Anthropometric Measurements: Options for Identifying Low Birth Weight Newborns in Kumasi,Ghana

Background

In Ghana, 32% of deliveries take place outside a health facility, and birth weight is not measured. Low birth weight (LBW) newborns who are at increased risk of death and disability, are not identified; 13%–14% of newborns in Ghana are LBW. We aimed at determining whether alternative anthropometrics could be used to identify LBW newborns when weighing scales are not available to measure birth weight.

Methods

We studied 973 mother and newborn pairs at the Komfo Anokye Teaching and the Suntreso Government hospitals between November 2011 and October 2012. We used standard techniques to record anthropometric measurements of newborns within 24 hours of birth; low birth weight was defined as birth weight <2.5kg. Pearson''s correlation coefficient and the area under the curve were used to determine the best predictors of low birth weight. The sensitivity, specificity and predictive values were reported with 95% confidence intervals at generated cut-off values.

Results

One-fifth (21.7%) of newborns weighed less than 2.5 kg. Among LBW newborns, the following measurements had the highest correlations with birth weight: chest circumference (r = 0.69), mid-upper arm circumference (r = 0.68) and calf circumference (r = 0.66); the areas under the curves of these three measurements demonstrated the highest accuracy in determining LBW newborns. Chest, mid-upper arm and calf circumferences at cut-off values of ≤29.8 cm, ≤9.4 cm and ≤9.5 cm respectively, had the best combination of maximum sensitivity, specificity and predictive values for identifying newborns with LBW.

Conclusions

Anthropometric measurements, such as the chest circumference, mid-upper arm circumference and calf circumference, offer an opportunity for the identification of and subsequent support for LBW newborns in settings in Ghana, where birth weights are not measured by standardized weighing scales.     

低出生体重儿肠道微生态构建影响因素的 动态监测

目的动态监测低出生体重儿肠道菌群,分析不同体重、不同喂养方式及疾病状态等因素对患儿肠道微生态的影响,为规范临床低出生体重儿宫外营养支持措施及治疗手段提供依据。方法应用16SrRNA荧光定量PCR技术检测正常新生儿和低出生体重儿生后第1、3、7天粪便中大肠埃希菌、肠球菌、乳杆菌及双歧杆菌的含量。结果 (1)在生后7d内,无论正常新生儿还是低出生体重儿,其粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌的含量均随日龄的增加而增加,且生后7d内正常新生儿的粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌的含量均显著高于低出生体重儿(P0.05),正常新生儿生后7d内粪便中各细菌的增长率均高于低出生体重儿。(2)体重2 000~2 500g的低出生体重儿粪便中大肠埃希菌和肠球菌在各日龄中的含量明显高于体重2 000g的新生儿(P0.05);同时其粪便中双歧杆菌和乳杆菌含量在3日龄和7日龄阶段明显高于体重2 000g的新生儿(P0.05)。(3)3日龄和7日龄母乳喂养组的低出生体重儿粪便中双歧杆菌和乳杆菌含量明显高于乳制品喂养组(P0.05);且母乳喂养组新生儿生后7日内粪便中大肠埃希菌、乳杆菌和双歧杆菌含量的增长率均高于乳制品喂养组,尤其是双歧杆菌的增长率(126.49%vs 54.81%)。(4)合并并发症的3日龄和7日龄的低出生体重儿,粪便中乳杆菌和双歧杆菌含量均明显低于无合并症的低出生体重儿(P0.05);且无并发症组的低出生体重儿其粪便中肠球菌、乳杆菌和双歧杆菌的增长率均高于有并发症组的低出生体重儿,大肠埃希菌增长率则低于有并发症组。结论低出生体重儿肠道菌群的定植时间晚且数量少,体重、喂养方式及有无并发症是影响新生儿肠道菌群丰度的重要因素。母乳喂养可促进低出生体重儿肠道中益生菌的定植。疾病因素会导致肠道菌群丰度的降低,使肠道菌群紊乱,其程度可能与病情的严重程度相关。     

Decreased Pattern Recognition Receptor Signaling,Interferon-Signature,and Bactericidal/Permeability-Increasing Protein Gene Expression in Cord Blood of Term Low Birth Weight Human Newborns

Background

Morbidity and mortality rates of low birth weight (LBW) newborns at term are higher than rates in normal birth weight (NBW) newborns. LBW newborns are at greater risk to acquire recurrent bacterial and viral infections during their first few weeks of life possibly as an outcome of compromised innate immune functions. As adaptive immunity is in a naive state, increased risk of infection of LBW as compared to NBW newborns may reflect impairments in innate immunity.

Methodology

To characterize the increased susceptibility to infections in LBW newborns we used microarray technology to identify differences in gene expression in LBW newborns (n = 8) compared to NBW newborns (n = 4) using cord blood. The results obtained from the microarray study were validated on a larger number of samples using real time RT-PCR (LBW = 22, NBW = 18) and western blotting (LBW = 12, NBW = 12). The Interferome database was used to identify interferon (IFN) signature genes and ingenuity pathway analysis identified canonical pathways and biological functions associated with the differentially expressed genes in LBW newborns. ELISAs for IFNs and bactericidal/permeability-increasing protein were performed in both LBW and NBW newborns and in adults (LBW = 18, NBW = 18, Adults  = 8).

Principal Findings

Upon microarray analysis, we identified 1,391 differentially expressed genes, of which, 1,065 genes were down-regulated and 326 genes were up-regulated in the LBW compared to NBW newborns. Of note, 70 IFN-signature genes were found to be significantly down-regulated in LBW compared to NBW newborns. Ingenuity pathway analysis revealed pattern recognition receptors signaling including Toll-Like Receptors (TLRs) -1, -5, and -8 genes and IFN signaling as the most significantly impacted pathways. Respiratory infectious diseases were the most significantly affected bio-functions in LBW newborns.

Conclusion and Significance

Diminished PRRs, IFN-signature, and BPI gene expression raises the possibility that impairments in these pathways contribute to the susceptibility of LBW term infants to infection.     

Factors affecting birth weight of a newborn--a community based study in rural Karnataka, India

Background

Low birth weight (LBW) is a major public health problem in many developing countries, especially so in India. Although we do not know all the causes of LBW, maternal and environmental factors appear to be significant risk factors in its occurrence.

Objectives

To know the factors affecting the birth weight of a newborn and to estimate the prevalence of LBW.

Methods

The present study was carried out amongst 1138 pregnant women and their newborns residing in area covered by Kinaye Primary Health Centre in rural Karnataka, India. The study was conducted from 1^st June 2008 to 31^st December 2009.

Results

The mean birth weight of newborns was 2.6 kg with a range of 1.2 to 3.8 kg. The prevalence of LBW was 22.9%. Among the studied risk factors, 25 of them were significantly associated with the birth weight of a newborn on univariate logistic regression analysis. Maternal education [Odds Ratio (OR) 3.2], exposure to passive smoking [OR 2.3], age at first pregnancy ≥25 years [OR 3.6], birth interval <2 years [OR 2.4], previous history of LBW baby [OR 3.3], weight gain ≤4 kg during pregnancy [OR 7.0], maternal weight at last week of gestation ≤45 kg [OR 2.3], pregnancy induced hypertension [OR 3.3], high risk pregnancy [OR 3.6] and late antenatal registration [OR 3.6] emerged as significant risk factors on multivariate analysis.

Conclusion

The problem of LBW is multidimensional, and hence, we need an integrated approach incorporating medical, social, economical and educational measures to address this issue.     

Foot Length,Chest Circumference,and Mid Upper Arm Circumference Are Good Predictors of Low Birth Weight and Prematurity in Ethnic Minority Newborns in Vietnam: A Hospital-Based Observational Study

Background

The evaluation of tools to accurately identify low birth weight (LBW) and/or premature newborns in resource-limited countries is a research priority. We explored the use of foot length, chest circumference, and mid-upper arm circumference (MUAC) measured within 24 h as diagnostic tools for identifying newborns who are LBW, premature, or both; and compared measurements taken at birth with those taken at five days of age.

Materials and Methods

An observational study was undertaken in Hoa Binh Province General Hospital, Vietnam, in ethnic minority newborns. Birth weight, foot length, chest circumference, and MUAC were measured within 24 h of birth and in a subset of 200, were repeated on day five of life. Gestational age was estimated using the New Ballard Score. Receiver Operating Characteristic curves and optimal cut-points (the point with the highest sensitivity and specificity where the sensitivity was at least 0.8) were calculated, for predicting prematurity, LBW, and both. Measurements within 24 h and at five days of life were compared.

Results

485 newborns were recruited. Chest circumference and MUAC measured within 24 h of birth were found to be highly predictive of LBW (both yielding area under the curve [AUC] of 0.98, 95% confidence interval [CI] 0.96–0.99), and performed marginally better than foot length (AUC 0.94, 95%CI 0.92–0.96). The optimal cut-points for measurements within 24 h of birth were ≤7.4cm for foot length; ≤30.4cm for chest circumference; and ≤ 9.0cm for MUAC. There was statistical evidence that anthropometric measurements taken within 24 h of birth were higher than measurements on day five (p<0.02 for all anthropometric measurements) but the magnitude of these differences was small (at most 2mm).

Conclusions

All measurements taken within 24 h of birth were good predictors of LBW, prematurity and both. Differences in measurements taken within 24 h and on day five were not clinically relevant. Further research will ensure that the application of these measures is reliable in community settings.     

低出生体重儿肠道菌群及肠道屏障功能的研究

目的研究低出生体重儿的肠道菌群分布情况和肠道屏障功能的变化。方法以低出生体重儿(1 500g≤体重2 500g)为研究对象,采用16SrRNA荧光定量PCR技术和JY-DLT肠道屏障功能分析系统检测低出生体重儿出生后第7天粪便中双歧杆菌、乳杆菌、大肠埃希菌、肠球菌4种细菌的含量以及血清中的二胺氧化酶、D-乳酸和细菌内毒素的浓度,比较正常新生儿与低出生体重儿肠道菌群和肠道屏障功能的差异,分析不同喂养方式、并发症对低出生体重儿肠道菌群及肠道屏障功能的影响。结果 (1)低出生体重儿组粪便中大肠埃希菌、肠球菌、乳杆菌、双歧杆菌含量均明显低于健康新生儿组(P0.05),血清中二胺氧化酶、D-乳酸高于健康新生儿组(P0.05),细菌内毒素水平差异无统计学意义(P0.05)。(2)母乳喂养组低出生体重儿粪便中双歧杆菌和乳杆菌含量明显高于乳制品喂养组(P0.05),且血清中二胺氧化酶和和D-乳酸含量低于乳制品喂养组(P0.05),细菌内毒素水平差异无统计学意义(P0.05)。(3)无并发症组低出生体重儿粪便中乳杆菌和双歧杆菌含量明显高于有并发症组(P0.05),其血清中二胺氧化酶、D-乳酸和细菌内毒素水平均低于有并发症的低出生体重儿(P0.05)。结论低出生体重儿的肠道菌群和肠道屏障功能都与正常新生儿存在差异,母乳喂养有助于肠道有益菌的定植和肠道屏障功能的恢复。     

Consequences of a low litter birth weight phenotype for postnatal lean growth performance and neonatal testicular morphology in the pig

The consequences of a low litter average birth weight phenotype for postnatal growth performance and carcass quality of all progeny, and testicular development in male offspring, were investigated. Using data from 25 sows with one, and 223 sows with two consecutive farrowing events, individual birth weight (BW) was measured and each litter between 9 and 16 total pigs born was classified as low (LBW), medium (MBW) or high (HBW) birth weight: low and high BW being defined as >1 standard deviation below or above, respectively, the population mean for each litter size. Litter average BW was repeatable within sows. At castration, testicular tissue was collected from 40 male pigs in LBW and HBW litters with individual BW close to their litter average BW and used for histomorphometric analysis. LBW piglets had a lower absolute number of germ cells, Sertoli cells and Leydig cells in their testes and a higher brain : testis weight ratio than HBW piglets. Overall, LBW litters had lower placental weight and higher brain : liver, brain : intestine and brain : Semitendinosus muscle weight ratios than MBW and HBW litters. In the nursery and grow–finish (GF) phase, pigs were kept in pens by BW classification (9 HBW, 17 MBW and 10 LBW pens) with 13 males and 13 females per pen. Average daily gain tended to be lower in LBW than HBW litters in lactation (P = 0.06) and throughout the nursery and GF phases (P < 0.01), resulting in an increasing difference in body weight between LBW, MBW and HBW litters (P < 0.05). Average daily feed intake was lower (P < 0.001) in LBW than HBW litters in the nursery and GF phases. Feed utilization efficiency (feed/gain) was similar for LBW and HBW litters in the nursery, but was lower (P < 0.001) in HBW than LBW litters in the GF phase. By design, slaughter weight was similar between BW classifications; however, LBW litters needed 9 more days to reach the same slaughter weight than HBW litters (P < 0.001). BW classification did not affect carcass composition traits. In conclusion, LBW litters showed benchmarks of intrauterine growth retardation, LBW had a negative impact on testicular development and germ and somatic cell populations, and was associated with decreased postnatal growth during all phases of production; however, no measurable effect on carcass composition traits was established.     

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on birth litter quality and growth performance to weaning

The effects of a marine oil-based n-3 long-chain polyunsaturated fatty acid (mLCPUFA) supplement fed to the sow from weaning, through the rebreeding period, during gestation and until end of lactation on litter characteristics from birth until weaning were studied in sows with known litter birth weight phenotypes. It was hypothesized that low birth weight (LBW) litters would benefit more from mLCPUFA supplementation than high birth weight litters. A total of 163 sows (mean parity=4.9±0.9) were rebred after weaning. Sows were pair-matched by parity and litter average birth weight of the previous three litters. Within pairs, sows were allocated to be fed either standard corn/soyabean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. Each litter between 9 and 16 total pigs born was classified as LBW or medium/high average birth weight (MHBW) litter and there was a significant correlation (P<0.001) between litter average birth weight of the current and previous litters within sows (r=0.49). Sow serum was harvested at day 113 of gestation for determination of immunoglobulin G (IgG) concentrations. The number of pigs born total and alive were lower (P=0.01) in mLCPUFA than CON sows, whereas the number of stillborn and mummified pigs were similar between treatments. Number of stillborns (trend) and mummies (P<0.01) were higher in LBW than MHBW litters. Tissue weights and brain : tissue weight ratios were similar between treatments, but LBW litters had decreased tissue weights and increased brain : tissue weight ratios compared with MHBW litters. Placental weight was lower (P=0.01) in LBW than MHBW litters, but was not different between treatments. Average and total litter weight at day 1 was similar between treatments. mLCPUFA increased weaning weight (P=0.08) and average daily gain (P<0.05) in MHBW litters, but not in LBW litters. Pre-weaning mortality was similar between treatments, but was higher (P<0.01) in LBW than MHBW litters. IgG concentration in sow serum was similar between treatments and litter birth weight categories. In conclusion, litter birth weight phenotype was repeatable within sows and LBW litters showed the benchmarks of intra-uterine growth retardation (lower placental weight and brain sparing effects). As maternal mLCPUFA supplementation decreased litter size overall, only improved litter growth rate until weaning in MHBW litters, and did not affect pre-weaning mortality, maternal mLCPUFA supplementation was not an effective strategy in our study for mitigating negative effects of a LBW litter phenotype.     

The epidemiology of low birth weight; changes in incidence in Aberdeen, 1948-72

Changes in the incidence of low birth weight (defined as 2500 gm or less) in Aberdeen, Scotland are explored. The article also focuses on the perinatal mortality rate associated with unexplained low birth weight (LBW). Results, when analysed in terms of age, parity and social class of the mother, showed that in para 0 the incidence was highest in 1948-52. There was very little variation in incidence in each five year group in terms of para 1. The incidence of LBW was most strongly influenced by the socioeconomic climate at the time of the mother's birth. At least in Aberdeen the incidence of LBW in short women was twice that in tall women. The author concludes that the epidemiological characteristics of LBW is very closely associated with the changes in the socioeconomic conditions in Britain in the last decade which have affected health, nutrition and reproductive efficiency.     

Central stiffening in adulthood linked to aberrant aortic remodeling under suboptimal intrauterine conditions

This study examined perturbed aortic development and subsequent wall stiffening as a link to later cardiovascular disease. Placental insufficiency was induced in pregnant guinea pigs at midgestation by uterine artery ligation. Near term, fetuses were killed and defined as normal birth weight (NBW), low birth weight (LBW), and intrauterine growth restricted (IUGR). Offspring were classified according to birth weight and killed in adulthood. Collagen and elastin content of aortas were analyzed using Sirius red and orcein staining, respectively. Immunofluorescence was used for detection of α-actin and nonmuscle myosin heavy chain (MHC-B), a marker of synthetic-type vascular smooth muscle cells (VSMCs). Ex vivo generation of length-tension curves was performed with aortic rings from adult offspring. Relative elastic fiber content was decreased by 10% in LBW and 14% in IUGR compared with NBW fetuses. In adulthood, relative elastic fiber content was 51% lower in LBW vs. NBW, and the number of elastic laminae adjusted for wall thickness was 25% lower in LBW (P < 0.01). The percent area stained for MHC-B was sixfold higher in LBW vs. NBW fetuses (P < 0.0001) and threefold higher in LBW vs. NBW adult offspring (P < 0.05). The increase in MHC-B in LBW offspring concurred with a 41% increase in total collagen content and a 33 and 56% increase in relative and total α-actin content, respectively (P < 0.05). Thus aortic wall stiffening in adulthood can be traced to altered matrix composition established under suboptimal intrauterine conditions that is amplified postnatally by the activity of synthetic VSMCs.     

Birth weight and postnatal dietary protein level affect performance, muscle metabolism and meat quality in pigs

Intrauterine growth restriction (IUGR), resulting in low birth body weight (LBW) occurs naturally in pigs. However, IUGR may also cause persistent changes in physiology and metabolism resulting in poorer performance, organogenesis and meat quality. As IUGR pigs have a lower daily gain from birth to slaughter they may differ in utilization of nutrients and requirements for dietary protein compared with their larger littermates. Thus, the objective in this study was to examine the interaction between birth body weight (BW) and the postnatal dietary protein level, in relation to postnatal performance, organogenesis, muscle metabolism and meat quality. The experiment was carried out with offspring from 16 purebred Danish Landrace gilts mated to Danish Landrace boars. The female and entire male pigs with LBW that survived at weaning were compared with the female and male pigs with the highest/high birth body weight (HBW) within each litter. The offspring were reared individually from weaning and were fed ad libitum a diet containing either a normal level of protein (NP) for optimal growth or an isocaloric diet containing a 30% lower protein content (LP) from 3 weeks to 150 days of age. At slaughter, we found no interactions between birth weight group and dietary protein level for any of the measured traits. The relative crown-rump length (cm/kg) at birth indicates that LBW pigs were thinner than HBW pigs. Daily gain and feed intake were reduced by 14% and 10%, respectively, while the kg feed/kg gain was slightly increased by 3% in LBW pigs compared with HBW pigs. The LP diet reduced daily gain by 27% due to reduced feed intake and increased kg feed/kg gain by 12% and 21%, respectively compared with the NP diet. LBW male pigs produced meat with a higher shear force than male HBW pigs and also LP pigs produced meat with higher shear force than NP pigs. The activity of lactate dehydrogenase in the Longissimus dorsi muscle (LD) was reduced in pigs fed the LP diet. Calpastatin was increased in LD of LBW pigs and decreased in pigs fed the NP diet. In conclusion, these results suggest a rejection of our hypothesis that low birth weight littermates have a lower requirement for dietary protein compared with heavy weight littermates. Furthermore, LBW male pigs and LP fed pigs of both genders produced less tender meat than HBW pigs or NP fed pigs, respectively.     

Effects of Maternal Pregnancy Intention,Depressive Symptoms and Social Support on Risk of Low Birth Weight: A Prospective Study from Southwestern Ethiopia

Background

Low birth weight (LBW) is the principal risk factor for neonatal and infant mortality in developing countries. This study examines the effects of unwanted pregnancy, prenatal depression and social support on the risk of low birth weight in rural southwestern Ethiopia. We hypothesized that unwanted pregnancy and prenatal depression increase the risk of low birth weight, while social support mediates this association.

Methods

Data for the study comes from a prospective study in which women were followed from pregnancy through to delivery. Six hundred twenty two women were followed and 537 birth weights were measured within 72 hours. Multivariable log binomial regression was used to model the risk of low birth weight.

Results

The mean birth weight was 2989 grams (SD±504 grams), and the incidence of LBW was 17.88%. The mean birth weight of babies after unwanted pregnancy was 114 g lower compared to births from intended pregnancy. Similarly, mean birth weight for babies among women with symptoms of antenatal depression was 116 grams lower. Results of unadjusted log-binomial regression showed that unwanted pregnancy, prenatal depression and social support were associated with LBW. The relationship between antenatal depressive symptoms and LBW was mediated by the presence of social support, while the association between LBW and unwanted pregnancy remained after multivariable adjustment.

Conclusion

The incidence of low birth weight is high in the study area. Poverty, nonuse of antenatal care, low social support and unwanted pregnancy contribute to this high incidence of low birth weight. Hence, identifying women’s pregnancy intention during antenatal care visits, and providing appropriate counseling and social support will help improve birth outcomes.     

Low Birthweight (LBW) and Neonatal Hyperbilirubinemia (NNH) in an Indian Cohort: Association of Homocysteine,Its Metabolic Pathway Genes and Micronutrients as Risk Factors

Background & Aims

Indian subcontinent has the highest child mortality rates along with a very high frequency of low birthweight (LBW). Folate and vitamin B12 (Vit-B12) are necessary during foetal development and their deficiency prevalence in Indians is very high. The objective of the present paper is to assess whether foetal homocysteine (Hcy)/folate metabolic pathway genes, their cofactors and homocysteine level independently (or collectively) predispose children to Low birth weight.

Methods

Cord blood was collected for the study. Frequency of 5 SNPs in 4-Hcy-pathway genes, and levels of Hcy, Vit-B12 and folate were evaluated.

Results

Of the 421 newborns recruited for the study, 38% showed low birth weight (<2.5kg) and 16% were preterm babies. 101 neonates developed neonatal hyperbilirubinemia (NNH). High prevalence of Vit-B12 (65%) and folate (27%) deficiency was observed in newborns along with hyperhomocystinemia (hypHcy-25%). Preterm delivery, micronutrient deficiency, hypHcy and MTHFR 677T SNP are associated as risk factor while G allele of TCN2 C776G is protective against LBW. MTHFR 677T allele and folate deficiency are also independent risk factors for NNH.

Conclusion

We record the highest incidence of Vit-B12, folate deficiency and elevated Hcy levels, of all the studies so far reported on neonates. These together with MTHFR 677T are potential risk factors for LBW. Association of impaired folate/Hcy metabolism with NNH is reported for the first time and the possible way of interaction is discussed. It appears that proper nutritional management during pregnancy would reduce the risk of complex clinical outcomes.     

Risk factors for low birth weight: Results from a case-control study in southern Spain

The main objective of this study is to examine the effect of several variables, including altitude of maternal residence, on delivering a low birth weight (LBW) newborn. A case-control study was done. Two hundred forty cases (single newborn weighing less than 2,500 g) and 374 controls (single newborn weighing more than 2,499 g) were included. Information was gathered from the clinical chart of delivering women, through a personal interview and the Spanish Census Bureau (for altitude). Predictors of LBW were assessed through stepwise logistic regression analysis. Several well-known LBW risk factors were identified: hypertension, weight gain during pregnancy, body size (mainly maternal prepregnancy weight), low social class, primiparity, and several conditions (spontaneous delivery, abruptio placentae). Altitude was an independent predictor of LBW at term (more than 37 weeks of gestational age) but not for preterm LBW. Nevertheless, a relationship between altitude and birth weight was not found in controls, although a moderate decreasing gradient with altitude was observed. The limitations of these findings are discussed. Am J Phys Anthropol 105:419–424, 1998. © 1998 Wiley-Liss, Inc.     

Changes in the association of low birth weight with socioeconomic status in Hawaii: 1970-1990

This study examines rates of low birth weight (LBW) in the state of Hawaii and changes in the association of LBW with socioeconomic status from 1970 to 1990. The analysis is based on aggregate data for census tracts. Rates of low birth weight were calculated for each census tract. Relative socioeconomic scores were calculated from average household income and years of education. The results show that (1) there was a decrease in the rate of low birth weight infants in Hawaii; and (2) that the correlation between socioeconomic status and low birth weight was substantially reduced, though a significant correlation remains. The paper suggests likely ceiling effects, but that the progressive public health policies and expansion of access to primary health care in Hawaii during this period played a major role in reducing the rate of low birth weight infants and in decreasing socioeconomic inequality on this important health indicator.     

Role of maternal exposures and newborn genotypes on newborn chromosome aberration frequencies

Maternal exposures may induce chromosome damage and birth defects in the fetus. Polymorphic variation in genes coding for enzymes involved in metabolic activation and detoxification of environmental procarcinogens may account for some of the differences in chromosome aberration frequencies in newborns. In this study, 40 mothers completed questionnaires regarding exposures they received during their pregnancy. Umbilical cord blood samples were analyzed for chromosome aberrations. An average of 1020 metaphase cell equivalents (equal to 1020 G-banded cells) were examined from each newborn. In 26 of the newborns, genotyping analysis was performed for genes functioning in metabolic activation and detoxification (cytochrome P450 genes: CYP2D6 and CYP1A1, and phase II genes: NAT1, NAT2, GSTT1, GSTM1, GSTP1, and epoxide hydrolase). A significant association between the CYP1A1 MspI polymorphism and chromosome aberration frequencies was observed in the newborns (p=0.02), with heterozygotes showing higher aberration frequencies than the wild type homozygotes. Some large differences in chromosome aberration frequencies for other genotypes were also noted, but these were not statistically significant. Exposure to tobacco smoke in utero also appeared to increase translocation frequencies. The mean frequency of translocations per 100 cell equivalents from newborns of mothers who smoked during pregnancy was significantly higher than that of newborns whose mothers did not smoke (0.21 vs. 0.11, respectively, p=0.045).     

Maternal residential proximity to nuclear facilities and low birth weight in offspring in Texas

Health effects of close residential proximity to nuclear facilities have been a concern for both the general public and health professionals. Here, a study is reported examining the association between maternal residential proximity to nuclear facilities and low birth weight (LBW) in offspring using data from 1996 through 2008 in Texas, USA. A case–control study design was used together with a proximity-based model for exposure assessment. First, the LBW case/control births were categorized into multiple proximity groups based on distances between their maternal residences and nuclear facilities. Then, a binary logistic regression model was used to examine the association between maternal residential proximity to nuclear facilities and low birth weight in offspring. The odds ratios were adjusted for birth year, public health region of maternal residence, child’s sex, gestational weeks, maternal age, education, and race/ethnicity. In addition, sensitivity analyses were conducted for the model. Compared with the reference group (more than 50 km from a nuclear facility), the exposed groups did not show a statistically significant increase in LBW risk [adjusted odds ratio (aOR) 0.91 (95% confidence interval (CI): 0.81, 1.03) for group 40–50 km; aOR 0.98 (CI 0.84, 1.13) for group 30–40 km; aOR 0.95 (CI 0.79, 1.15) for group 20–30 km; aOR 0.86 (CI 0.70, 1.04) for group 10–20 km; and aOR 0.98 (CI 0.59, 1.61) for group 0–10 km]. These results were also confirmed by results of the sensitivity analyses. The results suggest that maternal residential proximity to nuclear facilities is not a significant factor for LBW in offspring.     

Changes in the association of low birth weight with socioeconomic status in Hawaii: 1970–1990

Abstract

This study examines rates of low birth weight (LBW) in the state of Hawaii and changes in the association of LBW with socioeconomic status from 1970 to 1990. The analysis is based on aggregate data for census tracts. Rates of low birth weight were calculated for each census tract. Relative socioeconomic scores were calculated from average household income and years of education. The results show that (1) there was a decrease in the rate of low birth weight infants in Hawaii; and (2) that the correlation between socioeconomic status and low birth weight was substantially reduced, though a significant correlation remains. The paper suggests likely ceiling effects, but that the progressive public health policies and expansion of access to primary health care in Hawaii during this period played a major role in reducing the rate of low birth weight infants and in decreasing socioeconomic inequality on this important health indicator.     

Identifying Maternal Constraints on Fetal Growth and Subsequent Perinatal Outcomes Using a Multiple Embryo Implantation Model

IntroductionAlthough the majority of singleton births after in vitro fertilization (IVF) are uncomplicated, studies have suggested that IVF pregnancies may be independently associated with low birth weight (LBW), preterm birth (PTB), and perinatal mortality. These outcomes complicate multiple gestations as expected, but have also been reported in singletons. A multiple embryo implantation model allows for assessment of the early in utero environment, and therefore, assessment of any maternal constraints on developing fetuses. We question whether adverse perinatal outcomes associated with assisted reproductive techniques (ART) occur as a result of maternal physiologic adaptations.ResultsA total of 17,415 cycles were analyzed. The average maternal age was 36.9 (±5.0) years. An overall fertilization rate of 73.4% generated approximately 48,708 good quality cleavage-stage embryos. In most patients (92.8%), an average of 3 embryos were transferred. The clinical pregnancy rate was 39.2% (n = 6,281). The overall occurrence of multiple gestations was 38.2% (n = 2,608) consisting of 2,038 twin, 511 triplet, and 59 quadruplet pregnancies. Of these multiple gestations, 18.6% of twin, 54.2% of triplet and 76.3% of quadruplet gestations spontaneously reduced. Failure of the implanted embryo to progress was not related to maternal age. Singleton newborns resulting from multiple implantation sites had lower birth weights (P<0.01) and shorter gestational ages (P<0.01) than those from a single implanted embryo. The number of embryos transferred did not affect the gestational length of singleton newborns. Although the birth weights of singletons from multiple implantation sites (virtual singletons) were lower than true singletons, the birth weight of virtual singletons were comparable to the birth weights of true twin, triplet, and quadruplet live births. Multiple logistic regression revealed that virtual singletons were an independent risk factor for PTB (odds ratio: 4.55, 95% CI 2.23–9.29) and LBW (odds ratio: 3.61, 95% CI 1.78–7.32), even after controlling for the number of oocytes, stimulation protocol type, sperm source, total gonadotropins administered, age, embryo quality, and day of embryo transfer.ConclusionsOur study highlights that embryonic implantation sites during early gestation set the growth profile of each embryo, dictating later growth patterns. Specifically, spontaneous reduction of an embryo after multiple embryo implantations can confer greater perinatal risk in the form of LBW and PTB to the surviving fetus. Our findings suggest that maternal constraints or physiologic adaptations maybe one of the mechanisms mediating adverse perinatal outcomes when multiple embryo implantation occurs.