Anthropometric measurements for neonates, 23 to 29 weeks gestation, in the 1990s

Exposure of preterm neonates receiving total parenteral nutrition to phthalates and its impact on neurodevelopment at the age of 2 months

This prospective study assessed the exposure to phthalates of preterm neonates who received total parenteral nutrition (TPN) during their stay in the neonatal intensive care unit (NICU) and the risk of neurodevelopment delays at the age of 2 months. Our study recruited 33 preterm neonates who required TPN upon NICU admission. Urine samples for analyzing phthalate metabolites were obtained at admission and then daily until the last day of receiving TPN. Phthalates in the daily TPN received by the preterm neonates were analyzed. The neurodevelopment of the neonates was assessed using the Ages and Stages Questionnaire Edition 3 (ASQ-3). Diethyl phthalate and butyl benzyl phthalate were found in all TPN samples, while 27% and 83% contained dibutyl phthalate and di-(2-ethylhexyl) phthalate (DEHP), respectively. Yet, the daily dose of each phthalate that our preterm neonates received from TPN was much lower than the recommended tolerable limit. Urinary levels of monobenzyl phthalate and four metabolites of DEHP [i.e., mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP)] and the sum of four DEHP metabolites (∑₄DEHP) increased significantly in preterm neonates before discharge. However, these levels were not correlated with their phthalate parent compounds in TPN, suggesting other sources of exposure in the NICU. At 2 months, we found that urinary levels of mono-iso-butyl phthalate (MiBP), MECPP, MEHP, and ∑₄DEHP were inversely related to fine motor skills. After adjusting for head circumference, the inverse relationships remained significant, suggesting direct effects from phthalates. Given the extreme vulnerability of our population, it is critical to minimize exposure to phthalates during their NICU stay.

A systematic review and meta-analysis to revise the Fenton growth chart for preterm infants

Background

The aim of this study was to revise the 2003 Fenton Preterm Growth Chart, specifically to: a) harmonize the preterm growth chart with the new World Health Organization (WHO) Growth Standard, b) smooth the data between the preterm and WHO estimates, informed by the Preterm Multicentre Growth (PreM Growth) study while maintaining data integrity from 22 to 36 and at 50 weeks, and to c) re-scale the chart x-axis to actual age (rather than completed weeks) to support growth monitoring.

Methods

Systematic review, meta-analysis, and growth chart development. We systematically searched published and unpublished literature to find population-based preterm size at birth measurement (weight, length, and/or head circumference) references, from developed countries with: Corrected gestational ages through infant assessment and/or statistical correction; Data percentiles as low as 24 weeks gestational age or lower; Sample with greater than 500 infants less than 30 weeks. Growth curves for males and females were produced using cubic splines to 50 weeks post menstrual age. LMS parameters (skew, median, and standard deviation) were calculated.

Results

Six large population-based surveys of size at preterm birth representing 3,986,456 births (34,639 births < 30 weeks) from countries Germany, United States, Italy, Australia, Scotland, and Canada were combined in meta-analyses. Smooth growth chart curves were developed, while ensuring close agreement with the data between 24 and 36 weeks and at 50 weeks.

Conclusions

The revised sex-specific actual-age growth charts are based on the recommended growth goal for preterm infants, the fetus, followed by the term infant. These preterm growth charts, with the disjunction between these datasets smoothing informed by the international PreM Growth study, may support an improved transition of preterm infant growth monitoring to the WHO growth charts.

New reference curves for head circumference at birth, by gestational age

BACKGROUND

The measurement of head circumference (HC) at birth reflects intrauterine brain development. HC charts currently used in Canada are either dated, mixed-gender, nonrepresentative of lower gestational ages (GAs), or reflective of other populations.

METHODS

To create both birth weight and HC curves, we combined weight and HC data from the Canadian Neonatal Network (CNN) database (admissions in NICUs across Canada) with McGill's Obstetrical Neonatal Database (MOND; all births at a tertiary hospital in Montreal, Canada). We included CNN data for GAs of 23 to 34 weeks (2003-2007) and MOND data for GAs of 35 to 41 weeks (1995-2006). Nonsingletons, congenital anomalies, and measurements greater than ±4 SD from the mean were excluded. Distributions of birth weight and HC at each GA were statistically (penalized spline regression) smoothed. Birth weight curves were compared with recent Canadian reference curves and HC curves with historical and/or frequently used curves.

RESULTS

We included 39,896 births (3121 births at <30 weeks' GA) to generate the curves. Current weight curves were similar to Canadian reference charts for both genders. Weight and HC measurements in boys were higher than in girls. When classified according to recent international references, the proportion of CNN-MOND infants at ≥32 weeks' GA with HCs <10th percentile was significantly underestimated. When classified according to historical reference curves, a significant number of CNN-MOND infants of all GAs with HCs <10th and >90th percentiles were misclassified.

CONCLUSIONS

We developed recent gender-specific reference curves for HC at birth for singletons at 23 to 41 completed weeks' GA, which included a large number of very premature infants, reflecting the current geotemporal Canadian population.

New intrauterine growth curves based on United States data

OBJECTIVE

The objective of this study was to create and validate new intrauterine weight, length, and head circumference growth curves using a contemporary, large, racially diverse US sample and compare with the Lubchenco curves.

METHODS

Data on 391 681 infants (Pediatrix Medical Group) aged 22 to 42 weeks at birth from 248 hospitals within 33 US states (1998-2006) for birth weight, length, head circumference, estimated gestational age, gender, and race were used. Separate subsamples were used to create and validate curves. Smoothed percentile curves (3rd to 97th) were created by the Lambda Mu Sigma (LMS) method. The validation sample was used to confirm representativeness of the curves. The new curves were compared with the Lubchenco curves.

RESULTS

Final sample included 257 855 singleton infants (57.2% male) who survived to discharge. Gender-specific weight-, length-, and head circumference-for-age curves were created (n = 130 111) and successfully validated (n = 127 744). Small-for-gestational age and large-for-gestational age classifications using the Lubchenco curves differed significantly from the new curves for each gestational age (all P < .0001). The Lubchenco curves underestimated the percentage of infants who were small-for-gestational-age except for younger girls (< or =36 weeks), for whom it was more likely to be overestimated; underestimated percentage of infants (< or =36 weeks) who were large-for-gestational-age; and overestimated percentage of infants (>36 weeks) who were large-for-gestational-age.

CONCLUSIONS

The Lubchenco curves may not represent the current US population. The new intrauterine growth curves created and validated in this study, based on a contemporary, large, racially diverse US sample, provide clinicians with an updated tool for growth assessment in US NICUs. Research into the ability of the new definitions of small-for-gestational-age and large-for-gestational-age to identify high-risk infants in terms of short-term and long-term health outcomes is needed.

Resting heart rate does not predict growth in preterm infants

BACKGROUND

Previous reports indicate that preterm infants with higher baseline heart rate (HR) have greater weight gain than preterm infants with lower baseline HR. To verify this correlation and the potential utility of resting HR as a bench mark for risk of extrauterine growth restriction (EUGR), we studied preterm infants born between 32 and 36weeks gestation. Earlier gestation infants (27 to 31weeks) were included.

METHODS

In retrospective chart review we collected heart rate (HR) and growth data on 156 infants between 27.0 and 34.0weeks gestation from birth to hospital discharge.

RESULTS

There was a significant increase in weight gain from day 10 of life in infants with higher resting HR compared to infants with lower resting HR. However, upon controlling for birth weight and gestational age, there was no significant relationship between HR and weight gain for any gestational age group of premature infants.

CONCLUSIONS

Contrary to previous reports, there was no significant relationship between HR and growth at any gestational age after controlling for birth weight and gestational age. It is important to continue to search for a clinical marker of risk for poor growth in preterm infants and to give an opportunity for nutritional interventions which may support better growth and developmental outcomes.

Relationship between maternal and newborn anthropometric measurements in Sudan

BACKGROUND

The aim of the present study was to investigate the relationship between maternal and newborn anthropometry.

METHODS

In 1000 Sudanese mothers and newborns anthropometric measurements were taken within 24 h of birth. The relationship between maternal characteristics including age, years of education, social class and anthropometry, and newborn characteristics including gestational age, weight, body length, body circumference and skin-fold thickness, was investigated on multiple regression with backward selection, and multivariate anova (where appropriate) to identify the most important associations.

RESULTS

Maternal age and anthropometry were significantly associated with newborn anthropometry to a variable extent. The strongest associations (R2 > 5-6%) were found for mid-arm circumference, supine length and birthweight. The postpartum maternal lean body mass (LBM) was significantly associated with birthweight, body length and body circumference (P < 0.001), while skin-fold thickness was mainly associated with maternal age and maternal body mass index (BMI). Gestational age was only weakly associated with the maternal height (R2 > 1.3%) and the association between maternal anthropometry and the ponderal index (PI) of the newborn was negligible (R2 < 1%). Maternal education was significantly associated with birthweight and body circumference (except the abdominal), and the PI and the latter increased significantly with increasing number of years of education. No association between social class and newborn anthropometry was obtained.

CONCLUSION

There was a significant association between maternal LBM and newborn size and between maternal BMI and newborn fat stores. Maternal education and not social class was associated with newborn size.

Spanish growth studies 2008. New anthropometric standards

Cross-sectional and longitudinal growth studies have recently been conducted in Spain. These studies have allowed neonatal anthropometry in premature and term neonates and postnatal growth in children and adolescents to be evaluated. Moreover, a longitudinal study that allows pubertal growth to be evaluated for distinct groups according to maturation has also been published. Between 1999 and 2002, birth weight and vertex-heel length were evaluated in 9,362 newborns (4,884 boys and 4,478 girls), with a gestational age of 26-42 weeks. An increase in these values compared with previous Spanish studies (1987-1992) and sexual dimorphism were observed. Between 2000 and 2004, height, weight and body mass index (BMI) were evaluated in 32,064 individuals (16,607 males, 15,457 females) aged 0-24 years. An increasing secular trend was observed compared with data obtained 20 years previously. Increases in BMI exceeded those in height for BMI values above the 50th percentile. A longitudinal growth study of 458 healthy individuals (223 boys, 235 girls) born between 1978 and 1982 yielded pubertal growth and maturity standards for each of the five pubertal maturity groups. In addition, data on skinfolds, bone mass and intellectual development from birth to adulthood were also provided. Adult height in both studies was similar to that reported by European and American studies, but was lower than that reported for German, Swedish and Dutch populations. In males, BMI was higher than in other European populations and was close to that of the US population. In females, BMI was similar to that in European populations and was lower than that in the US population.

Growth curves for preterm infants

The commonly used growth curves for preterm infants are four decades old and may not be suitable for the current population. Uncertainty exists regarding the most suitable curves for monitoring the growth of preterm infants. While intrauterine growth rate appears to be the ideal growth that needs to be attained by the preterm infants, it may not be feasible given the limitations set by the morbidities of prematurity. Babson and Benda's chart has been updated using recent data from large samples of preterm infants making it useful for monitoring growth of infants in the preterm period. Once a corrected age of 40 weeks is reached, the recently released WHO growth curves can be used to monitor their ongoing growth. While aiming for achieving intrauterine growth velocities in postnatal life, one should not lose sight of the potential short term adverse effects of aggressive nutrition and long term adverse effects of excessive catch up growth.

Anthropometric and laboratory assessment of very low birth weight infants: the most helpful measurements and why

Very low birth weight (VLBW; < or =1500 g), preterm infants have numerous physiological and developmental concerns, including growth and the provision of adequate nutrients to sustain growth. Growth is an important health care outcome measure for VLBW infants. Provision of energy and nutrients at levels to support growth and development is the goal of nutrition support for VLBW infants. Anthropometry and laboratory data are useful components of growth and nutrition assessment. The objectives of this paper are to describe: 1) the clinical application and interpretation of anthropometric measures of growth, and 2) the utilization and interpretation of laboratory tests of nutritional status in VLBW infants.

Neonatology fellowship training in research pertaining to development and follow-up

The methodology of the study of the short- and long-term outcomes has changed over the 30-40 years since the indroduction of neonatal intensive care. The training of neonatal fellows in research pertaining to development and follow-up currently needs to include study of epidemiology and biostatistics, knowledge concerning normal and abnormal growth and development throughout the life span and clinical skills and/or knowledge concerning the assessment of neurologic and developmental outcomes.