Anthropometric standardisation and quality control protocols for the construction of new, international, fetal and newborn growth standards: the INTERGROWTH-21st Project

Etiologically Based Functional Taxonomy of the Preterm Birth Syndrome

Preterm birth (PTB) is a complex syndrome traditionally defined by a single parameter, namely, gestational age at birth (ie, ˂37 weeks). This approach has limitations for clinical usefulness and may explain the lack of progress in identifying cause-specific effective interventions. The authors offer a framework for a functional taxonomy of PTB based on (1) conceptual principles established a priori; (2) known etiologic factors; (3) specific, prospectively identified obstetric and neonatal clinical phenotypes; and (4) postnatal follow-up of growth and development up to 2 years of age. This taxonomy includes maternal, placental, and fetal conditions routinely recorded in data collection systems.

Serial head circumference measurements should be used to classify congenital microcephaly

BACKGROUND

Measuring the maximum occipitofrontal circumference only once at birth or within 24 h after birth may lead to misclassifications of microcephaly. This study compared the head circumference (HC) of newborns at birth or within 24 h after birth to their third day of life (DOL3) as well as evaluated maternal- and infant-specific factors associated with increased HC by DOL3.

METHODS

This prospective study included 1131 live births between February and May 2019 with a gestational age > 27 weeks. All newborns had their HC measured at birth or within 24 h after birth as well as on DOL3 before discharge. HC measurements were performed by trained personnel using non-elastic tape measures. The World Health Organization (WHO) and Fenton Growth Charts were used as reference ranges for interpretation of full-term and preterm neonates, respectively.

RESULTS

Paired sample t-test analyses found a statistically significant increase in HC measured on the DOL3 compared with HCs of the same newborns at birth or within 24 h of birth. The mean HC increase was 0.17 cm (95% confidence interval [0.13, 0.21], P < 0.001). The mean ± standard deviation HC within 24 h of birth and at DOL3 were 33.58 ± 1.53 cm and 33.75 ± 1.37 cm, respectively. Thirty-two newborns had HCs less than the third percentile (< P3) at birth, 25 of which had HC ≥ P3 at DOL3. After adjusting for mode of and presentation at delivery, newborns whose mothers experienced labor pains (β = 0.31, P < 0.001) and were either symmetrically (β = 0.59, P = 0.002) or asymmetrically small-for-gestational age (SGA; β = 0.37, P = 0.03) had significantly increased HC at DOL3. On average, newborns whose mothers experienced labor pain had 0.31 cm increases in HC at DOL3. Symmetrical SGA newborns also had an average 0.59 cm increase in HC at DOL3. Parity and gestational age were not associated with changes in HC.

CONCLUSIONS

Serial HC measurements on DOL3 or before newborns' discharge is crucial to classifying congenital microcephaly.

Effects of Early versus Standard Central Line Removal on the Growth of Preterm Infants with Very Low Birth Weight: A Non-Inferiority, Randomized Clinical Trial

Very preterm infants are usually supported by parenteral nutrition delivered through central lines (CLs) while progressing with enteral intake, although the optimal time point for their removal is unclear. This study evaluated the impact of the CL discontinuation time on the short-term growth outcomes of preterm infants. A non-inferiority, parallel-group, randomized controlled trial was conducted in four neonatal intensive care units in Poland. Preterm infants with very low birth weight (VLBW) without congenital abnormalities were eligible. Patients were allocated to discontinue central access at an enteral feeding volume of 100 mL/kg/day (intervention group) or 140 mL/kg/day (control group). The study's primary outcome was weight at 36 weeks' postmenstrual age, with a non-inferiority margin of -210 g. Overall, 211 patients were allocated to the intervention or control groups between January 2019 and February 2021, of which 101 and 100 were eligible for intention-to-treat analysis, respectively. The mean weight was 2232 g and 2200 g at 36 weeks' postmenstrual age in the intervention and control groups, respectively. The mean between-group difference was 32 g (95% confidence interval, -68 to 132; p = 0.531), which did not cross the specified margin of non-inferiority. No intervention-related adverse events were observed. Early CL removal was non-inferior to the standard type for short-term growth outcomes in VLBW infants.

The First United Arab Emirates National Representative Birth Cohort Study: Study Protocol

BACKGROUND

In recent years, the prevalence of non-communicable diseases (NCDs) has escalated. Evidence suggests that there are strong associations between nutrition in early life and the risk of disease in adulthood. This manuscript describes the study protocol of the First United Arab Emirates National Representative Birth Cohort Study (UAE-BCS), with the objective of investigating nutrition and lifestyle factors in the first 1,000 days of life. The main aims of the study are (1) to address critical issues relating to mother and child nutrition and their effect on growth and development, (2) to profile maternal nutrition, child growth, health, and development outcomes in early life, and (3) to study the associations between these factors among the Emirati population in the UAE.

METHODS/DESIGN

In this study, a multidisciplinary team of researchers was established including credible researchers from the UAE, Lebanon, Australia, and the United Kingdom to launch the First United Arab Emirates 3-year birth cohort study. We aim to recruit 260 pregnant Emirati women within their first trimester, which is defined by the study as from 8 to 12 weeks pregnant, from obstetrics and gynecology clinics in the UAE. Participants will be recruited via face-to-face interviews and will receive a total of 11 visits with 1 visit in each trimester of pregnancy and 8 visits after delivery. Maternal data collection includes, socio-demographic and lifestyle factors, dietary intake, anthropometric measurements, physical activity, maternal psychological state, and blood samples for biochemical analysis. Post-partum, visits will take place when the child is 0.5, 4, 6, 9, 12, 18, and 24 months old, with data collection including infant anthropometric measurements, young child feeding practices, dietary intake, supplement use and the eating environment at home, as well as all maternal data collection described above, apart from blood samples. Additional data collection for the child includes early child developmental assessments taking place at three timepoints: (1) within 2 weeks of birth, (2) at 10-14 months and (3) at 22-26 months of age. Early child developmental assessments for the infant include vision, hearing, cognition, motor skills, social-emotional reactivity, neurodevelopmental, and sleep assessments.

DISCUSSION

The United Arab Emirates Birth Cohort study protocol provides a standardized model of data collection methods for collaboration among the multisectoral teams within the United Arab Emirates to enrich the quality and research efficiency in early nutrition, thereby enhancing the health of mothers, infants, and children.

Anthropometric and Physiologic Parameters in Cleft Neonates: A Hospital-Based Study

The oro-facial morphology is greatly affected in neonates with a cleft lip and palate. The initial evaluation of neonate's body and maxillary arch dimensions is important for treatment planning and predicting growth in cleft patients. The objective of this study was comparative evaluation of the anthropometric and physiologic parameters of cleft and non-cleft neonates in a hospital-based set up. This cross sectional study was conducted on 88 cleft and non-cleft neonates (n = 44 in each group) aged between 0 and 30 days after obtaining approval from the institutional ethics committee and positive written informed consent from their parents. Neonates' body weight, body length, head length, head circumference, and maxillary arch dimensions were measured. Maxillary arch dimensions were measured on dental casts with digital sliding calipers. Statistical analyses performed using the independent t-test and one-way ANOVA analysis were followed by Bonferroni correction for post-hoc comparison. The results showed statistically significant differences in birth weight (p < 0.0001), head length (p < 0.01), head circumference (p < 0.007), and maxillary arch dimensions (p < 0.0001) between cleft and non-cleft neonates. These findings suggest that cleft neonates had significant anthropometric and physiologic variations than non-cleft neonates.

Association Between Preterm-Birth Phenotypes and Differential Morbidity, Growth, and Neurodevelopment at Age 2 Years: Results From the INTERBIO-21st Newborn Study

IMPORTANCE

The etiologic complexities of preterm birth remain inadequately understood, which may impede the development of better preventative and treatment measures.

OBJECTIVE

To examine the association between specific preterm-birth phenotypes and clinical, growth, and neurodevelopmental differences among preterm newborns compared with term newborns up to age 2 years.

DESIGN, SETTING, AND PARTICIPANTS

The INTERBIO-21st study included a cohort of preterm and term newborn singletons enrolled between March 2012 and June 2018 from maternity hospitals in 6 countries worldwide who were followed up from birth to age 2 years. All pregnancies were dated by ultrasonography. Data were analyzed from November 2019 to October 2020.

EXPOSURES/INTERVENTIONS

Preterm-birth phenotypes.

MAIN OUTCOMES AND MEASURES

Infant size, health, nutrition, and World Health Organization motor development milestones assessed at ages 1 and 2 years; neurodevelopment evaluated at age 2 years using the INTERGROWTH-21st Neurodevelopment Assessment (INTER-NDA) tool.

RESULTS

A total of 6529 infants (3312 boys [50.7%]) were included in the analysis. Of those, 1381 were preterm births (mean [SD] gestational age at birth, 34.4 [0.1] weeks; 5148 were term births (mean [SD] gestational age at birth, 39.4 [0] weeks). Among 1381 preterm newborns, 8 phenotypes were identified: no main maternal, fetal, or placental condition detected (485 infants [35.1%]); infections (289 infants [20.9%]); preeclampsia (162 infants [11.7%]); fetal distress (131 infants [9.5%]); intrauterine growth restriction (110 infants [8.0%]); severe maternal disease (85 infants [6.2%]); bleeding (71 infants [5.1%]); and congenital anomaly (48 infants [3.5%]). For all phenotypes, a previous preterm birth was a risk factor for recurrence. Each phenotype displayed differences in neonatal morbidity and infant outcomes. For example, infants with the no main condition detected phenotype had low neonatal morbidity but increased morbidity and hospitalization incidence at age 1 year (odds ratio [OR], 2.2; 95% CI, 1.8-2.7). Compared with term newborns, the highest risk of scoring lower than the 10th centile of INTER-NDA normative values was observed in the fine motor development domain among newborns with the fetal distress (OR, 10.6; 95% CI, 5.1-22.2) phenotype.

CONCLUSIONS AND RELEVANCE

Results of this study suggest that phenotypic classification may provide a better understanding of the etiologic factors and mechanisms associated with preterm birth than continuing to consider it an exclusively time-based entity.

Fetal cranial growth trajectories are associated with growth and neurodevelopment at 2 years of age: INTERBIO-21st Fetal Study

Many observational studies and some randomized trials demonstrate how fetal growth can be influenced by environmental insults (for example, maternal infections)¹ and preventive interventions (for example, multiple-micronutrient supplementation)² that can have a long-lasting effect on health, growth, neurodevelopment and even educational attainment and income in adulthood³. In a cohort of pregnant women (n = 3,598), followed-up between 2012 and 2019 at six sites worldwide⁴, we studied the associations between ultrasound-derived fetal cranial growth trajectories, measured longitudinally from <14 weeks' gestation, against international standards^5,6, and growth and neurodevelopment up to 2 years of age^7,8. We identified five trajectories associated with specific neurodevelopmental, behavioral, visual and growth outcomes, independent of fetal abdominal growth, postnatal morbidity and anthropometric measures at birth and age 2. The trajectories, which changed within a 20-25-week gestational age window, were associated with brain development at 2 years of age according to a mirror (positive/negative) pattern, mostly focused on maturation of cognitive, language and visual skills. Further research should explore the potential for preventive interventions in pregnancy to improve infant neurodevelopmental outcomes before the critical window of opportunity that precedes the divergence of growth at 20-25 weeks' gestation.

Measurement of Head Circumference: Implications for Microcephaly Surveillance in Zika-Affected Areas

Worldwide recognition of the Zika virus outbreak in the Americas was triggered by an unexplained increase in the frequency of microcephaly. While severe microcephaly is readily identifiable at birth, diagnosing less severe cases requires comparison of head circumference (HC) measurement to a growth chart. We examine measured values of HC and digit preference in those values, and, by extension, the prevalence of microcephaly at birth in two data sources: a research study in Honduras and routine surveillance data in Uruguay. The Zika in Pregnancy in Honduras study enrolled pregnant women prenatally and followed them until delivery. Head circumference was measured with insertion tapes (SECA 212), and instructions including consistent placement of the tape and a request to record HC to the millimeter were posted where newborns were examined. Three indicators of microcephaly were calculated: (1) HC more than 2 standard deviations (SD) below the mean, (2) HC more than 3 SD below the mean (referred to as “severe microcephaly”) and (3) HC less than the 3rd percentile for sex and gestational age, using the INTERGROWTH-21st growth standards. We compared these results from those from a previous analysis of surveillance HC data from the Uruguay Perinatal Information System (Sistema Informático Perinatal (SIP). Valid data on HC were available on 579 infants, 578 with gestational age data. Nine babies (1.56%, 95% CI 0.71–2.93) had HC < 2SD, including two (0.35%, 95% CI 0.04–1.24) with HC < 3SD, and 11 (1.9%, 95% CI, 0.79–3.02) were below the 3rd percentile. The distribution of HC showed strong digit preference: 72% of measures were to the whole centimeter (cm) and 19% to the half-cm. Training and use of insertion tapes had little effect on digit preference, nor were overall HC curves sufficient to detect an increase in microcephaly during the Zika epidemic in Honduras. When microcephaly prevalence needs to be carefully analyzed, such as during the Zika epidemic, researchers may need to interpret HC data with caution.

Changing trends of anaemia prevalence among female medical students in a metropolitan setting: Assessment through self-grading and haematological parameters

Objective:

To determine the trend of anaemia prevalence among female medical students (FMS) through self-grading along haematological parameters and its association with their nutritional indicators.

Methods:

This cross-sectional study was conducted at a public sector health university of Karachi among FMS from April to September 2016. After written informed consent, 216 FMS were assessed for height and weight, for nutrition habits by calculating minimum dietary diversity for women (MDD-W) and anaemia status by self-administered validated self-grading anaemia assessment questionnaire (SGAAQ). The haematological parameters were examined in venous blood sample on Sysmex (XN-3000). The data was analysed using IBM SPSS software version 24. Association between anaemia and nutritional indicators was determined by Chi-square and considered significant when p < 0.05.

Results:

Anaemia prevalence was 31% with highest frequency among obese (56%) and 29% FMS achieved MDD-W. The mean SGAAQ score, Hb (g/dl), MCV (fl), MCH (pg) and Ret-He (pg) differed significantly (p = <0.001) between anaemic and non-anaemic students. The mean Hb (g/dl) level was significantly higher for FMS who scored MDD-W >5 (p= 0.04).

Conclusion:

Malnutrition and anaemia co-exist despite appropriate awareness of anaemia among FMS. It was associated with self-assessment of anaemia and BMI groups but not with dietary diversity in the present study.

Does "Sitting" Stand Alone? A Brief Report Evaluating the Effects of Prenatal Sedentary Time on Maternal and Newborn Anthropometric Outcomes

BACKGROUND

Research on sedentary behavior and effects on maternal and newborn outcomes has been inconclusive. The objective of this report was to correlate sedentary time with maternal and fetal anthropometric measurements and compare the effect on sedentary time based on meeting prenatal activity guidelines.

METHODS

Healthy pregnant women (N = 61) in their second trimester (24-28 wk gestation) provided 7-day accelerometry data. Outcomes, including neonatal weight, length, and body fat percentage, were collected 24 to 48 hours after delivery. Placenta weight was measured immediately after delivery. Gestational weight gain was calculated by subtracting self-reported prepregnancy weight from measured weight at 38 weeks gestation. Correlations between sedentary time and outcomes were tested with Spearman and Pearson coefficient of correlations in all women separately and in accordance with the 2019 Canadian prenatal exercise guidelines.

RESULTS

No significant associations were found between sedentary time and the selected outcomes, even when compared by prenatal exercise level. There was no difference in total time spent sedentary between active (576.7 [52.8] min) and inactive women (599.3 [51.6] min).

CONCLUSIONS

Meeting exercise recommendations during pregnancy does not significantly decrease total sedentary time. Future studies should aim to evaluate the health effects of both decreasing sedentary time and meeting prenatal exercise guidelines.

Head circumference at birth and school performance: a nationwide cohort study of 536,921 children

BACKGROUND

Early measures of cognitive function are of great public health interest. We aimed to estimate the association between head circumference at birth, a measure of cerebral size, and school performance.

METHODS

We conducted a nationwide cohort study of all liveborn singletons in Denmark, 1997-2005. The association between birth head circumference z score and test scores in reading and mathematics from a nationwide mandatory computer-based school test program (7-16 years) was estimated by multivariable linear regression adjusted for potential confounders.

RESULTS

The cohort included 536,921 children. Compared to normocephalic children, children with microcephaly [<-2 standard deviations (SD)] had lower mean reading scores: second grade: -0.08 SD (95% CI -0.10 to -0.06), eighth grade: -0.07 SD (95% CI -0.10 to -0.04). Macrocephaly (>+2 SD) was associated with higher scores. In normocephalic children, each SD increase in head circumference was associated with a 0.03 SD (95% CI 0.03 to 0.04) increase in mean reading scores. The results were similar across grades within both reading and mathematics.

CONCLUSION

Prenatal brain growth may be causally related to childhood school performance. The demonstrated differences are unlikely to be clinically relevant at the individual level but may be important at a public health level.

Prediction of adverse perinatal outcome by fetal biometry: comparison of customized and population-based standards

OBJECTIVE

To compare the predictive performance of estimated fetal weight (EFW) percentiles, according to eight growth standards, to detect fetuses at risk for adverse perinatal outcome.

METHODS

This was a retrospective cohort study of 3437 African-American women. Population-based (Hadlock, INTERGROWTH-21^st , World Health Organization (WHO), Fetal Medicine Foundation (FMF)), ethnicity-specific (Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)), customized (Gestation-Related Optimal Weight (GROW)) and African-American customized (Perinatology Research Branch (PRB)/NICHD) growth standards were used to calculate EFW percentiles from the last available scan prior to delivery. Prediction performance indices and relative risk (RR) were calculated for EFW < 10^th and > 90^th percentiles, according to each standard, for individual and composite adverse perinatal outcomes. Sensitivity at a fixed (10%) false-positive rate (FPR) and partial (FPR < 10%) and full areas under the receiver-operating-characteristics curves (AUC) were compared between the standards.

RESULTS

Ten percent (341/3437) of neonates were classified as small-for-gestational age (SGA) at birth, and of these 16.4% (56/341) had at least one adverse perinatal outcome. SGA neonates had a 1.5-fold increased risk of any adverse perinatal outcome (P < 0.05). The screen-positive rate of EFW < 10^th percentile varied from 6.8% (NICHD) to 24.4% (FMF). EFW < 10^th percentile, according to all standards, was associated with an increased risk for each of the adverse perinatal outcomes considered (P < 0.05 for all). The highest RRs associated with EFW < 10^th percentile for each adverse outcome were 5.1 (95% CI, 2.1-12.3) for perinatal mortality (WHO); 5.0 (95% CI, 3.2-7.8) for perinatal hypoglycemia (NICHD); 3.4 (95% CI, 2.4-4.7) for mechanical ventilation (NICHD); 2.9 (95% CI, 1.8-4.6) for 5-min Apgar score < 7 (GROW); 2.7 (95% CI, 2.0-3.6) for neonatal intensive care unit (NICU) admission (NICHD); and 2.5 (95% CI, 1.9-3.1) for composite adverse perinatal outcome (NICHD). Although the RR CIs overlapped among all standards for each individual outcome, the RR of composite adverse perinatal outcome in pregnancies with EFW < 10^th percentile was higher according to the NICHD (2.46; 95% CI, 1.9-3.1) than the FMF (1.47; 95% CI, 1.2-1.8) standard. The sensitivity for composite adverse perinatal outcome varied substantially between standards, ranging from 15% for NICHD to 32% for FMF, due mostly to differences in FPR; this variation subsided when the FPR was set to the same value (10%). Analysis of AUC revealed significantly better performance for the prediction of perinatal mortality by the PRB/NICHD standard (AUC = 0.70) compared with the Hadlock (AUC = 0.66) and FMF (AUC = 0.64) standards. Evaluation of partial AUC (FPR < 10%) demonstrated that the INTERGROWTH-21^st standard performed better than the Hadlock standard for the prediction of NICU admission and mechanical ventilation (P < 0.05 for both). Although fetuses with EFW > 90^th percentile were also at risk for any adverse perinatal outcome according to the INTERGROWTH-21^st (RR = 1.4; 95% CI, 1.0-1.9) and Hadlock (RR = 1.7; 95% CI, 1.1-2.6) standards, many times fewer cases (2-5-fold lower sensitivity) were detected by using EFW > 90^th percentile, rather than EFW < 10^th percentile, in screening by these standards.

CONCLUSIONS

Fetuses with EFW < 10^th percentile or EFW > 90^th percentile were at increased risk of adverse perinatal outcomes according to all or some of the eight growth standards, respectively. The RR of a composite adverse perinatal outcome in pregnancies with EFW < 10^th percentile was higher for the most-stringent (NICHD) compared with the least-stringent (FMF) standard. The results of the complementary analysis of AUC suggest slightly improved detection of adverse perinatal outcome by more recent population-based (INTERGROWTH-21^st ) and customized (PRB/NICHD) standards compared with the Hadlock and FMF standards. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

Effect of early versus standard central line removal on growth of very low birthweight premature infants: a protocol for a non-inferiority randomised controlled trial

INTRODUCTION

Uncertainty exists regarding the optimal time for removal of central lines used to provide parenteral nutrition in preterm infants. The aim of this study is to determine whether earlier central line removal is non-inferior to its removal after reaching full enteral intake, in respect to growth outcome of preterm infants.

METHODS AND ANALYSIS

Very low birthweight premature infants will be recruited. Eligible infants will be randomised in equal proportions between two groups. In the intervention group central lines will be removed when infants reach 100 mL/kg/day of enteral intake. In the control group central lines will be removed when infants reach 140 mL/kg/day of enteral intake (full enteral intake). The primary outcome measure will be the difference between the two groups in weight at 36 weeks' postmenstrual age. Non-inferiority will be declared if the mean weight of children in the intervention group will be no worse than the mean weight of children from the control group, by a margin of -210 g.

ETHICS AND DISSEMINATION

The Bioethics Committee of the Medical University of Warsaw approved the study protocol prior to recruitment. The findings of this trial will be submitted to a peer-reviewed journal (neonatology, paediatrics or nutrition). Abstracts will be submitted to relevant national and international conferences.

TRIAL REGISTRATION NUMBER

NCT03730883.

PROTOCOL VERSION

Version 3. 14.08.2019.

Deep clinical and biological phenotyping of the preterm birth and small for gestational age syndromes: The INTERBIO-21 st Newborn Case-Control Study protocol

Background: INTERBIO-21 ^st is Phase II of the INTERGROWTH-21 ^st Project, the population-based, research initiative involving nearly 70,000 mothers and babies worldwide coordinated by Oxford University and performed by a multidisciplinary network of more than 400 healthcare professionals and scientists from 35 institutions in 21 countries worldwide. Phase I, conducted 2008-2015, consisted of nine complementary studies designed to describe optimal human growth and neurodevelopment, based conceptually on the WHO prescriptive approach. The studies generated a set of international standards for monitoring growth and neurodevelopment, which complement the existing WHO Child Growth Standards. Phase II aims to improve the functional classification of the highly heterogenous preterm birth and fetal growth restriction syndromes through a better understanding of how environmental exposures, clinical conditions and nutrition influence patterns of human growth from conception to childhood, as well as specific neurodevelopmental domains and associated behaviors at 2 years of age.

Methods: In the INTERBIO-21 ^st Newborn Case-Control Study, a major component of Phase II, our objective is to investigate the mechanisms potentially responsible for preterm birth and small for gestational age and their interactions, using deep phenotyping of clinical, growth and epidemiological data and associated nutritional, biochemical, omic and histological profiles. Here we describe the study sites, population characteristics, study design, methodology and standardization procedures for the collection of longitudinal clinical data and biological samples (maternal blood, umbilical cord blood, placental tissue, maternal feces and infant buccal swabs) for the study that was conducted between 2012 and 2018 in Brazil, Kenya, Pakistan, South Africa, Thailand and the UK.

Discussion: Our study provides a unique resource for the planned analyses given the range of potentially disadvantageous exposures (including poor nutrition, pregnancy complications and infections) in geographically diverse populations worldwide. The study should enhance current medical knowledge and provide new insights into environmental influences on human growth and neurodevelopment.

Deep clinical and biological phenotyping of the preterm birth and small for gestational age syndromes: The INTERBIO-21 st Newborn Case-Control Study protocol

Background: INTERBIO-21 ^st is Phase II of the INTERGROWTH-21 ^st Project, the population-based, research initiative involving nearly 70,000 mothers and babies worldwide coordinated by Oxford University and performed by a multidisciplinary network of more than 400 healthcare professionals and scientists from 35 institutions in 21 countries worldwide. Phase I, conducted 2008-2015, consisted of nine complementary studies designed to describe optimal human growth and neurodevelopment, based conceptually on the WHO prescriptive approach. The studies generated a set of international standards for monitoring growth and neurodevelopment, which complement the existing WHO Child Growth Standards. Phase II aims to improve the functional classification of the highly heterogenous preterm birth and fetal growth restriction syndromes through a better understanding of how environmental exposures, clinical conditions and nutrition influence patterns of human growth from conception to childhood, as well as specific neurodevelopmental domains and associated behaviors at 2 years of age. Methods: In the INTERBIO-21 ^st Newborn Case-Control Study, a major component of Phase II, our objective is to investigate the mechanisms potentially responsible for preterm birth and small for gestational age and their interactions, using deep phenotyping of clinical, growth and epidemiological data and associated nutritional, biochemical, omic and histological profiles. Here we describe the study sites, population characteristics, study design, methodology and standardization procedures for the collection of longitudinal clinical data and biological samples (maternal blood, umbilical cord blood, placental tissue, maternal feces and infant buccal swabs) for the study that was conducted between 2012 and 2018 in Brazil, Kenya, Pakistan, South Africa, Thailand and the UK. Discussion: Our study provides a unique resource for the planned analyses given the range of potentially disadvantageous exposures (including poor nutrition, pregnancy complications and infections) in geographically diverse populations worldwide. The study should enhance current medical knowledge and provide new insights into environmental influences on human growth and neurodevelopment.

Subgroups of lifestyle patterns among hypertension patients: a latent-class analysis

BACKGROUND

Hypertension remains one of the most important preventable risk factors for diseases and death. Identifying clustered patterns of modifiable lifestyle risk factors for hypertension and demographics factors related to these clustered patterns allows for targeting health prevention interventions. Therefore, this study aims to identify latent classes of hypertensive patients' lifestyle risk factors based on the clustering of four modifiable lifestyle risk factors: eating, physical activity patterns, smoking habits, and blood pressure control.

METHODS

A total of 750 patients (Mage = 65.38 years, SDage = 9.2 years) with diagnosed hypertension in urban and rural primary health care centers in Takab (Iran) were recruited randomly from August 2016 to February 2017. Latent class analysis was performed by using proc. LCA in SAS 9.2.

RESULTS

Three classes of lifestyle patterns were identified. About 14.4% of hypertensive patients were categorized in a low-risk class (I), 54.6% in an intermediate-risk class (II), and 31% in a high-risk class (III) of lifestyle. A one-year increase in age significantly increases the risk of membership in classes II and III. Similarly, being widowed or divorced increases the risk of membership in classes II and III. Also, having a higher education level decreases the risk of membership in classes II and III.

CONCLUSIONS

This study contributes to the literature on lifestyle behaviors among older adults and provides evidence that there are considerable differences in lifestyle behaviors between subgroups of older adult patients. The three profiles of hypertensive patients' conditions suggest that because behaviors often occur simultaneously within an individual level, a latent-class approach helps cluster co-occurrence risk behaviors and focuses on interventions targeted to several healthy behaviors among high-risk patients.

Endothelin-1, nitric oxide, serotonin and high blood pressure in male adolescents

Background

Essential arterial hypertension (EAH) in adolescents represents a social burden. The endothelium is involved in the pathogenesis of EAH. Imbalance of key vasoactive factors – namely nitric oxide (NO) and endothelin-1 (ET-1) – is observed, and serotonin (5-HT) release is also impaired. The relationship between the factors and high blood pressure (BP) has been established mainly in preclinical studies and in the adult age. The aim of the present manuscript is to establish the association between plasma ET-1, serum NO and 5-HT, platelet 5-HT levels and BP in male adolescents, analyzing their concentrations in controls, prehypertensive and hypertensive children. Consequently, we want to evaluate ET-1, NO and 5-HT levels as preclinical biomarkers of EAH.

Methods

Outpatient adolescents, examined at Children’s Republican Clinical Hospital of the Ministry of Health of the Republic of Tatarstan, were recruited between 26th of May and 25th of September 2016. Predictor variables identified were plasma ET-1, serum NO and 5-HT levels and were evaluated in serum and platelets of case and control groups.

Results

Plasma ET-1 and serum 5-HT concentrations in prehypertensive and hypertensive children were higher than in controls, with hypertensive adolescents showing higher levels of both factors compared with prehypertensive adolescents. Platelet 5-HT levels were lower in prehypertensive and hypertensive children compared with controls, while serum NO levels were higher in prehypertensive children than in hypertensive children.

Conclusion

Measurable ET-1, NO and 5-HT are related to BP in adolescents and may serve as diagnostic biomarkers of EAH. Furthermore, they could help to better define prehypertensive and hypertensive children.

Biparietal diameter measurements using the outer-to-outer versus outer-to-inner measurement: A question of pedantry?

Objectives

To compare two methods of measuring fetal biparietal diameter (BPD) - outer-to-inner (BPDoi) vs. outer-to-outer (BPDoo) calliper placement - and to compare the differences in EFW calculated using the Hadlock 4 formula and other common EFW formulae.

Methods

A total of 543 fetuses underwent a single ultrasound prospectively performed by 40 sonographers between 14 and 40 weeks of gestation, taking into account the intra- and inter-observer variability. The measurements for each fetus consisted of BPDoi and BPDoo, and EFW is calculated from HC, AC and FL measurements. The difference between BPDoo and BPDoi was estimated, and this difference was compared with gestational age using linear regression. Translational equations that allow interconversion of the two parameters were derived. EFW calculated from four different formulae using various combinations of biometric measurements was compared.

Results

The difference between BPDoi and BPDoo increases with gestational age, although this difference was small. For BPDoo, the regression equation is BPDoo = 0.555934 + 1.027318 × BPDoi. Similarly, for BPDoi, the regression equation is BPDoi = -0.403458 + 0.9714153 × BPDoo. There is a minimal difference in the EFW calculated from the four formulae, except for gestations prior to 27-28 weeks. EFW derived from INTERGROWTH-21st formulae plot is higher than that from Hadlock 3 or Hadlock 4 before 27-28 weeks.

Conclusions

Although the absolute difference between BPDoo and BPDoi increased across gestational age, this difference was small. The method of BPD measurement should follow that as prescribed in the EFW equation used in the local context. Estimation of fetal weight using Hadlock 3, Hadlock 4 and INTERGROWTH-21st is similar, with slight differences at gestations less than 27-28 weeks.

The INTERGROWTH-21st fetal growth standards: toward the global integration of pregnancy and pediatric care

The purpose of the INTERGROWTH-21^st project was to develop international, prescriptive standards for fetal growth assessed by ultrasound and fundal height, preterm postnatal growth, newborn size and body composition, maternal weight gain, and infant development at the age of 2 years. Hence, we have produced, based on World Health Organization recommendations, the first comprehensive set of international standards of optimal fetal and newborn growth that perfectly match the existing World Health Organization child growth standards. Uniquely, the same population was followed up longitudinally from 9 weeks of fetal life to 2 years of age, with growth, health, and nutritional status assessment at 2 years supporting the appropriateness of the population for construction of growth standards. The resulting package of clinical tools allows, for the first time, growth and development to be monitored from early pregnancy to infancy. The INTERGROWTH-21^st fetal growth standards, which are based on observing >4500 healthy pregnancies, nested in a study of >59,000 pregnancies from populations with low rates of adverse perinatal outcomes, show how fetuses should grow-rather than the more limited objective of past references, which describe how they have grown at specific times and locations. Our work has confirmed the fundamental biological principle that variation in human growth across different populations is mostly dependent on environmental, nutritional, and socioeconomic factors. We found that when mothers' nutritional and health needs are met and there are few environmental constraints on growth, <3.5% of the total variability of skeletal growth was due to differences between populations. We propose that not recognizing the concept of optimal growth could deprive the most vulnerable mothers and their babies of optimal care, because local growth charts normalize those at highest risk for growth restriction and overweight, and can be valuable for policymakers to ensure rigorous evaluation and effective resource allocation. We strongly encourage colleagues to join efforts to provide integrated, evidence-based growth monitoring to pregnant women and their infants worldwide. Presently, there are 23.3 million infants born small for gestational age in low- to middle-income countries according to the INTERGROWTH-21^st newborn size standards. We suggest that misclassification of these infants by using local charts could affect the delivery of optimal health care.

A new customized fetal growth standard for African American women: the PRB/NICHD Detroit study

BACKGROUND

The assessment of fetal growth disorders requires a standard. Current nomograms for the assessment of fetal growth in African American women have been derived either from neonatal (rather than fetal) biometry data or have not been customized for maternal ethnicity, weight, height, and parity and fetal sex.

OBJECTIVE

We sought to (1) develop a new customized fetal growth standard for African American mothers; and (2) compare such a standard to 3 existing standards for the classification of fetuses as small (SGA) or large (LGA) for gestational age.

STUDY DESIGN

A retrospective cohort study included 4183 women (4001 African American and 182 Caucasian) from the Detroit metropolitan area who underwent ultrasound examinations between 14-40 weeks of gestation (the median number of scans per pregnancy was 5, interquartile range 3-7) and for whom relevant covariate data were available. Longitudinal quantile regression was used to build models defining the "normal" estimated fetal weight (EFW) centiles for gestational age in African American women, adjusted for maternal height, weight, and parity and fetal sex, and excluding pathologic factors with a significant effect on fetal weight. The resulting Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (hereinafter, PRB/NICHD) growth standard was compared to 3 other existing standards--the customized gestation-related optimal weight (GROW) standard; the Eunice Kennedy Shriver National Institute of Child Health and Human Development (hereinafter, NICHD) African American standard; and the multinational World Health Organization (WHO) standard--utilized to screen fetuses for SGA (<10th centile) or LGA (>90th centile) based on the last available ultrasound examination for each pregnancy.

RESULTS

First, the mean birthweight at 40 weeks was 133 g higher for neonates born to Caucasian than to African American mothers and 150 g higher for male than female neonates; maternal weight, height, and parity had a positive effect on birthweight. Second, analysis of longitudinal EFW revealed the following features of fetal growth: (1) all weight centiles were about 2% higher for male than for female fetuses; (2) maternal height had a positive effect on EFW, with larger fetuses being affected more (2% increase in the 95th centile of weight for each 10-cm increase in height); and (3) maternal weight and parity had a positive effect on EFW that increased with gestation and varied among the weight centiles. Third, the screen-positive rate for SGA was 7.2% for the NICHD African American standard, 12.3% for the GROW standard, 13% for the WHO standard customized by fetal sex, and 14.4% for the PRB/NICHD customized standard. For all standards, the screen-positive rate for SGA was at least 2-fold higher among fetuses delivered preterm than at term. Fourth, the screen-positive rate for LGA was 8.7% for the GROW standard, 9.2% for the PRB/NICHD customized standard, 10.8% for the WHO standard customized by fetal sex, and 12.3% for the NICHD African American standard. Finally, the highest overall agreement among standards was between the GROW and PRB/NICHD customized standards (Cohen's interrater agreement, kappa = 0.85).

CONCLUSION

We developed a novel customized PRB/NICHD fetal growth standard from fetal data in an African American population without assuming proportionality of the effects of covariates, and without assuming that these effects are equal on all centiles of weight; we also provide an easy-to-use centile calculator. This standard classified more fetuses as being at risk for SGA compared to existing standards, especially among fetuses delivered preterm, but classified about the same number of LGA. The comparison among the 4 growth standards also revealed that the most important factor determining agreement among standards is whether they account for the same factors known to affect fetal growth.

The satisfactory growth and development at 2 years of age of the INTERGROWTH-21st Fetal Growth Standards cohort support its appropriateness for constructing international standards

Background

The World Health Organization recommends that human growth should be monitored with the use of international standards. However, in obstetric practice, we continue to monitor fetal growth using numerous local charts or equations that are based on different populations for each body structure. Consistent with World Health Organization recommendations, the INTERGROWTH-21^st Project has produced the first set of international standards to date pregnancies; to monitor fetal growth, estimated fetal weight, Doppler measures, and brain structures; to measure uterine growth, maternal nutrition, newborn infant size, and body composition; and to assess the postnatal growth of preterm babies. All these standards are based on the same healthy pregnancy cohort. Recognizing the importance of demonstrating that, postnatally, this cohort still adhered to the World Health Organization prescriptive approach, we followed their growth and development to the key milestone of 2 years of age.

Objective

The purpose of this study was to determine whether the babies in the INTERGROWTH-21^st Project maintained optimal growth and development in childhood.

Study Design

In the Infant Follow-up Study of the INTERGROWTH-21^st Project, we evaluated postnatal growth, nutrition, morbidity, and motor development up to 2 years of age in the children who contributed data to the construction of the international fetal growth, newborn infant size and body composition at birth, and preterm postnatal growth standards. Clinical care, feeding practices, anthropometric measures, and assessment of morbidity were standardized across study sites and documented at 1 and 2 years of age. Weight, length, and head circumference age- and sex-specific z-scores and percentiles and motor development milestones were estimated with the use of the World Health Organization Child Growth Standards and World Health Organization milestone distributions, respectively. For the preterm infants, corrected age was used. Variance components analysis was used to estimate the percentage variability among individuals within a study site compared with that among study sites.

Results

There were 3711 eligible singleton live births; 3042 children (82%) were evaluated at 2 years of age. There were no substantive differences between the included group and the lost-to-follow up group. Infant mortality rate was 3 per 1000; neonatal mortality rate was 1.6 per 1000. At the 2-year visit, the children included in the INTERGROWTH-21^st Fetal Growth Standards were at the 49th percentile for length, 50th percentile for head circumference, and 58th percentile for weight of the World Health Organization Child Growth Standards. Similar results were seen for the preterm subgroup that was included in the INTERGROWTH-21^st Preterm Postnatal Growth Standards. The cohort overlapped between the 3rd and 97th percentiles of the World Health Organization motor development milestones. We estimated that the variance among study sites explains only 5.5% of the total variability in the length of the children between birth and 2 years of age, although the variance among individuals within a study site explains 42.9% (ie, 8 times the amount explained by the variation among sites). An increase of 8.9 cm in adult height over mean parental height is estimated to occur in the cohort from low-middle income countries, provided that children continue to have adequate health, environmental, and nutritional conditions.

Conclusion

The cohort enrolled in the INTERGROWTH-21^st standards remained healthy with adequate growth and motor development up to 2 years of age, which supports its appropriateness for the construction of international fetal and preterm postnatal growth standards.

New approach for the identification of implausible values and outliers in longitudinal childhood anthropometric data

PURPOSE

We aimed to demonstrate the use of jackknife residuals to take advantage of the longitudinal nature of available growth data in assessing potential biologically implausible values and outliers.

METHODS

Artificial errors were induced in 5% of length, weight, and head circumference measurements, measured on 1211 participants from the Maternal Vitamin D for Infant Growth (MDIG) trial from birth to 24 months of age. Each child's sex- and age-standardized z-score or raw measurements were regressed as a function of age in child-specific models. Each error responsible for a biologically implausible decrease between a consecutive pair of measurements was identified based on the higher of the two absolute values of jackknife residuals in each pair. In further analyses, outliers were identified as those values beyond fixed cutoffs of the jackknife residuals (e.g., greater than +5 or less than -5 in primary analyses). Kappa, sensitivity, and specificity were calculated over 1000 simulations to assess the ability of the jackknife residual method to detect induced errors and to compare these methods with the use of conditional growth percentiles and conventional cross-sectional methods.

RESULTS

Among the induced errors that resulted in a biologically implausible decrease in measurement between two consecutive values, the jackknife residual method identified the correct value in 84.3%-91.5% of these instances when applied to the sex- and age-standardized z-scores, with kappa values ranging from 0.685 to 0.795. Sensitivity and specificity of the jackknife method were higher than those of the conditional growth percentile method, but specificity was lower than for conventional cross-sectional methods.

CONCLUSIONS

Using jackknife residuals provides a simple method to identify biologically implausible values and outliers in longitudinal child growth data sets in which each child contributes at least 4 serial measurements.

Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project

BackgroundWe aimed to describe newborn body composition and identify which anthropometric ratio (weight/length; BMI; or ponderal index, PI) best predicts fat mass (FM) and fat-free mass (FFM).MethodsAir-displacement plethysmography (PEA POD) was used to estimate FM, FFM, and body fat percentage (BF%). Associations between FFM, FM, and BF% and weight/length, BMI, and PI were evaluated in 1,019 newborns using multivariate regression analysis. Charts for FM, FFM, and BF% were generated using a prescriptive subsample (n=247). Standards for the best-predicting anthropometric ratio were calculated utilizing the same population used for the INTERGROWTH-21^st Newborn Size Standards (n=20,479).ResultsFFM and FM increased consistently during late pregnancy. Differential FM, BF%, and FFM patterns were observed for those born preterm (34⁺⁰-36⁺⁶ weeks' gestation) and with impaired intrauterine growth. Weight/length by gestational age (GA) was a better predictor of FFM and FM (adjusted R²=0.92 and 0.71, respectively) than BMI or PI, independent of sex, GA, and timing of measurement. Results were almost identical when only preterm newborns were studied. We present sex-specific centiles for weight/length ratio for GA.ConclusionsWeight/length best predicts newborn FFM and FM. There are differential FM, FFM, and BF% patterns by sex, GA, and size at birth.

International estimated fetal weight standards of the INTERGROWTH-21st Project

OBJECTIVE

Estimated fetal weight (EFW) and fetal biometry are complementary measures used to screen for fetal growth disturbances. Our aim was to provide international EFW standards to complement the INTERGROWTH-21st Fetal Growth Standards that are available for use worldwide.

METHODS

Women with an accurate gestational-age assessment, who were enrolled in the prospective, international, multicenter, population-based Fetal Growth Longitudinal Study (FGLS) and INTERBIO-21st Fetal Study (FS), two components of the INTERGROWTH-21st Project, had ultrasound scans every 5 weeks from 9-14 weeks' until 40 weeks' gestation. At each visit, measurements of fetal head circumference (HC), biparietal diameter, occipitofrontal diameter, abdominal circumference (AC) and femur length (FL) were obtained blindly by dedicated research sonographers using standardized methods and identical ultrasound machines. Birth weight was measured within 12 h of delivery by dedicated research anthropometrists using standardized methods and identical electronic scales. Live babies without any congenital abnormality, who were born within 14 days of the last ultrasound scan, were selected for inclusion. As most births occurred at around 40 weeks' gestation, we constructed a bootstrap model selection and estimation procedure based on resampling of the complete dataset under an approximately uniform distribution of birth weight, thus enriching the sample size at extremes of fetal sizes, to achieve consistent estimates across the full range of fetal weight. We constructed reference centiles using second-degree fractional polynomial models.

RESULTS

Of the overall population, 2404 babies were born within 14 days of the last ultrasound scan. Mean time between the last scan and birth was 7.7 (range, 0-14) days and was uniformly distributed. Birth weight was best estimated as a function of AC and HC (without FL) as log(EFW) = 5.084820 - 54.06633 × (AC/100)3  - 95.80076 × (AC/100)3  × log(AC/100) + 3.136370 × (HC/100), where EFW is in g and AC and HC are in cm. All other measures, gestational age, symphysis-fundus height, amniotic fluid indices and interactions between biometric measures and gestational age, were not retained in the selection process because they did not improve the prediction of EFW. Applying the formula to FGLS biometric data (n = 4231) enabled gestational age-specific EFW tables to be constructed. At term, the EFW centiles matched those of the INTERGROWTH-21st Newborn Size Standards but, at < 37 weeks' gestation, the EFW centiles were, as expected, higher than those of babies born preterm. Comparing EFW cross-sectional values with the INTERGROWTH-21st Preterm Postnatal Growth Standards confirmed that preterm postnatal growth is a different biological process from intrauterine growth.

CONCLUSIONS

We provide an assessment of EFW, as an adjunct to routine ultrasound biometry, from 22 to 40 weeks' gestation. However, we strongly encourage clinicians to evaluate fetal growth using separate biometric measures such as HC and AC, as well as EFW, to avoid the minimalist approach of focusing on a single value. © 2016 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Precision of recumbent crown-heel length when using an infantometer

BACKGROUND

Crown-heel length (CHL) measurement is influenced by technique, training, experience and subject cooperation. We investigated whether extending one or both of an infant's legs affects the precision of CHL taken using an infantometer. The influence of staff training and infant cooperation were also examined.

METHODS

CHL was measured in children (aged 2), infants (aged 1) and newborns, by extending one or both legs. The subject's level of cooperation was recorded. Mean differences were compared using Student's t-test; intra- and inter-observer variability were assessed using Bland-Altman plots with 95 % limits of agreement. Intra- and inter-observer technical errors of measurement (TEMs) were also calculated.

RESULTS

Measuring CHL in newborns using only one leg resulted in significantly longer measurements. Across all groups, there was less inter-observer variability using both legs; 95 % limits of agreement were lower and TEMs smaller. Larger measurement differences were seen if children were uncooperative.

CONCLUSIONS

This study supports measuring CHL with both legs extended. The two-leg technique reduces variability and increases precision by allowing the measurer to control better the position and movements of the infant's body.

Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21(st) Project

BACKGROUND

Charts of size at birth are used to assess the postnatal growth of preterm babies on the assumption that extrauterine growth should mimic that in the uterus.

METHODS

The INTERGROWTH-21(st) Project assessed fetal, newborn, and postnatal growth in eight geographically defined populations, in which maternal health care and nutritional needs were met. From these populations, the Fetal Growth Longitudinal Study selected low-risk women starting antenatal care before 14 weeks' gestation and monitored fetal growth by ultrasonography. All preterm births from this cohort were eligible for the Preterm Postnatal Follow-up Study, which included standardised anthropometric measurements, feeding practices based on breastfeeding, and data on morbidity, treatments, and development. To construct the preterm postnatal growth standards, we selected all live singletons born between 26 and before 37 weeks' gestation without congenital malformations, fetal growth restriction, or severe postnatal morbidity. We did analyses with second-degree fractional polynomial regression models in a multilevel framework accounting for repeated measures. Fetal and neonatal data were pooled from study sites and stratified by postmenstrual age. For neonates, boys and girls were assessed separately.

FINDINGS

From 4607 women enrolled in the study, there were 224 preterm singleton births, of which 201 (90%) were enrolled in the Preterm Postnatal Follow-up Study. Variance component analysis showed that only 0·2% and 4·0% of the total variability in postnatal length and head circumference, respectively, could be attributed to between-site differences, justifying pooling the data from all study sites. Preterm growth patterns differed from those for babies in the INTERGROWTH-21(st) Newborn Size Standards. They overlapped with the WHO Child Growth Standards for term babies by 64 weeks' postmenstrual age.

INTERPRETATION

Our data have yielded standards for postnatal growth in preterm infants. These standards should be used for the assessment of preterm infants until 64 weeks' postmenstrual age, after which the WHO Child Growth Standards are appropriate. Size-at-birth charts should not be used to measure postnatal growth of preterm infants.

FUNDING

Bill & Melinda Gates Foundation.

Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study

OBJECTIVE

To compare the standard methods for ultrasound measurement of fetal head circumference (HC) and biparietal diameter (BPD) (outer-to-outer (BPDoo) vs outer-to-inner (BPDoi) caliper placement), and compare acquisition of these measurements in transthalamic (TT) vs transventricular (TV) planes.

METHODS

This study utilized ultrasound images acquired from women participating in the Oxford arm of the INTERGROWTH-21(st) Project. In the first phase of the study, BPDoo and BPDoi were measured on stored images. In the second phase, real-time measurements of BPD, occipitofrontal diameter (OFD) and HC in TT and TV planes were obtained by pairs of sonographers. Reproducibility of measurements made by the same (intraobserver) and by different (interobserver) sonographers, as well as the reproducibility of caliper placement and measurements obtained in different planes, was assessed using Bland-Altman plots.

RESULTS

In Phase I, we analyzed ultrasound images of 108 singleton fetuses. The mean intraobserver and interobserver differences were < 2% (1.34 mm) and the 95% limits of agreement were < 5% (3 mm) for both BPDoo and BPDoi. Neither method for measuring BPD showed consistently better reproducibility. In Phase II, we analyzed ultrasound images of 100 different singleton fetuses. The mean intraobserver and interobserver differences were < 1% (2.26 mm) and the 95% limits of agreement were < 8% (14.45 mm) for all fetal head measurements obtained in TV and TT planes. Neither plane for measuring fetal head showed consistently better reproducibility. Measurement of HC using the ellipse facility was as reproducible as HC calculated from BPD and OFD. OFD by itself was the least reproducible of all fetal head measurements.

CONCLUSIONS

Measurements of BPDoi and BPDoo are equally reproducible; however, we believe BPDoo should be used in clinical practice as it allows fetal HC to be measured and compared with neonatal HC. For all head measurements, TV and TT planes provide equally reproducible values at any gestational age, and HC values are similar in both planes. Fetal head measurement in the TT plane is preferable as international standards in this plane are available; however, measurements in the TV plane can be plotted on the same standards. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Systematic Review of the Methodological Quality of Studies Aimed at Creating Gestational Weight Gain Charts

A range of adverse outcomes is associated with insufficient and excessive maternal weight gain in pregnancy, but there is no consensus regarding what constitutes optimal gestational weight gain (GWG). Differences in the methodological quality of GWG studies may explain the varying chart recommendations. The goal of this systematic review was to evaluate the methodological quality of studies that aimed to create GWG charts by scoring them against a set of predefined, independently agreed-upon criteria. These criteria were divided into 3 domains: study design (12 criteria), statistical methods (7 criteria), and reporting methods (4 criteria). The criteria were broken down further into items, and studies were assigned a quality score (QS) based on these criteria. For each item, studies were scored as either high (score = 0) or low (score = 1) risk of bias; a high QS correlated with a low risk of bias. The maximum possible QS was 34. The systematic search identified 12 eligible studies involving 2,268,556 women from 9 countries; their QSs ranged from 9 (26%) to 29 (85%) (median, 18; 53%). The most common sources for bias were found in study designs (i.e., not prospective); assessments of prepregnancy weight and gestational age; descriptions of weighing protocols; sample size calculations; and the multiple measurements taken at each visit. There is wide variation in the methodological quality of GWG studies constructing charts. High-quality studies are needed to guide future clinical recommendations. We recommend the following main requirements for future studies: prospective design, reliable evaluation of prepregnancy weight and gestational age, detailed description of measurement procedures and protocols, description of sample-size calculation, and the creation of smooth centile charts or z scores.

Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study

OBJECTIVE

To describe patterns in maternal gestational weight gain (GWG) in healthy pregnancies with good maternal and perinatal outcomes.

DESIGN

Prospective longitudinal observational study.

SETTING

Eight geographically diverse urban regions in Brazil, China, India, Italy, Kenya, Oman, United Kingdom, and United States, April 2009 to March 2014.

PARTICIPANTS

Healthy, well nourished, and educated women enrolled in the Fetal Growth Longitudinal Study component of the INTERGROWTH-21(st) Project, who had a body mass index (BMI) of 18.50-24.99 in the first trimester of pregnancy.

MAIN OUTCOME MEASURES

Maternal weight measured with standardised methods and identical equipment every five weeks (plus/minus one week) from the first antenatal visit (<14 weeks' gestation) to delivery. After confirmation that data from the study sites could be pooled, a multilevel, linear regression analysis accounting for repeated measures, adjusted for gestational age, was applied to produce the GWG values.

RESULTS

13,108 pregnant women at <14 weeks' gestation were screened, and 4607 met the eligibility criteria, provided consent, and were enrolled. The variance within sites (59.6%) was six times higher than the variance between sites (9.6%). The mean GWGs were 1.64 kg, 2.86 kg, 2.86 kg, 2.59 kg, and 2.56 kg for the gestational age windows 14-18(+6) weeks, 19-23(+6) weeks, 24-28(+6) weeks, 29-33(+6) weeks, and 34-40(+0) weeks, respectively. Total mean weight gain at 40 weeks' gestation was 13.7 (SD 4.5) kg for 3097 eligible women with a normal BMI in the first trimester. Of all the weight measurements, 71.7% (10,639/14,846) and 94.9% (14,085/14,846) fell within the expected 1 SD and 2 SD thresholds, respectively. Data were used to determine fitted 3rd, 10th, 25th, 50th, 75th, 90th, and 97th smoothed GWG centiles by exact week of gestation, with equations for the mean and standard deviation to calculate any desired centiles according to gestational age in exact weeks.

CONCLUSIONS

Weight gain in pregnancy is similar across the eight populations studied. Therefore, the standards generated in this study of healthy, well nourished women may be used to guide recommendations on optimal gestational weight gain worldwide.

Monitoring human growth and development: a continuum from the womb to the classroom

A comprehensive set of fully integrated anthropometric measures is needed to evaluate human growth from conception to infancy so that consistent judgments can be made about the appropriateness of fetal and infant growth. At present, there are 2 barriers to this strategy. First, descriptive reference charts, which are derived from local, unselected samples with inadequate methods and poor characterization of their putatively healthy populations, commonly are used rather than prescriptive standards. The use of prescriptive standards is justified by the extensive biologic, genetic, and epidemiologic evidence that skeletal growth is similar from conception to childhood across geographic populations, when health, nutrition, environmental, and health care needs are met. Second, clinicians currently screen fetuses, newborn infants, and infants at all levels of care with a wide range of charts and cutoff points, often with limited appreciation of the underlying population or quality of the study that generated the charts. Adding to the confusion, infants are evaluated after birth with a single prescriptive tool: the World Health Organization Child Growth Standards, which were derived from healthy, breastfed newborn infants, infants, and young children from populations that have been exposed to few growth-restricting factors. The International Fetal and Newborn Growth Consortium for the 21st Century Project addressed these issues by providing international standards for gestational age estimation, first-trimester fetal size, fetal growth, newborn size for gestational age, and postnatal growth of preterm infants, all of which complement the World Health Organization Child Growth Standards conceptually, methodologically, and analytically. Hence, growth and development can now, for the first time, be monitored globally across the vital first 1000 days and all the way to 5 years of age. It is clear that an integrative approach to monitoring growth and development from pregnancy to school age is desirable, scientifically supported, and likely to improve care, referral patterns, and reporting systems. Such integration can be achieved only through the use of international growth standards, especially in increasingly diverse, mixed ancestry populations. Resistance to new scientific developments has been hugely problematic in medicine; however, we are confident that the obstetric and neonatal communities will join their pediatric colleagues worldwide in the adoption of this integrative strategy.

Maternal vitamin D supplementation during pregnancy and lactation to promote infant growth in Dhaka, Bangladesh (MDIG trial): study protocol for a randomized controlled trial

Background

Vitamin D regulates bone mineral metabolism and skeletal development. Some observational studies have suggested that prenatal vitamin D deficiency increases the risk of adverse pregnancy and/or birth outcomes; however, there is scant evidence from controlled trials, leading the World Health Organization to advise against routine vitamin D supplementation in pregnancy. Importantly, little is known about the effect of maternal vitamin D status on infant linear growth in communities in South Asia where stunting is highly prevalent and maternal-infant vitamin D status is commonly suboptimal.

Methods/Design

The Maternal Vitamin D for Infant Growth study is a randomized, placebo-controlled, dose-ranging trial of maternal vitamin D supplementation during pregnancy and lactation in Dhaka, Bangladesh. The primary aims are to estimate (1) the effect of maternal prenatal oral vitamin D₃ supplementation (4200 IU/wk, 16,800 IU/wk, or 28,000 IU/wk, administered as weekly doses) versus placebo on infant length at 1 year of age and (2) the effect of maternal postpartum oral vitamin D₃ supplementation (28,000 IU/wk) versus placebo on length at 1 year of age among infants born to women who received vitamin D 28,000 IU/wk during pregnancy. Generally healthy pregnant women (n = 1300) in the second trimester (17–24 weeks of gestation) are randomized to one of five parallel arms: placebo 4200 IU/wk, 16,800 IU/wk, or 28,000 IU/wk in the prenatal period and placebo in the postpartum period or 28,000 IU/wk in the prenatal period and 28,000 IU/wk in the postpartum period. Household- and clinic-based follow-up of mother-infant pairs is conducted weekly by trained personnel until 26 weeks postpartum and every 3 months thereafter. The primary trial outcome measure is length for age z-score at 1 year of age. Anthropometric measurements, clinical information, and biological specimens collected at scheduled intervals will enable the assessment of a range of maternal, perinatal, and infant outcomes.

Discussion

The role of vitamin D in maternal and infant health remains unresolved. This trial is expected to contribute unique insights into the effects of improving maternal-infant vitamin D status in a low-income setting where stunting and adverse perinatal outcomes represent significant public health burdens.

Trial registration

ClinicalTrials.gov identifier: NCT01924013. Registered on 13 August 2013

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0825-8) contains supplementary material, which is available to authorized users.

Standardization of Research-Quality Anthropometric Measurement of Infants and Implementation in a Multicenter Study

Malnutrition is one of the earliest clinical manifestations of cystic fibrosis (CF) and is associated with poorer pulmonary and cognitive outcomes and survival later in life. Infant growth can be a responsive measure for clinical research in this age group if obtained and characterized accurately. We report here the methods to standardize and implement research-quality anthropometric measurement of infants with cystic fibrosis in the Baby Observational Nutrition Study multicenter trial.

Growth, head growth, and neurocognitive outcome in children born very preterm: methodological aspects and selected results

In light of the growing number of surviving children born very preterm, there is an increasing focus on their long-term outcomes in terms of growth, metabolic status, and neurocognitive development. Therefore, it is of importance to follow such children from birth onwards with the aim of identifying the causes of atypical development, developing preventative measures, and improving outcomes. Since such long-term follow-up needs to be conducted with the least possible burden, clinical investigations such as anthropometry and neurocognitive tests, if conducted rigorously, will continue to have a predominant role. The aim of this review is to discuss the complexity of longitudinal anthropometry in children born very preterm and to provide an overview of the main studies that have examined associations between growth, in particular head growth, and neurocognitive outcomes at around school age.

The likeness of fetal growth and newborn size across non-isolated populations in the INTERGROWTH-21st Project: the Fetal Growth Longitudinal Study and Newborn Cross-Sectional Study

BACKGROUND

Large differences exist in size at birth and in rates of impaired fetal growth worldwide. The relative effects of nutrition, disease, the environment, and genetics on these differences are often debated. In clinical practice, various references are often used to assess fetal growth and newborn size across populations and ethnic origins, whereas international standards for assessing growth in infants and children have been established. In the INTERGROWTH-21(st) Project, our aim was to assess fetal growth and newborn size in eight geographically defined urban populations in which the health and nutrition needs of mothers were met and adequate antenatal care was provided.

METHODS

For this study, fetal growth and newborn size were measured in two INTERGROWTH-21(st) component studies using prespecified markers and the same methods, equipment, and selection criteria. In the Fetal Growth Longitudinal Study (FGLS), we studied educated, affluent, healthy women, with adequate nutritional status who were at low risk of intrauterine growth restriction. The primary markers of fetal growth were ultrasound measurements of fetal crown-rump length at less than 14 weeks and 0 days of gestation and fetal head circumference from 14 weeks and 0 days to 40 weeks and 0 days of gestation, and birthlength for newborn size. In the concomitant, population-based Newborn Cross-Sectional Study (NCSS), we measured birthlength in all newborn babies from the eight geographically defined urban populations with the same methods, instruments, and staff as in FGLS. From this large NCSS cohort, we selected an FGLS-like subpopulation to match FGLS with the same eligibility criteria.

FINDINGS

Between May 14, 2009, and Aug 2, 2013, we enrolled 4607 women in FGLS and 59 137 women in NCSS. From NCSS, 20 486 (34·6%) women met the FGLS eligibility criteria, and constituted the FGLS-like subpopulation. With variance component analysis, only between 1·9% and 3·5% of the total variability in crown-rump length, fetal head circumference, and newborn birthlength could be attributed to between-site differences. With standardised site effect analysis in 16 gestational age windows from 9 weeks and 0 days of gestation to birth for the three measures (128 comparisons), only one was marginally higher than 0·5 SD of the standardised site difference range. Sensitivity analyses, excluding individual populations in turn from the pooling of all-site centiles across gestational ages, showed no noticeable effect on the 3rd, 50th, and 97th centiles derived from the remaining populations. Our populations were consistent at birth with those in the WHO Multicentre Growth Reference Study (MGRS). The mean birthlength for term newborn babies in that study was 49·5 cm (SD 1·9), which was very similar to that in the FGLS cohort (49·4 cm [1·9]) and the NCSS derived FGLS-like subpopulation (49·3 cm [1·8]).

INTERPRETATION

Fetal growth and newborn length are similar across diverse geographical settings when mothers' nutritional and health needs are met, and environmental constraints on growth are low. The findings for birthlength are in strong agreement with those of the WHO MGRS. These results provide the conceptual frame to create international standards for growth from conception to newborn baby, which will extend the present infant to childhood WHO MGRS standards.

FUNDING

Bill & Melinda Gates Foundation.

International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project

BACKGROUND

In 2006, WHO published international growth standards for children younger than 5 years, which are now accepted worldwide. In the INTERGROWTH-21(st) Project, our aim was to complement them by developing international standards for fetuses, newborn infants, and the postnatal growth period of preterm infants.

METHODS

INTERGROWTH-21(st) is a population-based project that assessed fetal growth and newborn size in eight geographically defined urban populations. These groups were selected because most of the health and nutrition needs of mothers were met, adequate antenatal care was provided, and there were no major environmental constraints on growth. As part of the Newborn Cross-Sectional Study (NCSS), a component of INTERGROWTH-21(st) Project, we measured weight, length, and head circumference in all newborn infants, in addition to collecting data prospectively for pregnancy and the perinatal period. To construct the newborn standards, we selected all pregnancies in women meeting (in addition to the underlying population characteristics) strict individual eligibility criteria for a population at low risk of impaired fetal growth (labelled the NCSS prescriptive subpopulation). Women had a reliable ultrasound estimate of gestational age using crown-rump length before 14 weeks of gestation or biparietal diameter if antenatal care started between 14 weeks and 24 weeks or less of gestation. Newborn anthropometric measures were obtained within 12 h of birth by identically trained anthropometric teams using the same equipment at all sites. Fractional polynomials assuming a skewed t distribution were used to estimate the fitted centiles.

FINDINGS

We identified 20,486 (35%) eligible women from the 59,137 pregnant women enrolled in NCSS between May 14, 2009, and Aug 2, 2013. We calculated sex-specific observed and smoothed centiles for weight, length, and head circumference for gestational age at birth. The observed and smoothed centiles were almost identical. We present the 3rd, 10th, 50th, 90th, and 97th centile curves according to gestational age and sex.

INTERPRETATION

We have developed, for routine clinical practice, international anthropometric standards to assess newborn size that are intended to complement the WHO Child Growth Standards and allow comparisons across multiethnic populations.

FUNDING

Bill & Melinda Gates Foundation.

Anthropometric protocols for the construction of new international fetal and newborn growth standards: the INTERGROWTH-21st Project

The primary aim of the INTERGROWTH-21(st) Project is to construct new, prescriptive standards describing optimal fetal and preterm postnatal growth. The anthropometric measurements include the head circumference, recumbent length and weight of the infants, and the stature and weight of the parents. In such a large, international, multicentre project, it is critical that all study sites follow standardised protocols to ensure maximal validity of the growth and nutrition indicators used. This paper describes, in detail, the selection of anthropometric personnel, equipment, and measurement and calibration protocols used to construct the new standards. Implementing these protocols at each study site ensures that the anthropometric data are of the highest quality to construct the international standards.