) was observed. However, no association was found between early pregnancy anaemia or Hb levels and the risk of congenital malformations. Sensitivity analysis verified the stability of the results.

CONCLUSIONS

Maternal anaemia during early pregnancy was associated with an increased risk of preterm birth, low birth weight and SGA and their rates may increase with the severity of maternal anaemia.

TRIAL REGISTRATION NUMBER

ChiCTR1800016635.

Risk factors and glycaemic control in small-for-gestational-age infants born to mothers with gestational diabetes mellitus: a case-control study using propensity score matching based on a large population

BACKGROUND

Small for gestational age (SGA) poses a significant concern for newborns, being linked to neonatal complications and potential metabolic disorders in adulthood, especially when born to mothers with gestational diabetes mellitus (GDM), elevating their risk of complications and mortality. However, the pregnancy risk factors and glycaemic control associated with SGA infants born to mothers with GDM remain unclear.

AIM

To identify the pregnancy risk factors and glycaemic control associated with SGA infants born to mothers with GDM.

METHOD

This case-control study was conducted among 1910 women with GDM in China. Data were collected by the integrated electronic medical record system. Using 1:4 propensity score matching analysis, we adjusted for gestational age as confounder. Univariate and multivariate analyses were performed to identify risk factors.

RESULTS

Risk factors for SGA born to mothers with GDM included a history of low birth weight, gestational hypertension, oligohydramnios, short maternal height, underweight pre-pregnancy body mass index and inadequate weight growth. While SGA was protected by weakly positive ketonuria levels in the first trimester, multiparous, anaemia and previous uterine scar were protective factors for SGA. Moreover, 2-hour postprandial glucose and haemoglobin A1c in the second trimester, as well as the 0-hour and 2-hour 75 g oral glucose tolerance test (OGTT) were linked to risk of SGA.

CONCLUSIONS

SGA infants are the result of multifactorial interactions among GDM pregnant women. Notably, glycaemic control levels were associated with SGA. There is a need for enhanced perinatal monitoring and antenatal care to reduce SGA.

The Long-Term Effect of Maternal Iron Levels in the Second Trimester on Mild Thinness among Preschoolers: The Modifying Effect of Small for Gestational Age

The supplementation of multiple micronutrients throughout pregnancy can reduce the risk of adverse birth outcomes and various diseases in children. However, the long-term effect of maternal multiple micronutrient levels in the second trimester on the overall development of preschoolers remains unknown. Therefore, 1017 singleton mother-infant pairs and 6-year-old preschoolers were recruited based on the China-Wuxi Birth Cohort Study. Meanwhile, information on the demographic characteristics of pregnant women and preschoolers, maternal copper, calcium, iron, magnesium, and zinc levels in whole blood during the second trimester, and neonatal outcomes, were collected. We aimed to investigate the long-term impact of maternal copper, calcium, iron, magnesium, and zinc levels in the second trimester on mild thinness among 6-year-old preschoolers, and the modifying effect of small for gestational age (SGA), within the Chinese population. Multiple logistic regression models revealed that high-level maternal iron in the second trimester reduced the risk of mild thinness [adjusted OR: 0.46 (95% CI: 0.26, 0.80)] among 6-year-old preschoolers. However, no significant association was found for the remaining four maternal essential metal elements. Additionally, the restricted cubic spline function showed that the risk of mild thinness decreased when maternal iron concentration exceeded 7.47 mmol/L in whole blood during the second trimester. Furthermore, subgroup analysis indicated that the long-term protective effect of high-level maternal iron on mild thinness was only observed in SGA infants. Summarily, high-level maternal iron in the second trimester distinctly lowers the risk of mild thinness among 6-year-old preschoolers, especially in preschoolers with birth outcomes of SGA. Our findings offer evidence for the implementation of iron supplementation in the second trimester as a preventive measure against mild thinness in children.

The Interactions between Maternal Iron Supplementation and Iron Metabolism-Related Genetic Polymorphisms on Birth Outcomes: A Prospective Study in Chinese

BACKGROUND

The effect of iron supplementation during pregnancy on birth outcomes may vary with maternal genetic background and needs more investigation.

OBJECTIVES

This prospective study aimed to evaluate the interactions between maternal iron supplementation and iron metabolism-related genetic polymorphisms on birth outcomes.

METHODS

This was a substudy from a community-based randomized control trial conducted in Northwest China, which included 860 women from the 2 micronutrient supplementation groups (folic acid [FA] and FA + iron group). Maternal peripheral blood, sociodemographic and health-related information, and neonatal birth outcomes were collected. Six single nucleotide polymorphisms in iron metabolism-related genes were genotyped. The alleles associated with decreased iron/hemoglobin status were used as the effect alleles. The genetic risk score (GRS) that reflected the genetic risk of low iron/hemoglobin status was estimated using the unweighted and weighted methods. Generalized estimating equations with small-sample corrections were applied to evaluate the interactions between iron supplementation and SNPs/GRS on birth outcomes.

RESULTS

There were significant interactions between maternal iron supplementation and rs7385804 (P = 0.009), rs149411 (P = 0.035), rs4820268 (P = 0.031), the unweighted GRS (P = 0.018), and the weighted GRS (P = 0.009) on birth weight. Compared with FA supplementation only, FA + iron supplementation significantly increased birth weight among women with more effect alleles in rs7385804 (β: 88.8 g, 95% CI: 9.2, 168.3) and the GRSs (the highest unweighted GRS, β: 135.5 g, 95% CI: 7.7, 263.4; the highest weighted GRS, β: 145.9 g, 95% CI: 43.4, 248.5); it had a trend of decreasing birth weight and increasing low birth weight risk among women with fewer effect alleles.

CONCLUSIONS

In our population, maternal genetic background related to iron metabolism plays a significant role in determining the efficacy of iron supplementation. Routine iron supplementation could be more beneficial to fetal weight growth among mothers with higher genetic risk for low iron/hemoglobin status.

Micronutrients in Maternal and Infant Health: Where We Are and Where We Should Go

The first 1000 days of life are defined by the World Health Organization as a "window of opportunity" for a person's growth and development, and nutrition is particularly important during this time window [...].

Anemia in pregnancy and sleep of 6-month-old infants: A prospective cohort study

Objective

Anemia has been reported to adversely influence sleep in infants. However, the association between anemia in pregnancy and infant sleep remains unclear. We aimed to examine the association between maternal anemia in pregnancy and sleep parameters of 6-month-old infants.

Methods

We enrolled 2,410 mother-infant pairs between 2018 and 2021 in Hefei. Data on maternal hemoglobin concentration were collected at 24–28 gestational weeks from the electronic medical records of the hospitals. Nocturnal and daytime sleep duration, number of night awakenings, nocturnal wakefulness, and sleep latency of infants aged 6 months were measured using the Brief Infant Sleep Questionnaire with five items. A restricted cubic spline model was used to examine the relationship between maternal hemoglobin concentration and infant nocturnal sleep duration after adjusting for potential confounders.

Results

In our study, 807 (33.5%) mothers had anemia during pregnancy. Compared to infants born to mothers without anemia, infants born to mothers with anemia in pregnancy had shorter nocturnal sleep duration [mean (SD), 560.29 (79.57) mins vs. 574.27 (75.36) mins] at the age of 6 months. Subgroup analysis showed consistent significant differences in nocturnal sleep duration between infant born to anemic and non-anemic mothers, except in case of stratification by preterm birth [mean difference (mins), 2.03 (95% CI, −20.01, −24.07)] and pre-pregnancy obesity [mean difference (mins), −0.85 (95% CI, −16.86, −15.16)]. A J-shaped nonlinear correlation curve was observed between maternal hemoglobin concentration and infant nocturnal sleep duration. Compared with mothers without daily iron supplementation, mothers who had daily iron supplementation had higher hemoglobin concentrations [mean (SD), 112.39 (11.33) g/L vs. 110.66 (10.65) g/L] at delivery and their infants had longer nocturnal sleep duration [mean (SD), 565.99 (82.46) mins vs. 553.66 (76.03) mins].

Conclusion

Anemia in pregnancy may have an adverse influence on the sleep of 6-mon-old infants, and the relationship between maternal hemoglobin concentration and nocturnal sleep duration is nonlinear.

Association of maternity formula supplementation during pregnancy with small for gestational age birth in Chinese newborns

OBJECTIVES

This study aimed to explore the association between maternity formula supplementation and small for gestational age (SGA) status in Chinese newborns.

METHODS

Data were from a population-based cross-sectional survey conducted in Shaanxi, Northwest China between August and December 2013. A total of 27 780 women pregnant with singletons and 356 with twins were included in this survey. Information on use of maternity formulas fortified with vitamins, folic acid, pantothenic acid, calcium, iron, zinc, and docosahexaenoic acid (DHA) was collected. SGA was defined as birthweight <10th percentile of fetal growth. Generalized linear models and estimating equation models were used to estimate crude odds ratios (ORs) or adjusted ORs with 95% confidence intervals (CIs) for SGA.

RESULTS

The rate of maternity formula supplementation during the entire pregnancy was 13.0% in the overall population. There was no significant association between maternal formula supplementation during pregnancy and the risk of total SGA birth (OR: 1.00; 95% CI, 0.90-1.11; P = 0.950). However, maternity formula supplementation during pregnancy was related to a lower risk of SGA for twins (OR: 0.49; 95% CI, 0.31-0.80; P = 0.004), twin A (OR: 0.50; 95% CI, 0.25-0.98; P = 0.045), and twin B (OR: 0.48; 95% CI, 0.25-0.95; P = 0.034). Furthermore, maternity formula supplementation during the first trimester was inversely associated with the risk of SGA birth of twins (OR: 0.32; 95% CI, 0.15-0.65; P = 0.002).

CONCLUSIONS

No significant association was observed between maternity formula supplementation and total SGA birth. However, women supplemented with maternal formula during pregnancy, especially during the first trimester, may have a reduced risk of SGA birth of twins.

Non-linear connections between maternal hemoglobin during the third trimester of pregnancy and birth weight outcomes in full-term newborns: Estimating the breakpoints

Objective

Anemia is still an unfinished global health problem, and adverse birth weight outcomes have everlasting influences on the health of later life. However, the non-linear connections and breakpoints of maternal hemoglobin with birth weight outcomes are still needed to be further elucidated. We aimed to reveal the non-linear connections between maternal hemoglobin during the third trimester of pregnancy and birth weight, low birth weight (LBW), macrosomia, small for gestational age (SGA), and large for gestational age (LGA) in full-term newborns and elucidate the breakpoints of the connections.

Methods

A total of 11,411 singletons, full-term, and live newborns, whose mothers conducted the examination of hemoglobin concentration before delivery, were included in this study. A generalized additive model was used to identify and visualize the non-linear connections between maternal hemoglobin and birth weight outcomes. Piecewise linear regression model was adopted to estimate the breakpoints of the connections and report the non-linear connections in detail.

Results

There were inverted "U"-shaped exposure-response connections between maternal hemoglobin concentration and birth weight and the risk of macrosomia. There was an increasing trend of the risk of LBW and a decreased trend of LGA with the increase in maternal hemoglobin concentration. The breakpoints of maternal hemoglobin for birth weight were 100 and 138 g/L, and those for SGA were 97 and 138 g/L. The breakpoints of maternal hemoglobin were 119 g/L for LBW, 105 g/L for macrosomia, and 106 g/L for LGA. When maternal hemoglobin concentration ranged from 100 to 138 g/L, maternal hemoglobin concentration increased per 1 g/L, and birth weight significantly decreased by 2.58 g (95% CI: -3.33, -1.83). When maternal hemoglobin concentration ranged from 97 to 138 g/L, maternal hemoglobin concentration increased per 1 g/L, and the risk of SGA significantly increased by 2% (95% CI: 1%, 3%). When maternal hemoglobin concentration was equal to or lower than 119 g/L, maternal hemoglobin concentration increased per 1 g/L, and the risk of LBW significantly increased by 3% (95% CI: 0%, 5%). When maternal hemoglobin concentration was higher than the breakpoints, the risks of macrosomia (OR = 0.99, 95% CI: 0.98, 0.99) and LGA (OR = 0.99, 95% CI: 0.98, 1.00) declined as the increase of maternal hemoglobin concentration.

Conclusions

There were non-linear connections between maternal hemoglobin and birth weight outcomes, and there are breakpoints in the connections. Cost-effective interventions targeting pregnant women in the prevention of abnormal maternal hemoglobin concentration should be taken to reduce the incidence of adverse birth weight outcomes.

Maternal hemoglobin levels and neonatal outcomes: the Japan Environment and Children's Study

BACKGROUND

Low birth weight (LBW), small for gestational age (SGA), and preterm birth (PTB) are important neonatal outcomes that may affect infant morbidity and mortality. The aim of this study is to investigate associations between maternal hemoglobin (Hb) concentrations and pregnancy outcomes of LBW, SGA, and PTB.

METHODS

This was a prospective birth cohort study using data of the Japan Environment and Children's Study. Participants were divided into five groups according to maternal Hb (g/dL) in the first and second trimesters: group 1, Hb < 9; group 2, 9 ≤ Hb < 11.0; group 3, 11.0 ≤ Hb < 13.0; group 4, 13.0 < Hb < 14.0; and group 5, 14.0 ≤ Hb. We examined the relationships between LBW, PTB, SGA, and maternal Hb in the first and second trimesters.

RESULTS

Excluding 29,673, a total of 74,392 newborns (first trimester: n = 39,084, second trimester: n = 35,308) were included. We obtained adjusted odds ratios (aORs) (95% confidence intervals (CIs)) using multivariate analysis; compared with group 3 in the first trimesters, women in group 1 were at increased risk of PTB (aOR, 3.20; 95% CI, 1.69-6.09), LBW (aOR, 2.21; 95% CI, 1.19-4.09). In the second trimester, multivariate analysis revealed that, compared with group 3 in the second trimester, women in group 1 were at increased risk of PTB (aOR, 2.30; 95% CI, 1.19-4.42) and women in group 5 were at increased risk of LBW (aOR, 1.87; 95% CI, 1.24-2.81) and PTB (aOR, 1.73; 95% CI, 1.06-2.83).

CONCLUSIONS

Elevated maternal Hb in the second trimester was associated with risks of PTB and LBW.

Association of low birthweight and small for gestational age with maternal ferritin levels: A retrospective cohort study in China

Background

Birthweight have profound impacts on health status throughout lifetime, however, the relationship between maternal ferritin level in pregnancy and birthweight of the newborn remains controversial.

Objective

This retrospective cohort research was to analyze the association between maternal ferritin levels during pregnancy with birthweight outcomes, primarily for low birthweight (LBW) and small for gestational age (SGA).

Methods

Newborns weighing lower than 2,500 grams were defined as LBW. SGA is defined as birthweight lower than the 10^th percentile of the distribution of newborns' birthweight of the same gestational age. Multivariable logistic regressions have been used to explore the association of maternal ferritin levels and birthweight related outcomes, in which the ferritin concentration was logarithm transformed in the model. We further used restricted cubic spline models to explore linear/non-linear dose–response manners of ferritin level and birthweight outcomes.

Results

A total of 3,566 pregnant women were included in the study. In the results of the present study, we observed that maternal ferritin levels were linearly associated with the risk of LBW (p-trend = 0.005) and SGA (p-trend = 0.04), with the adjusted odds ratios (ORs) of 1.78 (95% CI 1.37–2.32) for LBW and 1.87 (95% CI 1.38–2.54) for SGA with an increase in Ln-ferritin concentrations per unit. The adjusted ORs across quartiles of ferritin levels were 2.14 (95% CI 1.03–4.47) for Quartile 2, 3.13 (95% CI 1.47–6.69) for Quartile 3, and 3.63 (95% CI 1.52–8.68) for Quartile 4 for LBW. The adjusted ORs of LBW and SGA among women using supplemental iron were 0.56 (95% CI 0.38, 0.85) and 0.65 (95% CI 0.40, 1.05) compared with non-users, respectively.

Conclusions

Our findings found a linear dose–response relationship between ferritin levels and an increased risk of poor birthweight outcomes, suggesting that maternal ferritin level during pregnancy may provide an additional predictor for differentiating poor birthweight related outcomes. Further exploration should be conducted to ensure maternal ferritin thresholds and iron supplement doses.

The effect of maternal anaemia on low birth weight among newborns in Northwest Ethiopia

Low birth weight is an indicator of maternal-related multifactorial problems such as malnutrition, illness, and work overload. As a result, low birth weight is associated with maternal anaemia, and both of them were significant public health issues in developing nations. Low birth weight and anaemia are caused by insufficient nutrient intake, which is especially severe during pregnancy. So, this study aimed to assess the effect of maternal anaemia during the late trimester on low birth weight among newborns in Northwest Ethiopia. A systematic random sampling technique was used to select 211 participants for the primary data collection. Face-to-face interviews were used to collect data, while blood samples were collected using standard operating procedures. For further analysis, the data file was imported into Stata version 16 (MP) software. The binary logistic regression model was used to investigate significant factors related to low birth weight. Finally, the statistical significance of the variables was determined using a p value of ≤ 0.05. The prevalence of anaemia among pregnant women in the late trimester and newborns was 34 (16.11%, 95% CI: 11.42, 21.78) and 64 (30.33%, 95% CI: 24.20, 37.01), respectively. The mean ± standard deviation of the newborn babies' weight was 3.19 ± 0.49 kg. The proportion of low birth weight among newborns was 26 (12.32%, 95% CI: 8.20, 17.53%). The independent effect of anaemia on low birth weight was 4.19 times while all other factors were constant (COR = 4.19, 95% CI: 1.70, 10.30). Maternal educational status [unable to read and write (AOR = 10.94, 95% CI: 1.74, 68.58) and attained secondary education (AOR = 8.06, 95% CI: 1.53, 42.36)], and maternal anaemia (AOR = 3.51, 95% CI: 1.29, 9.55) were associated with low birth weight after adjusting with all other variables. In this study, the proportion of low birth weight was high. Here, maternal anaemia alone had a significant independent role in the development of low birth weight. Maternal education status and anaemic conditions were associated with low birth weight among newborns. Early detection and treatment of maternal anaemia during pregnancy is crucial with the usual nutritional-related care.

The Associations of Maternal Hemoglobin Concentration in Different Time Points and Its Changes during Pregnancy with Birth Weight Outcomes

Maternal hemoglobin (Hb) is related to nutritional status, which affects neonatal birth weight. However, it is very common for maternal Hb to fluctuate during pregnancy. To evaluate the associations of maternal Hb in different time points and its changes during pregnancy with neonatal birth weight, small for gestational age (SGA)/low birth weight (LBW) and large for gestational age (LGA)/macrosomia, we conducted this study by using data from the Electronic Medical Record System (EMRS) database of Zhoushan Maternal and Child Care Hospital in Zhejiang province, China. The pregnancy was divided into five periods: first, early-second, mediate-second, late-second, early-third and late-third trimesters; we further calculated the maternal Hb changes during pregnancy. Overall, the socio-demographic characteristics, health-related information and childbirth-related information of 24,183 mother−infant pairs were obtained. The average Hb concentration during the different periods were 123.95 ± 10.14, 117.95 ± 9.84, 114.31 ± 9.03, 113.26 ± 8.82, 113.29 ± 8.68 and 115.01 ± 8.85 g/L, respectively. Significant dose−response relationships between maternal Hb and birth weight were observed in the first, late-second and later trimesters (p non-linear < 0.05). Maternal Hb < 100 g/L was related to a high risk of LGA/macrosomia in the late-second (OR: 1.47, 95% CI: 1.18, 1.83) and later trimesters; additionally, high maternal Hb (>140 g/L) increased the risk of SGA/LBW in the first (OR: 1.26, 95% CI: 1.01, 1.57) and late-third trimesters (OR: 1.96, 95% CI: 1.20, 3.18). In addition, the increase in maternal Hb from the late-second to late-third trimesters had a positive correlation with SGA/LBW. In conclusion, maternal Hb markedly fluctuated during pregnancy; the negative dose−response association of maternal Hb in the late-second and third trimesters, and Hb change during pregnancy with neonatal birth weight outcomes were observed, respectively. Furthermore, the phenomenon of high Hb in the first trimester and after the late-second trimester and the increase of maternal Hb from the late-second to late-third trimesters more significantly increasing the risk of SGA/LBW should especially be given more attention. Its biological mechanism needs to be further explored.