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PubMed2000

A controlled study of the morphometric changes in the primary dentition of pre-term, very-low-birthweight children.

The aim of the present investigation was to compare the dimensions of the primary incisors from pre-term children and full-term controls. One hundred and eleven pre-term children, consisting of 86 very-low-birthweight (< 1,500 g), 25 low-birthweight (from 1,500 to 2,500 g), and 169 full-term, normal-birthweight (> 2,500 g) children, donated a total of 572 maxillary and mandibular primary central and lateral incisors for study. The teeth were measured by means of a digital micrometer. The results showed that there was a dose-response effect of birthweight on tooth size. The very-low-birthweight teeth showed the smallest dimensions, the normal-birthweight controls the largest, and the low-birthweight teeth intermediate dimensions (p < 0.001). In the maxillary primary central and lateral incisors, and the mandibular primary central incisors, very-low-birthweight teeth were from 6 to 11% smaller in both mesiodistal and faciolingual dimensions compared with normal-birthweight teeth (p < 0.001). The largest differences were observed in the maxillary lateral incisors, where mean decreases of 0.58 +/- 0.45 mm in mesiodistal and 0.50 +/- 0.40 mm in faciolingual dimensions (11% reduction in both measurements) were observed. In addition, in the mandibular and maxillary lateral incisors of very-low-birthweight children, the left-sided teeth were significantly smaller than those on the right side in both mesiodistal and faciolingual dimensions (p < 0.03).

Analysis of Variance↗
PubMed2004

Exploring the etiology of the association between birthweight and IQ in an adolescent twin sample.

The negative effects of very low birthweight on intellectual development have been well documented, and more recently this effect has been shown to generalize to birthweights within the normal range. In this study we investigate the etiology of this relationship by using a classical twin design to disentangle the contributions of genes and environment. A previous Dutch study (Boomsma et al., 2001) examining these effects indicated that genes were important in mediating the association of birthweight to full IQ measured at ages 7 and 10, but not at ages 5 and 12. Here the association between birthweight and IQ at age 16 is considered (N = 523 twin pairs). Using variance components modeling we found that the genetic variance in birthweight (4%) completely overlapped with that in verbal IQ but not performance or full IQ. Results further showed the importance of shared environmental effects on birthweight (~ 60%) but not on IQ (with genes explaining up to 72% of IQ variance). Models incorporating a direction of causation parameter between birthweight and IQ provided adequate fit to the data in either causal direction for performance and full IQ, but the model with verbal IQ causing birthweight was preferred to one in which birthweight influenced verbal IQ. As the measurement of birthweight precedes the measurement of twins' IQ at age 16, the influence of verbal IQ might be better considered as a proxy for parents' IQ or education, and it is possible that brighter mothers provide better prenatal environments for their children.

Adolescent↗
PubMed1997

Recent trend of the decrease in mean birthweights of infants in the western provinces of Gifu Prefecture, Japan.

The mean birthweight has decreased recently in Japan. The author assessed the etiology of this trend by comparing the birthweight during the years 1983-1984 and 1993-1994 in Central Japan. All birth certificates of 3767 and 3423 infants were available for 1983-1984 and 1993-1994, respectively. The mean birthweight decreased from 3165 g to 3128 g. The proportion of first infants whose mean birthweight decreased more than that of the other infants increased from 41.0% to 47.1%. Comparison and multivariate analysis revealed the main cause of decreased birthweight as a decrease of the mean birthweight of first infants and changes of the proportion of birth order. Influences of the increases in the proportion of multiple births and that of low birthweight infants to the decrease of mean birthweight were small. The mean birthweight of infants who were born in public hospitals was lower than that of infants born in clinics, private hospitals, and others. The proportion of low birthweight infants was also highest among the infants born in public hospitals. These results indicate that pregnant women with high risk factors are more likely to be referred to the care of public hospitals.

Adult↗
PubMed2001

Birthweight distribution at Korle-Bu Teaching Hospital, Ghana.

OBJECTIVES: To determine the birthweight distribution of singleton births at the Korle-Bu Teaching Hospital and to determine if selected socio-demographic and reproductive characteristics that are known to be associated with birthweight would show the association in our setting. DESIGN: A non-randomised cross-sectional survey of all deliveries within the study period. SETTING: Korle-Bu Teaching Hospital, a tertiary institution, delivering about 11,000 women a year. STUDY POPULATION: From 1st November to 12th December 1994, 866 singleton normally formed livebirths and fresh stillbirths were sequentially enrolled. DATA SOURCES: Data sources were the antenatal and delivery records of the subjects and an interviewer-administered questionnaire. RESULTS: The mean birthweight for the total sample was 3070 g +/- 616 g. One hundred and fifteen (13.3%) babies were low birthweight. The mean birthweight for those with reliable dates and born at term was 3262 g +/- 488.8 g. Multiple logistic regression analysis showed lack of antenatal malaria chemoprophylaxis and a history of previous low birthweight to be significantly associated with low birthweight. CONCLUSION: Although the mean birthweight of Korle-Bu babies was lower than those of USA and UK babies, it was comparable with those from other developing countries. Antenatal malaria chemoprophylaxis is a practical intervention that can produce an increase in mean birthweight and reduce the risk of low birthweight in our population.

Birth Weight↗
PubMed2000

Maternal smoking and birthweight: effect modification of period, maternal age and paternal smoking.

OBJECTIVE: To study the effect on birthweight of maternal smoking, and its modification by study period, maternal age and paternal smoking. DESIGN: A retrospective questionnaire based national survey comprising a random sample (n=34,799) of all mothers giving birth in Norway 1970-91. Variables studied were parental smoking during pregnancy, birthweight, maternal age and infant's year of birth. RESULTS: The overall difference in mean birthweight between non-smoking and smoking mothers was 197 g. The difference in birthweight between non-smoking and smoking mothers increased with maternal age from 182 g (<20 years of age) to 232 g (35+ years of age). There was no significant effect of paternal smoking on birthweight when the mother was a non-smoker. When the mother was a smoker and the father was a non-smoker, the birthweight, adjusted for maternal age, was reduced by 153 g (p<0.005). However, when both parents smoked, the birthweight, adjusted for maternal age, was reduced by 201 g (p<0.0005). Even though the prevalence of paternal smoking decreased by 38% during the study period, there was no significant increase in overall mean birthweight. IMPLICATION AND RELEVANCE OF RESULTS: The negative effect of maternal smoking on birthweight appears to increase with maternal age. For a non-smoking pregnant woman to live with a smoking partner has little, if any, effect on birthweight. The negative effect of paternal smoking was only observed when the mother was smoking and might reflect two possible mechanisms: (1) that a smoking mother has a greater cigarette consumption when the partner also smokes, and (2) that a smoking mother is less concerned about passive smoking than a non-smoking mother.

Adult↗
PubMed1996

Modulation of birthweight through gestational age and fetal growth.

Several factors are known to affect birthweight and their effects are variously mediated through gestational duration or through fetal growth conditional on this gestation. In order to quantify independent associations of birthweight conditional and unconditional on gestational age, all 2538 mothers of singleton babies delivered during 1993 in two Maternity Hospitals in Athens were interviewed and their obstetric records abstracted. Birthweight was modelled as outcome variable through multiple regression including 32 potentially predictive factors. The regression model was fitted with and without gestational age as an additional independent variable in order to apportion birthweight associations into those independent of, or mediated through, gestational length. The factors studied were found to be classifiable into the following categories: factors associated with birthweight mostly through increases in gestational duration, either positively (age at menarche, long menstrual cycles, parity 4 or higher), or negatively (single motherhood, maternal age, tobacco smoking); those associated with birthweight mostly through increase of birthweight conditional on gestational duration, either positively (male gender, short menstrual cycles, maternal pre-pregnancy weight, anaemia, oedema) or inversely (employment during pregnancy, stillbirth, primiparity, pregnancy induced hypertension, coffee drinking); and those associated with birthweight through apparently dual effects, either positively (maternal education) or inversely (perceived stress, bleeding during pregnancy). The other studied factors were not demonstrably related to birthweight in this data set. Identification and quantification of these relations is useful for understanding underlying physiological and pathophysiological processes and for increasing specificity in exploring the association of birthweight with adult onset diseases, like coronary heart disease or cancer.

Adolescent↗
PubMed1996

Birthweight standards for south Indian babies.

OBJECTIVE: To obtain birthweight standards for south Indian babies. DESIGN: Prospective cohort study. SETTING: A tertiary care hospital in south India. PATIENTS AND METHODS: Data from 11, 641 singleton live births between 1991 and 1994 were used to calculate smoothed gestation specific birthweight centiles for four categories based on sex of the infant and birth order. Smoothed gestation specific birthweight centiles were also calculated for all births between 37-41 weeks without adjustments for sex of infant or birth order. Data for births between 37 and 41 weeks were reanalysed using non-adjusted birthweight centiles and birthweight centiles adjusted for sex and birth order to determine misclassification of data. Multiple regression analysis was used to determine the influence of various variables on birthweight. RESULTS: Factors influencing birthweight were gestation at birth, sex of infant, birth order and maternal height. A quadratic equation including these variables and the square of the gestational age explained 18% of variation in birthweight. Female infants were on the average 113 g (95% CI 26-200 g) lighter than male infants. Later born babies were on the average 130 g (95% CI 40-220 g) heavier than first born babies. Therefore significant misclassification of infants occurred when non-adjusted birthweight centiles were used. Babies born to women whose heights were outside the interquartile range (150-158 cm) were 81 g lighter or heavier than those born to women within this range. CONCLUSIONS: Birthweight centiles for gestation when used should be adjusted for birth order, sex of infant and maternal height.

Birth Order↗
PubMedDate not supplied

Psychosocial stressors and low birthweight in an urban population.

INTRODUCTION: Low birthweight is a major determinant of infant mortality, as well as a contributor to infant and childhood morbidity. A key issue is how to reduce the incidence of low birthweight in the United States. One emerging factor is exposure to psychosocial stressors. In this research, we evaluated the association between exposure to psychosocial stressors and low birthweight in a population of urban, low-income pregnant women. METHODS: Over 2,000 pregnant women 18 years of age and older were enrolled in this prospective study and recruited at their first prenatal care visit. We obtained information on maternal exposure to stressors. After the pregnancy, we abstracted clinical records of each woman enrolled in the study. Logistic regression was used to estimate the adjusted odds ratio for the association between stressor group membership and low birthweight, controlling for the effects of confounding factors. RESULTS: In logistic regression analyses stratified by race, for African-American women, the following variables were significantly associated with low birthweight: smoking, hypertension, low prepregnancy weight, hospitalization during pregnancy, previous preterm birth, and exposure to stressors. For Caucasian women, significant predictors were: smoking, drug use, hospitalization during pregnancy, hypertension, and previous preterm birth. Exposure to stressors was also significantly associated with many clinical and behavioral risks for low birthweight. CONCLUSION: Our results suggest two potential mechanisms for an association between stressors and low birthweight. Exposure to stressors may be indirectly associated with low birthweight through a relationship with clinical and behavioral risks for low birthweight. Exposure to psychosocial stressors may also be directly associated with risk of low birthweight among African-American women.

Adolescent↗
PubMed1994

Birthweight and adult health outcomes in a biethnic population in the USA.

Recent data indicate that low-birthweight adults are at a higher risk than their high-birthweight peers of developing ischemic heart disease or a cluster of conditions known as the IRS, which includes dyslipidaemias, hypertension, unfavorable body fat distribution and NIDDM. Thus far these observations have been limited to Caucasians from the United Kingdom. we extended these observations to a broader segment of the general population by studying the association of birthweight and adult health outcomes in a biethnic population of the United States. We divided a group of 564 young adult Mexican-American and non-Hispanic white men and women participants of the San Antonio Heart Study into tertiles of birthweight and compared metabolic, anthropometric, haemodynamic, and demographic characteristics across these tertile categories. Additionally, we studied birthweight as a predictor of the clustering of diseases associated with the IRS, defined as any two or more of the following conditions: hypertension, NIDDM or impaired glucose tolerance, dyslipidaemia. Normotensive, non-diabetic individuals whose birthweight was in the lowest tertile had significantly higher levels of fasting serum insulin and a more truncal fat deposition pattern than individuals whose birthweight was in the highest tertile, independently of sex, ethnicity, and current socioeconomic status. Also, the odds of expressing the IRS increased 1.72 times (95% confidence interval: 1.16-2.55) for each tertile decrease in birthweight. These findings were independent of sex, ethnicity, and current levels of socioeconomic status or obesity. In conclusion, low birthweight could be a major independent risk factor for the development of adult chronic conditions commonly associated with insulin resistance in the general population.

Adult↗
PubMed2003

Birthweight of offspring and paternal insulin resistance and paternal diabetes in late adulthood: cross sectional survey.

AIMS/HYPOTHESIS: It has been proposed that genetic factors involved in insulin action could explain part of the link between low birthweight and risk of cardiovascular disease and diabetes in adulthood. To confirm this we examined the association between offspring birthweight and paternal insulin resistance and diabetes in late adulthood. METHODS: We did a cross-sectional survey of 4252 men who were 60 to 79 years of age and from 24 British towns. Of these, 2788 men provided details of their offsprings' birthweight and sex. RESULTS: Offspring birthweight was inversely associated with paternal insulin resistance defined by the homeostasis model assessment (HOMA) score and with Type 2 diabetes in late adulthood. Fathers of offspring in the highest quartile of sex-standardised birthweight SD scores had a 34% reduction in odds of having a high HOMA insulin resistance score (OR=0.66, 95% CI: 0.47 to 0.92) compared with fathers of offspring in the lowest quartile after adjustment for potential confounders. A stronger inverse association was seen between offspring birthweight and risk of paternal diabetes (adjusted OR=0.59, 95% CI: 0.39 to 0.88 top quartile vs lowest quartile). For each increase of offspring-birthweight SD score the odds of high HOMA scores decreased by 13% (OR=0.87, 95% CI: 0.78 to 0.98) and the odds for diabetes by 17% (OR=0.83, 95% CI: 0.72 to 0.95), after full adjustment. CONCLUSIONS/INTERPRETATION: Offspring birthweight is inversely associated with paternal insulin resistance and diabetes in late adulthood, supporting the hypothesis that genetic factors related to insulin action contribute to the association between birthweight and adult cardiovascular disease and diabetes risk.

Aged↗
PubMed1996

Low birthweight in a public prenatal care program: behavioral and psychosocial risk factors and psychosocial intervention.

A retrospective, observational study of 3073 low income African American, Latina, and White women receiving comprehensive prenatal care at 26 provider sites was completed. The purpose of the study was to test three hypotheses. First, after adjustment for biomedical complications, the presence of maternal behavioral and psychosocial factors would be associated with an increased rate of low birthweight infants. Second, increased time spent in psychosocial services would negate the relationship between maternal psychosocial factors and low birthweight. Third, after adjusting for biomedical, behavioral, and psychosocial factors, rates of low birthweight would no longer differ by race. Maternal smoking (over five cigarettes per week), maternal low weight for height and/or weight gain, negative mood (depression, anxiety, and/or hostility) and rejection of the pregnancy were found to be related to an increased rate of low birthweight birth (< 2500 g). Receiving more than 45 min of psychosocial services was related to a reduced rate of low birthweight birth for all women regardless of risk profile. The rate of low birthweight remained higher in African American women after adjusting for all significant maternal biomedical, behavioral, and psychosocial risk and intervention factors. Further analyses revealed that the strength and direction of the relationship between time spent in psychosocial services and low birthweight remained after controlling for the number of prenatal care visits, the time spent in nutrition or health educational services, and gestational age. Also, the time spent in psychosocial services was related to a reduced rate of low birthweight even after excluding time spent in psychosocial services in the third trimester of pregnancy or excluding women who received their first psychosocial assessment in the third trimester from the analysis. Although definitive evidence from randomized trials of psychosocial services is lacking, receiving over 45 min of psychosocial services was related to a reduced risk of low birthweight for all women in this study. Therefore, general psychosocial services appears to be an important component of prenatal care for all low income women.

Adult↗
PubMed1996

Birthweight, body-mass index in middle age, and incident coronary heart disease.

BACKGROUND: Several studies have shown a relation between fetal development, as shown by birthweight, and later coronary heart disease. This study investigated whether this relation is predominantly the consequence of early life exposures, or can best be explained in terms of an interaction between influences in early life and in adulthood. METHODS: This prospective study in Caerphilly, South Wales, included 1258 men, aged 45-59 at initial screening, who were able to provide birthweight data. These men are from an initial cohort of 2512 men, from whom information has been obtained in a series of examinations since 1979 on health-related behaviours, incidence of coronary heart disease, and risk factors. The main outcome measure was fatal and non-fatal coronary heart disease during 10 years of follow-up. FINDINGS: Higher birthweight was related to lower risk of coronary heart disease during the follow-up period: coronary heart disease occurred in 46 (11.6%) men in the lowest birthweight tertile, 44 (12.0%) of those in the middle tertile, and 38 (9.1%) of those in the highest tertile (p = 0.03). Stratification of the cohort by body-mass index (BMI) revealed a significant interaction such that the inverse association between birthweight and risk of coronary heart disease was restricted to men in the top tertile of BMI (interaction test p = 0.048 adjusted for age, and p = 0.012 fully adjusted). Within the top BMI tertile, coronary heart disease occurred in 19 (16.4%) of men in the lowest birthweight tertile, 13 (12.6%) of those in the middle tertile, and 13 (7.5%) of those in the highest tertile (p = 0.0005). These associations were not changed substantially by adjustment for age, father's social class, own social class, marital status, fibrinogen and cholesterol concentrations, systolic blood pressure, and smoking history. INTERPRETATION: The association between birthweight and risk of coronary heart disease cannot be explained by associations with childhood or adulthood socioeconomic status. Nor do conventional risk factors for coronary heart disease in adulthood account for the association. However, there is an important interaction between birthweight and BMI such that the increased risk of coronary heart disease associated with low birthweight is restricted to people who have high BMI in adulthood. Risk of coronary heart disease seems to be defined by the combined effect of early-life and later-life exposures.

Birth Weight↗
PubMed1999

Relationship between birthweight and blood pressure in childhood.

Studies have shown an inverse relationship between birthweight and blood pressure in later life. The objective of this study is to analyze the relationship between birthweight and blood pressure in childhood in a North American-based population. Data on 2,958 births with follow-up at 7 years of age from the Providence, RI, cohort of the Collaborative Perinatal Project of the National Institute of Neurological Diseases and Stroke were retrospectively analyzed using univariate and multivariate analytic methods. Bivariate analysis of the total cohort showed a direct relationship between follow-up weight at age 7 years and birthweight (r = 0.24; P < 0.001) and follow-up weight with systolic (SBP) and diastolic blood pressure (DBP; r = 0.33; P < 0.001 and r = 0.22; P < 0.001, respectively). On multivariate analysis, follow-up weight and height were the strongest predictors of SBP and DBP. There was also a significant inverse relationship between birthweight and SBP. A cohort of term infants (n = 2,561) was subdivided into birthweight-for-gestational-age groupings to further evaluate the effects of birthweight on blood pressure. Small-for-gestational-age (SGA) infants were markedly smaller at age 7 years than those large-for-gestational-age (LGA; 21 +/- 4 kg v 26 +/- 4 kg; P < 0.01). Despite the direct association between follow-up weight and blood pressure, the mean blood pressure did not differ between SGA (103/58 mm Hg) and LGA patients (103/59 mm Hg). To assess whether birthweight was an independent predictor of blood pressure, blood pressures were predicted using linear regression equations. For every 1-kg decrease in birthweight in term infants, SBP at 7 years increased by 1.3 mm Hg and DBP by 0.6 mm Hg. In conclusion, controlling for weight and height in term infants at 7 years of age has an inverse linear effect on blood pressure. This suggests that birthweight in relation to gestation may be a contributor to the multifactorial cause of essential hypertension.

Birth Weight↗
PubMed1999

A population-based cohort study of the relation between maternal birthweight and risk of gestational diabetes mellitus in four racial/ethnic groups.

Intrauterine growth retardation and low birthweight have been associated with an increased risk of insulin resistance and type II diabetes later in life. We hypothesised that maternal low birthweight is associated with an increased risk of gestational diabetes mellitus (GDM). Study subjects comprised women giving birth in Washington State between 1987 and 1995. Information for 21,528 births to non-Hispanic white women, 6359 to African-American women, 7456 to Native American women and 6496 to Hispanic women was available for analysis. All information was derived from statewide computerised vital records and hospital discharge summaries of obstetric and neonatal admissions with linkage to birth certificates of mothers. Maternal birthweight was collected from subjects' birth certificates. Information from both the birth certificates and the obstetric and neonatal admissions database was used to determine whether subjects developed GDM. Poisson regression models were estimated to calculate unadjusted and adjusted risk ratios (RRs) and 95% confidence intervals (CIs) for GDM by categories of maternal birthweight. The cumulative incidence of GDM among non-Hispanic white, African-American, Native American and Hispanic women was 2.8, 2.6, 2.7 and 3.0% respectively. After adjusting for maternal age, parity, cigarette smoking, history of chronic hypertension and participation in the Medicaid programme, non-Hispanic white women with a birthweight < 2000 g were 1.7 times more likely to have had their pregnancy complicated by GDM (RR = 1.7; 95% CI 0.8, 3.3) than those with a birthweight 3000-3999 g. The corresponding adjusted RRs for African-American, Native American, and Hispanic women were 2.8 [95% CI 1.2, 6.1], 3.1 [95% CI 1.2, 8.2] and 2.4 [95% CI 0.9, 6.0] respectively. Among African-American women, those with a birthweight > or = 4000 g also experienced a twofold increased risk of GDM (RR = 2.1; 95% CI 1.0, 4.1). This association of high birthweight and increased GDM risk was not found among women in the other three racial/ethnic groups. These findings suggest that individuals with low birthweight constitute a group at increased risk for GDM.

Adolescent↗
PubMed2001

Cerebral palsy, low birthweight and socio-economic deprivation: inequalities in a major cause of childhood disability.

There is currently little and conflicting evidence concerning the existence of socio-economic inequalities in cerebral palsy prevalence, or the extent to which this is influenced by socio-economic inequalities in low birthweight, a strong risk factor for cerebral palsy. The study is based on 753 children registered with cerebral palsy, resident in the former Oxford Regional Health Authority area and born in the years 1984-90. Two population definitions were used: 1. Children with cerebral palsy resident at birth in the area, with resident births as denominator, 2. Children with cerebral palsy resident at age 5 in the area, with children of ages 1-7 resident in the area in the 1991 census as denominator. Children with cerebral palsy and all births/children were classified according to the Carstairs area deprivation index (grouped into quintiles) of their ward of residence. The prevalence among residents at birth varied from 2.08 per 1000 births in the most affluent quintile to 3.33 in the most deprived quintile (trend P < 0.001). Although there was a tendency for children to move to more affluent areas during early childhood, the socio-economic gradient was similar at age 5. A greater proportion of births in the more deprived quintiles were of low or very low birthweight, the proportion rising from 5.6% in the most affluent quintile to 8.2% in the most deprived. Within the normal birthweight category there was a trend for higher prevalence of cerebral palsy in more deprived quintiles, from 1.29 per 1000 in the most affluent quintile to 2.42 in the most deprived quintile (trend P < 0.001). Within the low birthweight and very low birthweight groups, separately or combined, there was no evidence of any relationship between cerebral palsy prevalence and deprivation. We estimate that up to 17% of cerebral palsy cases might be "preventable" in terms of the reduction to be expected if the whole population had the rate of cerebral palsy of the most affluent quintile. Although the strong socio-economic gradient for cerebral palsy was restricted to the normal birthweight category, we estimate that two-thirds of the excess cases in the population associated with greater socio-economic deprivation were normal birthweight cases, and one-third were low birthweight cases owing to the greater prevalence of low birthweight in more deprived populations. The pattern of socio-economic inequalities should be further explored in other regions, and should be taken into account in aetiological research, and in the effective delivery and evaluation of services.

Cerebral Palsy↗
PubMed1997

Maternal nutrition and socio-economic status as determinants of birthweight in chronically malnourished African women.

The birthweight is the most important determinant of mortality and morbidity in the neonatal period and may have an influence on health in adult life. The high rate of low birthweight in developing countries is therefore a major health problem. Maternal malnutrition is usually assumed to be a causal factor but other environmental factors are also involved. In this study we analysed maternal nutritional and socio-economic factors as determinants of birthweight in term infants from a rural African society characterised by a high rate of chronic malnutrition. Relations of maternal weight, gestational weight gain, parity, socio-economic status and infant sex with birthweight were analysed in 1,477 women and child pairs. The selected women were followed from early pregnancy and had an uncomplicated delivery at term of a living singleton child. The gestational weight gain was 5.6 (SD 6.0) kg and the mean birthweight 2.933 kg (SD 408). Maternal weight, representing the maternal long-term nutritional situation, was the most important independent determinant of birthweight, accounting for 13.0% of the variance in birthweight. The weight gain, representing the short-term nutritional situation, explained only 5.6% of the variance. Birthweight increased by 20 g (CI 18-23) for each kg maternal weight and by 15 g (CI 12-18) for each kg gestational weight gained. The socio-economic difference in birth-weight was 153 g (CI 109-196) 88 of which (CI 48-128) remained unexplained after adjustment for differences in maternal weight, parity and gender. Improved long-term nutritional situation and living conditions seems to be the most important prerequisites to counteract low birthweight in developing countries.

Birth Weight↗
PubMed1999

A new dimension to the Barker hypothesis: low birthweight and susceptibility to renal disease.

BACKGROUND: There is an epidemic of renal failure among Aborigines in the Australia's Northern Territory. The incidence is more than 1000 per million, and is doubling every three to four years. We evaluated the relationship of birthweight to renal disease in adults in one high-risk community. METHODS: We screened more than 80% of people in the community for renal disease, using the urine albumin/creatinine ratio (ACR, g/mol) as the marker, and reviewed records for birthweights. RESULTS: Birthweights were available with increasing frequency for people born after 1956. In 317 adults aged 20 to 38 years at screening, the mean birthweight (SD) was 2.712+/-0.4 kg, and 35% had been low birthweight (LBW, less than 2.5 kg). Birthweight was positively correlated with body mass index (BMI), blood pressure, and diabetes rates, but was inversely correlated with ACR. The odds ratio for overt albuminuria in LBW persons compared with those of higher birthweights was 2.82 (CI, 1.26 to 6.31) after adjusting for other factors, and LBW contributed to an estimated 27% (CI, 3 to 45%) of the population-based prevalence of overt albuminuria. Multivariate models suggest that increasing BMI and blood pressure and decreasing birthweight act in concert to amplify the increases in ACR that accompany increasing age. CONCLUSIONS: LBW contributes to renal disease in this high-risk population. The association might be mediated through impaired nephrogenesis caused by intrauterine malnutrition. The renal disease epidemic in Aborigines may partly be the legacy of greatly improved survival of LBW babies over the last four decades. Disease rates should eventually plateau as birthweights continue to improve, if postnatal risk factors can also be contained.

Adult↗
PubMed2003

Shearing during pregnancy--review of a policy to increase birthweight and survival of lambs in New Zealand pastoral farming systems.

Over the past decade, lambing percentages have risen in conjunction with a rise in the percentage of multiple lambs born. Multiple-born lambs are smaller than their singleton counterparts and are particularly susceptible to starvation-exposure. Any technique that can increase the birthweight or thermoregulatory capability, or both, of otherwise lightweight lambs has the potential to substantially increase survival of multiple-born lambs. In the United Kingdom under housed conditions, shearing during pregnancy has been shown to increase both the birthweight and thermoregulatory capability of newborn lambs. However, shearing during pregnancy under pastoral conditions has failed to consistently affect the newborn lamb's thermoregulatory capability. In contrast, under New Zealand's pastoral conditions shearing during pregnancy has been found to increase birthweight, but results have been inconsistent in both magnitude and birth-rank specificity. Increase in feed intake by the dam, types of shearing comb used and changes in gestation length do not explain the variation observed. When studies involving shearing during pregnancy are collated it becomes apparent that there are two criteria that must be met to achieve a birthweight response. Firstly, the dam must have the potential to respond and secondly, the dam must have the means to respond. Any increase in lamb survival through shearing during pregnancy would be predominantly through an increase in birthweight of otherwise lightweight lambs. However, in the few studies conducted to date, an increase in birthweight has not resulted in a statistically significant increase in survival. For an increase in birthweight to have a positive effect on lamb survival, lambs must be otherwise destined to be born within a birthweight range in which survival rate is below optimum (<4.0 kg), and the increase in birthweight observed must move a significant proportion of otherwise lightweight lambs into a higher range of survival rate.

Journal Article↗