Serum zinc levels of cord blood: Relation to birth weight and gestational period

BackgroundZn-deficiency has been associated with numerous alterations during pregnancy including low birth weight; however, the research relating neonatal zinc status and birth weight has not produced reliable results.ObjectiveTo compare the serum Zn-levels of cord blood in healthy newborns and low birth weight newborns, and to assess a possible relationship between zinc concentration and neonatal birth weight and gestational age.Material and methods123 newborns divided in “study group” (n = 50) with <2500 g birth weight neonates and “control group” (n = 73) with ≥2500 g birth weight neonates were enrolled. Study group was subdivided according to gestational age in preterm (<37 weeks) and full-term (≥37 weeks). Serum cord blood samples were collected and the Zn-levels were analyzed using flame Atomic Absorption Spectrophotometry method and the result was expressed in μmol/L. The Zn-levels were compared between the groups (Mann–Whitney-U test) and the Zn-levels were correlated with the birth weight and gestational age (Spearman's rank correlations).ResultsStatistically significant low positive correlation between Zn-levels and birth weight (ρ = 0.283; p = 0.005) was found. No statistically significant difference between Zn-levels of study and control groups [17.00 ± 0.43 vs. 18.16 ± 0.32 (p = 0.053)] was found. Statistically significant low positive correlation between Zn-levels and gestational age (ρ = 0.351; p = 0.001) was found. No statistically significant difference between Zn-levels of preterm as compare to full-term newborns [16.33 ± 0.42 vs. 18.43 ± 0.93 (p = 0.079)] was found. Zn-level of preterm subgroup was significantly lower compared to control group (p = 0.001).ConclusionsDespite low birth weight preterm neonates had significantly lower serum zinc levels of cord blood than healthy term neonates, the correlation between cord blood zinc levels and birth weight and gestational age was lower. The results are not enough to relate the change in cord blood zinc concentration to the birth weight values or gestational period. In relation to complicated pregnancies, further studies regarding zinc levels in blood in our population are required.     

Correlation between circulating biomarkers of oxidative stress of maternal and umbilical cord blood at birth

The objective of the work was to study the relationship between the oxidative state of the mother and the newborn at the moment of birth. We measured oxidative stress markers (carbonyl groups, lipid peroxides and total antioxidant capacity (TAC)) and found a good correlation between the oxidative state of the normal mother and the neonate, since a high mother oxidative stress corresponds to an even higher oxidative stress of the newborn in umbilical cord blood. We also found that smoking mothers and their newborns had a higher concentration of the carbonyl group, lipid peroxides and less TAC. Newborns from these mothers weighed significantly less than others at birth. These data suggest a need for interest in monitoring the oxidative state of mothers during the pregnancy period, especially taking into account that the oxidative level could be involved in later risks of metabolic diseases for both mother and newborn.     

Correlation between circulating biomarkers of oxidative stress of maternal and umbilical cord blood at birth

The objective of the work was to study the relationship between the oxidative state of the mother and the newborn at the moment of birth. We measured oxidative stress markers (carbonyl groups, lipid peroxides and total antioxidant capacity (TAC)) and found a good correlation between the oxidative state of the normal mother and the neonate, since a high mother oxidative stress corresponds to an even higher oxidative stress of the newborn in umbilical cord blood. We also found that smoking mothers and their newborns had a higher concentration of the carbonyl group, lipid peroxides and less TAC. Newborns from these mothers weighed significantly less than others at birth. These data suggest a need for interest in monitoring the oxidative state of mothers during the pregnancy period, especially taking into account that the oxidative level could be involved in later risks of metabolic diseases for both mother and newborn.     

Correlation between maternal plasma homocysteine and zinc levels in preeclamptic women

Women with preeclampsia have been shown to have elevated blood levels of the metabolite homocysteine, and alterations in blood levels of zinc and copper have also been reported. This study measured plasma levels of zinc, copper, and homocysteine in women with preeclampsia and in women with healthy, normotensive pregnancies. For the patients with preeclampsia compared with controls, significantly higher mean plasma levels were found of homocysteine (16.39 vs 9.45 nmol/mL; p≤0.001), zinc (15.53 vs 11.93 μg/g protein; p < 0.05), and copper (47.90 vs 31.60 μg/g protein; p=0.001). The ratio of plasma Cu/Zn levels tended to be higher in preeclamptic women and could be taken as an index of inflammatory reaction, but the difference was not significant. Homocysteine concentrations correlated positively with plasma zinc concentrations in women with preeclampsia (r=0.588, p=0.003) but not in women with healthy pregnancies. No correlations were observed between plasma levels of homocysteine and copper. Thus, the present study found evidence that preeclampsia might be associated with hyperhomocysteinemia and elevated blood levels of zinc and copper. Furthermore, elevated blood levels of zinc were significantly associated with hyperhomocysteinemia in preeclampsia. More studies are warranted to investigate further any relationship between altered homocysteine metabolism and levels of zinc and copper in preeclampsia.     

Relation of cord blood thyroxine and thyrotropin levels to gestational age and birth weight.

A program of screening cord blood for evidence of primary neonatal hypothyroidism was implemented in a general hospital. In 13 months 3456 newborns were screened: the thyroxine (T4) and triiodothyronine (T3) concentrations were measured in cord blood samples, and when the T4 level was below 8.0 micrograms/dl thyrotropin was also assayed in the sample. The two-tier program was effective. One hypothyroid newborn was detected and treated. More boys than girls had T4 levels below 8.0 micrograms/dl (9.7% v. 4.7%). The T4 level correlated with birth weight slightly better in the boys (r = 0.28 v. 0.21), and in the boys this correlation was stronger when the birth weight was lower. Regression analysis of the data for 54 sets of twins indicated that the T4 level was more strongly related to gestational age than to birth weight.     

Serum copper,zinc levels,and copper

Serum copper and zinc levels were determined in 20 healthy women and in 100 women with gynecological tumors. Malignant and benign tumor cases were separated according to their postoperative, histopathological examinations. The stages of malignant and benign tumors were also established histologically. Seventy benign and 30 malignant genital tumors (carcinoma of cervix in situ, cervix, ovary endometrium, and vulva) of the patients were differentiated histopathologically. The serum Cu/Zn ratios of patients were increased significantly from the control group (0.32±0.35) to the benign group (1.22±0.63) and from the benign group to the malignant group (2.24±1.03). Nine of 30 malignant cases were determined as false negative (30%) and 15 of 70 benign cases were determined as false positive (14.2%) according to the serum Cu/Zn ratios of patients. Serum copper levels of 30 malignant and 10 benign tumor cases showed linear correlation with serum ceruloplasmin values.     

Relationship between zinc levels and plasma leptin in hemodialysis patients

Recent evidences suggested a possible relationship between zinc deficiency and leptin levels in pathogenesis of anorexia in chronic kidney disease. The present study addressed the relationship between zinc and leptin in hemodialysis (HD) patients.MethodsFifty HD patients (54.3 ± 12.7 years old, 62% men) were studied and compared to 21 healthy volunteers (50.7 ± 15.7 years old, 43% men). Biochemical data, serum zinc, plasma leptin, IL-6, TNF-α and C-Reactive Protein levels were determined. Anthropometric parameters, food intake and appetite score were also assessed.ResultsThe leptin levels were higher in HD patients (16.1 μg/mL (0.21–118.25) vs 6.0 μg/mL (0.50–23.10)) in healthy volunteers (p = 0.04), whereas serum zinc levels were lower (54.5 ± 16.3 μg/dL) compared to healthy volunteers (78.4 ± 9.4 μg/dL) (p = 0.0001). The plasma leptin was correlated negatively with plasma zinc (r = ?0.33; p = 0.007), energy (r = ?0.38; p = 0.002) and protein intake (r = ?0.34; p = 0.006) and, positively correlated with BMI (r = 0.54; p = 0.0001), % body fat (r = 0.70; p = 0.0001) and conicity index (r = 0.46; p = 0.001). Plasma zinc was associated with hemoglobin (r = 0.30; p = 0.04) and negatively associated with TNF-α (r = ?0.37; p = 0.002) and C-Reactive Protein (r = ?0.37; p = 0.004). There was no correlation among Zn, leptin and appetite score in these patients.ConclusionThis study showed that low plasma zinc levels are negatively associated with high leptin levels in HD patients.     

Some essential elements in maternal and cord blood in relation to birth weight and gestational age of the baby

Maternal and cord blood were collected from 54 Indian women at parturition and analyzed for Zn, Cu, and Fe by flame atomic absorption spectrophotometry to determine the relationship between levels of these elements in mother’s and infant’s blood and maternal age, birth weight, and gestational age of the baby. The blood Zn level of mothers in the age group 24–28 yr was significantly higher than those of mothers in the age group of 18–23 yr (p<0.05). Similarly, mothers in the 24 to 28-yr group also had higher blood Fe level than mothers in the group 29–38 yr (p<0.05). The levels of Zn, Cu, and Fe were higher in the maternal blood and lower, but not significantly, in the cord blood of low-birth-weight babies than in those of normal-birth-weight babies. However, differences in the levels of Zn, Cu, and Fe between maternal and cord blood of the two birth-weight groups was statistically significant. There were no significant differences in the levels of the three elements in maternal or cord blood by the gestational age of the baby. A weak but significant correlation was found between the birth weight of the baby and the Fe level in the cord blood (r=0.26; p<0.05). Also, weak significant correlations were observed between gestational age of the baby and Fe (r=0.23; p<0.05) and Cu (r=0.31; p<0.05) levels in the cord blood. Although, there are many confounders of low birth weight and preterm deliveries, a diminished placental transfer of these essential elements could be one of the several etiological factors for low birth weight of newborns.     

Newborn umbilical cord blood DNA methylation and gene expression levels exhibit limited association with birth weight

Most cases of fetal growth retardation are unexplained. These newborns are at high risk of serious illness or death in the neonatal period and exhibit significantly increased risk of specific chronic illnesses later in life. While there are several hypotheses to explain the well-established association between low birth weight and later risk of disease, the true etiology is unknown. To search for molecular patterns that may explain the biological basis for reduced fetal growth in a clinically normal cohort, and possibly provide clues for the lifelong increased risk of disease, we surveyed genome-wide DNA methylation and gene expression patterns in the umbilical cord blood of newborns born in Shelby County, TN. While we did not find genome-wide significant associations of birth weight with either leukocytic gene expression or DNA methylation, we did find suggestive associations in several genes with known effects on pre- or postnatal growth and health. As with previous molecular epidemiological studies of birth weight, we did not sample the most biologically relevant tissues in the newborn. However, our discovery of biologically plausible associations in a peripheral tissue suggests that further studies of tissues key to fetal growth regulation are warranted.     

新生儿出生体重、胎龄与血清铁水平相关性分析

目的探讨新生儿出生体重、胎龄与血清铁水平的相关性,为促进新生儿生长发育提供科学依据。方法采用全自动生化分析法分别对49例足月儿及49例早产儿的血清铁(SI)、血清铁蛋白(SF)和总铁结合力(TIBC)进行检测。结果足月儿的血清铁、血清铁蛋白和总铁结合力水平均明显高于早产儿(P0.05),而且血清铁蛋白、血清铁水平与出生体重、胎龄密切相关(P0.05)。结论足月儿与早产儿的铁含量存在明显差异,适量补充铁剂,可促进小儿体格与智能的健康成长。     

Relationship among levels of leptin and zinc,copper, and zinc/copper ratio in plasma of patients with essential hypertension and healthy normotensive subjects

Obesity is among the main contributing factors in the etiology of essential hypertension (EHT). Leptin, the product of the ob gene, is expressed mainly in adipose tissue. We examined the relationship between two trace elements, zinc (Zn) and copper (Cu), and leptin in patients with EHT (n=35) and normotensive (NT) controls (n=50) because leptin as well as Zn and Cu were reported to be associated with the pathophysiology of EHT. Plasma leptin levels were determined with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Atomic absorption spectrophotometry was utilized to determine plasma Zn and Cu levels. There was a negative correlation between leptin and Zn, and the Zn/Cu ratio (r=−0.359, p<0.05; r=0.361, p<0.05, respectively) in pooled subjects. When subjects were divided based on the presence or absence of hypertension, there was a negative correlation between leptin and Zn (r=−0.375, p<0.05) as well as leptin and Zn/Cu ratio (r=−0.398, p<0.05) in NT subjects. Similar trends were observed when leptin/BMI (body mass index) levels were utilized. There was no significant correlations between levels of Cu and leptin or leptin/BMI. In conclusion, in addition to high leptin levels, Zn and the Zn/Cu ratio were lower in patients with EHT compared to NT controls.     

Maternal serum leptin during pregnancy and infant birth weight: The influence of maternal overweight and obesity

Objective:

Few studies have examined whether the distinct metabolic patterns found in obese and nonobese pregnant women have different effects on the growing fetus. Our objective was to estimate the influence of longitudinal variation in maternal serum leptin levels on variation in infant birth weight in overweight/obese versus normal‐weight women.

Design and Methods:

In a prospective cohort of 286 gravidas, maternal weight and serum leptin levels at 6–10, 10–14, 16–20, 22–26, and 32–36 weeks gestation were measured. Effects of leptin levels on infant birth weight adjusted for gestational age at delivery (aBW) were analyzed using a linear regression model that accounted for the relationship of time‐varying predictors to the log‐transformed leptin concentrations.

Results:

Different relationships of aBW to maternal serum leptin and its rate of change across pregnancy were exhibited by overweight/obese and normal‐weight gravidas. For normal‐weight women, aBW is not associated with either the magnitude of the logarithm of the leptin concentration or with its rate of change in either the first or second half of pregnancy. Conversely, for overweight/obese women, an increase in the rate of change in maternal serum leptin in the second half of pregnancy is significantly associated with a decrease in aBW. This effect is distinct from that of maternal weight.

Conclusion:

Differences in the effect of maternal serum leptin on fetal growth between overweight/ obese and normal‐weight women suggest metabolic and physiologic heterogeneity between these groups. Such differences may be involved in the long‐term physiologic effects of the obese intrauterine environment on the health of the offspring.     

Relation between maternal haemoglobin concentration and birth weight in different ethnic groups.

OBJECTIVE--To assess the relation of the lowest haemoglobin concentration in pregnancy with birth weight and the rates of low birth weight and preterm delivery in different ethnic groups. DESIGN--Retrospective analysis of 153,602 pregnancies with ethnic group and birth weight recorded on a regional pregnancy database during 1988-91. The haemoglobin measurement used was the lowest recorded during pregnancy. SETTING--North West Thames region. SUBJECTS--115,262 white women, 22,206 Indo-Pakistanis, 4570 Afro-Caribbeans, 2642 mediterraneans, 3905 black Africans, 2351 orientals, and 2666 others. MAIN OUTCOME MEASURES--Birth weight and rates of low birth weight (< 2500 g) and preterm delivery (< 37 completed weeks). RESULTS--Maximum mean birth weight in white women was achieved with a lowest haemoglobin concentration in pregnancy of 85-95 g/l; the lowest incidence of low birth weight and preterm labour occurred with a lowest haemoglobin of 95-105 g/l. A similar pattern occurred in all ethnic groups. CONCLUSIONS--The magnitude of the fall in haemoglobin concentration in pregnancy is related to birth weight; failure of the haemoglobin concentration to fall below 105 g/l indicates an increased risk of low birth weight and preterm delivery. This phenomenon is seen in all ethnic groups. Some ethnic groups have higher rates of low birth weight and preterm delivery than white women, and they also have higher rates of low haemoglobin concentrations. This increased rate of "anaemia," however, does not account for their higher rates of low birth weight, which occurs at all haemoglobin concentrations.     

Low birth weight, maternal birth-spacing decisions, and future reproduction

The aim of this study is an analysis of the possible adaptive consequences of delivery of low birth weight infants. We attempt to reveal the cost and benefit components of bearing small children, estimate the chance of the infants’ survival, and calculate the mothers’ reproductive success. According to life-history theory, under certain circumstances mothers can enhance their lifetime fitness by lowering the rate of investment in an infant and/or enhancing the rate of subsequent births. We assume that living in a risky environment and giving birth to a small infant may involve a shift from qualitative to quantitative production of offspring. Given high infant mortality rates, parents will have a reproductive interest in producing a relatively large number of children with a smaller amount of prenatal investment. This hypothesis was tested among 650 Gypsy and 717 non-Gypsy Hungarian mothers. Our study has revealed that 23.8% of the Gypsy mothers had low birth weight (<2,500 g) children, whose mortality rate is very high. These mothers also had more spontaneous abortions and stillbirths than those with normal weight children. As a possible response to these reproductive failures, they shortened birth spacing, gaining 2–4 years across their reproductive lifespan for having additional children. Because of the relatively short interbirth intervals, by the end of their fertility period, Gypsy mothers with one or two low birth weight infants have significantly more children than their ethnic Hungarian counterparts. They appear to compensate for handicaps associated with low birth weights by having a larger number of closely spaced children following the birth of one or more infants with a reduced probability of survival. The possible alternative explanations are discussed, and the long-term reproductive benefits are estimated for both ethnic groups.