促红细胞生成素、外周血有核红细胞与胎儿宫内生长发育受限及预后关系的研究

目的:测定小于胎龄儿(SGA)和适于胎龄儿(AGA)血中的EPO、有核红细胞、血气分析的变化,找出胎儿宫内发育迟缓与EPO、有核红细胞、血气分析之间的关系,以期待为临床找到一种反映SGA慢性缺氧的理想指标。方法:采用ELISA法对24例SGA和28例AGA血中EPO浓度进行定量检测,末梢血涂片经瑞氏染色计数100个白细胞中含有的有核红细胞数(NRBC/100WBC),并根据血常规中的白细胞数计算出有核红细胞的绝对计数(NRBC)。同时检测动脉血pH、BE和HCO3-等指标。生后3~5天进行头部CT检查,以确定神经系统病变情况。结果:①SGA组和AGA组的体重分别是(1 463.83±273.73)g和(1 925.8±309.91)g;EPO值分别是(109.4±51.36)m IU/m l和(13.99±6.54)m IU/m l。NRBC/100WBC数分别是(56.67±24.75)个和(8.57±4.28)个;NRBC数分别是(5.627±3.14)×109/L和(0.98±0.506)×109/L;RBC数分别是(4.486±0.446)×1012/L和(4.61±0.333)×1012/L;pH值分别是(7.297±0.116 3)和(7.36±0.052 5);BE值分别是(-4.616±5.048)mmol/L和(-1.82±2.047)mmol/L;HCO3-值分别是(22.81±5.246)mmo/L和(24.725±2.38)mmol/L。其中体重、EPO、NRBC/100 WBC、NRBC、pH、BE两组比较有显著性差异(P<0.05)。两组的RBC、HCO3-比较无显著性差异(P>0.05)。②经过相关性分析,SGA组的体重与EPO呈显著负相关,r值为-0.470(P<0.05);AGA组的体重与EPO无相关性,r值为0.128(P>0.05)。③EPO分别和NRBC/100WBC、NRBC呈正相关,r值分别是0.642(P<0.05)和0.595(P<0.05);EPO分别和BE、HCO3呈负相关,r值分别是-0.434(P<0.05)和-0.487(P<0.05)。④SGA组根据预后两组颅内出血7名,包括死亡2名,缺氧缺血性脑病3名。头部CT正常的为对照组。两组进行率的比较,P<0.05,差异显著,说明EPO、有核红细胞的绝对计数显著升高的SGA预后较差。结论:①血中的EPO、NRBC/100WBC、NRBC、BE、pH在SGA组均明显高于AGA组,而RBC数在两组间无显著性差异。②SGA组的体重与EPO呈显著负相关。③血中EPO分别与NRBC/100WBC,NRBC呈显著正相关,与BE、HCO3-呈负相关。④EPO、NRBC是反映小于胎龄儿慢性缺氧的理想指标,与预后密切相关。     

An investigation of folate-related genetic factors in the determination of birthweight

Recent evidence suggests that maternal folate status in early gestation is a significant determinant of infant birthweight. Folate metabolism is known to be controlled by genetic factors, with a number of polymorphic variations in folate metabolising genes identified, several of which have well-documented functional effects. The current study investigated whether folate-related polymorphic variation, in association with low maternal folate status, influences birthweight. Red blood cell (RBC) folate analysis and genotyping of five polymorphisms in folate-related genes [Methylenetetrahydrofolate reductase (MTHFR) 677C>T; MTHFR 1298A>C; cystathionine-beta-synthase (CbetaS) 844ins68bp; serine hydroxymethyltransferase (SHMT) 1420C>T; reduced folate carrier-1 (RFC-1) 80G>A] were undertaken in mothers and infants from 998 pregnancies. These data were analysed in relation to infant birthweight, adjusted for gender and gestational age (z-score). Low maternal RBC folate status was associated with reduced infant birthweight. None of the genetic variants studied showed an independent association with infant birthweight. However, two genetic variants were shown to have a significant effect on birthweight when found in association with low maternal RBC folate status. When individuals with variant genotypes and mothers with folate in the lowest quintile were compared with wild-type individuals and mothers with folate in the highest quintile, the following differences in mean birthweight (z-score) were observed; maternal MTHFR 677C>T (-0.56 [95% CI -1.00, -0.12]P=0.01) and infant CbetaS 844ins68bp (-0.71 [95% CI -1.97, -0.07]P=0.03). The findings of this study suggest that folate-related genetic polymorphisms do not directly influence infant birthweight. However, when placed on a background of deficient maternal nutritional status, they may detrimentally affect fetal growth.     

Association between change in maternal physical activity during pregnancy and infant size,in a sample overweight or obese women

ABSTRACT

Physical activity (PA) naturally declines during pregnancy and its effects on infant size are unclear, especially in overweight or obese pregnancies, a low-active subpopulation that tends deliver heavier infants. The objective of this study was to evaluate changes in prenatal PA and infant birthweight in a group of overweight or obese pregnant women. We employed a prospective analysis using data from a randomized controlled exercise trial (2001 to 2006) in sedentary, overweight or obese pregnant women in Michigan. Women with complete data on peak oxygen consumption, daily PA (via pedometers) and birthweight were included in the analyses. Change in PA was estimated via repeated measures analyses, and then its influence on infant birthweight was assessed via linear regression. Eighty-nine pregnant women were included and considered low-active (6,579.91 ± 2379.17 steps/day). PA declined from months 4 to 8 (?399.73 ± 371.38 steps?day^?1?month^?1). Analyses showed that the decline in PA (β = ?0.28 g, 95%CI: ?0.70, 0.25 g, p = .35) was not associated with birthweight. The findings of this study demonstrated that the decline in maternal PA during mid- to late-pregnancy, in overweight or obese women, was unrelated to infant birthweight. Future investigations should employ rigorous measurements of PA and infant anthropometry in this subpopulation.     

Effects of carbon monoxide air pollution in pregnancy on neonatal nucleated red blood cells

In an analytical cross-sectional study, the effects of carbon monoxide air pollution on carboxyhaemoglobin (COHb) and absolute nucleated red blood cells (nRBC) of the cord venous blood, were evaluated in 41 newborns delivered by caesarean section at term to mothers who had lived in an air-polluted area in the centre of Tehran during their pregnancies (study group). The parameters used were compared with 32 cord venous bloods of term caesarean-delivered newborns of mothers living in a healthy air area outside the city during their pregnancies. A significant difference was observed between the two groups in the cord COHb levels (mean +/- SD 10.51 +/- 4.79 vs. 1.58 +/- 0.96, P <0.001), cord nRBC (723.87 +/- 275.23 x 10(6)/L vs. 248.44 +/- 160.79 x 10(6)/L, P <0.001). A significant correlation was found between ambient carbon monoxide and cord COHb in the study and control groups, respectively (r=0.863, P=0.0001; r=0.691, P=0.0001), and also cord COHb and cord nRBC in the study group (r=0.360, P=0.01). Neonates born to mothers exposed to carbon monoxide air pollution had increased circulating absolute nRBC counts compared with those of the control group. We speculate that air pollution exposure in pregnancy should be avoided, because it may have negative effects on fetal oxygenation.     

Racial differences in birthweight for gestational age and infant mortality in extremely-low-risk US populations

Using national data, we develop and contrast the birth-weight percentiles for gestational age by infants of extremely-low-risk (ELR) White and African-American women and examine racial differences in the proportion of small-for-gestational-age (SGA) births. We then scrutinise racial variations in infant mortality rates of the infants of ELR women. We further compare the infant mortality rates of infants at or below the 10th percentile of birthweight for gestational age of each race group to determine whether infants with similar restricted fetal growth have comparable risks of subsequent mortality. Single live births, 34-42 weeks' gestation, to White and African-American US-resident mothers were selected from the 1990-91 US Linked Live Birth--Infant Death File (n = 4,360,829). Extremely-low-risk mothers were defined as: married, aged 20-34 years, 13+ years of education, multiparae, with average parity for age, adequate prenatal care, vaginal delivery, and no reports of medical risk factors, tobacco use or alcohol use during pregnancy. Marked racial variation in birthweight percentiles by gestational age was evident. Compared with ELR White mothers, the risk of an SGA infant was 2.64 times greater for ELR African-American mothers and the risk of infant mortality was 1.61 times greater. For the ELR group, the infant mortality rates of African-American and White infants at or below the 10th percentile of birthweight for gestational age of their respective maternal race group were essentially identical after controlling for gestational age. In conclusion, race differences in fetal growth patterns remained after controlling for risk status. Efforts to remove racial disparities in infant mortality will need to develop aetiological pathways that can explain why African-Americans have relatively higher rates of preterm birth and higher infant mortality rates among term and non-SGA infants.     

Immune function in intrauterine growth retardation

A one-year longitudinal study was carried out on 2 groups of Kenyan intrauterine growth retarded infants and normal weight full-term infants to determine the effects of intrauterine malnutrition and other nutrient deficiencies on immune function. Three birth weight groups were studied: <2500 gm (≤3rd percentile); 2500–2799 gm (3rd to 10th percentile); and ≥2800 gm (> 10th percentile). B cell function was studied by determination of B lymphocytes and serum levels of IgG, IgM, IgA and IgE. T-cell function was studied by measuring lymphocyte numbers, the percent and absolute number of T-cells by E-rosette technique, lymphocyte responsiveness to PHA and the intradermal PPD response to BCG vaccine. Maternal and infant nutritional studies were obtained concurrently. At birth B cells and immunoglobulins were normal and comparable in all groups except that seven of 41 infants had elevated IgE levels in their cord blood. By 7 months adult levels of IgG, IgM and IgE were achieved in the intrauterine growth retarded infants. Their mothers had significantly higher levels of IgG than the control mothers. Total lymphocyte counts, T-cells and percent T-cells were significantly reduced at birth in the IUGR groups. This abnormality persisted until one year in the smallest (≤2500 g) birthweight group. The IUGR infants had a higher incidence of cutaneous anergy to PPD than did control infants. Cell-mediated immunity correlated significantly with birthweight, blood levels of iron and thiamin at birth and with folate, hemoglobin, pyridoxine and riboflavin at 6 and 12 months.     

Maternal smoking, birthweight and gestational age in sudden infant death syndrome (SIDS) babies and their surviving siblings

To evaluate the effect of maternal smoking on intrauterine growth of babies who died of sudden infant death syndrome (SIDS), birthweights of SIDS infants and their surviving siblings were compared with birthweights of infants in sibships were all infants survived the first year of life. We studied 184 349 mothers with at least two births registered in the population-based Swedish Medical Birth Registry during 1983–91. The mother being the unit of analysis, birthweight and gestational age of her infants were the repeated measures used in a repeated measures analysis of variance. Mothers whose first two infants survived at least 1 year, smoked less than mothers of SIDS infants, 25 and 41% ( P < 5 0.01). Overall, SIDS mothers did not smoke more while pregnant with the SIDS infant than while pregnant with the surviving sibling. SIDS siblings weighted, on average, 90 g less than infants in non-affected sibships. SIDS babies were even lighter, 193 g, and had 3.8 days shorter mean gestational age, compared with same birth-order babies in non-affected sibships. After adjustment for gestational age, the birthweight difference changed only slightly for SIDS siblings, while the difference for SIDS infants was reduced from 193 to 110 g. Further adjustment for smoking reduced the birthweight difference for SIDS siblings, from 74 to 50 g, and SIDS infants, from 110 to 82 g. Intrauterine growth retardation of sibships with a SIDS baby is explained only partly by maternal smoking. The even lower birthweight of the SIDS baby, resulting from shorter gestational age, cannot be explained by smoking, suggesting pregnancy factors specific to the SIDS baby and not to its siblings.     

Race and birthweight in biracial infants.

OBJECTIVES. The purpose of the study was to determine the role of infant race as a determinant of the Black-White disparity in low birthweight (< 2500 g). METHODS. Univariate analysis and multivariate logistic regression were performed on Illinois vital records from 1982 and 1983 and on 1980 United States census income data. RESULTS. Fourteen percent of the infants born to Black mothers and White fathers were of low birthweight, compared with 9% of infants born to White mothers and Black fathers and 6% of a random sample of White infants. Both groups of biracial infants were more likely to have been born to unmarried mothers and to reside in very low-income (< $10,000 per year) census tracts than were White infants. When all confounding variables were entered into a logistic model, the adjusted odds ratio of low birthweight for biracial infants born to Black mothers and White fathers equaled 1.4. When biracial infants born to White mothers and Black fathers were compared with White infants, the adjusted odds ratio of low birthweight equaled 1.0. CONCLUSIONS. Paternal and consequent infant race does not affect the birthweight distribution of those born to White mothers and Black fathers. Unidentified factors closely related to maternal race underlie the Black-White disparity in infant birthweight.     

北京市4区婴幼儿体成分检测及超重肥胖影响因素研究

目的 了解北京市婴幼儿超重肥胖流行现状,结合体成分检测结果,探究影响婴幼儿身体成分的影响因素.方法 2021年1-4月于北京市海淀区、昌平区、石景山区及通州区4区开展多中心现况调查,招募单胎且无明显畸形和遗传代谢病的0～2岁婴幼儿作为研究对象.调查内容包括问卷调查(婴幼儿一般人口学特征、母亲孕期及分娩情况和婴幼儿出生情...     

The intergenerational relationship between mother's birthweight, infant birthweight and infant mortality in black and white mothers

Summary. The relationship between the birthweight of white and black mothers and the outcomes of their infants were examined using the 1988 National Maternal and Infant Health Survey. White and black women who were low birthweight themselves were at increased risk of delivering very low birthweight (VLBW), moderately low birthweight (MLBW), extremely preterm and small size for gestational age (SGA) infants. Adjustment for the confounding effects of prepregnant weight and height reduced the risks of all these outcomes slightly, and more substantially reduced the maternal birthweight associated risk of moderately low birthweight among white mothers. There was little effect of maternal birthweight on infant birthweight-specific infant mortality in white mothers; however, black mothers who weighed less than 4 lbs at birth were at significantly increased risk of delivering a normal birthweight infant who subsequently died. Although the risks for the various outcomes associated with low maternal birthweight were not consistently higher in black mothers compared with white mothers, adjustment for prepregnant weight and height had a greater effect in white mothers than in black mothers. We suggest that interventions to reduce the risks for adverse pregnancy outcomes associated with low maternal birthweight should attempt to optimise prepregnant weight and foster child health and growth.     

Mortality risk of small infants varies with their mother's birthweight and race

We analysed a transgenerational linked birth file to investigate the relationship between maternal birthweight and infant birthweight-specific mortality risk for white and African American infants. Birth records of 267,303 infants born between 1989 and 1991 were linked to records of their mothers, born between 1956 and 1976, and to their own death certificates for those dying in the first year. The means, standard deviations and z-scores were calculated for each race- and generation-specific birthweight distribution. Investigators then analysed the mortality of very small infants (birthweight at least two standard deviations below their mean) for three maternal birthweight categories. Over half of the infant deaths involved births with weights more than two standard deviations below the relevant population mean birthweight (comprising 4.2% of white and 6.9% of African American births respectively). African American infants experienced higher mortality rates at all levels of standardised birthweight, from z-scores of -3 to +3. The relative risk of mortality associated with very small infant size was less for infants delivered to smaller birthweight mothers when compared with those whose mothers were average sized or large at birth. This differential effect was confined to neonatal deaths and was more prominent in the white subpopulation.     

Prenatal weight gains related to the birth of healthy-sized infants to low-income women

Prepregnancy weight status and weight gain during pregnancy are major independent variables associated with infant birth weight. This study quantitated the influence of weight gain on birth weight and identified rates and total amounts of weight gain related to the birth of healthy-sized infants to healthy low-income women who entered pregnancy underweight, at normal weight, overweight, or obese. Data used in the study were obtained from randomly sampled prenatal health records from Maternal and Infant Care (MIC) projects in Cleveland and Minneapolis. Subsamples of healthy mothers who delivered healthy-sized infants were identified from each sample, and rates and total amounts of weight gain by prepregnancy weight status group were calculated. There were 384 healthy mother and healthy-sized infant pairs in the Cleveland subsample and 75 such pairs in the Minneapolis sample. Multiple regression analysis revealed that the influence of prenatal weight gain and birth weight varied depending on prepregnancy weight status. Prenatal weight gains related to the birth of healthy-sized infants (newborns with birth weights of 3,000 to 4,500 gm) to healthy mothers in the Cleveland MIC sample averaged 33 lb for underweight, 32 lb for normal weight, 29 lb for overweight, and 19 lb for obese women. Except for obese women, rates and total amount of weight gain associated with the birth of healthy-sized infants were equivalent for the two samples.     

Explaining the 2001-02 infant mortality increase: data from the linked birth/infant death data set.

The U.S. infant mortality rate increased from 6.8 infant deaths per 1,000 live births in 2001 to 7.0 in 2002, the first increase in more than 40 years. From 2001 to 2002 infant mortality rates increased for very low birthweight infants as well as for preterm and very preterm infants. Although infant mortality rates for very low birthweight infants increased, most of the increase in the infant mortality rate from 2001 to 2002 was due to a change in the distribution of births by birthweight and, more specifically, to an increase in infants born weighing less than 750 grams (1 lb 10 1/2 oz). The majority of infants born weighing less than 750 grams die within the first year of life; thus, these births contribute disproportionately to the overall infant mortality rate. Increases in births at less than 750 grams occurred for non-Hispanic white, non-Hispanic black, and Hispanic women. Most of the increase occurred among mothers 20-34 years of age. Although multiple births contributed disproportionately, most of the increase in births at less than 750 grams occurred among singletons. Three hypotheses were evaluated to assess their possible impact on the increase in less than 750-gram births: first, possible changes in the reporting of births or fetal deaths; second, possible changes in the risk profile of births; and third, possible changes in medical management of pregnancy. Although each of these factors may have contributed to the increase, the relative effects of these and other factors remain unclear. More-detailed studies are needed to further explain the 2001-02 infant mortality increase.     

Enzymic evaluation of thiamin, riboflavin and pyridoxine status of parturient mothers and their newborn infants in a Mediterranean area of Spain

OBJECTIVE: To determine the biochemical status of thiamin, riboflavin and pyridoxine in parturient mothers and their newborn infants in a Mediterranean region. DESIGN: Transveral study. SETTING: St Joan University Hospital and Faculty of Medicine & Health Sciences, Universitat Rovira i Virgili, Reus, Spain. SUBJECTS: 131 healthy parturient mothers, with normal pregnancies and deliveries in St Joan University Hospital, and their newborn infants. INTERVENTIONS: Erythrocyte haemolysates were prepared from maternal blood at delivery and infants' umbilical cord blood and used to measure micronutrient status using the transketolase, glutathione reductase and aspartate aminotransferase coenzyme stimulation tests. RESULTS: Maternal and infant coenzyme activities were significantly correlated, but infant coenzyme status was better than maternal, with significantly higher basal and stimulated activity (P < 0.001) and significantly lower activation coefficients (P < 0.001). Inadequate thiamin, riboflavin or pyridoxine status occured in 38.2 62.6% (50-82) of the mothers and 3.1-37.4% (4 49) of the infants; 85.2% (46/54), 12.9% (4/31) and 24.1% (12/54) of infants born to mothers with biochemical deficiency of either thiamin, riboflavin or pyridoxine, respectively also had inadequate status. Maternal deficiencies in more than one vitamin further increased the risk of infant thiamin and pyridoxine deficiency. Maternal and infant riboflavin status were significantly correlated with fetal development (e.g. length at birth, P < 0.001). The incidence of thiamin deficiency in paturient mothers in Spain was the highest out of a 12-country comparison. CONCLUSIONS: Inadequate status for each vitamin was evident in mothers and infants. Maternal status of each individual vitamin, but especially riboflavin, was affected by maternal status of the other vitamins. Infant thiamin status was the most adversely affected by maternal deficiencies in more than one vitamin. Infant riboflavin status, however, was apparently protected from adverse maternal status.     

婴儿血铅与母亲血铅和乳铅等因素的相关性研究

目的了解婴儿血铅与母亲血铅和乳铅等因素的相关关系,为防治儿童铅中毒提供参考依据。方法2002年11至12月,采用石墨炉原子吸收光谱法,测定厦门市177名0～11个月的婴儿及其母亲的血铅,并对小儿出生情况及其母亲、家庭环境等相关因素进行问卷调查。结果177例婴儿血铅的几何均值为(0.37±0.15)μmol/L,范围为0.12～1.36μmol/L,≥0.48μmol/L者46例(占25.99%);母亲血铅的均值为(0.50±0.14)μmol/L,范围为0.21～2.38μmol/L;177例中有160例为母乳喂养儿,其中105例采集出乳汁,乳铅的几何均值为(0.17±0.08)μmol/L,婴儿血铅与母亲的血铅和乳铅密切相关,表明母体的铅可以通过乳汁影响到婴儿血铅水平。旧商业区婴儿的血铅、婴儿母亲乳铅水平均高于其他地区,婴儿血铅水平主要与母亲血铅、婴儿月龄和母亲在职等呈正相关关系,而与母亲身高等因素呈负相关关系。结论母乳喂养儿的血铅水平除了与母亲血铅水平相关外,还与乳铅密切相关,因此在婴儿喂养方式的选择和家庭抚育行为方面须引起重视。