Placental weight, birth measurements, and blood pressure at age 8 years

Longitudinal study of birthweight, blood pressure, and markers of arterial stiffness in children age six among the TIDES cohort

OBJECTIVE

Although some studies have observed an association between birthweight and cardiovascular disease in adulthood, fewer have investigated whether birthweight is linked to cardiovascular health in early childhood. This study assesses the association between birthweight and cardiovascular outcomes in children 6 years of age.

STUDY DESIGN

Birthweight, blood pressure (BP), and markers of arterial stiffness in children, including brachial artery distensibility and carotid-femoral pulse wave velocity (cfPWV), were obtained from 324 participants in The Infant Development and the Environment Study, a prospective multisite pregnancy cohort. Birthweight was converted into sex-specific birthweight-for-gestational-age (bw/ga) z -scores based on the INTERGROWTH-21st standard. Following 2017 American Academy of Pediatrics guidelines, SBP and DBP were transformed into sex, age, and height-specific z -scores. Associations between birthweight and cardiovascular outcomes were assessed using nested multivariable linear regression models among the overall and sex-stratified samples.

RESULTS

Among the overall sample, bw/ga z -score was positively associated with cfPWV [b = 0.11 m/s, 95% confidence interval (CI): 0.01 m/s, 0.21 m/s] in crude and adjusted models. No associations between birthweight and cardiovascular outcomes were detected among the sex-stratified analyses.

CONCLUSION

Overall, birthweight was not related to cardiovascular outcomes in children 6 years old. However, infants born with a higher birthweight may be at risk for higher cfPWV in childhood. Early intervention in pregnant people at risk of delivering high birthweight infants may be warranted if results are replicated.

The thrifty phenotype hypothesis: The association between ultrasound and Doppler studies in fetal growth restriction and the development of adult disease

Barker pioneered the idea that the epidemic of coronary heart disease in Western countries in the 20th century, which paradoxically coincided with improved standards of living and nutrition, has its origin in fetal life. Indeed, there is substantial evidence associating low birthweight because of fetal growth restriction with an increased risk of vascular disease in later adult life. These conclusions led to the second part of the Barker hypothesis, the thrifty phenotype, in which adaptation to undernutrition in fetal life leads to permanent metabolic and endocrine changes. Such changes are beneficial if the undernutrition persists after birth but may predispose the individual to obesity and impaired glucose tolerance if conditions improve. The hypothesis assumes that a poor nutrient supply during a critical period of in utero life may "program" a permanent structural or functional change in the fetus, thereby altering the distribution of cell types, gene expression, or both. The fetus, in response to placental undernutrition and to maintain sufficient vascular supply to the brain, decreases resistance to blood flow in the middle cerebral artery. Simultaneously, because of the limited blood supply to the fetus, the arterial redistribution process is accompanied by increased resistance to flow to other fetal vital organs, such as the heart, kidneys, liver, and pancreas. It may explain why individuals exposed to ischemic changes in utero develop dyslipidemia, lower nephron number, and impaired glucose tolerance, all factors contributing to metabolic syndrome later in life. Nevertheless, support for the hypotheses comes mainly from studies in rodents and retrospective epidemiologic studies. This review focused on ultrasound and Doppler studies of human fetal growth restriction in several fetal organs: the placenta, fetal circulation, brain, heart, kidneys, adrenal glands, liver, and pancreas. Support for the hypothesis was provided by animal studies involving conditions that create fetuses with growth restriction with effects on various fetal organs and by human studies that correlate impaired fetal circulation with the in utero development and function of fetal organs.

Association of chemerin gene promoter methylation in maternal blood and breast milk during gestational diabetes

The intrauterine environment and early-life nutrition are regulated by maternal biomarkers in the blood and breast milk. We aimed to explore epigenetic modifications that may contribute to differential chemerin expression in maternal plasma, colostrum, and breast milk and find its association with fetal cord blood and infant weight at 6 weeks postpartum. Thirty-three gestational diabetes mellitus (GDM) mothers and 33 normoglycemic mothers (NGT) were recruited. Two maternal blood samples (28th week of gestation and 6 weeks postpartum), cord blood, colostrum, and mature milk were collected. Methylation-specific polymerase chain reaction and enzyme-linked immunosorbent assay were conducted. The weight of the babies was measured at birth and 6 weeks postpartum. Serum chemerin levels at the 28th gestational week and 6 weeks postpartum were significantly lower for the NGT group as compared to the GDM group; (P < 0.05). Higher colostrum chemerin concentrations were observed in the GDM group and remained elevated in mature milk as compared to NGT (P < 0.05). Colostrum and breast milk chemerin levels showed an independent association with infant weight at 6 weeks postpartum (r = 0.270; P = 0.034) (r = 0.464; P < 0.001). Forty percent GDM mothers expressed unmethylated chemerin reflecting increased chemerin concentration in the maternal blood. This pattern was also observed in newborn cord blood where 52% of samples showed unmethylated chemerin in contrast to none in babies born to normoglycemic mothers. The results of this study highlight the critical importance of altered chemerin regulation in gestational diabetic mothers and its effect during early life period and suggest a possible role in contributing to childhood obesity.

Gestational growth trajectories derived from a dynamic fetal-placental scaling law

Fetal trajectories characterizing growth rates in utero have relied primarily on goodness of fit rather than mechanistic properties exhibited in utero. Here, we use a validated fetal-placental allometric scaling law and a first principles differential equations model of placental volume growth to generate biologically meaningful fetal-placental growth curves. The growth curves form the foundation for understanding healthy versus at-risk fetal growth and for identifying the timing of key events in utero.

Social dominance predicts hippocampal glucocorticoid receptor recruitment and resilience to prenatal adversity

The developing fetus is highly sensitive to prenatal stress, which may alter Hypothalamic-Pituitary-Adrenal (HPA) axis programming and increase the risk of behavioral disorders. There is high variability among the human population, wherein many offspring of stressed pregnancies display resilience to adversity, while the remainder displays vulnerability. In order to identify biological substrates mediating between resilience or vulnerability to prenatal adversity, we exposed stress-resistant Dominant (Dom) and stress-sensitive Submissive (Sub) mice to mild prenatal restraint stress (PRS, 45 min on gestational days (GD) 15, 16 and 17). We hypothesized that PRS would differentially alter prenatal programming of limbic regions regulating the HPA axis and affect among Dom and Sub offspring. Indeed, PRS increased Sub offspring’s serum corticosterone, and exaggerated their anxiety- and depressive-like behavior, while Dom offspring remained resilient to the hormonal and behavioral consequences of PRS. Moreover, PRS exposure markedly facilitated glucocorticoid receptor (GR) recruitment to the hippocampus among Dom mice in response to restraint stress, which may be responsible for their resilience to stressful challenge. These findings suggest proclivity to adaptive or maladaptive prenatal programming of hippocampal GR recruitment to be inheritable and predictable by social dominance or submissiveness.

Gender differences in developmental programming of cardiovascular diseases

Hypertension is a risk factor for cardiovascular disease, the leading cause of death worldwide. Although multiple factors contribute to the pathogenesis of hypertension, studies by Dr David Barker reporting an inverse relationship between birth weight and blood pressure led to the hypothesis that slow growth during fetal life increased blood pressure and the risk for cardiovascular disease in later life. It is now recognized that growth during infancy and childhood, in addition to exposure to adverse influences during fetal life, contributes to the developmental programming of increased cardiovascular risk. Numerous epidemiological studies support the link between influences during early life and later cardiovascular health; experimental models provide proof of principle and indicate that numerous mechanisms contribute to the developmental origins of chronic disease. Sex has an impact on the severity of cardiovascular risk in experimental models of developmental insult. Yet, few studies examine the influence of sex on blood pressure and cardiovascular health in low-birth weight men and women. Fewer still assess the impact of ageing on sex differences in programmed cardiovascular risk. Thus, the aim of the present review is to highlight current data about sex differences in the developmental programming of blood pressure and cardiovascular disease.

Blastomere removal from cleavage-stage mouse embryos alters placental function, which is associated with placental oxidative stress and inflammation

Blastomere biopsy is an essential technique in preimplantation genetic diagnosis (PGD), a screening test that can detect genetic abnormalities of embryos before their transfer into uterus. Our results showed that the weights of fetuses derived from biopsied embryos were lower than that of non-biopsied counterparts at E12.5, E15.5, and E18.5. The ratio of fetal/placental (F/P) weights in the biopsied group was significantly lower than that in the non-biopsied group at E18.5. At E18.5, the mRNAs for selected glucose transporters, system A amino acid transporters, system L amino acid transporters, and imprinted genes were downregulated in the placentae of biopsied group, and the GLUT1 and CAT3 protein levels were decreased too. More apoptotic cells were detected by TUNEL in the placentae of biopsied group. Placentae from biopsied embryos exhibited lower levels of SOD and GSH. Furthermore, the concentration of MDA increased in the placentae from biopsied group. The levels of IL1B, IL6, and TNFA also significantly increased in the placentae of biopsied group. This study suggested that placental function may be sensitive to blastomere biopsy procedures, and placental oxidative stress and inflammation associated with blastomere biopsy may be critical factors of abnormal placental function and further influence the fetal development.

IVF affects embryonic development in a sex-biased manner in mice

Increasing evidence indicates that IVF (IVF includes in vitro fertilization and culture) embryos and babies are associated with a series of health complications, and some of them show sex-dimorphic patterns. Therefore, we hypothesized that IVF procedures have sex-biased or even sex-specific effects on embryonic and fetal development. Here, we demonstrate that IVF-induced side effects show significant sexual dimorphic patterns from the pre-implantation to the prenatal stage. During the pre-implantation stage, female IVF embryos appear to be more vulnerable to IVF-induced effects, including an increased percentage of apoptosis (7.22±1.94 vs 0.71±0.76, P<0.01), and dysregulated expression of representative sex-dimorphic genes (Xist, Hprt, Pgk1 and Hsp70). During the mid-gestation stage, IVF males had a higher survival rate than IVF females at E13.5 (male:female=1.33:1), accompanied with a female-biased pregnancy loss. In addition, while both IVF males and females had reduced placental vasculogenesis/angiogenesis, the compensatory placental overgrowth was more evident in IVF males. During the late-gestation period, IVF fetuses had a higher sex ratio (male:female=1.48:1) at E19.5, and both male and female IVF placentas showed overgrowth. After birth, IVF males grew faster than their in vivo (IVO) counterparts, while IVF females showed a similar growth pattern with IVO females. The present study provides a new insight into understanding IVF-induced health complications during embryonic and fetal development. By understanding and minimizing these sex-biased effects of the IVF process, the health of IVF-conceived babies may be improved in the future.

Fetal endocrine and metabolic adaptations to hypoxia: the role of the hypothalamic-pituitary-adrenal axis

In utero, hypoxia is a significant yet common stress that perturbs homeostasis and can occur due to preeclampsia, preterm labor, maternal smoking, heart or lung disease, obesity, and high altitude. The fetus has the extraordinary capacity to respond to stress during development. This is mediated in part by the hypothalamic-pituitary-adrenal (HPA) axis and more recently explored changes in perirenal adipose tissue (PAT) in response to hypoxia. Obvious ethical considerations limit studies of the human fetus, and fetal studies in the rodent model are limited due to size considerations and major differences in developmental landmarks. The sheep is a common model that has been used extensively to study the effects of both acute and chronic hypoxia on fetal development. In response to high-altitude-induced, moderate long-term hypoxia (LTH), both the HPA axis and PAT adapt to preserve normal fetal growth and development while allowing for responses to acute stress. Although these adaptations appear beneficial during fetal development, they may become deleterious postnatally and into adulthood. The goal of this review is to examine the role of the HPA axis in the convergence of endocrine and metabolic adaptive responses to hypoxia in the fetus.

Placental adaptations in growth restriction

The placenta is the primary interface between the fetus and mother and plays an important role in maintaining fetal development and growth by facilitating the transfer of substrates and participating in modulating the maternal immune response to prevent immunological rejection of the conceptus. The major substrates required for fetal growth include oxygen, glucose, amino acids and fatty acids, and their transport processes depend on morphological characteristics of the placenta, such as placental size, morphology, blood flow and vascularity. Other factors including insulin-like growth factors, apoptosis, autophagy and glucocorticoid exposure also affect placental growth and substrate transport capacity. Intrauterine growth restriction (IUGR) is often a consequence of insufficiency, and is associated with a high incidence of perinatal morbidity and mortality, as well as increased risk of cardiovascular and metabolic diseases in later life. Several different experimental methods have been used to induce placental insufficiency and IUGR in animal models and a range of factors that regulate placental growth and substrate transport capacity have been demonstrated. While no model system completely recapitulates human IUGR, these animal models allow us to carefully dissect cellular and molecular mechanisms to improve our understanding and facilitate development of therapeutic interventions.

Nutrition in early life and the programming of adult disease: a review

Foetal development and infancy are life stages that are characterised by rapid growth, development and maturation of organs and systems. Variation in the quality or quantity of nutrients consumed by mothers during pregnancy, or infants during the first year of life, can exert permanent and powerful effects upon developing tissues. These effects are termed 'programming' and represent an important risk factor for noncommunicable diseases of adulthood, including the metabolic syndrome and coronary heart disease. This narrative review provides an overview of the evidence-base showing that indicators of nutritional deficit in pregnancy are associated with a greater risk of type-2 diabetes and cardiovascular mortality. There is also a limited evidence-base that suggests some relationship between breastfeeding and the timing and type of foods used in weaning, and disease in later life. Many of the associations reported between indicators of early growth and adult disease appear to interact with specific genotypes. This supports the idea that programming is one of several cumulative influences upon health and disease acting across the lifespan. Experimental studies have provided important clues to the mechanisms that link nutritional challenges in early life to disease in adulthood. It is suggested that nutritional programming is a product of the altered expression of genes that regulate the cell cycle, resulting in effective remodelling of tissue structure and functionality. The observation that traits programmed by nutritional exposures in foetal life can be transmitted to further generations adds weight the argument that heritable epigenetic modifications play a critical role in nutritional programming.

Fetal stress and programming of hypoxic/ischemic-sensitive phenotype in the neonatal brain: mechanisms and possible interventions

Growing evidence of epidemiological, clinical and experimental studies has clearly shown a close link between adverse in utero environment and the increased risk of neurological, psychological and psychiatric disorders in later life. Fetal stresses, such as hypoxia, malnutrition, and fetal exposure to nicotine, alcohol, cocaine and glucocorticoids may directly or indirectly act at cellular and molecular levels to alter the brain development and result in programming of heightened brain vulnerability to hypoxic-ischemic encephalopathy and the development of neurological diseases in the postnatal life. The underlying mechanisms are not well understood. However, glucocorticoids may play a crucial role in epigenetic programming of neurological disorders of fetal origins. This review summarizes the recent studies about the effects of fetal stress on the abnormal brain development, focusing on the cellular, molecular and epigenetic mechanisms and highlighting the central effects of glucocorticoids on programming of hypoxic-ischemic-sensitive phenotype in the neonatal brain, which may enhance the understanding of brain pathophysiology resulting from fetal stress and help explore potential targets of timely diagnosis, prevention and intervention in neonatal hypoxic-ischemic encephalopathy and other brain disorders.

Placental morphologic features and chorionic surface vasculature at term are highly correlated with 3-dimensional sonographic measurements at 11 to 14 weeks

OBJECTIVES

The purpose of this study was to examine the potential for 3-dimensional sonographic measurement of the early placenta in predicting ultimate placental morphologic features at delivery.

METHODS

In this prospective cohort study, we collected 3-dimensional sonographic volume sets of placentas at 11 to 14 weeks and then collected the placentas after delivery. The sonographic data were manipulated to obtain various novel measurements of early gross placental morphologic features and the umbilical cord insertion location. The placental weight, chorionic plate area, cord location, and mean chorionic vascular density were obtained from the delivered postpartum placentas. Analyses were performed to identify potential early placental characteristics that were correlated with the ultimate placental morphologic features. The placental weight, cord marginality, and mean chorionic vascular density served as the outcome measures of interest.

RESULTS

Measurements of the early placental volume correlated with the delivered placental weight. An irregular early placental shape, as measured by sonography, was significantly inversely correlated with placental weight (P < .05). The placental morphologic index, a measure of a flatter placenta, was inversely correlated with both the placental weight and chorionic plate area, possibly indicating the importance of placental thickness even in the first trimester before villous arborization. In addition, early sonographic measures of the location of the umbilical cord insertion were significantly correlated with the ultimate marginality of the cord insertion as well as the mean chorionic vascular density (P < .05).

CONCLUSIONS

Many important ultimate placental morphologic features are likely predetermined early in pregnancy. Three-dimensional sonography may play an increasing role in the in utero evaluation of the early placenta.

Placental programming of blood pressure in Indian children

Aim

To determine whether the size and shape of the placental surface predict blood pressure in childhood.

Methods

We studied blood pressure in 471 nine-year-old Indian children whose placental length, breadth and weight were measured in a prospective birth cohort study.

Results

In the daughters of short mothers (<median height), systolic blood pressure (SBP) rose as placental breadth increased (β = 0.69 mmHg/cm, p = 0.05) and as the ratio of placental surface area to birthweight increased (p = 0.0003). In the daughters of tall mothers, SBP rose as the difference between placental length and breadth increased (β = 1.40 mmHg/cm, p = 0.007), that is as the surface became more oval. Among boys, associations with placental size were only statistically significant after adjusting for current BMI and height. After adjustment, SBP rose as placental breadth, area and weight decreased (for breadth β = −0.68 mmHg/cm, p < 0.05 for all three measurements).

Conclusions

The size and shape of the placental surface predict childhood blood pressure. Blood pressure may be programmed by variation in the normal processes of placentation: these include implantation, expansion of the chorionic surface in mid-gestation and compensatory expansion of the chorionic surface in late gestation.

Glucocorticoids, prenatal stress and the programming of disease

An adverse foetal environment is associated with increased risk of cardiovascular, metabolic, neuroendocrine and psychological disorders in adulthood. Exposure to stress and its glucocorticoid hormone mediators may underpin this association. In humans and in animal models, prenatal stress, excess exogenous glucocorticoids or inhibition of 11β-hydroxysteroid dehydrogenase type 2 (HSD2; the placental barrier to maternal glucocorticoids) reduces birth weight and causes hyperglycemia, hypertension, increased HPA axis reactivity, and increased anxiety-related behaviour. Molecular mechanisms that underlie the 'developmental programming' effects of excess glucocorticoids/prenatal stress include epigenetic changes in target gene promoters. In the case of the intracellular glucocorticoid receptor (GR), this alters tissue-specific GR expression levels, which has persistent and profound effects on glucocorticoid signalling in certain tissues (e.g. brain, liver, and adipose). Crucially, changes in gene expression persist long after the initial challenge, predisposing the individual to disease in later life. Intriguingly, the effects of a challenged pregnancy appear to be transmitted possibly to one or two subsequent generations, suggesting that these epigenetic effects persist.

Parental factors affecting the weights of the placenta and the offspring

AIM

To determine parental, especially paternal factors associated with the weight of the placenta and offspring.

METHODS

This population-based birth-cohort study includes 2947 singleton children born from April 2006 to 2007 and living in Drenthe, The Netherlands. Placental weight and birth weight were measured and questionnaires were filled out for this cohort. Associations between parental factors, and the weight of the placenta and the offspring were evaluated using univariate and multivariate linear regression models.

RESULTS

Univariate regression revealed that the paternal birth weight and body mass index (BMI) of the father were predictors for placental and birth weight of the offspring. However, they were not independent predictors. Independent predictors for placental weight were the maternal factors of pre-pregnancy BMI, birth weight, and diabetes. The maternal factors of weight gain during pregnancy, birth weight, smoking during pregnancy, and diabetes were independent predictors for birth weight of the offspring.

CONCLUSION

Paternal as well as maternal factors influence the weight of the placenta and the offspring.

[Anemia in pregnancy: characteristics in Szabolcs-Szatmár-Bereg County, Hungary]

Nowadays anemia is the most common disease of internal medicine during pregnancy. It could cause harmful consequences both to mother and to child.

AIM

authors examined connection between the blood count data (hemoglobin, red cell mean corpuscular volume), the ferritin level and the pregnancy age, the mothers' age, schooling, the number of earlier pregnancies, abortions and miscarriages frequency of women who gave birth in 2008 at Szabolcs-Szatmár-Bereg County, Hungary.

METHODS

Authors analyzed the records of health visitors in 2008 year in their county.

RESULTS

rate of anemia's occurrence in the first trimester was 2.54%, 0.71% in the second and 1.87% in the third trimester, and it was significantly frequented among the youthful (10.30%), the low schooled (5.55%), and the multipara women (2.56%). There was no difference in the rate of abortions; however, miscarriages were more frequent among pregnant women with anemia (7.14% vs. 5.46%). Low mean red cell corpuscular volume values were more frequent in all groups (6.06-22.88%) then the number of pregnant women with anemia. This fact refers to decreased iron stores in most cases. Ferritin level determination was made in 2.42% of cases only, but among these pathological low values was found in 93.1%.

CONCLUSIONS

Authors draw attention to the careful nursing of youthful, low schooled and multipara pregnant women, majority of them suffer from iron deficiency. They call attention to the right analysis of blood count, the start of correct iron supplementation in early pregnancy and the need of correction of iron stores before conception, too. Authors also give recommendations to this work on the basis of references.

Effect of the method of conception and embryo transfer procedure on mid-gestation placenta and fetal development in an IVF mouse model

BACKGROUND

Abnormal placentation is a potential mechanism to explain the increased incidence of low birthweight observed after IVF. This study evaluates, in a mouse model, whether the method of conception and embryo transfer affect placentation and fetal development.

METHODS

IVF blastocysts (CF1 x B6D2F1/J) were cultured in Whitten's medium (IVF(WM), n = 55) or K modified simplex optimized medium with amino acids (IVF(KAA), n = 56). Embryos were transferred to the uteri of pseudo-pregnant recipients. Two control groups were created: unmanipulated embryos produced by natural mating (in vivo group, n = 64) and embryos produced by natural mating that were flushed from uterus and immediately transferred to pseudo-pregnant recipients (flushed blastocysts, FB group, n = 57). At gestation age 12.5 days, implantation sites were collected and fixed; fetuses and placentas were weighed and their developmental stage (DS) evaluated. Placental areas and vascular volume fractions were calculated; parametric statistics were applied as appropriate.

RESULTS

IVF fetuses showed a modest but significant delay in development compared with FB mice (P < 0.05). In addition, IVF conceptuses were consistently smaller than FB (P < 0.05). Importantly, these differences persisted when analyzing fetuses of similar DS. The placenta/fetus ratio was larger in the IVF group (IVF(WM) 0.95; IVF(KAA) = 0.90) than the FB group (0.72) (P < 0.05 for all comparisons). Gross morphology of the placenta and ratio labyrinth/fetal area were equivalent in the IVF and FB groups, as were percentage of fetal blood vessels, maternal blood spaces and trophoblastic components.

CONCLUSIONS

In vitro embryo culture affects fetal and placental development; this could explain the lower birthweight in IVF offspring.

Review and hypothesis: syndromes with severe intrauterine growth restriction and very short stature--are they related to the epigenetic mechanism(s) of fetal survival involved in the developmental origins of adult health and disease?

Diagnosing the specific type of severe intrauterine growth restriction (IUGR) that also has post-birth growth restriction is often difficult. Eight relatively common syndromes are discussed identifying their unique distinguishing features, overlapping features, and those features common to all eight syndromes. Many of these signs take a few years to develop and the lifetime natural history of the disorders has not yet been completely clarified. The theory behind developmental origins of adult health and disease suggests that there are mammalian epigenetic fetal survival mechanisms that downregulate fetal growth, both in order for the fetus to survive until birth and to prepare it for a restricted extra-uterine environment, and that these mechanisms have long lasting effects on the adult health of the individual. Silver-Russell syndrome phenotype has recently been recognized to be related to imprinting/methylation defects. Perhaps all eight syndromes, including those with single gene mutation origin, involve the mammalian mechanism(s) of fetal survival downsizing. Insights into those mechanisms should provide avenues to understanding the natural history, the heterogeneity and possible therapy not only for these eight syndromes, but for the common adult diseases with which IUGR is associated.

The surface area of the placenta and hypertension in the offspring in later life

Hypertension is more common among people who had low birthweight. Birthweight depends on the mothers body size and on the growth of the placenta. We studied a group of 2003 subjects, of whom 644 were being treated for hypertension. They were born during 1934-44 in a hospital that kept detailed records of maternal and placental size. Hypertension was associated with reduced placental weight and surface area. These associations were strongest in the offspring of mothers with below average height or low socioeconomic status. In people whose mothers had below average height (160 cm) the prevalence of hypertension fell from 38% if the placental area was 200 cm(2) or less to 21% if the area was more than 320 cm(2) (p=0.0007). In the offspring of tall, middle class mothers, who were likely to have been the best nourished, hypertension was predicted by large placental weight in relation to birthweight. The odds ratio rose from 1.0 if the ratio of placental weight to birthweight was 0.17 or less to 1.9 (95% confidence interval 0.8 to 5.0) if the ratio was more than 0.21 (p for trend =0.03). We conclude that the effects of placental area on hypertension depend on the mothers nutritional state. Poor maternal nutrition may compound the adverse effects of small placental size. In better-nourished mothers the placental surface may expand to compensate for fetal undernutrition. Growth along the minor axis of the surface may be more nutritionally sensitive than growth along the major axis.

Role of the kidney in the prenatal and early postnatal programming of hypertension

Epidemiologic studies from several different populations have demonstrated that prenatal insults, which adversely affect fetal growth, result in an increased incidence of hypertension when the offspring reaches adulthood. It is now becoming evident that low-birth-weight infants are also at increased risk for chronic kidney disease. To determine how prenatal insults result in hypertension and chronic kidney disease, investigators have used animal models that mimic the adverse events that occur in pregnant women, such as dietary protein or total caloric deprivation, uteroplacental insufficiency, and prenatal administration of glucocorticoids. This review examines the role of the kidney in generating and maintaining an increase in blood pressure in these animal models. This review also discusses how early postnatal adverse events may have repercussions in later life. Causes for the increase in blood pressure by perinatal insults are likely multifactorial and involve a reduction in nephron number, dysregulation of the systemic and intrarenal renin-angiotensin system, increased renal sympathetic nerve activity, and increased tubular sodium transport. Understanding the mechanism for the increase in blood pressure and renal injury resulting from prenatal insults may lead to therapies that prevent hypertension and the development of chronic kidney and cardiovascular disease.

Gross placental structure in a low-risk population of singleton, term, first-born infants

Suboptimal fetal growth has been associated with an increased risk of adult disease, which may be exacerbated by an increased placental weight-to-fetal weight ratio. Placental weight is a summary measure of placental growth and development throughout pregnancy. However, measures of placental structure, including the chorionic disk surface area and thickness and eccentricity of the umbilical cord insertion, have been shown to account for additional variance in birth weight beyond that explained by placental weight. Little is known of the variability of these placental parameters in low-risk populations; their association with maternal, pregnancy, and neonatal characteristics; and the agreement between manual and digital measures. This study used manual and digital image analysis techniques to examine gross placental anatomy in 513 low-risk, singleton, term, first-born infants. Parametric methods compared groups and examined relationships among variables. Maternal birth weight, prepregnancy weight, and body mass index were associated with increased placental and birth weight (all P < 0.005), but only maternal birth weight was associated with increased placental surface area (P < 0.0005) and thickness (P = 0.005). Smoking during pregnancy reduced birth weight and increased the eccentricity of umbilical cord insertion (P = 0.012 and 0.034, respectively). The variability in these placental parameters was consistently lower than that reported in the literature, and correlations between digital and manual measurements were reasonable (r = .87-.71). Detailed analyses of gross placental structure can provide biologically relevant information regarding placental growth and development and, potentially, their consequences.

Effects of maternal undernutrition on glomerular ultrastructure in rat offspring

BACKGROUND

Intrauterine growth restriction (IUGR) can reduce glomerutar number and increase blood pressure in rats. The aim of this study was to assess the effects of maternal undernutrition during late gestation on-glomerutar ultrastructure in adult rat offspring.

METHODS

Timed pregnant Sprague-Dawley rats were used. Control dams received regular food throughout pregnancy, while experimental dams received 50% of control food intake from days 15-21 of gestation. GLomerular ultrastructure was quantified in male offspring at 16 weeks of age.

RESULTS

The ultrastructure of the filtration apparatus in the IUGR rat glomeruli was indistinguishable from that in the control rat glomeruli. The relative volumes of the glomerulus occupied by podocytes, capillaries, and mesangium, and the thickness of the glomerular basement membrane (GBM), and width of the filtration slit were comparable between control and IUGR rats.

CONCLUSION

These results indicate that glomerular ultrastructure is not affected by maternal undernutrition and suggest that altered glomerular ultrastructure is not a contributory factor to the pathogenesis of hypertension following maternal undernutrition.

Effects of maternal undernutrition on renal angiotensin II and chymase in hypertensive offspring

Intrauterine growth restriction (IUGR) can program the future development of hypertension in adulthood. The renin-angiotensin system has been reported to play a role in IUGR-induced hypertension. The aims of this study were to investigate the effects of IUGR on renal angiotensin-converting enzyme (ACE), angiotensin II (Ang II) and chymase in IUGR-induced hypertension. Timed pregnant Sprague-Dawley rats received 50% rations of control food intakes from days 15 to 21 of gestation. Control rats received regular food throughout the pregnancies. Arterial blood pressure and glomerular number were measured and immunohistochemical studies were performed on kidney tissues in adult male offspring at 16 weeks of age. IUGR rats exhibited significantly lower body and kidney weights and reduced number of glomeruli when compared with control rats. IUGR rats had significantly higher systolic blood pressure than control rats. Immunoreactivity of ACE was comparable between control and IUGR rats whereas immunoreactivities of chymase and Ang II were significantly higher in IUGR rats than in control rats. In conclusion, immunohistochemical studies document up-regulation of ACE-independent Ang II and chymase in IUGR kidney and indicate that overactivity of chymase may result in increased intrarenal Ang II production, which could contribute to the development of hypertension in intrauterine undernourished rats.

Size at birth, obesity and blood pressure at age five

BACKGROUND

The fetal origins hypothesis indicates that morphometric evidence of fetal nutritional deprivation is predictive of excessive weight gain/obesity, insulin resistance, and cardiovascular disease after birth. However, it is unclear whether these effects are present in offspring with "normal" birth weights in contemporary Western society, whether they are population specific, and how early in life they appear. This study was designed to examine these questions in a select populace of morphometrically diverse offspring to test the null hypothesis that morphometric evidence of nutritional restriction in utero has no effect on the presence of either obesity or increased blood pressure at ages 5 and 6.

METHODS

We present a prospective study of 101 offspring born of well-nourished, middle and upper socioeconomic-class women who participated in studies of diet and exercise during pregnancy. At birth and age 5 to 6 the offspring underwent morphometric evaluation with the additional measurement of blood pressure at age 5 to 6.

RESULTS

There were no significant negative correlations between neonatal morphometrics and either blood pressure or obesity at age 5 to 6. There were, however, direct positive correlations between birth weight and both weight and BMI at age 5 to 6 (p < 0.0001).

CONCLUSIONS

In this specific populace, morphometrics at age 5 to 6 correlated with size at birth. However, there was no relationship between mophometric evidence of in utero nutritional deprivation at birth and either blood pressure or obesity at age 5 to 6.

Fetal growth and childhood cholesterol levels in the United States

Research has linked fetal environment to subsequent adult disease. This study examines the extent to which infants born small-for-gestational age (SGA) were at risk for high cholesterol levels in early childhood (ages 4-6 years). Data were obtained from 1727 children aged 4-6 years who participated in the cross-sectional third US National Health and Nutrition Examination Survey and had both birth certificates and blood cholesterol information. The odds of having moderately elevated (170-199 mg/dL) or high (> or =200 mg/dL) serum total cholesterol after being born SGA were determined after controlling for sex, race/ethnicity, education of household head, saturated fat intake, parental history of high cholesterol and overweight status. Approximately 11% of participants were SGA. Proportions of children with moderately elevated and high cholesterol levels were approximately 28 and 8%, respectively. SGA children were almost twice as likely (odds ratio 1.97, 95% confidence interval [0.8, 4.8]) to have high cholesterol vs. low cholesterol than non-SGA children, although the result was not statistically significant. Multiple linear regression demonstrated a similar inverse, non-significant relationship between gestation-adjusted birthweight and cholesterol (beta = -2.3, P = 0.33). These data indicate a possible association between reduced fetal growth, represented by birthweight adjusted for gestational age, and increased cholesterol levels in early childhood.

Mid-trimester amniotic fluid methionine concentrations: a predictor of birth weight and length

The association between body size at birth and risk of later cardiovascular disease is thought to be a consequence of metabolic changes that accompany slow growth in utero. The metabolism of methionine and homocysteine has been investigated in relation to cardiovascular risk and has also been assigned an important role in organogenesis and normal fetal growth. We determined concentrations of cobalamin, folate, methionine, cysteine, cystathionine, and the marker of B-vitamin function, homocysteine, in 625 samples of amniotic fluid obtained in the second trimester from normal pregnancies. Both vitamins and metabolites varied according to gestational age. The most noticeable observation was that methionine in amniotic fluid during gestational weeks 13 to 17 strongly predicted final birth weight and length. Metabolism of methionine may be a critical factor affecting fetal growth.

Reference values for the weight of freshly delivered term placentas and for placental weight–birth weight ratios

BACKGROUND

There is evidence for a correlation between placental weight and future chronic disease, notably hypertension and diabetes. However, there are no reference scales for placentas that are readily weighed in the delivery room.

METHODS

This cross-sectional study generated reference values for the weight of freshly delivered untrimmed placentas, and placental weight-birth weight (pw/bw) ratios from a database of 11,141 uncomplicated singleton term pregnancies (37-42 weeks). The data analysis followed stringent validated and state of the art methodological recommendations. A regression model was fitted to estimate the mean and standard deviation for placental weight and pw/bw ratios at each week of gestational age.

RESULTS

Reference scales, percentile tables and regression equations are presented for placental weights according to the mode of delivery and for pw/bw ratios. Mean placental weight from vaginal deliveries was 76 g lighter than from Caesarean sections (545+/-107 g versus 621+/-139 g, respectively, P<0.05). Mean placental weight increased by 60 g from 37 to 42 weeks irrespective of the mode of delivery. The pw/bw ratio decreased from 17.6 to 15.6 between 37 and 42 weeks.

CONCLUSION

For the first time, reference values for freshly delivered term placental weights depending on the mode of delivery were generated. In the light of growing evidence for a correlation of placental weight with chronic diseases in later life, these values provide the possibility to judge placentas at site for abnormalities in weight and to estimate the potential risks for chronic diseases in later life.

Glucocorticoid "Programming" and PTSD Risk

Epidemiological data have linked an adverse fetal environment with increased risks of cardiovascular, metabolic, neuroendocrine, and psychiatric disorders in adulthood. Prenatal stress and/or glucocorticoid excess might underlie this link. In animal models, prenatal stress, glucocorticoid exposure or inhibition/knockout of 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta-HSD-2), the feto-placental barrier to maternal glucocorticoids, reduces birth weight and causes permanent hypertension, hyperglycemia, increased hypothalamic-pituitary-adrenal (HPA) axis activity and behavior resembling of anxiety. In humans, 11 beta-HSD-2 gene mutations cause low birth weight and placental 11 beta-HSD-2 activity correlates directly with birth weight and inversely with infant blood pressure. Low birth weight babies have higher plasma cortisol levels throughout adult life, indicating HPA programming. In human pregnancy, severe maternal stress affects the offspring HPA axis and associates with neuropsychiatric disorders. Posttraumatic stress disorder (PTSD) appears to be a variable in the effects. Intriguingly, some of these effects appear to be 'inherited' into a further generation, itself unexposed to exogenous glucocorticoids at any point in the lifespan from fertilization, implying epigenetic marks persist into subsequent generation(s). Overall, the data suggest that prenatal exposure to excess glucocorticoids programs peripheral and CNS functions in adult life, predisposing to some pathologies, perhaps protecting from others, and these may be transmitted perhaps to one or two subsequent generations.

The association between pregnancy processes, preterm delivery, low birth weight, and postpartum depressions--the need for interdisciplinary integration

Pregnancy and peripartum/perinatal periods are characterized by significant biologic as well as psychosocial processes and changes that influence the 2 individuals at focus (mother and fetus), as well as their interactions with the immediate environment. Multiple intertwined pathologic pregnancy processes (hormonal, biologic, stress and other mental occurrences) may lead to fetal distress, preterm delivery (PTD), low birth weight (LBW), and other delivery complications as well as to postpartum disorders. PTD and LBW in particular have been demonstrated to be associated with significant mortality as well as short- and long-term morbidity. Underlying processes and risk factors for PTD, LBW and postpartum disorders may overlap. Their impact on the offspring is compounded. Currently, the multiple clinical and research disciplines that are concerned with the various aspects of pregnancy, delivery, and postpartum period are not conceptually and practically integrated. Specifically, obstetricians are more concerned with delivery complications, whereas mental health professionals are concerned with postpartum depression. An interdisciplinary approach is needed for better understanding of developmental processes and the development of measurements and interventions to prevent long-term impact on the offspring.

Glucocorticoid programming

Epidemiological evidence suggests that an adverse fetal environment permanently programs physiology, leading to increased risks of cardiovascular, metabolic, and neuroendocrine disorders in adulthood. Prenatal glucocorticoid excess or stress might link fetal maturation and adult pathophysiology. In a variety of animal models, prenatal glucocorticoid exposure or inhibition of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), the fetoplacental "barrier" to maternal glucocorticoids, reduces birth weight and causes permanent hypertension, hyperglycemia, and increased hypothalamic-pituitary-adrenal axis (HPA) activity and behavior resembling anxiety. In humans, 11beta-HSD2 gene mutations cause low birth weight and reduced placental 11beta-HSD2 activity associated with intrauterine growth retardation. Low birth weight babies have higher plasma cortisol levels throughout adult life, indicating HPA programming. The molecular mechanisms may reflect permanent changes in the expression of specific transcription factors; key is the glucocorticoid receptor itself. Differential programming of the glucocorticoid receptor in different tissues reflects effects upon one or more of the multiple tissue-specific alternate first exons/promoters of the glucocorticoid receptor gene. Overall, the data suggest that either pharmacological or physiological exposure to excess glucocorticoids prenatally programs pathologies in adult life.

Developmental origins of the metabolic syndrome: prediction, plasticity, and programming

The "fetal" or "early" origins of adult disease hypothesis was originally put forward by David Barker and colleagues and stated that environmental factors, particularly nutrition, act in early life to program the risks for adverse health outcomes in adult life. This hypothesis has been supported by a worldwide series of epidemiological studies that have provided evidence for the association between the perturbation of the early nutritional environment and the major risk factors (hypertension, insulin resistance, and obesity) for cardiovascular disease, diabetes, and the metabolic syndrome in adult life. It is also clear from experimental studies that a range of molecular, cellular, metabolic, neuroendocrine, and physiological adaptations to changes in the early nutritional environment result in a permanent alteration of the developmental pattern of cellular proliferation and differentiation in key tissue and organ systems that result in pathological consequences in adult life. This review focuses on those experimental studies that have investigated the critical windows during which perturbations of the intrauterine environment have major effects, the nature of the epigenetic, structural, and functional adaptive responses which result in a permanent programming of cardiovascular and metabolic function, and the role of the interaction between the pre- and postnatal environment in determining final health outcomes.

Size at birth and cardiovascular responses to psychological stressors: evidence for prenatal programming in women

BACKGROUND

Epidemiological studies have repeatedly shown inverse associations between size at birth and blood pressure in later life. There is some evidence to suggest that exaggerated blood pressure responses to psychological stressors are a forerunner of sustained hypertension.

OBJECTIVE

To determine whether individuals who were smaller at birth have greater blood pressure and heart rate responses to psychological stressors.

DESIGN

Prospective cohort study.

METHODS

A total of 104 men and 79 women (mean age 26.3 years) were recruited from the Adelaide Family Heart Study cohort. Blood pressure was monitored continuously throughout the study using a Portapres and participants undertook a series of three stress tests: Stroop, mirror drawing and public speech. The stress response was defined as the increment from baseline to the mean blood pressure during the three tasks.

RESULTS

In women, a 1 kg increase in birthweight was associated with an 8.7 mmHg (95% confidence interval: 3.6-13.8, P = 0.001) reduction in the systolic and a 4.1 mmHg (1.6-6.6, P = 0.002) reduction in the diastolic response to stress. The heart rate response to stress was also inversely related to birthweight. These results remained significant after correction for gestational age and other potential confounding factors. Similar results were found for birth length and head circumference. There were no such relationships in men.

CONCLUSIONS

This study provides the first human evidence that cardiovascular responses to psychological stressors may be programmed antenatally and suggests a potential mechanism linking reduced fetal growth with raised blood pressure and cardiovascular disease in later life.

Fetal phenotypes and neonatal and early childhood outcomes in twins

OBJECTIVES

The purpose of this study was to evaluate factors associated with, and postnatal consequences of, altered patterns of fetal growth in twins.

STUDY DESIGN

Fetal growth was measured at 28 weeks' gestation on 218 twins, including head circumference, abdominal circumference, and femur length, and characterized as > or < or =10th %ile; children were followed up until the age of three years. Logistic regression was used to generate odds ratios of perinatal factors associated with reduced fetal growth.

RESULTS

Maternal height <62 inches was associated with reductions in femur length (adjusted odds ratio [AOR] 3.88, 95% CI 1.42-10.57) and abdominal circumference (AOR 8.63, 95% CI 2.41-30.94), while primiparity had a protective effect on both of these fetal measurements (AOR 0.28, 95% CI 0.13-0.64, and AOR 0.18, 95% CI 0.06-0.60, respectively), as well as head circumference (AOR 0.32, 95% CI 0.15-0.69). Smoking adversely affected femur and head growth (AOR 24.10, 95% CI 3.69-157.57, and AOR 10.82, 95% CI 1.73-67.79, respectively). Fetal reduction adversely affected femur and abdomen growth (AOR 5.85, 95% CI 1.52-22.51 and AOR 4.90, 95% CI 1.01-23.86, respectively), and monochorionicity and maternal weight gain <0.65 lb/wk before 20 weeks adversely affected femur growth (AOR 5.47, 95% CI 1.65-18.10, and AOR 3.39, 95% CI 1.34-8.59, respectively). At age 3 years, all categories of twins with reduced growth by 28 weeks' gestation were significantly shorter in height, and those with reduced abdominal circumference or head circumference at 28 weeks were also significantly lighter in weight compared with twins with adequate fetal growth by 28 weeks' gestation.

CONCLUSION

These data identify short maternal height, smoking, monochorionicity, fetal reduction, and inadequate weight gain before 20 weeks as risk factors associated with reduced twin fetal growth by 28 weeks' gestation and significant residual reductions in height and weight through 3 years of age.

Indicators of Fetal Growth Do Not Independently Predict Blood Pressure in 8-Year-Old Australians

Inverse associations between size at birth and blood pressure (BP) in later life are commonly statistically significant only after adjustment for current size, consistent with change in size as the determinant. Few studies have been prospective or have included a range of potential confounders. Using regression models, including maternal and demographic variables, we examined associations between size at birth and BP in Australian children followed from week 16 of gestation to the age of 8 years. BP measurements were available from 1417 children born after 37 weeks gestation without congenital abnormalities. In models adjusted only for sex, the birthweight (BW), birth length, ponderal index, head circumference, chest circumference, abdominal girth, mid-arm circumference, triceps skinfold, placental weight, or BW/placental weight ratio did not significantly predict SBP in 8-year-olds. With adjustment for current size, associations were inverse but not statistically significant (regression coefficients: BW, −1.11; 95% confidence limits [CL], −2.22, 0.01; birth length, −0.25; 95% CL, −0.52, 0.24) and remained nonsignificant after adjustment for confounders. Current weight, height, or body mass index significantly predicted SBP and DBP ( P <0.001) with differences of 8/4 mm Hg between upper and lower quartiles; effects were similar in infants with lower and higher BW. These findings are consistent with postnatal change in size as the major determinant of BP in 8-year-olds and are important in the context of the worldwide “epidemic” of obesity in childhood as a likely precursor of increasing rates of hypertension in adults.

Evolutionary perspectives on pregnancy: maternal age at menarche and infant birth weight

We present a novel evolutionary analysis of low birth weight (LBW). LBW is a well-known risk factor for increased infant morbidity and mortality. Its causes, however, remain obscure and there is a vital need for new approaches. Life history theory, the most dynamic branch of evolutionary ecology, provides important insights into the potential role of LBW in human reproductive strategies. Life history theory's primary rationale for LBW is the trade-off between current and future reproduction. This trade-off underlies the prediction that under conditions of environmental risk and uncertainty (experienced subjectively as psychosocial stress) it can be evolutionarily adaptive to reproduce at a young age. One component of early reproduction is early menarche. Early reproduction tends to maximise offspring quantity, but parental investment theory's assumption of a quantity-quality trade-off holds that maximizing offspring quantity reduces quality, of which LBW may be the major component. We therefore predict that women who experienced early psychosocial stress and had early menarche are more likely to produce LBW babies. Furthermore, the extension of parent-offspring conflict theory in utero suggests that the fetus will attempt to resist its mother's efforts to reduce its resources, allocating more of what it does receive to the placenta in order to extract more maternal resources to increase its own quality. We propose that LBW babies born to mothers who experience early psychosocial stress and have early menarche are more likely to have a higher placental/fetal weight ratio. We review evidence in support of these hypotheses and discuss the implications for public health.

Fetal origins of cardiovascular disease

Several epidemiologic studies have shown that intrauterine growth retardation is a risk factor for the development of cardiovascular disease in later life. In this review, we discuss these epidemiologic studies and animal models that have been developed to investigate the pathophysiology of this phenomenon. We discuss data suggesting that intrauterine growth retardation leads to fetal exposure to maternal glucocorticoids. In addition, we present other data showing that fetal exposure of glucocorticoids during specific times of fetal development results in focal and segmental glomerulosclerosis, a reduced number of nephrons, hypertension, and diabetes. These studies suggest that at critical times during fetal development fetal injury programs the development of cardiovascular disease and diabetes in later life.

Nutrition in early life. How important is it?

While few would argue the importance of nutrition during adult life, temporary excess or deficiency has typically been thought to be of little long-term consequence. Recent data, summarized above, suggests that this may not be the case during in utero life, when alterations in the quantity or quality of nutrients provided may have life-long consequences. Perhaps even more surprisingly, decisions made in the neonatal period, such as whether to breastfeed or bottle feed, may have impacts on later health that, while small individually, have huge public health implications. Clarification of the links between adult health and fetal/neonatal nutrition are clearly required. Prospective studies, though difficult because of the time involved, will play a key role in this process, as will more basic research on the mechanisms underlying both normal and pathologic fetal development.

The role of the placenta in fetal programming-a review

The fetal origins hypothesis proposes that adult cardiovascular and metabolic disease originate through developmental plasticity and fetal adaptations arising from failure of the materno-placental supply of nutrients to match fetal requirements. The hypothesis is supported by experimental data in animals indicating that maternal nutrition can programme long term effects on the offspring without necessarily affecting size at birth. There is now evidence linking body composition in pregnant women and the balance of nutrient intake during pregnancy with raised levels of cardiovascular risk factors in the offspring. Maternal body composition and diet are thought to affect fetal development and programming as a result of both direct effects on substrate availability to the fetus and indirectly through changes in placental function and structure. Alterations in placental growth and vascular resistance, altered nutrient and hormone metabolism in the placenta, and changes in nutrient transfer and partitioning between mother, placenta and fetus all have important effects on the fetal adaptations thought to be central to programming. Future interventions to improve placental function are likely to have lifelong health benefits for the offspring.

Glucocorticoid programming of the fetus; adult phenotypes and molecular mechanisms

It has been long recognised that the glucocorticoid administration to pregnant mammals (including humans) reduces offspring birth weight. Epidemiologically, low weight or thinness at birth is associated with an increased risk of cardiovascular and metabolic disorders in adult life. So, does fetal exposure to glucocorticoids produce such 'programming' of adult disorders? Here data are reviewed which show, in rodents and other model species, that antenatal exposure to glucocorticoids reduces offspring birth weight and produces permanent hypertension, hyperglycaemia, hyperinsulinaemia, altered behaviour and neuroendocrine responses throughout the lifespan. This occurs with exogenous (dexamethasone) or endogenous glucocorticoids, the latter achieved by inhibiting 11 beta-hydroxysteroid dehydrogenase type 2, the feto-placental enzymic barrier to maternal glucocorticoids. Processes underlying fetal programming include determination of the 'set point' of the hypothalamic-pituitary-adrenal axis and of tissue glucocorticoid receptor expression. Detailed molecular mechanisms are being dissected. Analogous stress axis hyperreactivity occurs in lower birth weight humans and may be an early manifestation and indicate approaches to manipulation or prevention of the phenotype.

Abdominal fat and birth size in healthy prepubertal children

BACKGROUND

Studies examining the foetal origins hypothesis suggest that small birth size may be a marker of foetal adaptations that programme future propensity to adult disease. We explore the hypothesis that birth size may relate to fat distribution in childhood and that fat distribution may be a link between birth size and adult disease.

OBJECTIVE

To investigate the relationship between birth size and abdominal fat, blood pressure, lipids, insulin and insulin:glucose ratio in prepubertal children.

DESIGN

Cross-sectional study, based on a birth cohort of consecutive full-term births.

SUBJECTS

Two hundred and fifty-five (137 females) healthy, 7- and 8-y-old children.

MEASUREMENTS

Body composition and abdominal fat was measured by dual energy X-ray absorptiometry. Lipid, glucose and insulin profiles were measured after an overnight fast and an automated BP monitor was used for blood pressure measurements.

RESULTS

There was a negative association between abdominal fat and birth weight s.d. score across a range of normal birth weights (beta=-0.18; 95% CI=-0.31 to -0.04, P=0.009) and a positive association with weight s.d. score at 7/8 y (beta=0.35; 95% CI=0.24 to 0.46, P<0.001). Children who were born with the lowest weight s.d. score and had the greatest weight s.d. score at 7/8 y had significantly more (P<0.001) abdominal fat, as a percentage of total fat (6.53+/-1.3%) than those who had the highest birth weight s.d. score and the lowest weight s.d. score at 7/8 y (4.14+/-0.5%). Similar results were seen if head circumference, but not ponderal index, was used as an indicator of birth size. Increased abdominal fat was associated with higher total cholesterol:HDL cholesterol, higher triglyceride concentration and increased diastolic blood pressure.

CONCLUSIONS

Birth weight independently predicted abdominal fat. Children with the highest amount of abdominal fat were those who tended to be born lighter and gained weight centiles. Increased abdominal fat was associated with precursor risk factors for ischaemic heart disease.

Fetal programming of cardiovascular function through exposure to maternal undernutrition

A substantial and robust body of epidemiological evidence indicates that prenatal dietary experience may be a factor determining cardiovascular disease risk. Retrospective cohort studies indicate that low birth weight and disproportion at birth are powerful predictors of later disease risk. This prenatal influence on non-communicable disease in later life has been termed programming. Maternal nutritional status has been proposed to be the major programming influence on the developing fetus. The evidence from epidemiological studies of nutrition, fetal development and birth outcome is, however, often weak and inconclusive. The validity of the nutritional programming concept is highly dependent on experimental studies in animals. The feeding of low-protein diets in rat pregnancy results in perturbations in fetal growth and dimensions at birth. The offspring of rats fed low-protein diets exhibit a number of metabolic and physiological disturbances, and are consistently found to have high blood pressure from early postnatal life. This experimental model has been used to explore potential mechanisms of programming through which maternal diet may programme the cardiovascular function of the fetus. Indications from this work are that fetal exposure to maternally-derived glucocorticoids plays a key role in the programming mechanism. Secondary to this activity, the fetal hypothalamic-pituitary-adrenal axis may stimulate renin-angiotensin system activity, resulting in increased vascular resistance and hypertension.

Birth weight and cognitive function at age 11 years: the Scottish Mental Survey 1932

AIMS

To examine the relation between birth weight and cognitive function at age 11 years, and to examine whether this relation is independent of social class.

METHODS

Retrospective cohort study based on birth records from 1921 and cognitive function measured while at school at age 11 in 1932. Subjects were 985 live singletons born in the Edinburgh Royal Maternity and Simpson Memorial Hospital in 1921. Moray House Test scores from the Scottish Mental Survey 1932 were traced on 449 of these children.

RESULTS

Mean score on Moray House Test increased from 30.6 at a birth weight of <2500 g to 44.7 at 4001-4500 g, after correcting for gestational age, maternal age, parity, social class, and legitimacy of birth. Multiple regression showed that 15.6% of the variance in Moray House Test score is contributed by a combination of social class (6.6%), birth weight (3.8%), child's exact age (2.4%), maternal parity (2.0%), and illegitimacy (1.5%). Structural equation modelling confirmed the independent contribution from each of these variables in predicting cognitive ability. A model in which birth weight acted as a mediator of social class had poor fit statistics.

CONCLUSION

In this 1921 birth cohort, social class and birth weight have independent effects on cognitive function at age 11. Future research will relate these childhood data to health and cognition in old age.

Glucocorticoid programming of pituitary-adrenal function: mechanisms and physiological consequences

Increasing epidemiological evidence supports the notion that adverse events in fetal life permanently alter the structure and physiology of the adult offspring, a phenomenon dubbed 'fetal programming'. In particular, low weight or thinness at birth in humans is associated with an increased risk of cardiovascular and metabolic disorders as well as neuroendocrine dysfunction in adult life. Glucocorticoid administration during pregnancy is well-documented to both reduce offspring birth weight and alter the maturation of organs (hence their use to accelerate fetal lung maturation in premature labour). Here data are reviewed which show, in rodents and other models, that antenatal exposure to endogenous or exogenous glucocorticoids reduces offspring birth weight and produces permanent hypertension, hyperglycaemia, hyperinsulinaemia, altered behaviour and neuroendocrine responses throughout the lifespan. Processes underlying fetal programming include determination of the 'set point' of the hypothalamic-pituitary-adrenal (HPA) axis and of tissue glucocorticoid receptor (GR) expression. Similar HPA axis hyperreactivity occurs in lower birth weight humans and may be an early manifestation of the 'low birth weight' phenotype.