Tracking and determinants of subcutaneous fat mass in early childhood: the Generation R Study

Body composition assessment in 6-month-old infants: A comparison of two- and three-compartment models using data from the Baby-bod study

BACKGROUND/OBJECTIVES

An appreciation of infant body composition is helpful to understand the 'quality' of growth in early life. Air displacement plethysmography (ADP) using PEA POD and the deuterium dilution (DD) technique are commonly used body composition approaches in infants. We evaluated the comparability of body composition assessed using both techniques with two-compartment (2C) and three-compartment (3C) models in 6-month-old infants.

SUBJECTS/METHODS

Infant fat mass (FM) and percent fat mass (%FM) obtained from a 2C model using PEA POD (2C-PP) and a 2C model using the deuterium dilution technique (2C-DD) were compared to those derived from a 3C model, and to each other, using Bland-Altman analysis and Deming regression.

RESULTS

Measurements were available from 68 infants (93% Caucasian, 53% male). The mean biases were not significant between any of the method comparisons. However, significant constant and proportional biases were identified in 2C-DD vs 3C and 2C-PP vs 2C-DD, but not in the 2C-PP vs 3C comparison. Furthermore, we observed significant associations between the mean differences and infants' percent total body water (%TBW).

CONCLUSIONS

While no significant between-method mean differences were found in body composition estimates, some comparisons revealed significant constant and proportional biases and notable associations between the mean differences and %TBW were observed. Our results emphasise the importance of method choice, ensuring methodological uniformity in long-term studies, and carefully considering and regulating multiple pre-analytical variables, such as the hydration status of the participants.

Impact of Gestational Diabetes Detection Thresholds on Infant Growth and Body Composition: A Prospective Cohort Study Within a Randomized Trial

OBJECTIVE

Gestational diabetes mellitus (GDM) is associated with offspring metabolic disease, including childhood obesity, but causal mediators remain to be established. We assessed the impact of lower versus higher thresholds for detection and treatment of GDM on infant risk factors for obesity, including body composition, growth, nutrition, and appetite.

RESEARCH DESIGN AND METHODS

In this prospective cohort study within the Gestational Diabetes Mellitus Trial of Diagnostic Detection Thresholds (GEMS), pregnant women were randomly allocated to detection of GDM using the lower criteria of the International Association of Diabetes and Pregnancy Study Groups or higher New Zealand criteria (ACTRN12615000290594). Randomly selected control infants of women without GDM were compared with infants exposed to A) GDM by lower but not higher criteria, with usual treatment for diabetes in pregnancy; B) GDM by lower but not higher criteria, untreated; or C) GDM by higher criteria, treated. The primary outcome was whole-body fat mass at 5-6 months.

RESULTS

There were 760 infants enrolled, and 432 were assessed for the primary outcome. Fat mass was not significantly different between control infants (2.05 kg) and exposure groups: A) GDM by lower but not higher criteria, treated (1.96 kg), adjusted mean difference (aMD) -0.09 (95% CI -0.29, 0.10); B) GDM by lower but not higher criteria, untreated (1.94 kg), aMD -0.15 (95% CI -0.35, 0.06); and C) GDM detected and treated using higher thresholds (1.87 kg), aMD -0.17 (95% CI -0.37, 0.03).

CONCLUSIONS

GDM detected using lower but not higher criteria, was not associated with increased infant fat mass at 5-6 months, regardless of maternal treatment. GDM detected and treated using higher thresholds was also not associated with increased fat mass at 5-6 months.

Skinfold-based-equations to assess longitudinal body composition in children from birth to age 5 years

BACKGROUND & AIMS

In order to identify children at risk for excess adiposity, it is important to determine body composition longitudinally throughout childhood. However, most frequently used techniques in research are expensive and time-consuming and, therefore, not feasible for use in general clinical practice. Skinfold measurements can be used as proxy for adiposity, but current anthropometry-based-equations have random and systematic errors, especially when used longitudinally in pre-pubertal children. We developed and validated skinfold-based-equations to estimate total fat mass (FM) longitudinally in children aged 0-5 years.

METHODS

This study was embedded in the Sophia Pluto study, a prospective birth cohort. In 998 healthy term-born children, we longitudinally measured anthropometrics, including skinfolds and determined FM using Air Displacement Plethysmography (ADP) by PEA POD and Dual energy X-ray Absorptiometry (DXA) from birth to age 5 years. Of each child one random measurement was used in the determination cohort, others for validation. Linear regression was used to determine the best fitting FM-prediction model based on anthropometric measurements using ADP and DXA as reference methods. For validation, we used calibration plots to determine predictive value and agreement between measured and predicted FM.

RESULTS

Three skinfold-based-equations were developed for adjoined age ranges (0-6 months, 6-24 months and 2-5 years), based on FM-trajectories. Validation of these prediction equations showed significant correlations between measured and predicted FM (R: 0.921, 0.779 and 0.893, respectively) and good agreement with small mean prediction errors of 1, 24 and -96 g, respectively.

CONCLUSIONS

We developed and validated reliable skinfold-based-equations which may be used longitudinally from birth to age 5 years in general practice and large epidemiological studies.

Metabolomics in early life and the association with body composition at age 2 years

BACKGROUND AND OBJECTIVES

Early life is a critical window for adiposity programming. Metabolic-profile in early life may reflect this programming and correlate with later life adiposity. We investigated if metabolic-profile at 3 months of age is predictive for body composition at 2 years and if there are differences between boys and girls and between infant feeding types.

METHODS

In 318 healthy term-born infants, we determined body composition with skinfold measurements and abdominal ultrasound at 3 months and 2 years of age. High-throughput-metabolic-profiling was performed on 3-month-blood-samples. Using random-forest-machine-learning-models, we studied if the metabolic-profile at 3 months can predict body composition outcomes at 2 years of age.

RESULTS

Plasma metabolite-profile at 3 months was found to predict body composition at 2 years, based on truncal: peripheral-fat-skinfold-ratio (T:P-ratio), with a predictive value of 75.8%, sensitivity of 100% and specificity of 50%. Predictive value was higher in boys (Q²  = 0.322) than girls (Q²  = 0.117). Of the 15 metabolite variables most strongly associated with T:P-ratio, 11 were also associated with visceral fat at 2 years of age.

CONCLUSION

Several plasma metabolites (LysoPC(22:2), dimethylarginine and others) at 3 months associate with body composition outcome at 2 years. These results highlight the importance of the first months of life for adiposity programming.

The association between fetal growth and neonatal adiposity in urban South African infants

OBJECTIVE

To examine associations between maternal body mass index (BMI), gestational weight gain (GWG) and fetal growth and neonatal adiposity in urban South Africans.

METHODS

Maternal BMI was assessed at recruitment and GWG (kg/week) was calculated. Longitudinal fetal growth was measured via ultrasound and modelled using Superimposition by Translation and Rotation (SITAR). Neonatal adiposity was assessed using air displacement plethysmography or dual-energy X-ray absorptiometry. Multiple linear regression models were used to examine associations between maternal BMI, GWG and SITAR fetal growth parameters and neonatal fat mass index (FMI; kg/m³ ) in 304 mother-neonate pairs.

RESULTS

In pooled analyses, longitudinally modelled abdominal circumference size (β = 0.64 kg/m³ , P < .001) and velocity (β = 8.39 kg/m³ , P < .001) and biparietal diameter velocity (β = 4.55 kg/m³ , P = .020) were positively associated with neonatal FMI. GWG was positively associated with neonatal FMI in preliminary models (β = 1.07 kg/m³ per 1 kg/week; P = .040), with pooled models indicating mediation via fetal growth.

CONCLUSION

In utero abdominal growth is predictive of neonatal adiposity. Additionally, greater fetal growth - particularly of the abdominal circumference - mediates the effect of GWG on neonatal adiposity. In settings such as South Africa, strategies to ensure healthy pregnancy weight gain can contribute to prevention of intergenerational obesity risk.

Association Between Fat Mass in Early Life and Later Fat Mass Trajectories

IMPORTANCE

A rapid increase in weight in early life is associated with an increased risk for adiposity and cardiovascular diseases at age 21 years and beyond. However, data on associations of early change in measured fat mass percentage (FM%) with adiposity development are lacking.

OBJECTIVE

To investigate whether a rapid increase in FM% in the first months of life is associated with higher trajectories of body fat mass during the first 2 years of life.

DESIGN, SETTING, AND PARTICIPANTS

A birth cohort consisting of 401 healthy, term-born infants of the Sophia Pluto Cohort Study was analyzed. Participants were born between January 7, 2013, and October 13, 2017. Data were analyzed from February 1, 2020, to May 20, 2020.

INTERVENTIONS

Longitudinal measurements of FM% by air-displacement plethysmography and dual-energy x-ray absorptiometry, and abdominal subcutaneous and visceral fat mass (FM) by ultrasonography in infants at ages 1, 3, 6, 9, 12, 18, and 24 months. A rapid increase in FM% was defined as a change in FM% of greater than 0.67 standard deviation scores (SDS).

MAIN OUTCOMES AND MEASURES

Associations between change in FM% SDS in the first and second 6-month period of life with body composition at age 2 years and whether a rapid increase in FM% SDS during the first 6 months leads to higher body FM and abdominal FM trajectories during the first 2 years of life.

RESULTS

Of the 401 participants, 228 infants (57%) were male. Change in FM% SDS from age 1 to 6 months was positively associated with FM% (β, 0.044; 95% CI, 0.017-0.068), FMI (β, 0.061; 95% CI, 0.032-0.091), and abdominal subcutaneous FM (β, 0.064; 95% CI, 0.036-0.092) at age 2 years, but not with visceral FM. In contrast, no associations were found within the 6- to 12-month period. Infants with a rapid increase in FM% of greater than 0.67 SDS in the first 6 months of life had higher trajectories of FM%, FM index, and subcutaneous FM during the first 2 years of life (all P≤.001), but visceral FM index was not significantly different compared with infants without a rapid increase (P = .12).

CONCLUSIONS AND RELEVANCE

In this study, only the change in FM% in the first 6 months of life was associated with more adiposity at age 2 years. Infants with a rapid increase in FM% had higher trajectories of FM% and FM index during the first 2 years of life. These findings appear to support a critical window for adiposity programming in early life.

Fetal exposure to phthalates and bisphenols and childhood general and organ fat. A population-based prospective cohort study

OBJECTIVES

Fetal exposure to phthalates and bisphenols might have long-lasting effects on growth and fat development. Not much is known about the effects on general and organ fat development in childhood. We assessed the associations of fetal exposure to phthalates and bisphenols with general and organ fat measures in school-aged children.

METHODS

In a population-based, prospective cohort study among 1128 mother-child pairs, we measured maternal urinary phthalate metabolites and bisphenol concentrations in first, second, and third trimester. Offspring body mass index, fat mass index by dual-energy X-ray absorptiometry, and visceral and pericardial fat indices and liver fat fraction were measured by magnetic resonance imaging at 10 years.

RESULTS

After adjustment for confounders and correction for multiple testing, an interquartile range increase in first trimester phthalic acid concentrations remained associated with a 0.14 (95% confidence interval: 0.05, 0.22) standard deviation score increase in pericardial fat index. We also observed tendencies for associations of higher maternal low molecular weight phthalate urinary concentrations in second trimester with childhood pericardial fat index, but these were not significant after adjustment for multiple testing. High molecular weight phthalate, di-2-ethylhexyl phthalate, and di-n-octyl phthalate concentrations were not associated with childhood outcomes. Maternal urinary bisphenol concentrations were not associated with childhood adiposity.

CONCLUSIONS

Maternal first trimester phthalic acid concentrations are associated with increased childhood pericardial fat index at 10 years of age, whereas maternal bisphenol concentrations are not associated with childhood adiposity. We did not find significant sex-specific effects. These findings should be considered as hypothesis generating and need further replication and identification of underlying mechanisms.

The external phenotype of aging

Aging is widely studied as a physiological process. Segmental aging can also occur prematurely in Mendelian disorders, and these can act this way as excellent sources of information, specifically for the underlying mechanisms. Adequate recognition of such aging characteristics in Mendelian disorders needs a well-defined phenotype of aging. Here the external phenotype of aging is described that can be recognized in the consulting room without major additional studies. Existing definitions of the signs and symptoms in Elements of Morphology or Human Phenotype Ontology are added or a new definition is suggested if none is available.

Longitudinal body composition assessment in healthy term-born infants until 2 years of age using ADP and DXA with vacuum cushion

OBJECTIVES

Accelerated gain in fat mass (FM) in early life increases the risk for adult diseases. Longitudinal data on infant body composition are crucial for clinical and research use, but very difficult to obtain due to limited measurement tools and unsuccessful measurements between age 6-24 months. We compared FM% by dual-energy X-ray absorptiometry (DXA), with cushion to reduce movement artifacts, with FM% by air-displacement plethysmography (ADP) and evaluated the reliability of this cushion during DXA by comparing FM% with and without cushion. Subsequently, we constructed sex-specific longitudinal body composition charts from 1-24 months.

METHODS

In 692 healthy, term-born infants (Sophia Pluto Cohort), FM% was measured by ADP from 1-6 months and DXA with cushion from 6-24 months. At 6 months, FM% was measured in triplicate by ADP and DXA with and without cushion(n = 278), later on in smaller numbers.

RESULTS

At 6 months, mean FM% by DXA with cushion was 24.1 and by ADP 25.0, mean difference of 0.9% (Bland-Altman p = 0.321, no proportional bias). Mean FM% by DXA without cushion was 12.5% higher compared to ADP (Bland-Altman p < 0.001). DXA without cushion showed higher mean FM% compared to DXA with cushion (+11.6%, p < 0.001) at 6 months. Longitudinally, FM% increased between 1-6 months and decreased from 6-24 months(both p < 0.001).

CONCLUSIONS

In infants, DXA scan with cushion limits movement artifacts and shows reliable FM%, comparable to ADP. This allowed us to construct longitudinal body composition charts until 24 months. Our study shows that FM% increases from 1-6 months and gradually declines until 24 months.

Types and amounts of complementary foods and beverages consumed and growth, size, and body composition: a systematic review

BACKGROUND

Systematic reviews (SRs) were conducted by the Nutrition Evidence Systematic Review (NESR) team for the USDA's and the Department of Health and Human Services' Pregnancy and Birth to 24 Months Project.

OBJECTIVES

The aim was to describe the SRs examining the relationship between types and amounts of complementary foods and beverages (CFBs) and growth, size, and body-composition outcomes.

METHODS

The NESR team collaborated with subject matter experts to conduct this SR. The literature was searched and screened using predetermined criteria. For each included study, data were extracted and risk of bias was assessed. The evidence was qualitatively synthesized to develop a conclusion statement, and the strength of evidence was graded.

RESULTS

This SR includes 49 articles that examined type, amount, or both of CFBs consumed and growth, size, and body-composition outcomes. Moderate evidence suggests that consuming either different amounts of meat, meat instead of iron-fortified cereal, or types of CFBs with different fats or fatty acids does not favorably or unfavorably influence growth, size, or body composition. In relation to overweight/obesity, insufficient evidence is available with regard to the intake of meat or CFBs with different fats or fatty acids. Limited evidence suggests that type and amount of fortified infant cereal does not favorably or unfavorably influence growth, size, body composition, or overweight/obesity. Limited evidence suggests that sugar-sweetened beverage consumption during the complementary feeding period is associated with increased obesity risk in childhood but is not associated with other measures of growth, size, or body composition. Limited evidence showed a positive association between juice intake and infant weight-for-length and child body mass index z scores. Insufficient evidence is available on other CFBs or dietary patterns in relation to outcomes.

CONCLUSIONS

Although several conclusions were drawn, additional research is needed that includes randomized controlled trials, examines a wider range of CFBs, considers issues of reverse causality, and adjusts for potential confounders to address gaps and limitations in the evidence.

Timing of introduction of complementary foods and beverages and growth, size, and body composition: a systematic review

BACKGROUND

The systematic review described in this article was conducted as part of the USDA and Department of Health and Human Services Pregnancy and Birth to 24 Months Project.

OBJECTIVES

The aim was to describe the relationship between timing of introduction of complementary foods and beverages (CFBs) and growth, size, and body-composition outcomes across the life span.

METHODS

The literature was searched and selected using predetermined criteria. Data were extracted and risk of bias assessed for each included study. Evidence was qualitatively synthesized, conclusion statements were developed, and the strength of the evidence was graded.

RESULTS

Eighty-one articles were included in this systematic review that addressed timing of CFB introduction relative to growth, size, and body-composition outcomes from infancy through adulthood. Moderate evidence suggests that introduction of CFBs between the ages of 4 and 5 mo compared with ∼6 mo is not associated with weight status, body composition, body circumferences, weight, or length among generally healthy, full-term infants. Limited evidence suggests that introduction of CFBs before age 4 mo may be associated with higher odds of overweight/obesity. Insufficient evidence exists regarding introduction at age ≥7 mo.

CONCLUSIONS

Although several conclusions were drawn in this systematic review, additional research is needed to address gaps and limitations in the evidence on timing of introduction of CFBs and growth, size, and body composition, such as randomized controlled trials that examine multiple outcomes and/or CFB introduction between the ages of 4 and 6 mo, and research that accounts for potential confounders such as feeding practices and baseline growth status and considers issues of reverse causality.

Subcutaneous fat mass in infancy and abdominal, pericardial and liver fat assessed by Magnetic Resonance Imaging at the age of 10 years

BACKGROUND/OBJECTIVES

Fat mass development in infancy contributes to later adiposity, but its relation to ectopic fat depots is unknown. We examined the associations of infant subcutaneous fat with childhood general and organ-specific fat.

SUBJECTS/METHODS

Among 593 children from a population-based prospective cohort study, we obtained total subcutaneous fat mass (as sum of biceps, triceps, suprailiacal, and subscapular skinfolds thickness), central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thickness/total subcutaneous fat) at 1.5, 6 and 24 months of age. At 10 years, we assessed BMI, fat mass index (FMI) based on total body fat by dual-energy X-ray absorptiometry, and abdominal subcutaneous, visceral and pericardial fat mass indices, and liver fat fraction by Magnetic Resonance Imaging.

RESULTS

A higher central-to-total subcutaneous fat ratio at 1.5 months only and higher total subcutaneous fat at 6 and 24 months were associated with higher BMI, FMI and subcutaneous fat mass index at 10 years. The observed associations were the strongest between total subcutaneous fat at 24 months and these childhood outcomes (difference per 1-SDS increase in total subcutaneous fat: 0.15 SDS (95% Confidence Interval (CI) 0.08, 0.23), 0.17 SDS (95% CI 0.10, 0.24), 0.16 SDS (95% CI 0.08, 0.23) for BMI, FMI and childhood subcutaneous fat mass index, respectively). Infant subcutaneous fat measures at any time point were not associated with visceral and pericardial fat mass indices, and liver fat fraction at 10 years.

CONCLUSIONS

Our results suggest that infant subcutaneous fat is associated with later childhood abdominal subcutaneous fat and general adiposity, but not with other organ-specific fat depots.

Maternal traditional dietary pattern and antiretroviral treatment exposure are associated with neonatal size and adiposity in urban, black South Africans

This study examines the associations between maternal Traditional dietary pattern adherence and HIV/treatment with neonatal size and adiposity in urban, black South Africans, as well as how specific maternal factors - that is BMI and gestational weight gain (GWG) - may influence these associations. Multiple linear regression models were used to examine associations among maternal Traditional diet pattern adherence (pattern score), HIV/treatment status (three groups: HIV negative, HIV positive (antenatal antiretroviral treatment (ART) initiation), HIV positive (pre-pregnancy ART initiation)), BMI and GWG (kg/week), and newborn (1) weight:length ratio (WLR, kg/m) in 393 mother-neonate pairs, and (2) Peapod estimated fat mass index (FMI, kg/m3) in a 171-pair subsample. In fully adjusted models, maternal obesity and GWG were associated with 0·25 kg/m (P=0·008) and 0·48 kg/m (P=0·002) higher newborn WLR, whereas Traditional diet pattern score was associated with lower newborn WLR (-0·04 kg/m per +1 sd; P=0·033). In addition, Traditional diet pattern score was associated with 0·13 kg/m3 (P=0·027) and 0·32 kg/m3 (P=0·005) lower FMI in the total sample and in newborns of normal-weight women, respectively. HIV-positive (pre-pregnancy ART) v. HIV-negative (ref) status was associated with 1·11 kg/m3 (P=0·002) higher newborn FMI. Promotion of a Traditional dietary pattern, alongside a healthy maternal pre-conception weight, in South African women may reduce newborn adiposity and metabolic risk profiles. In HIV-positive women, targeted monitoring and management strategies are necessary to limit treatment-associated effects on in utero fat deposition.

Air displacement plethysmography (pea pod) in full-term and pre-term infants: a comprehensive review of accuracy, reproducibility, and practical challenges

Air displacement plethysmography (ADP) has been widely utilised to track body composition because it is considered to be practical, reliable, and valid. Pea Pod is the infant version of ADP that accommodates infants up to the age of 6 months and has been widely utilised to assess the body composition of full-term infants, and more recently pre-term infants. The primary goal of this comprehensive review is to 1) discuss the accuracy/reproducibility of Pea Pod in both full- and pre-term infants, 2) highlight and discuss practical challenges and potential sources of measurement errors in relation to Pea Pod operating principles, and 3) make suggestions for future research direction to overcome the identified limitations.

Impact of Early Infant Growth, Duration of Breastfeeding and Maternal Factors on Total Body Fat Mass and Visceral Fat at 3 and 6 Months of Age

BACKGROUND

Accelerated gain in fat mass in the first months of life is considered to be a risk factor for adult diseases, given the tracking of infancy fat mass into adulthood. Our objective was to assess the influence of early growth, type of feeding and maternal variables on fat mass in early life.

METHODS

In 300 healthy term infants, we longitudinally measured fat mass percentage (FM%) by air-displacement-plethysmography at 1, 3, and 6 months and abdominal visceral and subcutaneous fat measured by ultrasound at 3 and 6 months.

RESULTS

Both gain in FM% and weight-for-length in the first 3 months were positively associated with FM% at 6 months of age and visceral fat at 3 months of age. Gain in FM% and weight-for-length between 3 and 6 months were both positively associated with visceral fat at 6 months. Breastfeeding duration associated positively with subcutaneous fat but not with visceral fat at 3 and 6 months. Maternal characteristics did not associate with FM% or visceral fat at 3 or 6 months.

CONCLUSION

Higher gain in FM% or in weight-for-length in the first postnatal months leads not only to higher FM% but also more to accumulation of visceral fat. Exclusive breastfeeding appears to promote subcutaneous but not visceral fat in the first 6 months.

Longitudinal fat mass and visceral fat during the first 6 months after birth in healthy infants: support for a critical window for adiposity in early life

INTRODUCTION

Body composition in early life influences the development of obesity during childhood and beyond. It is, therefore, important to adequately determine longitudinal body composition during the first months of life.

PATIENTS AND METHODS

In 203 healthy term infants, we investigated longitudinal body composition, including fat mass percentage (FM%) and fat-free mass (FFM), by air-displacement plethysmography, at 1, 3 and 6 months of age and abdominal visceral fat and abdominal subcutaneous fat, by ultrasound, at 3 and 6 months.

RESULTS

We found a significant increase in FM% between 1 and 3 months but not between 3 and 6 months (p < 0.001, p = 0.098, respectively). Girls had higher FM% than boys at 1 and 6 months (p = 0.05, p < 0.001 respectively) and less FFM than boys at 1, 3 and 6 months (p = 0.02, p = 0.02, p < 0.001, respectively). There was a large variation in FM% at all ages even between infants with similar weight standard deviation scores. Visceral fat and abdominal subcutaneous fat did not change between 3 and 6 months. FM% was highly correlated with abdominal subcutaneous fat but not with visceral fat.

CONCLUSION

Changes in FM% occur mainly in the first 3 months of life, and FM%, visceral and abdominal subcutaneous fat do not change between 3 and 6 months, supporting the concept of a critical window for adiposity development in the first three months of life. In addition, our study provides longitudinal reference data of FM%, FFM, visceral fat and abdominal subcutaneous fat during the first 6 months of life.

Associations of maternal obesity and excessive weight gain during pregnancy with subcutaneous fat mass in infancy

BACKGROUND

Not much is known about the associations of maternal obesity and excessive gestational weight gain with body fat in infancy.

OBJECTIVE

To examine the associations of maternal pre-pregnancy body mass index and gestational weight gain with infant subcutaneous fat.

METHODS

In a population-based prospective cohort study among 845 mothers and their infants, we obtained maternal pre-pregnancy body mass index and measured maternal weight during pregnancy. At 1.5, 6 and 24months, we estimated infant total subcutaneous fat (sum of biceps, triceps, suprailiacal and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat).

RESULTS

Maternal body mass index was positively associated with higher infant body mass index from 6months onwards. Maternal body mass index was not associated with infant subcutaneous fat measures at 1.5 or 6months. A 1-standard deviation scores (SDS) higher maternal body mass index was associated with a 0.09 (95% Confidence Interval 0.01, 0.17) SDS higher infant total subcutaneous fat at 24months, but not with central-to-total subcutaneous fat ratio. No associations were present for maternal total or period-specific gestational weight gain with infant fat.

CONCLUSION

Maternal body mass index was positively associated with infant body mass index and total subcutaneous fat in late infancy. Maternal total and period-specific gestational weight gain were not associated with infant body fat mass measures.

The Generation R Study: design and cohort update 2017

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood. This multidisciplinary study focuses on several health outcomes including behaviour and cognition, body composition, eye development, growth, hearing, heart and vascular development, infectious disease and immunity, oral health and facial growth, respiratory health, allergy and skin disorders of children and their parents. Main exposures of interest include environmental, endocrine, genomic (genetic, epigenetic, microbiome), lifestyle related, nutritional and socio-demographic determinants. In total, 9778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. Response at baseline was 61%, and general follow-up rates until the age of 10 years were around 80%. Data collection in children and their parents includes questionnaires, interviews, detailed physical and ultrasound examinations, behavioural observations, lung function, Magnetic Resonance Imaging and biological sampling. Genome and epigenome wide association screens are available. Eventually, results from the Generation R Study contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

The Generation R Study: design and cohort update 2017

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood. This multidisciplinary study focuses on several health outcomes including behaviour and cognition, body composition, eye development, growth, hearing, heart and vascular development, infectious disease and immunity, oral health and facial growth, respiratory health, allergy and skin disorders of children and their parents. Main exposures of interest include environmental, endocrine, genomic (genetic, epigenetic, microbiome), lifestyle related, nutritional and socio-demographic determinants. In total, 9778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. Response at baseline was 61%, and general follow-up rates until the age of 10 years were around 80%. Data collection in children and their parents includes questionnaires, interviews, detailed physical and ultrasound examinations, behavioural observations, lung function, Magnetic Resonance Imaging and biological sampling. Genome and epigenome wide association screens are available. Eventually, results from the Generation R Study contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

Diabetes in pregnancy and infant adiposity: systematic review and meta-analysis

OBJECTIVE

Maternal glycaemia and anthropometry-derived newborn adiposity are strongly correlated. The children of mothers with diabetes are at greater risk of adverse metabolic health, and increased adiposity is a plausible mediator. We undertook a systematic review and meta-analysis to compare adiposity in infants of diabetic mothers (IDM) and infants of mothers without diabetes (NIDM).

DESIGN

We identified observational studies reporting adiposity in IDM and NIDM. We searched references, traced forward citations and contacted authors for additional data. We considered all body composition techniques and compared fat mass, fat-free mass, body fat % and skinfold thickness. We used random effects meta-analyses and performed subgroup analyses by maternal diabetes type (type 1, type 2 and gestational) and infant sex. We examined the influence of pre-pregnancy body mass index (BMI) and conducted sensitivity analyses.

RESULTS

We included data from 35 papers and over 24 000 infants. IDM have greater fat mass than NIDM (mean difference (95% CI)): 83 g (49 to 117). Fat mass is greater in infants of mothers with gestational diabetes: 62 g (29 to 94) and type 1 diabetes: 268 g (139 to 397). Insufficient studies reported data for type 2 diabetes separately. Compared with NIDM, fat mass was greater in IDM boys: 87 g (30 to 145), but not significantly different in IDM girls: 42 g (-33 to 116). There was no attenuation after adjustment for maternal BMI.

CONCLUSIONS

IDM have significantly greater adiposity in comparison with NIDM. These findings are justification for studies to determine whether measures to reduce infant adiposity will improve later health.

Perinatal, sociodemographic and lifestyle correlates of increased total and visceral fat mass levels in schoolchildren in Greece: the Healthy Growth Study

Objective

To identify possibly independent associations of perinatal, sociodemographic and lifestyle factors with childhood total and visceral body fat.

Design

A representative sample of 2655 schoolchildren (9–13 years) participated in the Healthy Growth Study, a cross-sectional epidemiological study.

Setting

Seventy-seven primary schools in four large regions in Greece.

Subjects

A sample of 1228 children having full data on total and visceral fat mass levels, as well as on anthropometric, dietary, physical activity, physical examination, socio-economic and perinatal indices, was examined.

Results

Maternal (OR=3·03 and 1·77) and paternal obesity (OR=1·62 and 1·78), maternal smoking during pregnancy (OR=1·72 and 1·93) and rapid infant weight gain (OR=1·42 and 1·96) were significantly and positively associated with children’s increased total and visceral fat mass levels, respectively. Children’s television watching for >2 h/d (OR=1·40) and maternal pre-pregnancy obesity (OR=2·46) were associated with children’s increased total and visceral fat mass level, respectively. Furthermore, increased children’s physical activity (OR=0·66 and 0·47) were significantly and negatively associated with children’s total and visceral fat mass levels, respectively. Lastly, both father’s age >46 years (OR=0·57) and higher maternal educational level (OR=0·45) were associated with children’s increased total visceral fat mass level.

Conclusions

Parental sociodemographic characteristics, perinatal indices and pre-adolescent lifestyle behaviours were associated with children’s abnormal levels of total and visceral fat mass. Any future programme for childhood prevention either from the perinatal age or at late childhood should take these indices into consideration.

Maternal and Fetal Determinants of Neonatal Body Composition

BACKGROUND

Body composition in early life influences the development of obesity during childhood and beyond. It is, therefore, important to adequately determine neonatal body composition. Fetal growth and maternal factors might influence neonatal fat mass percentage (FM%), independent of birth weight.

METHODS

In 194 healthy neonates, we investigated neonatal body composition, measured by air-displacement plethysmography (PEAPOD), and its associations with estimated fetal weight (EFW), neonatal anthropometric data, maternal preconceptional body mass index (BMI) and maternal weight gain during pregnancy.

RESULTS

There was a large variation in neonatal FM%, even in case of a similar birth weight, corrected for gender and gestational age. Neonatal FM% was associated with EFW at 30 and 36 weeks of gestation and with catch-up in weight between 30 and 36 weeks of gestation, but not with EFW at 20 weeks (p < 0.01, p < 0.01 and p = 0.64, respectively). Neonatal FM% was also associated with preconceptional BMI of the mother (p < 0.01). There was no correlation with maternal weight gain.

CONCLUSION

Our study shows that term neonates have a large variation in FM%. Neonatal FM% is associated with EFW at 30 and 36 weeks, catch-up in weight between 30 and 36 weeks of gestation and preconceptional BMI of the mother.

Associations of Infant Subcutaneous Fat Mass with Total and Abdominal Fat Mass at School-Age: The Generation R Study

BACKGROUND

Skinfold thickness enables the measurement of overall and regional subcutaneous fatness in infancy and may be associated with total and abdominal body fat in later childhood. We examined the associations of subcutaneous fat in infancy with total and abdominal fat at school-age.

METHODS

In a population-based prospective cohort study among 821 children, we calculated total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months. At 6 years, we measured fat mass index (total fat/height(3) ), central-to-total fat ratio (trunk fat/total fat), and android-to-gynoid fat ratio (android fat/gynoid fat) by dual-energy X-ray absorptiometry and preperitoneal fat mass area by abdominal ultrasound.

RESULTS

Central-to-total subcutaneous fat ratio at 1.5 months was positively associated with fat mass index and central-to-total fat ratio at 6 years, whereas both total and central-to-total subcutaneous fat ratio at 24 months were positively associated with all childhood adiposity measures. A 1-standard-deviation scores higher total subcutaneous fat at 24 months was associated with an increased risk of childhood overweight (odds ratio 1.70, 95% confidence interval 1.36, 2.12). These associations were weaker than those for body mass index and stronger among girls than boys.

CONCLUSIONS

Subcutaneous fat in infancy is positively associated with total and abdominal fat at school-age. Our results also suggest that skinfold thicknesses add little value to estimate later body fat, as compared with body mass index.

Maternal plasma n-3 and n-6 polyunsaturated fatty acid concentrations during pregnancy and subcutaneous fat mass in infancy

OBJECTIVE

The associations of maternal plasma n-3 and n-6 polyunsaturated fatty acid (PUFA) concentrations during pregnancy with infant subcutaneous fat were examined.

METHODS

In a population-based prospective cohort study among 904 mothers and their infants, maternal plasma n-3 and n-6 PUFA concentrations were measured at midpregnancy. Body mass index, total subcutaneous fat, and central-to-total subcutaneous fat ratio were calculated at 1.5, 6, and 24 months.

RESULTS

Maternal n-3 PUFA levels were not consistently associated with infant body mass index or total subcutaneous fat. Higher maternal total n-3 PUFA levels, and specifically eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid, were associated with higher central-to-total subcutaneous fat ratio at 1.5 months, whereas higher maternal total n-3 PUFA levels were associated with lower central-to-total subcutaneous fat ratio at 6 months (all P values < 0.05). These associations were not present at 24 months. Maternal n-6 PUFA levels were not consistently associated with infant subcutaneous fat. A higher n-6/n-3 ratio was associated with lower central-to-total subcutaneous fat ratio at 1.5 months only (P value < 0.05).

CONCLUSIONS

Maternal n-3 PUFA levels during pregnancy may have transient effects on infant subcutaneous fat. Further studies are needed to assess the effects of maternal PUFA concentrations on fat mass development during early infancy.

Subcutaneous fat mass in infancy and cardiovascular risk factors at school-age: The generation R study

OBJECTIVE

To examine the associations of infant subcutaneous fat with cardiovascular risk factors at school-age.

METHODS

In a population-based prospective cohort study among 808 children, total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months were estimated. At 6 years, body mass index, blood pressure, cholesterol, triglycerides, and insulin levels were measured.

RESULTS

Infant subcutaneous fat measures were not associated with childhood blood pressure, triglycerides, or insulin levels. A 1-standard-deviation score (SDS) higher total subcutaneous fat at 1.5 months was, independently of body mass index, associated with lower low-density lipoprotein (LDL)-cholesterol levels at 6 years. In contrast, a 1-SDS higher total subcutaneous fat at 24 months was associated with higher total-cholesterol [difference 0.13 (95% confidence interval (CI) 0.03, 0.23) SDS] and LDL-cholesterol levels [difference 0.12 (95% CI 0.02, 0.21) SDS] at 6 years. There were no associations of central-to-total subcutaneous fat ratio with childhood cholesterol levels.

CONCLUSIONS

These results suggest that infant total subcutaneous fat is weakly associated with cholesterol levels at school-age. Further studies are needed to assess the long-term cardiometabolic consequences of infant body fat.

Tracking of abdominal subcutaneous and preperitoneal fat mass during childhood. The Generation R Study

BACKGROUND

Overweight and obesity in early life tends to track into later life. Not much is known about tracking of abdominal fat. Our objective was to examine the extent of tracking of abdominal fat measures during the first six years of life.

DESIGN

We performed a prospective cohort study among 393 Dutch children followed from the age of 2 years (90% range 1.9; 2.3) until the age of 6 years (90% range 5.7; 6.2). At both ages, we performed abdominal ultrasound to measure abdominal subcutaneous and preperitoneal fat distances and areas, and we calculated the preperitoneal/subcutaneous fat distance ratio. High abdominal fat measures were defined as values in the upper 15%.

RESULTS

Abdominal subcutaneous fat distance and area, and preperitoneal fat area at 2 years were correlated with their corresponding measures at 6 years (all P-values <0.01), with the strongest coefficients for abdominal subcutaneous fat measures. Preperitoneal fat distance at the age of 2 years was not correlated with the corresponding measure at 6 years. The tracking coefficient for preperitoneal/subcutaneous fat distance ratio from 2 to 6 years was r=0.36 (P<0.01). Children with high abdominal subcutaneous fat measures at 2 years had increased risk of having high abdominal subcutaneous fat measures at 6 years (odds ratios 9.2 (95% confidence interval (CI) 4.1-20.8) and 12.4 (95% CI 5.4-28.6) for subcutaneous fat distance and area, respectively). These associations were not observed for preperitoneal fat measures.

CONCLUSIONS

Our findings suggest that both abdominal subcutaneous and preperitoneal fat mass measures track during childhood, but with stronger tracking for abdominal subcutaneous fat measures. An adverse abdominal fat distribution in early life may have long-term consequences.

Maternal smoking during pregnancy and childhood overweight and fat distribution: the KOALA Birth Cohort Study

What is already known about this subject There is an association between maternal smoking during pregnancy and higher body mass index (BMI) and overweight in childhood. What this study adds The association between maternal smoking during pregnancy and childhood overweight develops with age, starting with a lower birth weight, followed by weight catch-up in the first year after birth, finally leading to overweight at school age. Children of mothers who had smoked during pregnancy had a higher risk of exceeding the 85th percentile of BMI, waist circumference and total skinfold thickness at school age.

BACKGROUND

Maternal smoking during pregnancy is associated with childhood overweight, but the association with fat distribution is not clear.

OBJECTIVE

To explore the longitudinal association between smoking during pregnancy and childhood overweight and fat distribution.

METHODS

In the KOALA Birth Cohort Study, repeated questionnaires were administered to 2698 mother-child pairs, including questions on smoking at 14 and 34 weeks of pregnancy. Main outcomes were birth weight, weight gain in the first year, body mass index (BMI) z-scores and overweight (BMI ≥85th percentile) at 1, 2, 4-5 and 6-7 years (n = 1730) and waist circumference and four skinfold thicknesses measured at home visits at age 6-7 years in a subgroup (n = 418). We used multivariable linear and logistic regression, with generalized estimating equations (GEE) for repeated measurements.

RESULTS

Maternal smoking was associated with lower birth weight, higher weight gain in the first year and increasing overweight after infancy (change with age P = 0.02 in the GEE). Maternal smoking vs. non-smoking during pregnancy was associated with a higher risk of the child exceeding the 85th percentile of BMI (adjusted odds ratio [aOR] 3.72; 95% CI 1.33-10.4), waist circumference (aOR 2.65; 95% CI 1.06-6.59) and sum of skinfold thicknesses (aOR 4.45; 95% CI 1.63-12.2) at the age of 6-7 years.

CONCLUSIONS

Maternal smoking during pregnancy is associated with lower birth weight, weight catch-up and development of overweight into childhood.

Investigating the relationship between prenatal growth and postnatal outcomes: a systematic review of the literature

Theories regarding the relationship between pre- and postnatal growth and programming of health have been based on characteristics at birth, with little or no reference to the patterns of growth occurring in utero. Review of the literature to identify studies using ultrasonographically obtained fetal dimensions to track prenatal growth and relate these patterns of growth to postnatal anthropometry and cardiovascular and metabolic risk factors. Review of Medline, Scopus and Proquest for studies reporting on ultrasonographically derived estimates of fetal growth and their association with postnatal anthropometry, body composition or cardiovascular and metabolic risk factors. Quality of papers were assessed using the method developed by Downs and Black. Twenty-nine studies met the inclusion criteria, with a mean score of high quality. Twenty of the studies had follow-up in infancy, five in childhood, three in adolescence and one in adulthood. The associations observed suggest that centile tracking may occur early in pregnancy though whether this is as early as the first trimester is uncertain. The second trimester may be a critical period for the programming of blood pressure and abdominal circumference may be the most sensitive fetal dimension to indicate any programming.

Stronger influence of maternal than paternal obesity on infant and early childhood body mass index: the Fels Longitudinal Study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Excessive early childhood adiposity is a prevalent and increasing concern in many parts of the world. Parental obesity is one of the several factors previously associated with infant and early childhood weight, length and adiposity. Parental obesity represents a surrogate marker of the complex interplay among genetic, epigenetic and shared environmental factors, and is potentially modifiable. The relative contributions of maternal and paternal body mass index (BMI) to infant and early childhood growth, as well as the timing of such effects, have not been firmly established.

WHAT THIS STUDY ADDS

Utilizing serial infant measurements and growth curve modelling, this is the largest study to fully characterize and formally compare associations between maternal and paternal BMI and offspring growth across the entire infancy and early childhood period. Maternal obesity is a stronger determinant of offspring BMI than paternal obesity at birth and from 2 to 3 years of age, suggesting that prevention efforts focused particularly on maternal lifestyle and BMI may be important in reducing excess infant BMI. The observation that maternal BMI effects are not constant, but rather present at birth, wane and re-emerge during late infancy, suggests that there is a window of opportunity in early infancy when targeted interventions on children of obese mothers may be most effective.

BACKGROUND/OBJECTIVE

Parental obesity influences infant body size. To fully characterize their relative effects on infant adiposity, associations between maternal and paternal body mass index (BMI) category (normal: ≤25 kg m(-2) , overweight: 25 - <30 kg m(-2) , obese: ≥30 kg m(-2) ) and infant BMI were compared in Fels Longitudinal Study participants.

METHODS

A median of 9 serial weight and length measures from birth to 3.5 years were obtained from 912 European American children born in 1928-2008. Using multivariable mixed effects regression, contributions of maternal vs. paternal BMI status to infant BMI growth curves were evaluated. Cubic spline models also included parental covariates, infant sex, age and birth variables, and interactions with child's age.

RESULTS

Infant BMI curves were significantly different across the three maternal BMI categories (Poverall  < 0.0001), and offspring of obese mothers had greater mean BMI at birth and between 1.5 and 3.5 years than those of over- and normal weight mothers (P ≤ 0.02). Average differences between offspring of obese and normal weight mothers were similar at birth (0.8 kg m(-2) , P = 0.0009) and between 2 and 3.5 years (0.7-0.8 kg m(-2) , P < 0.0001). Infants of obese fathers also had BMI growth curves distinct from those of normal weight fathers (P = 0.02). Infant BMI was more strongly associated with maternal than paternal obesity overall (P < 0.0001); significant differences were observed at birth (1.11 kg m(-2) , P = 0.006) and from 2 to 3 years (0.62 kg m(-2) , P3 years  = 0.02).

CONCLUSION

At birth and in later infancy, maternal BMI has a stronger influence on BMI growth than paternal BMI, suggesting weight control in reproductive age women may be of particular benefit for preventing excess infant BMI.

The Generation R Study: design and cohort update 2012

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health during fetal life, childhood and adulthood. The study focuses on six areas of research: (1) maternal health; (2) growth and physical development; (3) behavioural and cognitive development; (4) respiratory health and allergies; (5) diseases in childhood; and (6) health and healthcare for children and their parents. Main exposures of interest include environmental, endocrine, genetic and epigenetic, lifestyle related, nutritional and socio-demographic determinants. In total, n = 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. Response at baseline was 61 %, and general follow-up rates until the age of 6 years exceed 80 %. Data collection in mothers, fathers and children include questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome and epigenome wide association screen is available in the participating children. From the age of 5 years, regular detailed hands-on assessments are performed in a dedicated research center including advanced imaging facilities such as Magnetic Resonance Imaging. Eventually, results forthcoming from the Generation R Study contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

The Generation R Study: design and cohort update 2010

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health during fetal life, childhood and adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioural and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. General follow-up rates until the age of 4 years exceed 75%. Data collection in mothers, fathers and preschool children included questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome wide association screen is available in the participating children. Regular detailed hands on assessment are performed from the age of 5 years onwards. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

Early growth patterns and long-term obesity risk

PURPOSE OF REVIEW

This review is an update on recent findings regarding early growth patterns and later obesity. These data are important because the potential programming of obesity in early life provides hope for new prevention strategies targeting early growth for long-term benefits.

RECENT FINDINGS

Recent findings regarding the association of childhood or adulthood obesity with fetal growth, gestational weight gain, maternal diabetes, or infancy weight gain are reviewed. Some related outcomes and potential mechanisms are also described. Most studies remain observational and confirm previous findings, but some intervention studies have begun to appear in the recent literature and support some, but not other, observed associations.

SUMMARY

Past and recent findings confirm the association of early growth patterns with obesity. However, causality must be demonstrated and safety must be established before translating these findings into public health recommendations.

Growth in foetal life and infancy is associated with abdominal adiposity at the age of 2 years: the generation R study

OBJECTIVE

Early weight gain is associated with an increased risk of obesity. It is not known whether rapid weight gain in foetal life and infancy is also associated with increased abdominal adiposity. We examined the associations of foetal and postnatal growth characteristics with abdominal fat mass at the age of 2 years.

DESIGN

This study was performed in 481 children participating in a prospective cohort study from early foetal life onward.

MEASUREMENTS

Foetal and postnatal growth characteristics in second and third trimester, at birth and at the age of 2 years were related to abdominal fat mass (subcutaneous distance and area, preperitoneal distance and area) measured by ultrasound at the age of 2 years.

RESULTS

Foetal and birth weight were not associated with abdominal subcutaneous fat mass. Estimated foetal weight in second trimester of pregnancy was inversely associated with preperitoneal fat area [-3.73% (95% confidence interval -7.23, -0.10)] per standard deviation score increase in weight. Weight gain from birth to the age of 2 years was positively associated with preperitoneal fat mass measures. These associations remained significant after adjustment for age, sex, breastfeeding and body mass index. Positive associations were found between catch-up growth in weight and abdominal fat mass measures.

CONCLUSIONS

Our results suggest that rapid growth rates during foetal life and infancy are associated with increased abdominal subcutaneous and preperitoneal fat mass in healthy children. Further studies need to explore whether these associations persist in later life and are related to metabolic syndrome outcomes.

New fetal weight estimation models using fractional limb volume

OBJECTIVES

The main goal of this study was to determine the accuracy and precision of new fetal weight estimation models, based on fractional limb volume and conventional two-dimensional (2D) sonographic measurements during the second and third trimesters of pregnancy.

METHODS

A prospective cross-sectional study of 271 fetuses was performed using three-dimensional ultrasonography to extract standard measurements-biparietal diameter (BPD), abdominal circumference (AC) and femoral diaphysis length (FDL)-plus fractional arm volume (AVol) and fractional thigh volume (TVol) within 4 days of delivery. Weighted multiple linear regression analysis was used to develop 'modified Hadlock' models and new models using transformed predictors that included soft tissue parameters for estimating birth weight. Estimated and observed birth weights were compared using mean percent difference (systematic weight estimation error) and the SD of the percent differences (random weight estimation error). The proportion of newborns with estimated birth weight within 5 or 10% of actual birth weight were compared using McNemar's test.

RESULTS

Birth weights in the study group ranged from 235 to 5790 g, with equal proportions of male and female infants. Six new fetal weight estimation models were compared with the results for modified Hadlock models with sample-specific coefficients. All the new models were very accurate, with mean percent differences that were not significantly different from zero. Model 3 (which used the natural logarithms of BPD, AC and AVol) and Model 6 (which used the natural logarithms of BPD, AC and TVol) provided the most precise weight estimations (random error = 6.6% of actual birth weight) as compared with 8.5% for the best original Hadlock model and 7.6% for a modified Hadlock model using sample-specific coefficients. Model 5 (which used the natural logarithms of AC and TVol) classified an additional 9.1% and 8.3% of the fetuses within 5% and 10% of actual birth weight and Model 6 classified an additional 7.3% and 4.1% of infants within 5% and 10% of actual birth weight.

CONCLUSION

The precision of fetal weight estimation can be improved by adding fractional limb volume measurements to conventional 2D biometry. New models that consider fractional limb volume may offer novel insight into the contribution of soft tissue development to weight estimation.