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PubMed2000

Maternal height, pregnancy weight gain, and birthweight.

The Institute of Medicine recommends that short women gain less weight during pregnancy than taller women in order to reduce the risk of high birthweight, which can lead to feto-pelvic disproportion. This recommendation, however, is based on clinical judgment rather than on epidemiologic evidence, as few studies have examined the relationships between maternal height, pregnancy weight gain, and infant birthweight. Our objective was to determine whether maternal height is an independent risk factor for infant birthweight and to assess whether maternal height modifies the effect of pregnancy weight gain on infant birthweight. We examined the relationship between maternal height and infant birthweight in a multi-ethnic cohort of 8,870 women with uncomplicated pregnancies who delivered singleton infants at the University of California, San Francisco, 1980-1990. Using multiple linear regression, we modeled the contribution of height and weight gain to birthweight in four different ethnic groups. Increasing maternal height was significantly and positively associated with infant birthweight in White, Black, and Asian women, but not Hispanic women. The relationship between pregnancy weight gain and infant birthweight was not modified by maternal height. Am. J. Hum. Biol. 12:682-687, 2000. Copyright 2000 Wiley-Liss, Inc.

Journal Article↗

PubMed1981

Optimal birthweights in Peruvian populations at high and low altitudes.

This study tests the hypothesis that optimum birthweight for survival is lower among hospital-born infants in Puno, Peru (altitude 3860 m) than that among their counterparts at low altitude in Tacna, Peru (altitude 600 m). The data are derived from hospital birth records for 1971 and 1972 and municipal death records for 1971 through 1973. Linking these records permits analysis of the patterns of mortality in relation to birthweight. Stabilizing selection upon birthweight is operating in both populations. The high altitude population has a lower mean birthweight and a lower optimal birthweight. The Puno population is closer to its optimal birthweight distribution and, as a result of mortality during infancy, is approaching its optimum birthweight distribution for survival more rapidly than the Tacna population. It appears that the high altitude Puno population may well be adapted to its environment in the sense that there is less selective mortality on birthweight phenotypes.

Altitude↗

PubMed2005

Low birthweight is associated with specific changes in muscle insulin-signalling protein expression.

AIMS/HYPOTHESIS: People with low birthweight have an increased risk of developing type 2 diabetes mellitus in adulthood. The mechanistic basis of this phenomenon is not known. Here we investigate the effect of early growth restriction on the expression of insulin-signalling proteins in skeletal muscle in a human cohort and a rat model. METHODS: We recruited 20 young men with low birthweight (mean birthweight 2702+/-202 g) and 20 age-matched control subjects (mean birthweight 3801+/-99 g). Biopsies were obtained from the vastus lateralis muscle and protein expression of selected insulin-signalling proteins was determined. Rats used for this study were male offspring born to dams fed a standard (20%) protein diet or a low (8%) protein diet during pregnancy and lactation. Protein expression was determined in soleus muscle from adult offspring. RESULTS: Low-birthweight subjects showed reduced muscle expression of protein kinase C (PKC)zeta, p85alpha, p110beta and GLUT4. PKCzeta, GLUT4 and p85 were also reduced in the muscle of rats fed a low-protein diet. Other proteins studied were unchanged in low-birthweight humans and in rats fed a low-protein diet when compared with control groups. CONCLUSIONS/INTERPRETATION: We found decreased expression of specific insulin-signalling proteins in low-birthweight subjects compared to controls. These changes precede the onset of impaired glucose tolerance. The similarity of protein expression profile in the men with low birthweight compared to that of the offspring of rats fed a low-protein diet suggests that the rodent model is an accurate representation of the human situation. It also provides a potential mechanistic explanation as to why the fetal environment plays an important role in determining risk of developing type 2 diabetes.

Adult↗

PubMed2006

Relationships of maternal and paternal birthweights to features of the metabolic syndrome in adult offspring: an inter-generational study in South India.

AIMS/HYPOTHESIS: The association between lower birthweight and metabolic syndrome may result from fetal undernutrition (fetal programming hypothesis) and/or genes causing both low birthweight and insulin resistance (fetal insulin hypothesis). We studied associations between the birthweight of parents and metabolic syndrome in the offspring. METHODS: We identified men and women (aged 35-68 years), who had been born in Holdsworth Memorial Hospital, Mysore, India. We also identified the offspring (20-46 years) of these men and women. In total, 283 offspring of 193 mothers and 223 offspring of 144 fathers were studied. Investigations included anthropometry, oral glucose tolerance, plasma insulin and lipid concentrations and blood pressure. The metabolic syndrome was defined using WHO criteria. RESULTS: Among the offspring, lower birthweight was associated with an increased risk of glucose intolerance (impaired glucose tolerance, impaired fasting glucose or type 2 diabetes) and higher cholesterol and triacylglycerol concentrations (p < 0.05 for all adjusted for sex and age). Most outcomes in the offspring, including most individual components of the metabolic syndrome, were unrelated to parental birthweight. However, both maternal and paternal birthweight were inversely related to offspring metabolic syndrome (odds ratio [OR] 0.36 [95% CI: 0.13-1.01] per kg, p = 0.053 for mother-offspring pairs; OR 0.26 [0.07-0.93], p = 0.04 for father-offspring pairs, adjusted for offspring age, sex, BMI and socioeconomic status). Maternal birthweight was inversely related to offspring systolic blood pressure (beta = -2.5 mmHg [-5.00 to 0.03] per kg maternal birthweight; p = 0.052). CONCLUSIONS/INTERPRETATION: Factors in both parents may influence the risk of metabolic syndrome in their offspring. There are several possible explanations, but the findings are consistent with the fetal insulin (genetic) hypothesis.

Adult↗

PubMed2002

Birthweight percentiles by gestational age in Kuwait.

Our aim is develop a curve for singleton birthweight based on accurately calculated gestational age. A retrospective analysis of all singleton live births from 22-44 completed weeks of gestation during the period from September 1998 to December 2000 in the two largest birth birth centers in Kuwait was conducted. Neonates with major congenital anomalies and those with unrecorded gestational age were excluded from the study population. Total population and gender-specific birthweight percentiles according to gestational age were developed after smoothening of growth curves. A total of 35768 births were included in the development of the birthweight curve. Percentiles of birthweight for all population and by gender are presented. There was significant difference in birthweight among different ethnic groups in this population. At term, 9.8% of births are smaller than the 10th percentile and 10.0% are larger than the 90th percentile. Plotting birthweight in our population on percentile curves derived from the United States or United Kingdom would generally overestimate small for gestational age newborns and underestimate large for gestational age newborns. We conclude that the diagnosis of clinically significant birthweight abnormalities depends on the fetal growth curve used. A population specific curve of fetal growth dated by ultrasonography would provide a reliable reference for birthweight distribution.

Birth Weight↗

PubMed1988

Identification of women at high risk for preterm-low-birthweight births.

Preterm-low-birthweight births comprise a subset of extremely high-risk low-birthweight infants. While numerous studies have evaluated risk factors to predict an individual's chance of a high-risk pregnancy, few have identified risk factors specifically related to preterm-low-birthweight births. Risk factors for preterm-low-birthweight births were analyzed in a sample of 11,623 women from northwest North Carolina enrolled in a low-birth-weight prevention program. Significant risk factors for preterm-low-birthweight births in this population were identified, and weights were assigned to each factor. Application of the weighting system to each patient's specific risk factors identifies women at high risk for a preterm-low-birthweight birth and assists in the determination of appropriate intervention. These data make use of all current information in the low-birthweight births prevention project. Prospective assessment of the scoring system as the project continues should improve the ability to identify and intervene with women at highest risk for a preterm-low-birthweight birth.

Adult↗

PubMed1984

Factors influencing birthweight for gestational age, with special respect to risk factors for intrauterine growth retardation.

In a prospective clinical study from an unselected, area-based population, the influence on birthweight for gestational age of different factors was studied, with special respect to 15 risk factors for intrauterine growth retardation (IUGR) recognizable in early pregnancy. In the multiple regression analyses performed, birthweight for gestational age was used as the dependent variable. Only 10% of the variance in birthweight for gestational age could be explained. A correlation was found between the number of risk factors and birthweight for gestational age. Four risk factors had a significant negative influence on birthweight for gestational age: smoking, previous birth of a low birthweight infant, a low prepregnancy weight and addiction. No single risk factor influenced birthweight for gestational age as much as parity. When a risk factor was present the expected increase in birthweight for gestational age with increasing parity did not appear.

Birth Weight↗

PubMed2007

Trends in cerebral palsy among infants of very low birthweight (<1500 g) or born prematurely (<32 weeks) in 16 European centres: a database study.

BACKGROUND: The risk of cerebral palsy, the commonest physical disability of children in western Europe, is higher in infants of very low birthweight (VLBW)--those born weighing less than 1500 g--and those from multiple pregnancies than in infants of normal birthweight. An increasing proportion of infants from both of these groups survive into childhood. This paper describes changes in the frequency and distribution of cerebral palsy by sex and neurological subtype in infants with a birthweight below 1000 g and 1000-1499 g in the period 1980-96. METHODS: A group of 16 European centres, Surveillance of Cerebral Palsy in Europe, agreed a standard definition of cerebral palsy and inclusion and exclusion criteria. Data for children with cerebral palsy born in the years 1980-96 were pooled. The data were analysed to describe the distribution and prevalence of cerebral palsy in VLBW infants. Prevalence trends were expressed as both per 1000 livebirths and per 1000 neonatal survivors. FINDINGS: There were 1575 VLBW infants born with cerebral palsy; 414 (26%) were of birthweight less than 1000 g and 317 (20%) were from multiple pregnancies. 1426 (94%) had spastic cerebral palsy, which was unilateral (hemiplegic) in 336 (24%). The birth prevalence fell from 60.6 (99%CI 37.8-91.4) per 1000 liveborn VLBW infants in 1980 to 39.5 (28.6-53.0) per 1000 VLBW infants in 1996. This decline was related to a reduction in the frequency of bilateral spastic cerebral palsy among infants of birthweight 1000-1499 g. The frequency of cerebral palsy was higher in male than female babies in the group of birthweight 1000-1499 g (61.0 [53.8-68..2] vs 49.5 [42.8-56.2] per 1000 livebirths; p=0.0025) but not in the group of birthweight below 1000 g. INTERPRETATION: These data from a large population base provide evidence that the prevalence of cerebral palsy in children of birthweight less than 1500 g has fallen, which has important implications for parents, health services, and society.

Birth Weight↗

PubMed2003

Late sequelae of low birthweight: mediators of poor school performance at 11 years.

This study examined the effect of low birthweight on school achievement and the mediating roles of cognitive and behavioural factors. The sample (115 females, 100 males) was selected from a longitudinal study of first-born singleton children, born between 1986 and 1988 of German-speaking parents, recruited from eight hospitals of the Rhine-Neckar region in Germany. Twenty-nine very-low-birthweight (VLBW; less than 1500g), 74 low-birthweight (LBW; 1500 to 2500 g) and 112 normal-birthweight children (NBW; more than 2500 g), all without severe neurological disability, were assessed at 11 years on cognitive, motor, scholastic, and behavioural measures. The scholastic measures included a school performance score and a teacher recommendation for type of secondary school the child should attend. LBW and VLBW children performed less well than the NBW group in all areas. LBW and VLBW groups remained at risk for school difficulties into late childhood, even when not neurologically impaired. Arithmetic, vocabulary, concentration, non-verbal intelligence, and attention problems were significant mediators of the effect of low birthweight on the school performance score. Arithmetic, vocabulary, motor skills, and attention problems were found to be mediating factors of birthweight on teacher's recommendations. The poor outcome of the low birthweight children could not be attributed to further obstetric risk factors. Parents and pediatricians should be made aware of specific long-term deficits of low birthweight children that may impair school performance, although they may be within a normal curriculum.

Child Development↗

PubMed2002

Maternal height, birthweight and cephalo pelvic disproportion in urban Nigeria and rural Malawi.

BACKGROUND: Cephalo pelvic disproportion (CPD) has been attributed to short stature. It has been suggested that nutritional supplementation to promote linear growth would increase birthweight and the risk of CPD. The objective of this study was to examine the factors associated with CPD, with particular reference to birthweight, stature, parity and maternal age. DESIGN: Factors associated with CPD were analyzed using data abstracted from a detailed early hospital report from Ibadan, Nigeria and from a recent rural pregnancy study conducted in the Shire Valley, Malawi. RESULTS: In Nigeria, of 107 CPD cases admitted to hospital in Ibadan during 1953-54, 79% were women > 20 years. Birthweight values increased significantly with age and parity. In 19.6% of cases, the baby had a low birthweight (< 2500 g). In Malawi, among the 1523 women delivering, the incidence of CPD was 2.3%. Of the 35 cases of CPD, only four were adolescents. Birthweights increased with increasing parity, age and height (p < 0.001). In 6.4% of CPD cases, the baby had a low birthweight. Nulliparity (OR 4.0; CI 1.7-9.3; p = 0.0001), birthweight >or= 3400 g (OR 4.6; CI 2.1-10.0; p = 0.0001) and height <or= 154 cm (OR 3.8; CI 1.8-7.9; p = 0.0003) were associated with an increased risk of CPD. Adolescent mothers were less likely to experience CPD (OR 0.3; C.I. 0.8-0.9; p = 0.03). CONCLUSIONS: Adolescents are not at high risk of CPD. Nutritional supplementation of girls and adolescents should not be discouraged for fear of increasing the risk of CPD by improving birthweight. When CPD is present, it may result from childhood rickets and calcium deficiency.

Adolescent↗

PubMed2001

Polycystic ovary syndrome after precocious pubarche: ontogeny of the low-birthweight effect.

OBJECTIVE: Young girls with precocious pubarche (PP) are at increased risk of developing polycystic ovary syndrome (PCOS), including hyperinsulinism, dyslipidaemia and ovarian hyperandrogenism, particularly if PP itself was preceded by a low birthweight. Resistance to insulin is thought to be a key factor in the pathogenesis of this sequence. We aimed to elucidate the peripubertal ontogeny of the low birthweight effect on hyperinsulinism, dyslipidaemia and ovarian dysfunction after PP. PATIENTS AND DESIGN: We obtained fully longitudinal data from 51 girls with a history of PP and compared normal-birthweight (n = 26) with low-birthweight (n = 25) girls (birthweight SD score 0.0 +/- 0-2 vs. - 2.4 +/- 0.2) for measurements obtained at diagnosis of PP (mean age 7.0 years), in early puberty (10.4 years) and after menarche (14.3 years). MEASUREMENTS: Fasting serum lipids and lipoproteins, together with insulin responses to an oral glucose load, were assessed at diagnosis of PP, in early puberty and after menarche; serum gonadotropins were measured in early puberty and after menarche; ovarian function was examined postmenarche. RESULTS: Comparisons of endocrine-metabolic results between normal- and low-birthweight PP girls showed no detectable differences before puberty. The hypertriglyceridaemia and elevated LDL-cholesterol levels characterizing low-birthweight PP girls became detectable by early puberty; reduced insulin sensitivity was not evident until postmenarche, when the tendency to ovarian dysfunction also became obvious. Body mass indices of normal- and low-birthweight subgroups were identical in early puberty and postmenarche. CONCLUSIONS: These longitudinal data show that, in PP girls, the endocrine-metabolic risk conferred by prenatal growth restraint is not readily detectable until puberty or postmenarche, and is not attributable to a higher body mass index.

Birth Weight↗

PubMed1997

The relationship between maternal birthweight and gestational age in twins and singletons and those of their offspring in Norway.

In order to elucidate whether maternal plurality affects offspring intrauterine growth, the relationship between birthweight and gestational age of twins and singletons and those of their first singleton liveborn children in Norway was studied using data from the Medical Birth Registry. The population-based sample consisted of 49,698 mother-offspring pairs (48,842 with singleton and 856 with twin-mothers). In bivariate analyses, no significant differences in mean birthweight and gestational age of offspring of twin and singleton mothers were found, although the mean birthweight and gestational age of the twin-mothers themselves were significantly lower than those of singletons (819 g and 14 days respectively). In multiple regression analysis, the expected birthweight of offspring was 230.3 g (95% CI: 193.2-267.4 g) higher when the mother was a twin than when the mother was a singleton, when controlling for non-standardised maternal birthweight. When adjusting for relative maternal birthweight (z-score), the association between maternal plurality and offspring birthweight was not statistically significant. The results suggest that being born as a twin has no substantial consequences on offspring growth in utero and show that mean differences in birthweight between twins and singletons should be standardised when both groups are included in multivariate studies.

Birth Weight↗

PubMed2003

Birthweight and relationship with infant, child and adult mortality in the Jerusalem perinatal study.

There is growing evidence that several chronic adult diseases, such as coronary heart disease and stroke, can result from events occurring in fetal life. The aim of this study was to examine the relation between birthweight and all-cause mortality in young adults. We studied total mortality in a population-based cohort of 80 936 offspring born in Jerusalem in 1964-76. During an average follow-up of 28.8 years 2 324 984 person-years were contributed and 2092 deaths occurred. Overall, in both genders, the univariable and the multivariable Cox-proportional hazard models indicated a strong negative relationship between birthweight and total mortality, mostly because of infant deaths. At ages 1-14 birthweight seemed unrelated to all-cause mortality. In males aged 15+, birthweight was again a significant predictor of death (Hazard ratio (HR) = 0.88, 95% confidence interval (CI) [0.78, 0.99], for 1 standard deviation (SD) increase in birthweight). The analysis by categories suggested a general decreasing of the risk of mortality with increasing birthweight (HRs = 1.0, 1.02, 0.85, 0.77, 0.57 for those belonging to birthweight groups of < 2500 g, 2500-2999 g, 3000-3499 g, 3500-3999 g and > or = 4000 g, respectively). In females aged 15+ there was a J-shaped relation between birthweight and mortality but these associations were not statistically significant. These findings add to a growing body of evidence that events during intrauterine life have remote consequences for adult health and underline the need to consider gender differences.

Adult↗

PubMed2001

Malaria in pregnancy: adverse effects on haemoglobin levels and birthweight in primigravidae and multigravidae.

BACKGROUND: In areas of endemic transmission, malaria in pregnancy is associated with severe maternal anaemia and low birthweight babies. The prevalence of infection is highest in primigravidae (PG), and hence control efforts are usually geared towards this high risk group. Using a sensitive measure of placental infection, we investigated the relationship between active-acute, active-chronic and past placental infection with maternal anaemia and low birthweight in women of all gravidities. METHODS: Between January 1996 and July 1997, 912 women delivering in Kilifi District Hospital, Kenya, were recruited. Haemoglobin and peripheral malaria slides were taken prior to delivery, placental biopsies and smears were taken at the time of delivery and birthweight and maternal height and weight were measured soon after birth. Information was obtained on socio-economic and educational status. The association between placental malaria, severe anaemia and low birthweight was investigated for women of different gravidities. FINDINGS: By placental histology, the prevalence of active or past malaria in all gravidities was high, ranging from 64% in PG to 30% in gravidities 5 and above. In gravidities 1-4, active malaria infection was associated with severe maternal anaemia, adjusted OR 2.21 (95% CI 1.36, 3.61). There was a significant interaction between chronic or past malaria and severe anaemia in their effects on birthweight, whereby the risk of low birthweight was very high in women with both chronic or past placental malaria and severe anaemia: OR 4.53 (1.19, 17.2) in PG; 13.5 (4.57, 40) in gravidities 2-4. INTERPRETATION: In this area of moderate malaria transmission, women of all parities have substantially increased risk of low birthweight and severe anaemia as a result of malaria infection in pregnancy. The risk of low birthweight is likely to be particularly high in areas with a high prevalence of severe anaemia.

Adolescent↗

PubMed2005

Fetal and neonatal mortality among twin gestations in a Canadian population: the effect of intrapair birthweight discordance.

The purpose of this study was to examine the association between intrapair birthweight discordance and fetal and neonatal mortality. This was a historical cohort study, using the Statistics Canada linked birth-infant death file. Twin births in Canada (excluding Ontario) for the period 1986-1997 were studied. Outcome measures were fetal and neonatal mortality. Among 59,034 twin births, 53% had 0 to 9% birthweight difference; 30% had 10 to 19% discordance; 11% had 20 to 29% discordance; and 6% had > or = 30% discordance. Maternal age, parity, sex discordance, and gestational age were important factors affecting birth weight discordance. Fetal death rates were 0.95, 1.26, 3.14, and 11.10%, respectively, in infants with a birthweight discordance of 0 to 9, 10 to 19, 20 to 29, and > or = 30%. Corresponding figures for neonatal death rates were 1.90, 2.32, 3.05, and 8.86%, respectively. Adjustment for important confounding variables including the actual birthweight and gestational age substantially reduced the birthweight discordance-related risk of fetal and neonatal mortality, but the results remained statistically significant and clinically important. The birthweight discordance-related risk of fetal and neonatal mortality was higher in smaller twins than in larger twins and higher in infants with gestational age > or = 37 weeks than those < 37 weeks. Birthweight discordance is an important risk factor for fetal and neonatal mortality, and the birthweight discordance-related risk of fetal and neonatal mortality is higher in smaller twins than in larger twins and higher in term twins than in preterm twins.

Adult↗

PubMed1990

Secular trend in birthweight in an industrial hospital in India.

Measurement of birthweight is an indicator of community health. The mean birthweight (MBW) of babies born in 1963, 1983 and 1986 were measured in 2254, 3550 and 3368 babies, respectively. Mean (SD) birthweight was found to be 2652 (553) g in 1963, 2724 (502) g in 1983 and 2726 (478) g in 1986. There was a rise in MBW (72 g) between 1963 and 1983 and a reduction in the percentage incidence of low birthweight from 34.29% to 26.06%. A change in birthweight distribution (was also seen, except in extreme weight groups. The improvement in birthweight is statistically significant (p less than 0.001). A trend for increase has been noticed in birthweights, and the mean birthweight values are the same as the national average.

Age Factors↗

PubMedDate not supplied

Regional patterns of birthweights in Papua New Guinea in relation to diet, environment and socio-economic factors.

Regional differences in mean birthweight in rural Papua New Guinea (PNG) and the importance of differences in family diet and maternal education and socio-economic status on such patterns were explored using birthweight data collected by the 1982/83 PNG National Nutrition Survey. A total of 6137 birthweight measurements from 85 PNG districts were available, representing 22% of all children included in the survey. The nature of possible selection biases are assessed and their implications discussed. Hierarchical Bayesian spatial models based on conditional autoregressive (CAR) priors were used to model spatial patterns in birthweights and their relation to different sets of covariates. Birthweights were found to exhibit striking geographical differences. Children from the central PNG highlands and from affluent lowland areas had the highest birthweights, while they were lowest in the (largely lowland) Sepik, Western, Madang and Milne Bay Provinces and in remote highland fringe areas. Maternal education, socio-economic status and diet were all important predictors, but only differences in family diet were correlated with the observed spatial patterns. The results of the present study highlight the importance of nutrition and socio-economic status in explaining differences in birthweights in PNG. Besides improving maternal health, interventions for improving birthweights in PNG should therefore aim at strengthening the economic base of rural populations and promote the cultivation and consumption of high quality foods.

Birth Weight↗

PubMedDate not supplied

Birthweight for length: ponderal index, body mass index or Benn index?

This study compares how effectively the ponderal index and the body mass index adjust birthweight for length at different gestations, and derives an improved index suitable for all gestations. The study was a cross-sectional survey, in a London teaching hospital, using a total of 999 neonates of 33 weeks gestation or later. Main outcome measures were the ponderal index (birthweight/length3), body mass index (birthweight/length2), and Benn index (birthweight/length(n)), where the length power n varies with gestation and is estimated by log-log regression. Results showed that up to 39 weeks gestation, the ponderal index is uncorrelated with length and so is a good index of birthweight for length. Past 39 weeks gestation, the ponderal index is negatively correlated with length, while the body mass index is uncorrelated, so that the body mass index is better. Neither index is optimal at all gestations. Deriving the Benn index (birthweight/length(n)) for each week of gestation, choosing n to make the index uncorrelated with length, shows that n falls steadily and very significantly (p < 0.0001) with increasing gestation. This in turn means that predicted birthweight for length depends on gestation: for a neonate 48 cm long, predicted birthweight varies from 2485 g at 34 weeks to 3030 g at 43 weeks, a 20% range. However, for a 54 cm long infant, predicted birthweight is the same at all gestations. A Benn index where the value of n changes linearly with gestation is described. We conclude that the ponderal index is not appropriate for measuring intra-uterine malnutrition, as it fails to adjust for length at all gestations. No other index of birthweight/length(n) with constant n is any better, as different gestations require different indices. Birthweight predicted from an infant's length depends on the infant's gestation. If, as Barker proposes, thinness at birth assessed by birthweight for length is used to predict later health status, more account needs to be taken of the complex relationship between birthweight, length and gestation.

Birth Weight↗