Term infants with fetal growth restriction are not at increased risk for low intelligence scores at age 17 years

Short-term neonatal and long-term neurodevelopmental outcome of children born term low birth weight

This study aimed to examine the impact of term LBW on short-term neonatal and long-term neurodevelopmental outcomes in children 5-7 years of age. This is a population-based cohort study that merged national data from the Korea National Health Insurance claims and National Health Screening Program for Infants and Children. The participants were women who gave birth at a gestational age of ≥ 37 weeks between 2013 and 2015 in the Republic of Korea, and were tracked during 2020 for the neurodevelopmental surveillance of their children. Among 830,806 women who gave birth during the study period, 31,700 (3.8%) of their babies weighed less than 2500 g. By Cox proportional hazard analysis, children aged 5-7 years who had LBW were associated with any developmental, motor developmental delay, cognitive developmental delay, autism spectrum, attention deficit hyperactivity disorders, and epileptic and febrile seizures.Children born with term LBW were more vulnerable to neurodevelopmental disorders at 5-7 years of age than those with normal and large birth weights. This study further substantiates counseling parents regarding the long-term outcomes of children being born underweight.

Small-for-Gestational-Age and Vocabulary and Achievement Test Scores at Age 9 Among Children Born at Term in a Contemporary U.S. Sample

INTRODUCTION

Children that are small-for-gestational-age (SGA) at birth are at an increased risk for cognitive impairment, even if born at term (37-41 weeks). This study examined associations between sex-specific SGA and vocabulary and achievement tests in 9 year old children born at term using a contemporary population-based US sample.

METHODS

A secondary data analysis was conducted on a sample of 2144 children born at term in 1998-2000 who participated in a US birth cohort study that oversampled non-marital births, which in the U.S. are associated with socioeconomic disadvantage and racial minority status. Vocabulary and achievement tests were administered to participants at age 9. Unadjusted and adjusted Ordinary Least Squares and logistic regression models of associations between SGA and test scores were estimated.

RESULTS

Sex-specific SGA was associated with 2-5 point lower test scores and 1-2 times the odds of scores less than 85 (> 1 SD below the national mean) across most outcomes. In adjusted models, measures of SGA were associated with low scores on the Woodcock-Johnson Applied Problems test (OR 2.257; 95% CI 1.434, 3.551) and the Woodcock-Johnson Passage Comprehension test (OR 1.554; 95% CI 1.132, 2.134).

CONCLUSION

The findings validate previous studies of SGA at term and cognitive outcomes and provide further evidence using a contemporary high-risk population-based US sample. The findings suggest that SGA children born at term should be recruited for early interventions to promote improved cognitive functioning in school.

Prenatal Predictors of Neurobehavioral Outcome in Children with Fetal Growth Restriction at 6 Years of Age: A Retrospective Cohort Study

(1) Background: Fetal growth restriction (FGR) increases the risk of adverse neurodevelopmental outcomes, especially in preterm newborns. This study aims to describe the behavioral results of FGR at 6 years of age and to demonstrate the relationship of certain predictive factors with this development. (2) Methods: This retrospective cohort study included 70 children born in 2015 at the University Hospital Carlos Haya, Málaga, Spain who had been exposed to FGR during pregnancy; neonatal and infant data were recorded retrospectively. Children were assessed prospectively at 6 years of age by means of a strengths and difficulties questionnaire (SDQ) to study behavioral outcomes. (3) Results: We demonstrated that there are higher behavioral disability rates in children exposed to FGR during pregnancy and, in particular, high rates of hyperactivity or conduct problems. We also proved a negative relationship between the birth weight percentile and the total behavioral scale score, along with a positive correlation between hyperactivity and the emotional and behavioral scales. Learning difficulties were more frequent in early-onset FGR than in late-onset FGR. (4) Conclusions: Our study of behavioral development has demonstrated higher behavioral disability rates in children with FGR at 6 years of age; specifically, high rates of hyperactivity or conduct problems. At the same time, we have proved a negative relationship between the birth weight percentile and the total behavioral scale score.

A Study of the Literature on Intrauterine Treatment Options for Chronic Placental Insufficiency with Intrauterine Growth Restriction Using Intrauterine Intravascular Amino Acid Supplementation

BACKGROUND

Intrauterine growth retardation (IUGR) is a very serious prenatal condition with 3-5% incidence of all pregnancies. It results from numerous factors, including chronic placental insufficiency. IUGR is associated with an increased risk of mortality and morbidity and is considered a major cause of fetal mortality. Currently, treatment options are significantly limited and often result in preterm delivery. Postpartum, IUGR infants also have higher risks of disease and neurological abnormalities.

METHODS

The PubMed database was searched using the keywords "IUGR", "fetal growth restriction", "treatment", "management" and "placental insufficiency" for the period between 1975 and 2023. These terms were also combined together.

RESULTS

There were 4160 papers, reviews and articles dealing with the topic of IUGR. In total, only 15 papers directly dealt with a prepartum therapy of IUGR; 10 of these were based on an animal model. Overall, the main focus was on maternal intravenous therapy with amino acids or intraamniotic infusion. Treatment methods have been tested since the 1970s to supplement the fetuses with nutrients lacking due to chronic placental insufficiency in various ways. In some studies, pregnant women were implanted with a subcutaneous intravascular perinatal port system, thus infusing the fetuses with a continuous amino acid solution. Prolongation of pregnancy was achieved, as well as improvement in fetal growth. However, insufficient benefit was observed in infusion with commercial amino acid solution in fetuses below 28 weeks' gestation. The authors attribute this primarily to the enormous variation in amino acid concentrations of the commercially available solutions compared with those observed in the plasma of preterm infants. These different concentrations are particularly important because differences in the fetal brain caused by metabolic changes have been demonstrated in the rabbit model. Several brain metabolites and amino acids were significantly decreased in IUGR brain tissue samples, resulting in abnormal neurodevelopment with decreased brain volume.

DISCUSSION

There are currently only a few studies and case reports with correspondingly low case numbers. Most of the studies refer to prenatal treatment by supplementation of amino acids and nutrients to prolong pregnancy and support fetal growth. However, there is no infusion solution that matches the amino acid concentrations found in fetal plasma. The commercially available solutions have mismatched amino acid concentrations and have not shown sufficient benefit in fetuses below 28 weeks' gestation. More treatment avenues need to be explored and existing ones improved to better treat multifactorial IUGR fetuses.

Neurodevelopment Outcome in Children with Fetal Growth Restriction at Six Years of Age: A Retrospective Cohort Study

OBJECTIVE

This study aimed to describe neurodevelopment in fetal growth restriction children at the age of six. Secondly, we tried to demonstrate influencing factors that can improve or exacerbate this development, as well as predictive factors that might select a population at risk to assist with early childhood support.

METHOD

It was a study of 70 children affected with FGR. FGR was based on these definitions: birth weight below the 3rd percentile or birth weight below the 10th percentile with an abnormal hemodynamic Doppler study. Neurodevelopment was assessed at 6 years old by means of Batelle Development Inventory. A global development quotient under a 100 score was considered a neurodevelopment delay. All variables regarding pregnancy care, delivery episode, postpartum, neonatal care, sociodemographic issues, and the need for support in the first years were studied.

RESULTS

The mean gestational age at diagnosis was 33.14 weeks (standard deviation (SD = 4.31), with 32.9% of early-onset diagnoses. The mean gestational age at delivery was 35.61 (SD = 3.21), and the cesarean rate was 64.3%. The average age of the children at the moment of the evaluation was 76.20-month-old (SD = 3.70). The mean global development quotient was 97.28 (SD = 13.97). We were able to record a 57.1% of global development delay. In the cases of cognition, only 17.1% of the children registered a delay. Motor and communication skills were the most frequently affected. We discovered that socioeconomic status was positively related to the global development quotient, as well as both gestational age at delivery and middle cerebral artery pulsatility index was positively related to the global development quotient.

CONCLUSIONS

We found a higher neurodevelopment delay rate (57.1%). We could relate a higher gestational age at delivery and a higher MCA percentile with better global neurodevelopment quotients.

Brain Sparing Effect on Neurodevelopment in Children with Intrauterine Growth Restriction: A Systematic Review

Background: Fetal growth restriction (FGR) is a pregnancy complication. Multiple studies have connected FGR to poor cognitive development, behavior disorders, and academic difficulties during childhood. Brain sparing has traditionally been defined as an adaptive phenomenon in which the brain obtains the blood flow that it needs. However, this adaptive phenomenon might not have a complete protective effect. This publication aims to systematically review the consequences of brain redistribution on neurodevelopment in children who presented with placental intrauterine growth restriction. Methods: We performed a systematic review according to PRISMA guidelines. It included studies on intrauterine growth restriction or small-for-gestational-age (SGA) fetuses, which middle cerebral artery was measured, and neurodevelopment assessed during childhood. PUBMED and EMBASE databases were searched for relevant published studies. Results: Of the 526 studies reviewed, only 12 were included. Brain sparing was associated with poor cognitive function and lower scores in IQ. Cerebral redistribution was related to better executive function and better behavior at 4 years old but not at 12 years old. Conclusions: We can assume that fetal brain sparing could not be a fully protective phenomenon. We could not find clinical differences in behavioral and executive functions because the results were heterogeneous. Some cognitive abilities could be affected in FGR brain sparing fetuses.

Postnatal delayed growth impacts cognition but rescues programmed impaired pulmonary vascular development in an IUGR rat model

BACKGROUND AND AIMS

Intrauterine growth restriction (IUGR) is a state of slower fetal growth usually followed by a catch-up growth. Postnatal catch-up growth in IUGR models increases the incidence of pulmonary arterial hypertension in adulthood. Here, we hypothesize that the adverse pulmonary vascular consequences of IUGR may be improved by slowing down postnatal growth velocity. Meanwhile, cognitive function was also studied.

METHODS AND RESULTS

We established an IUGR rat model by restricting maternal food throughout gestation. After birth, pups were fed a regular or restricted diet during lactation by changing litter size. Thus, there were three experimental groups according to the dam/offspring diet: C/C (gold standard), IUGR with catch-up growth (R/C) and IUGR with delayed growth (R/D). In adulthood (14 weeks of age), we assessed pulmonary vascular development by hemodynamic measurement and immunohistochemistry. Our results showed that adult R/C offspring developed an elevated mean pulmonary arterial pressure (mPAP) and pulmonary arteriolar remodeling accompanied with decreased eNOS mRNA and protein expressions compared to C/C or R/D offspring. This suggested that delayed postnatal growth improved pulmonary circulation compared to postnatal catch-up growth. Conversely, adult R/D offspring performed poorly in cognition. Behavior test and electrophysiology results exhibited a reduced synaptic plasticity. Furthermore, decreased mRNA expression levels of the memory-related gene zif268 and transcription factor recruitment factor p300 in the hippocampus region were also observed in R/D group.

CONCLUSION

These findings indicate that delayed postnatal growth results in cognitive impairment, but it reverses elevations in mPAP induced by postnatal catch-up growth following IUGR.

Impact of Twin-to-Twin Transfusion Syndrome, Preterm Birth, and Vision Loss on Development

This study compared the developmental outcomes of twin boys (one who is blind and one who is sighted) who were born prematurely and diagnosed with twin-to-twin transfusion syndrome (TTTS) at age 24 months. The results indicate a disparity in the developmental outcomes of the twins. Although the medical risk factors that are associated with TTTS and preterm births, as well as vision loss, appear to have a negative impact on developmental outcomes, it is impossible to determine the degree to which any factor is responsible for this result.

Hyperbaric oxygenation and glucose/amino acids substitution in human severe placental insufficiency

In the first case, the AA and glucose were infused through a perinatal port system into the umbilical vein at 30 weeks' gestation due to severe IUGR. The patient received daily hyperbaric oxygenation (HBO, 100% O₂) with 1.4 atmospheres absolute for 50 min for 7 days. At 31⁺⁴ weeks' gestation, the patient gave birth spontaneously to a newborn weighing 1378 g, pH 7.33, APGAR score 4/6/intubation. In follow‐up examinations at 5 years of age, the boy was doing well without any neurological disturbance or developmental delay. In the second case, the patient presented at 25/⁵ weeks' gestation suffering from severe IUGR received HBO and maternal AA infusions. The cardiotocography was monitored continuously during HBO treatment. The short‐time variations improved during HBO from 2.9 to 9 msec. The patient developed pathologic CTG and uterine contractions 1 day later and gave birth to a hypotrophic newborn weighing 420 g. After initial adequate stabilization, the extremely preterm newborn unfortunately died 6 days later. Fetal nutrition combined with HBO is technically possible and may allow the prolongation of the pregnancy. Fetal‐specific amino‐acid composition would facilitate the treatment options of IUGR fetuses and extremely preterm newborn.

A longitudinal study of cognitive and educational outcomes of those born small for gestational age

AIM

This study examined the long-term cognitive and educational outcomes of being born small for gestational age (SGA) and assessed whether the family's attitude towards education modified the effect of being born SGA on educational attainment.

METHODS

We used anonymised data on 9598 individuals from the Stockholm Birth Cohort. This study focused on babies born in 1953 in the Stockholm metropolitan area, who were followed up for 50 years, and included educational data at the age of 13 and 48. Ordinary least squares regression analyses, modification analyses and logistic regression analyses were conducted.

RESULTS

The findings suggested that individuals who were born SGA (n = 798) had lower mean verbal, spatial and numerical test scores than those born appropriate for gestational age (AGA) (n = 7364) and large for gestational age (n = 1436). The SGA/AGA differences were small, but statistically significant, and the effects of being born SGA on the test scores was modified by the family's attitude towards education. The findings also suggested that attaining higher education was largely, but not entirely, explained by the family's attitude towards education.

CONCLUSION

The detrimental effects of being born SGA were limited on cognitive and educational outcomes, but may have been reduced by positive family attitudes.

Effects of combined IUGR and prenatal stress on the development of the hippocampus in a fetal guinea pig model

Intrauterine growth restriction (IUGR) and maternal stress during pregnancy are two compromises that negatively impact neurodevelopment and increase the risk of developing later life neuropsychiatric disorders such as schizophrenia, depression and behavioural disorders. Neurosteroids, particularly allopregnanolone, are important in protecting the developing brain and promoting many essential neurodevelopmental processes. Individually, IUGR and prenatal stress (PS) reduce myelination and neurogenesis within affected fetal brains, however less information is available on the combined effects of these two disorders on the term fetal brain. This study aimed to investigate how IUGR and PS impairs the neurosteroid pathway when combined using a guinea pig model, and how these then disrupt the neurodevelopment of the fetus. Uterine artery blood flow restriction was performed at GA30-35 to induce growth restriction, whilst PS was induced by exposure of the dam to a strobe light during gestation commencing GA40 and repeated every 5 days. Exposure in this model caused reductions in hippocampal CA1 MBP immunostaining of male fetuses in both IUGR alone and IUGR+PS paradigms but only by IUGR in the subcortical white mater, compared with control males. Plasma allopregnanolone was reduced by both stressors irrespective of sex, whereas GFAP or MAP2 expression were not affected by either stressor. Female neurodevelopment, as assessed by these markers, was unimpeded by these compromises. The addition of prenatal stress did not further compound these deficits.

Cognitive ability in adolescents born small for gestational age: Associations with fetal growth velocity, head circumference and postnatal growth

BACKGROUND

Small size at birth may be associated with impaired cognitive ability later in life. The aim of this study was to examine the effect of being born small for gestational age (SGA), with or without intrauterine growth restriction (IUGR) on cognitive ability in late adolescence.

STUDY DESIGN

A follow-up study of a former cohort included 123 participants (52 males); 47 born SGA and 76 born appropriate for gestational age (AGA). Fetal growth velocity (FGV) was determined by serial ultrasound measurements during the third trimester. A control group matched for age and birthplace was included. The original Wechsler Adult Intelligence Scale (WAIS) was administered, and verbal, performance and full-scale Intelligence Quotient (IQ) scores were calculated.

RESULTS

There was no difference in IQ between adolescents born SGA and AGA. FGV or IUGR during the third trimester did not influence cognitive ability in late adolescence. Full-scale IQ was positively related to head circumference (HC) in adolescence (B: 1.30, 95% CI: 0.32-2.28, p=0.01). HC at birth and three months was positively associated with full-scale IQ. Catch-up growth in the group of SGA children was associated with a significantly increased height, larger HC, increased levels of insulin-like growth factor-I (IGF-I) and increased full-scale IQ compared to those born SGA without catch-up growth.

CONCLUSION

SGA and IUGR may not be harmful for adult cognitive ability, at least not in individuals born at near-term. However, known risk factors of impaired fetal growth may explain the link between early growth and cognitive ability in adulthood.

Neurodevelopment of small-for-gestational age infants: behavioral aspects in first year

The purpose of this study was to compare the behavior of full-term small-for-gestational age (SGA) with full-term appropriate-for gestational age (AGA) infants in the first year of life. We prospectively evaluated 68 infants in the 2nd month, 67 in the 6th month and 69 in the 12th month. The Bayley Scales of Infant Development-II were used, with emphasis on the Behavior Rating Scale (BRS). The groups were similar concerning the item “interest in test materials and stimuli”; there was a trend toward differences in the items “negative affect”, “hypersensitivity to test materials” and “adaptation to change in test materials”. The mean of Raw Score was significantly lower for the SGA group in the items “predominant state”, “liability of state of arousal”, “positive affect”, “soothability when upset”, “energy”, “exploration of objects and surroundings”, “orientation toward examiner”. A lower BRS score was associated with the SGA group in the 2nd month.

Developmental outcomes of late-preterm infants at 2 and 4 years

This study compared healthy late-preterm (34-36 week) and healthy full-term (37-41 week) singleton infants on a range of cognitive, motor, and behavioral outcomes at 2 and 4 years. Eighteen developmental outcomes were analyzed using the Early Childhood Longitudinal Survey-Birth Cohort, a nationally representative panel study. Ordinary Least Squares and logistic regressions were performed to estimate unadjusted and adjusted differences in developmental outcomes between late-preterm and full-term children. In unadjusted models, late-preterm children scored more poorly than full-term children on most assessments of cognitive ability at 2 and 4 years. After adjusting for demographic, economic, and obstetrical factors, late-preterm children continued to score lower than full-term children on language use at 2 years and on literacy, language, and math at 4 years, but scored at least one standard deviation below the mean on only one of the eighteen outcomes. Late-preterm birth is associated with subtle deficits in cognitive functioning as early as age 2 years. Although the effects may be too small to have clinical relevance, they suggest a trend toward poorer outcomes that have been documented at older ages and suggest that early testing and intervention may enhance the cognitive development of late-preterm children.

Prenatal and perinatal factors associated with intellectual disability

Prenatal and perinatal risk factors associated with intellectual disability (ID) were studied in 8-year-old Utah children from a 1994 birth cohort (N  =  26,108) using broad ascertainment methods and birth records following the most current recording guidelines. Risk factor analyses were performed inclusive and exclusive of children with a known or suspected underlying genetic disorder. Risk factors identified were poly/oligohydramnios, advanced paternal/maternal age, prematurity, fetal distress, premature rupture of membranes, primary/repeat cesarean sections, low birth weight, assisted ventilation greater than 30 min, small-for-gestational age, low Apgar scores, and congenital infection. Although several risk factors lost significance once children with underlying genetic disorders were excluded, socioeconomic variables were among those that maintained a prominent association with increased ID risk.

Intrauterine growth and neuropsychological performance in very low birth weight preschoolers

In this study we examined the association between intrauterine growth, indexed either as a categorical variable or continuous dimension, and neuropsychological outcome, in a very low birth weight (VLBW) sample of 143 preschoolers. When the commonly used split at the 10th percentile rank was applied to classify intrauterine growth restriction (IUGR), we found that the growth restricted group (n = 25) exhibited significantly poorer performance in the global motor domain, but not on any other neuropsychological measure. In contrast, when adequacy of intrauterine growth was indexed by standardized birth weight, a continuous dimension, this early risk factor explained a unique portion of the variance in global cognitive abilities and visuospatial skills, as well as in global, fine, and gross motor skills. These findings are consistent with recent magnetic resonance imaging data disclosing global neurodevelopmental changes in the brains of preterm infants with IUGR. When cases classified with IUGR (<10th percentile) were excluded, the relationship between adequacy of intrauterine growth and global cognitive abilities remained significant despite range restriction. Hence, an association between appropriateness of intrauterine growth and global intellectual outcome may be observed even within the population of VLBW preschoolers with adequate standardized birth weight.

Determinants of cognitive ability at 7 years: a longitudinal case-control study of children born small-for-gestational age at term

The aim of this study was to identify the determinants of children's intelligence at 7 years, including pregnancy, postnatal, demographic factors, and small-for-gestational age (SGA) birth at term. Information was collected at birth (n = 871), 1 year (n = 744), 3.5 years (n = 550), and 7 years (n = 591). Approximately half of the children in this study were born SGA (birthweight <or=10th percentile). There was no significant difference found between IQ scores for SGA children compared to AGA children, after adjustment for potential confounders (p = 0.45). Paternal education, developmental delay, and birth order were associated with intelligence scores at 7 years in the multiple regression analysis. This study found no long-term effect of SGA birth at term on intelligence in middle childhood. Potentially modifiable postnatal and demographic factors were found to be strong predictors of intelligence at 7 years.

Verbal short-term memory span in children: long-term modality dependent effects of intrauterine growth restriction

BACKGROUND

Recent reports showed that children born with intrauterine growth restriction (IUGR) are at greater risk of experiencing verbal short-term memory span (STM) deficits that may impede their learning capacities at school. It is still unknown whether these deficits are modality dependent.

METHODS

This long-term, prospective design study examined modality-dependent verbal STM functions in children who were diagnosed at birth with IUGR (n = 138) and a control group (n = 64). Their STM skills were evaluated individually at 9 years of age with four conditions of the Visual-Aural Digit Span Test (VADS; Koppitz, 1981): auditory-oral, auditory-written, visuospatial-oral and visuospatial-written. Cognitive competence was evaluated with the short form of the Wechsler Intelligence Scales for Children--revised (WISC-R95; Wechsler, 1998).

RESULTS

We found IUGR-related specific auditory-oral STM deficits (p < .036) in conjunction with two double dissociations: an auditory-visuospatial (p < .014) and an input-output processing distinction (p < .014). Cognitive competence had a significant effect on all four conditions; however, the effect of IUGR on the auditory-oral condition was not overridden by the effect of intelligence quotient (IQ).

CONCLUSIONS

Intrauterine growth restriction affects global competence and inter-modality processing, as well as distinct auditory input processing related to verbal STM functions. The findings support a long-term relationship between prenatal aberrant head growth and auditory verbal STM deficits by the end of the first decade of life. Empirical, clinical and educational implications are presented.

Birth weight and cognitive ability in childhood among siblings and nonsiblings

OBJECTIVES

The purpose of this work was to examine whether the positive association between birth weight and childhood cognitive ability is seen within siblings from the same family, as well as between nonsiblings, and to determine whether these associations vary with age.

METHODS

We compared the association of birth weight with cognitive ability measured at ages 5 to 6, 7 to 9, and 11 to 12 years among a total of 5402 children from different families with that among 2236 to 3083 sibships from the National Longitudinal Study of Youth 1979-Children.

RESULTS

In the whole cohort, there were positive associations between birth weight and cognitive ability at all ages, with the association increasing with age from a 0.81-point increase at ages 5 to 6 years to 1.30 and 1.44 points at ages 7 to 9 and 11 to 12 years, respectively, per 1 SD of gestational age- and gender-adjusted birth weight z score. With adjustment for covariates, there was marked attenuation of these associations. Mean differences were 0.28 points in children aged 5 to 6 years, 0.67 points in those aged 7 to 9 years, and 0.52 points in those aged 11 to 12 years after adjusting for child's gender, race or ethnicity, year of birth, and age at test; maternal age, height, parity, education, smoking during pregnancy, and cognitive ability; and household income. Our family-based analyses that separated within- and between-family effects found that the between-family associations were much stronger than the within-family associations. However, adjustment for potential confounders attenuated the between-family associations, and there was no evidence for a difference in association comparing the between- and within-family associations.

CONCLUSIONS

In these data, the positive association between birth weight and childhood cognitive ability at ages 5 to 12 years is explained largely by family characteristics rather than a specific intrauterine effect.

Effects of being born small for gestational age on long-term intellectual performance

Size at birth has been associated repeatedly with increased risk of cardiovascular morbidity and mortality later in life. However, there is accumulating evidence to suggest an association between being born small for gestational age (SGA) and increased risk of lower intelligence, poor academic performance, low social competence and behavioural problems, compared with individuals born appropriate for gestational age. Crude neurological handicaps, such as cerebral palsy, are extremely rare in children born SGA at term. Such handicaps are more common in very premature children. However, there does appear to be an increase in the risk for non-severe neurological dysfunction in individuals born SGA. Intellectual performance is evaluated in young children in several different ways, including standardized tests such as Weschler's Intelligence Scale - Revised, and teachers and parents' reports. In adulthood, indirect variables such as education and occupation are used in addition to standardized tests. It may be possible to modify the effects of SGA on intellectual development by breast feeding the baby for more than 6 months. Nutrient-enriched formula does not have any advantages when it comes to intellectual development, and induces a risk of rapid weight gain and eventually overweight. Growth hormone treatment may also have some effect on intelligence quotient.

Prenatal and postnatal growth and cognitive abilities at 56 months of age: a longitudinal study of infants born at term

OBJECTIVE

The aim of the study was to investigate whether weight, length, BMI (kilograms per meter squared), and head circumference at birth and their postnatal growth are associated with cognitive abilities at 56 months of age among infants born at term.

PATIENTS AND METHODS

Our sample was composed of 1056 Finnish children born at term, (37 to 41 weeks) free of any major impairments. Weight, length, and head circumference were measured at birth and at 5, 20, and 56 months of age, and BMI was calculated. We assessed cognitive abilities by conducting tests of general reasoning, visual-motor integration, verbal competence, and language comprehension at 56 months of age.

RESULTS

Firstly, for every 1 SD lower in weight or BMI at birth, general reasoning and/or visual-motor integration was >1.20 points lower, and for every 1 SD lower in length or head circumference at birth, abilities across all of the cognitive domains were >1.31 points lower. Second, for every 1 SD slower gain in weight or BMI from birth to 5 months, general reasoning and visual-motor integration decreased by >0.97 points; for every 1 SD slower gain in length from 5 to 20 months and from 20 to 56 months, respectively, visual-motor integration, and verbal competence and language comprehension decreased by >1.03 points; and for every 1 SD slower increase in head circumference from birth to 5 months and from 5 to 20 months, respectively, visual-motor integration and language comprehension decreased by >1.17 points. Third, tests for nonlinear relationships revealed that, in some cases, large body size and faster growth were also associated with lower scores in cognitive tests.

CONCLUSIONS

Our findings suggest that, even within the range of children born at term, prenatal and postnatal growth in body size are associated with individual differences in cognitive abilities.

Intrauterine growth restriction and risk for arterial hypertension: a causal relationship?

AIMS

Intrauterine growth restriction (IUGR) has been demonstrated to have serious consequences for health in adult age. These include an increased risk for metabolic syndrome, pulmonary and cardiovascular disorders. These disorders are in part secondary to the development of arterial hypertension, which has been demonstrated to be more frequent in individuals subjected to restricted intrauterine growth.

METHODS

A review on publications on pathogenesis and epidemiology of hypertension associated to IUGR.

RESULTS

Current concepts for this association include a reduced nephrogenesis and increased arterial stiffness, impaired sympathetic regulation and steroid metabolism secondary to IUGR. Early postnatal risk-modifying factors include among others catch-up growth leading to childhood overweight.

CONCLUSION

IUGR increases the risk of hypertension in adult life. Identifying relevant risk factors for arterial hypertension will be the basis for the development of preventive concepts to be applied for predisposed individuals.

Associations of birth size, gestational age, and adult size with intellectual performance: evidence from a cohort of Norwegian men

The influences of prenatal and postnatal growth on intellectual performance are unclear. We examined the associations of birth size and gestational age with intellectual performance and explored whether these associations were influenced by adult body size and social factors. In this nationwide cohort study, the records of 317,761 male infants registered in the Medical Birth Registry of Norway (1967-1979) were linked to the Norwegian Conscript Service (1984-1999). The variation in intelligence test score at age 18 due to birth weight and birth length was evaluated using absolute and standardized (z scores) values. Mean intelligence score increased by gestational age, birth weight, and birth length. However, a decline in intellectual performance was observed for gestational age >41 wk and birth weight >4500 g. There was a strong interaction on intellectual performance between birth size and gestational age (p < 0.0005). Adjusting for adult size strongly attenuated the association of birth size with intellectual performance. The overall R of intellectual performance explained by birth size was <1%; however, adding adult body size and social factors to the model increased R to 12%. In conclusion, the association of birth size with intellectual performance was weak, but still present after adjustment for adult body size and social factors.

Are babies born to short, primiparous, or thin mothers "normally" or "abnormally" small?

OBJECTIVES

To examine whether the smaller size of infants born to primiparous, short, or thin mothers is associated with increased risks of perinatal mortality.

STUDY DESIGN

We compared gestational age-specific patterns of "revealed" small-for-gestational-age (SGA) birth (number of SGA births expressed as a proportion of fetuses remaining in utero at each gestational age) with the patterns for perinatal mortality among singleton late fetal deaths and live births (n = 791,523) to Swedish mothers in 1992 to 2001.

RESULTS

Based on a single standard for SGA, primiparae were at substantially higher risk of revealed SGA throughout gestation, paralleling the pattern for perinatal mortality. However, for short and thin women, risks of revealed SGA were much more consistent with those for perinatal mortality when SGA was based on height-specific or body mass index-specific standards, respectively, rather than on the single standard. Overweight and obese mothers had lower revealed SGA rates based on either standard but higher perinatal mortality rates.

CONCLUSIONS

Slower fetal growth due to maternal short stature or low prepregnancy body mass index appears to be physiologic, whereas the slower growth of fetuses born to primiparous women is associated with higher risks of perinatal death.

The Jerusalem Perinatal Study cohort, 1964-2005: methods and a review of the main results

The Jerusalem Perinatal Study recorded information on population-based cohorts of 92 408 live- and stillbirths in 1964-76, and their parents, with active surveillance of infant deaths and birth defects. Data on maternal conditions, obstetric complications and interventions during labour and delivery were recorded for 92% of the births. Subsets were surveyed with antenatal interviews in 1965-68 (n = 11 467), paediatric admissions to hospital (n = 17 782) and postpartum interviews in 1975-76 (n = 16 912). Data from some offspring were linked to records of a health examination at age 17. The offspring, mothers and fathers have been traced recently, their vital status assessed, and the data linked to Israel's Cancer Registry and Psychiatric Registry. This paper describes the different types of data available, their sources, and some potential biases. Characteristics of this unique population are shown. Findings from the study are reviewed and a list of references is provided. The cohorts provide a unique source of data for a wide variety of studies.

Impact of prenatal and/or postnatal growth problems in low birth weight preterm infants on school-age outcomes: an 8-year longitudinal evaluation

OBJECTIVE

The objective of this study was to assess the 8-year growth, cognitive, behavioral status, health status, and academic achievement in low birth weight preterm infants who had failure to thrive only, were small for gestational age only, had failure to thrive plus were small for gestational age, or had normal growth.

METHODS

A total of 985 infants received standardized evaluations to age 8; 180 infants met the criteria for failure to thrive between 4 and 36 months' gestational corrected age. The following outcome variables were collected at age 8: growth, cognitive, behavioral status, health status, and academic achievement. Multivariate analyses were performed among the 4 growth groups on all 8-year outcome variables.

RESULTS

Children who both were small for gestational age and had failure to thrive were the smallest in all growth variables at age 8, and they also demonstrated the lowest cognitive and academic achievement scores. The children with failure to thrive only were significantly smaller than the children with normal growth in all growth variables and had significantly lower IQ scores. Those who were small for gestational age only did not differ from those with normal growth in any cognitive or academic achievement measures. There were no differences among the 4 groups in behavioral status or general health status.

CONCLUSION

Low birth weight preterm infants who develop postnatal growth problems, particularly when associated with prenatal growth problems, demonstrate lower physical size, cognitive scores, and academic achievement at age 8. There does not seem to be an independent affect of small for gestational age status on 8-year cognitive status and academic achievement when postnatal growth is adequate.

Changes in white matter diffusion anisotropy in adolescents born prematurely

Being born with very low birth weight (VLBW, birth weight<or=1500 g) or small for gestational age (SGA) carries an increased risk of cerebral white matter damage. The reduced cognitive and motor skills these two groups exhibit suggest that the early injuries to white matter persist into adolescence. White matter integrity was assessed using voxel-wise statistical analysis of fractional anisotropy (FA) maps between three groups of adolescents at age 15; the VLBW group (n=34), the SGA group (n=42) and a control group with normal birth weight (n=47). The FA maps were normalized to a study specific template and group differences were assessed using an analysis of covariance with gender as a confounder (FDR-corrected P<0.05). The main finding is that the VLBW group has significantly reduced FA values in several white matter regions, including the corpus callosum, internal capsule and superior fasciculus compared to the control group. Some of the observed reduction in anisotropy, particularly that observed in the corpus callosum, may have been caused by inaccurate spatial normalization, but this can only explain 30% of the area with reduced anisotropy. Analysis of the eigenvalues of the diffusion tensor show that the reduced FA values in the VLBW group is primarily due to an increase in the two lowest eigenvalues of the diffusion tensor. We speculate that this may be caused by reduced myelination. For the SGA group, we find no statistically significant differences in anisotropy compared to the control group.

Neurocognitive Development in Children Experiencing Intrauterine Growth Retardation and Born Small for Gestational Age: Pathological, Constitutional and Therapeutic Pathways

Interest in the neurocognitive and psychosocial outcomes in children who are born small for gestational age (SGA) has increased since the recent approval of growth hormone (GH) therapy in this indication. The objective of GH treatment in SGA children is to provide a symptomatic treatment for growth retardation. From a patient perspective, the ultimate goals of GH therapy are the reduction in the present or future risk of neurocognitive, psychological, social or occupational impairment, not the accompanying improvements in growth velocity and final height per se. Therefore, from a scientific perspective, neurocognitive and psychosocial endpoints become relevant domains of assessment to determine the final treatment benefit experienced by the patient born SGA. This article reviews recent available studies on developmental risks in SGA, and then transforms the empirical findings into an integrated conceptual framework on the sources and mediators of neurocognitive and psychosocial outcomes in intrauterine growth retardation and SGA. This framework depicts two distinct therapeutic pathways by which GH therapy may improve neurocognitive and behavioural outcomes. The first ('traditional') pathway is the prevention of exposure to short-stature-related stressors via an improvement in growth velocity and final height. The second pathway refers to potential metabolic, and thus neurotropic and psychotropic, effects of GH binding at receptors in the central nervous system, thus changing neuronal activity. To date, the existence and potential mechanisms of such physiologically and not psychologically mediated effects of GH on neurocognitive functioning in SGA patients remain hypothetical.

Outcome of low birthweight in China: a 16-year longitudinal study

AIM

To compare the growth and neurodevelopment of low-birthweight (LBW) and normal-birthweight (control) infants born and raised in China.

DESIGN

Prospective cohort study.

SUBJECTS AND SETTING

203 LBW (1200-2499 g) and 71 control (> or =2500 g) infants born at two Shanghai hospitals in 1983 did not differ for date of birth, gender, parental occupation, parental weight and age. LBW <10th centile at > or =37 wk gestation was defined as small for gestational age (SGA, n=102). LBW at < 37 wk gestation was defined as preterm (n=101).

MAIN OUTCOME MEASURES

Weight, height, head circumference, Gesell developmental quotient (DQ), Wechsler intelligence quotient (IQ), and scholastic achievement score.

RESULTS

Of the 274 enrolled subjects, 234 (85%) returned at 6 mo, 135 (49%) at 6 y, and 104 (38%) at 16 y. SGA, preterm, and control subjects did not differ in rates of follow-up or baseline characteristics. However, SGA and preterm were lower than control subjects in weight and head circumference through 16 y, height through 4 y, DQ through 3 y, IQ at 5 and 16 y, and scholastic achievement at 16 y. Catch-up to growth in the control group, defined as >3rd centile, and normal IQ, defined as > or =85, were both more common among preterm than SGA subjects.

CONCLUSIONS

Adolescents in China with birthweights of 1200-2499 g, and particularly those who were SGA, lag behind peers with birthweights >2500 g in physical growth, cognitive capacity, and school achievement. The findings suggest that LBW adolescents in China today represent a population in need of evaluation and support.

Psychiatric symptoms in low birth weight adolescents, assessed by screening questionnaires

OBJECTIVE

The aim of this study was to explore psychiatric symptoms in low birth weight adolescents, and the usefulness of questionnaires compared with psychiatric interview. DESIGN/STUDY GROUPS: A population-based follow-up study of 56 very low birth weight (VLBW), 60 term small for gestational age (SGA) and 83 control adolescents at 14 years of age was made.

OUTCOME MEASURES

The Achenbach System of Empirically Based Assessment (ASEBA) and the Strengths and Difficulties Questionnaire (SDQ) were rated by adolescents, parents and teachers. The results were compared with diagnostic assessment based on the semi-structured interview, Schedule for Affective Disorders and Schizophrenia for School Aged Children (K-SADS).

RESULTS

VLBW adolescents had more psychiatric symptoms than controls, especially attention deficit, emotional, behavioural, social and also academic problems. Although less consistent, the SGA group had more emotional, conduct and attention deficit symptoms than controls. Results remained essentially the same when adolescents with low estimated IQ were excluded, and persisted after controlling for possible confounders. The sensitivity and specificity of ASEBA and SDQ differed between informants and groups.

CONCLUSION

VLBW adolescents are at risk of developing psychiatric symptoms, and reduced social and academic skills by the age of 14. Term SGA adolescents may have discrete emotional, behavioural and attention deficit symptoms. ASEBA and SDQ provide a useful supplement to psychiatric interview.

Current concepts in intrauterine growth restriction

Regulation of fetal growth is multifactorial and complex. Diverse factors, including intrinsic fetal conditions as well as maternal and environmental factors, can lead to intrauterine growth restriction (IUGR). The interaction of these factors governs the partitioning of nutrients and rate of fetal cellular proliferation and maturation. Although IUGR is probably a physiologic adaptive response to various stimuli, it is associated with distinct short- and long-term morbidities. Immediate morbidities include those associated with prematurity and inadequate nutrient reserve, while childhood morbidities relate to impaired maturation and disrupted organ development. Potential long-term effects of IUGR are debated and explained by the fetal programming hypothesis. In formulating a comprehensive approach to the management and follow-up of the growth-restricted fetus and infant, physicians should take into consideration the etiology, timing, and severity of IUGR. In addition, they should be cognizant of the immediate perinatal response of the growth-restricted infant as well as the childhood and long-term associated morbidities. A multi disciplinary approach is imperative, including early recognition and obstetrical management of IUGR, assessment of the growth-restricted newborn in the delivery room, possible monitoring in the neonatal intensive care unit, and appropriate pediatric follow-up. Future research is necessary to establish effective preventive, diagnostic, and therapeutic strategies for IUGR, perhaps affecting the health of future generations.

Intrauterine growth retardation in full-term newborn infants with birth weights greater than 2,500 g

Intrauterine growth retardation (IUGR) is an overlooked problem in full-term infants with birth weights greater than 2,500 g. Birth weight less than the 10th percentile underestimates the presence of IUGR. The purpose of this study was to determine the prevalence of IUGR in full-term infants and to identify sociodemographic and maternal characteristics associated with IUGR. The Ohio Department of Health Vital Statistics database was used to obtain data related to sociodemographic and maternal characteristics. The fetal growth ratio (FGR) was used to determine the presence of IUGR. The sample consisted of 1,569 infants with normal ratios and 1,364 infants classified as IUGR. Infants with IUGR were more often male and African American or Asian American. Maternal characteristics associated with IUGR included history of smoking during pregnancy, lower pre-pregnancy weight, lower weight gain during pregnancy, and inadequate prenatal care. IUGR is present in a significant number of full-term infants with birth weights greater than 2,500 g. The long-term effects of IUGR in these infants remain to be determined.

Insulin-Like Growth Factors and Their Binding Proteins in Children Born Small for Gestational Age: Implication for Growth Hormone Therapy

The insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important regulators of growth and metabolism and are the key mediators of the actions of growth hormone (GH). Children born small for gestational age (SGA) have a host of medical problems including an increased risk of poor growth later in life, a tendency to develop metabolic abnormalities and a high incidence of learning disabilities. IGFs and related molecules may be linked to all of these concerns. Mouse models of IGF-I and IGF-II deficiencies have phenotypes reminiscent of human SGA, including slow growth, insulin resistance, and mental dysfunction. Humans with IGF-I mutations are born SGA and exhibit very poor subsequent growth, metabolic syndrome and mental retardation. Current management of children born SGA who present with growth failure during childhood includes treatment with GH. SGA children usually have growth factor levels within the normal range; however, as a group, they display lower IGFBP-3 levels in relation to their IGF-I levels. GH is effective in improving growth in children born SGA, but higher doses of GH are required to achieve optimal outcome, suggesting a component of GH insensitivity in SGA children. As in other indications for GH, a rational monitoring approach (focusing on maintaining IGF levels in the high normal range) is prudent.

Brain volumes in adult survivors of very low birth weight: a sibling-controlled study

OBJECTIVES

To establish whether adults who were born very low birth weight (VLBW) show altered volumes of certain brain structures.

METHODS

Unmatched case-control study was conducted of 33 individuals from a cohort of VLBW (<1500 g) infants who were born between 1966 and 1977 and 18 of their normal birth weight siblings. Whole brain, gray matter, ventricular, corpus callosum, and hippocampal volumes were measured on structural magnetic resonance imaging scans.

RESULTS

VLBW individuals had a 46% increase in total ventricular volume and a 17% reduction in posterior corpus callosum volume. No differences in whole brain, gray matter, or hippocampal volumes were observed.

CONCLUSION

Specific differences exist in the volumes of certain brain structures in adults who were born VLBW compared with their normal birth weight siblings.

Learning, cognitive, and attentional problems in adolescents born small for gestational age

OBJECTIVE

To determine whether the presence, severity, or symmetry of growth restriction in term infants is an independent risk factor for learning, cognitive, and attentional problems in adolescence.

METHODS

A total of 7388 term infants have been followed prospectively since birth. At 14 years, 5059 mothers completed a Child Behavior Checklist and provided information on their child's school progress. A total of 5051 adolescents completed a Youth Self Report, with 3703 also undergoing psychometric testing with Ravens Progressive Matrices and Wide Range Achievement Test (WRAT) reading subtest. Outcomes were compared on the basis of birth weight groups and measures of body symmetry and were adjusted for the level of social risk at birth.

RESULTS

Adolescents who were born small for gestational age (SGA), when compared with their appropriately grown counterparts (>10th percentile), were more likely to experience learning difficulties, with a higher prevalence in those of birth weight < or =3rd percentile. Girls of birth weight < or =3rd percentile were more likely to have attentional problems and low WRAT reading scores. There was no significant difference in Ravens IQ or mean WRAT reading scores between SGA and non-SGA groups. There was no association between body symmetry and any of the outcomes studied.

CONCLUSIONS

SGA status seems to have only modest independent effects on learning, cognition, and attention in adolescence. Severity but not symmetry of growth restriction predicted learning difficulties.

The epidemiology of adverse pregnancy outcomes: an overview

This paper provides an overview of the occurrence, etiology and temporal trends of adverse pregnancy outcomes. Disparities between developed and developing countries are highlighted for maternal mortality, infant mortality, stillbirth and low birth weight. The higher rate of low birth weight in developing countries is primarily due to intrauterine growth restriction rather than preterm birth. Much of the excess intrauterine growth restriction is caused by short maternal stature, low prepregnancy body mass index and low gestational weight gain (due to low energy intake). No important contribution has been established for micronutrient intake, nor have different fetal growth trajectories been demonstrated to reflect the timing of exposure to nutritional or other etiologic factors. Infant mortality has declined substantially over time both in developed and developing countries despite no decline (and even an increase) in low birth weight. Several developed countries have reported a temporal increase in fetal growth in infants born at term, a reduction in stillbirth rates and prevention of neural tube defects. More progress is required, however, in understanding the etiology and prevention of preterm birth.

The epidemiology of mental retardation: challenges and opportunities in the new millennium

There are a number of problems and challenges in relating the science of epidemiology to mental retardation (MR). These relate to how MR is defined and classified and how these definitions may change over time. These as well as other differences in ascertainment sources and methods need to be considered when comparing MR prevalence over time and place. On the other hand, advances in technology also provide new and efficient methods of data collection both by data linkage and by use of web-based methods to study rare diseases. While prevalence studies have not been individually reviewed, we have examined the range of data including recent studies relating to how prevalence differs according to age, gender, social class and ethnicity. Some problems with available etiological classification systems have been identified. Recent etiological studies, most of which use different classification systems, have been reviewed and explanations have been postulated to account for differences in results. Individual risk factors for MR are considered whilst the option of considering a population as opposed to a high risk strategy to MR prevention is raised. This might well involve improving the social milieu surrounding the occurrence of individual risk factors. The impact of biotechnological advances such as antenatal and neonatal screening and assisted reproduction on MR are discussed. The issue of how inequalities in access to technology may impact on case identification and even have the potential to further widen inequalities is raised. The importance of extending the use of epidemiological tools to study the social, health and economic burden of MR is also emphasized. However, in order to apply to MR the "prevention-intervention-research" cycle, which surely underpins all epidemiology, it is vital to ensure that the methodological challenges we raise are adequately addressed.