The influence of fetal growth reference standards on assessment of cognitive and academic outcomes of very preterm children

Predictive ability of fetal growth charts in identifying kindergarten-age developmental challenges: a cohort study

BACKGROUND

The Society for Maternal-Fetal Medicine recommends defining fetal growth restriction as an estimated fetal weight or abdominal circumference <10th percentile of a population-based reference. However, because multiple references are available, an understanding of their ability to identify infants at increased risk due to fetal growth restriction is critical. Previous studies have focused on the ability of different population references to identify short-term outcomes, but fetal growth restriction also has longer-term consequences for child development.

OBJECTIVE

This study aimed to estimate the association between estimated fetal weight percentiles on the INTERGROWTH-21st and World Health Organization fetal growth charts and kindergarten-age childhood development, and establish the charts' discriminatory ability in predicting kindergarten-age developmental challenges.

STUDY DESIGN

We conducted a retrospective cohort study linking obstetrical ultrasound scans conducted at BC Women's Hospital, Vancouver, Canada, with population-based standardized kindergarten test results. The cohort was limited to nonanomalous, singleton fetuses scanned at ≥28 weeks' gestation from 2000 to 2011, with follow-up until 2017. We classified estimated fetal weight into percentiles using the INTERGROWTH-21st and World Health Organization charts. We used generalized additive modeling to link estimated fetal weight percentile with routine province-wide kindergarten readiness test results. We calculated the area under the receiver-operating characteristic curve and other measures of diagnostic accuracy with 95% confidence intervals at select percentile cut-points of the charts. We repeated analyses using the Hadlock chart to help contextualize findings. The main outcome measure was the total Early Development Instrument score (/50). Secondary outcomes were Early Development Instrument subdomain scores for language and cognitive development, and for communication skills and general knowledge, as well as designation of "developmentally vulnerable" or "special needs".

RESULTS

Among 3418 eligible fetuses, those with lower estimated fetal weight percentiles had systematically lower Early Development Instrument scores and increased risks of developmental vulnerability. However, the clinical significance of differences was modest in magnitude (eg, total Early Development Instrument score -2.8 [95% confidence interval, -5.1 to -0.5] in children with an estimated fetal weight in 3rd-9th percentile of INTERGROWTH-21st chart [vs reference of 31st-90th]). The charts' predictive abilities for adverse child development were limited (eg, area under the receiver-operating characteristic curve <0.53 for all 3 charts).

CONCLUSION

Lower estimated fetal weight percentiles on the INTERGROWTH-21st and World Health Organization charts indicate increased risks of adverse kindergarten-age child development at the population level, but are not accurate individual-level predictors of adverse child development.

Death and severe morbidity in isolated periviable small-for-gestational-age fetuses

OBJECTIVE

This study aims to predict perinatal death or severe sequelae in isolated small-for-gestational-age fetuses, diagnosed at a periviable gestational age, based on ultrasound and Doppler parameters at diagnosis.

DESIGN

Observational study.

SETTING

A tertiary perinatal centre.

POPULATION

A cohort of singleton non-malformed fetuses suspected to be small for gestational age (estimated fetal weight, EFW, <10th centile) diagnosed at 22.0-25.6 weeks of gestation. The following parameters were recorded at diagnosis: severe smallness (<3rd centile); absent or reversed end-diastolic velocity in umbilical artery; abnormal middle cerebral artery Doppler; abnormal cerebroplacental ratio; abnormal uterine artery Doppler; and absent or reversed end-diastolic velocity in the ductus venosus.

METHODS

Logistic regression analysis.

MAIN OUTCOME MEASURES

Predictive performance of EFW and Doppler parameters for short-term adverse outcome of perinatal morbimortality and composite serious adverse outcomes (death, neurological impairment or severe bronchopulmonary dysplasia).

RESULTS

A total of 155 pregnancies were included. There were 13 (8.4%) intrauterine and 11 (7.7%) neonatal deaths. A short-term adverse perinatal outcome occurred in 40 (25.8%) pregnancies. There were 31 (20%) cases of serious adverse outcomes. For the prediction of serious adverse outcomes, the combination of absent or reversed end-diastolic velocity in the umbilical artery and impaired middle cerebral artery detected by Doppler evaluation achieved a detection rate of 87%, with a false-positive rate of 14% (accuracy 86%).

CONCLUSION

In periviable isolated small-for-gestational-age fetuses, a Doppler evaluation of the umbilical and fetal brain circulation can accurately predict short-term adverse perinatal complications and serious adverse outcomes.

First 1,000 days: enough for mothers but not for children? Long-term outcomes of an early intervention on maternal depressed mood and child cognitive development: follow-up of a randomised controlled trial

BACKGROUND

Child cognitive development is often compromised in contexts of poverty and adversity, and these deficits tend to endure and affect the child across the life course. In the conditions of poverty and violence that characterise many low- and middle-income countries (LMIC), the capacity of parents to provide the kind of care that promotes good child development may be severely compromised, especially where caregivers suffer from depression. One avenue of early intervention focuses on the quality of the early mother-infant relationship. The aim of this study was to examine the long-term impact of an early intervention to improve the mother-infant relationship quality on child cognitive outcomes at 13 years of age. We also estimated the current costs to replicate the intervention.

METHOD

We re-recruited 333 children from an early childhood maternal-infant attachment intervention, 'Thula Sana', when the children were 13 years old, to assess whether there were impacts of the intervention on child cognitive outcomes, and maternal mood. We used the Kaufman Assessment Battery to assess the child cognitive development and the Patient Health Questionnaire (PHQ-9) and the Self-Reporting Questionnaire (SRQ-20) to assess maternal mental health.

RESULTS

Effect estimates indicated a pattern of null findings for the impact of the intervention on child cognitive development. However, the intervention had an effect on caregiver psychological distress (PHQ-9, ES = -0.17 [CI: -1.95, 0.05] and SRQ-20, ES = -0.30 [CI: -2.41, -0.19]), but not anxiety. The annual cost per mother-child pair to replicate the Thula Sana intervention in 2019 was estimated at ZAR13,365 ($780).

CONCLUSION

In a socio-economically deprived peri-urban settlement in South Africa, a home visiting intervention, delivered by community workers to mothers in pregnancy and the first six postpartum months, had no overall effect on child cognitive development at 13 years of age. However, those caregivers who were part of the original intervention showed lasting improvements in depressed mood. Despite the fact that there was no intervention effect on long-term child outcomes, the improvements in maternal mood are important.

Customized birth-weight centiles and placenta-related fetal growth restriction

OBJECTIVE

The value of using customized birth-weight centiles to improve the diagnostic accuracy for fetal growth restriction (FGR), in comparison with using population-based charts, remains a matter of debate. One potential explanation for the conflicting data is that most studies used measures of perinatal mortality and morbidity as proxies for placenta-mediated FGR, many of which are not specific and may be confounded by other factors such as prematurity. The aim of this study was to compare the diagnostic accuracy of small-for-gestational age (SGA) at birth, defined according to customized vs population-based charts, for associated abnormal placental pathology.

METHODS

This was a secondary analysis of data from a prospective cohort study on risk factors for placenta-mediated complications and abnormal placental pathology in low-risk nulliparous women. All placentae were sent for detailed histopathological examination by two perinatal pathologists. The primary exposure was SGA, defined as birth weight < 10^th centile for gestational age using either a customized (SGA_cust ) or a population-based (SGA_pop ) birth-weight reference. The outcomes of interest were one of three types of abnormal placental pathology associated with FGR: maternal vascular malperfusion (MVM), chronic villitis and fetal vascular malperfusion (FVM). Adjusted relative risks (aRR) with 95% CIs were estimated using modified Poisson regression analysis, with adjustment for smoking, body mass index and aspirin treatment.

RESULTS

A total of 857 nulliparous women met the study criteria. The proportions of infants identified as SGA based on the customized and population-based charts were 12.6% (108/857) and 11.4% (98/857), respectively. A diagnosis of SGA using either customized or population-based charts was associated with an increased risk of any placental pathology (aRR, 3.04 (95% CI, 2.29-4.04) and 1.60 (95% CI, 1.10-2.31), respectively) and MVM pathology (aRR, 12.33 (95% CI, 6.60-23.03) and 5.29 (95% CI, 2.87-9.76), respectively). SGA_cust , but not SGA_pop , was also associated with an increased risk for chronic villitis (aRR, 1.85 (95% CI, 1.07-3.18)) and FVM pathology (aRR, 2.48 (95% CI, 1.25-4.93)). SGA_cust had a higher detection rate for any placental pathology (30.3% vs 17.1%; P < 0.001), MVM pathology (63.2% vs 39.5%; P = 0.003) and chronic villitis (20.8% vs 8.3%; P = 0.007) than did SGA_pop , for a similar false-positive rate. This was mainly the result of a higher detection rate for abnormal pathology in the white and East-Asian subgroups and a lower false-positive rate for abnormal pathology in the South-Asian subgroup by SGA_cust than by SGA_pop . In addition, pregnancies in the SGA_cust group, but not those in the SGA_pop group, were more likely to be complicated by preterm birth and a low 5-min Apgar score than were the corresponding non-SGA group.

CONCLUSION

These findings suggest that customized birth-weight centiles may be superior to population-based birth-weight centiles in detecting FGR that is due to underlying placental disease. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Follow-Up de Nascidos Prematuros: Uma Revisão Sistemática da Literatura

Resumo Objetivou-se mapear estudos científicos sobre follow-up de prematuros na área da psicologia. Buscou-se no portal BVS artigos empíricos publicados até dezembro de 2017 pelos descritores prematur* AND follow up AND child AND psychology. A partir dos critérios adotados, analisou-se 48 artigos, nas categorias: faixa etária em que os prematuros foram avaliados; objetivos do estudo; tipo de avaliação realizada; e resultados encontrados. Destaca-se que a metade realizou o follow-up entre o nascimento e a adolescência, a maioria investigou o desenvolvimento neuropsicológico e encontrou associações entre a prematuridade, déficits cognitivos e psicológicos. Compreende-se que os estudos priorizam as repercussões no desenvolvimento de habilidades e competências, dando pouca atenção aos aspectos psíquicos e às interações criança-pais-ambiente.

Association between tobacco and/or alcohol consumption during pregnancy and infant development: BRISA Cohort

Fetuses exposed to alcohol and/or tobacco are at risk for perinatal adversities. However, little is currently known about the association of the separate or concomitant use of alcohol and tobacco with infant motor and cognitive development. Thus, the objective of the present study was to investigate the association between maternal consumption of alcohol and/or tobacco during pregnancy and the motor and cognitive development of children starting from the second year of life. The study included 1006 children of a cohort started during the prenatal period (22-25 weeks of pregnancy), evaluated at birth and reevaluated during the second year of life in 2011/2013. The children were divided into four groups according to the alcohol and/or tobacco consumption reported by their mothers at childbirth: no consumption (NC), separate alcohol consumption (AC), separate tobacco consumption (TC), and concomitant use of both (ACTC). The Bayley Scale of Infant and Toddler Development Third Edition screening tool was used for the assessment of motor and cognitive development. Adjusted Poisson regression models were used to determine the association between groups and delayed development. The results indicated that only the ACTC group showed a higher risk of motor delay, specifically regarding fine motor skills, compared to the NC group (RR=2.81; 95%CI: 1.65; 4.77). Separate alcohol or tobacco consumption was not associated with delayed gross motor or cognitive development. However, the concomitant use of the two substances increased the risk of delayed acquisition of fine motor skills.

Foetal growth restriction has negative influence on narrative skills in 8-10-year-old children

AIM

The risk for neurocognitive difficulties is increased in children born with foetal growth restriction (FGR), but no data exist yet on their narrative skills. The narrative skills of 8- to 10-year-old children born with FGR between 24 and 40 weeks were compared with those of children born with appropriate growth for gestational age (AGA).

METHODS

A prospectively collected cohort of 36 children with FGR was recruited prenatally at a Finnish tertiary hospital from 1998-2001, and 31 children with AGA served as controls. Narrative skills were assessed using a standardised test, and correlations between narrative, communication, reading and spelling skills were studied.

RESULTS

Children born with FGR produced significantly less information and shorter utterances in their narratives than the AGA group. Children born preterm with FGR performed significantly more poorly in their narratives than the preterm AGA group. Poor narrative skills correlated with poor communication, reading and spelling skills.

CONCLUSION

Children born with FGR had poorer narrative skills compared with their AGA peers at the age of 8-10 years, and narrative skills were linked to other language-based skills, which underlines the importance of early detection and preventive measures to optimise the educational outcome of children born with FGR.

Association of Intrauterine Growth Restriction and Small for Gestational Age Status With Childhood Cognitive Outcomes: A Systematic Review and Meta-analysis

IMPORTANCE

The magnitude of the association of intrauterine growth restriction (IUGR) and small for gestational age (SGA) status with cognitive outcomes in preterm and term-born children has not been established.

OBJECTIVE

To examine cognitive outcomes of preterm and term-born children who had IUGR and were SGA compared with children who were appropriate for gestational age (AGA) during the first 12 years of life.

DATA SOURCES

For this systematic review and meta-analysis, the Scopus, PubMed, Web of Science, Science Direct, PsycInfo, and ERIC databases were searched for English-language, peer-reviewed literature published between January 1, 2000, and February 20, 2020. The following Medical Subject Heading terms for IUGR and SGA and cognitive outcomes were used: intrauterine growth restriction, intrauterine growth retardation, small for gestational age AND neurodevelopment, neurodevelopmental outcome, developmental outcomes, and cognitive development.

STUDY SELECTION

Inclusion criteria were assessment of cognitive outcomes (full-scale IQ or a cognitive subscale), inclusion of an AGA group as comparison group, and inclusion of gestational age at birth and completion of cognitive assessment up to 12 years of age.

DATA EXTRACTION AND SYNTHESIS

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines were followed. Data were double screened for full-text articles, and a subset were independently coded by 2 authors. Standardized mean differences (SMDs) and odd ratios from individual studies were pooled by applying random-effects models.

MAIN OUTCOMES AND MEASURES

Cognitive outcomes, defined as mental, cognitive, or IQ scores, estimated with standardized practitioner-based cognitive tests or as borderline intellectual impairment (BII), defined as mental, cognitive, or IQ scores at least 1 SD below the mean cognitive score.

RESULTS

In this study of 89 samples from 60 studies including 52 822 children, children who had IUGR and were SGA had significantly poorer cognitive outcomes (eg, cognitive scores and BII) than children with AGA in childhood. For cognitive scores, associations are consistent for preterm (SMD, -0.27; 95% CI, -0.38 to -0.17) and term-born children (SMD, -0.39; 95% CI, -0.50 to -0.28), with higher effect sizes reported for term-born IUGR and AGA group comparisons (SMD, -0.58; 95% CI, -0.82 to -0.35). Analyses on BII revealed a significantly increased risk in the preterm children who had IUGR and were SGA (odds ratio, 1.57; 95% CI, 1.40-1.77) compared with the children with AGA.

CONCLUSIONS AND RELEVANCE

Growth vulnerabilities assessed antenatally (IUGR) and at the time of birth (SGA) are significantly associated with lower childhood cognitive outcomes in preterm and term-born children compared with children with AGA. These findings highlight the need to develop interventions that boost cognitive functions in these high-risk groups.

Small for gestational age-cognitive performance from infancy to adulthood: an observational study

OBJECTIVE

To determine whether cognitive performance from infancy to adulthood is affected by being born small for gestational age (SGA), and if this depends on the SGA reference used. Furthermore, to determine SGA's effect while considering the effects of very preterm/very low birthweight (VP/VLBW), socio-economic status (SES) and parent-infant relationship.

DESIGN, SETTING AND POPULATION

A total of 414 participants (197 term-born, 217 VP/VLBW) of the Bavarian Longitudinal Study.

METHODS

Small for gestational age was classified using neonatal or fetal growth references. SES and the parent-infant relationship were assessed before the infant was 5 months old.

MAIN OUTCOME MEASURES

Developmental (DQ) and intelligence (IQ) tests assessed cognitive performance on six occasions, from 5 months to 26 years of age.

RESULTS

The fetal reference classified more infants as SGA (<10th centile) than the neonatal reference (n = 138, 33% versus n = 75, 18%). Using linear mixed models, SGA was associated with IQ -8 points lower than appropriate for gestational age, regardless of reference used (95% CI -13.66 to -0.64 and 95% CI -13.75 to -1.98). This difference narrowed minimally into adulthood. Being VP/VLBW was associated with IQ -16 (95% CI -21.01 to -10.04) points lower than term-born participants. Low SES was associated with IQ -14 (95% CI -18.55 to -9.06) points lower than high SES. A poor parent-infant relationship was associated with IQ -10 points lower than those with a good relationship (95% CI -13.91 to -6.47).

CONCLUSIONS

Small for gestational age is associated with lower IQ throughout development, independent of VP/VLBW birth, low SES or poor parent-child relationship. Social factors effects on IQ comparable to those of SGA and should be considered for interventions.

TWEETABLE ABSTRACT

Small for gestational age is associated with lower cognitive performance from infancy to adulthood.

Risk factors for bronchiolitis hospitalization in infants: A French nationwide retrospective cohort study over four consecutive seasons (2009-2013)

Objectives

Large studies are needed to update risk factors of bronchiolitis hospitalization. We performed a nationwide analysis of hospitalization rates for bronchiolitis over four consecutive bronchiolitis seasons to identify underlying medical disorders at risk of bronchiolitis hospitalization and assess their frequency.

Methods

Data were retrieved from the French National Hospital Discharge database. Of all infants discharged alive from maternity wards from January 2008 to December 2013 in France (N = 3,884,791), we identified four consecutive cohorts at risk of bronchiolitis during the seasons of 2009–2010 to 2012–2013. The main outcome was bronchiolitis hospitalization during a season. Individual risk factors were collected.

Results

Among infants, 6.0% were preterm and 2.0% had ≥1 chronic condition including 0.2% bronchopulmonary dysplasia (BPD) and 0.2% hemodynamically significant congenital heart disease (HS-CHD). Bronchiolitis hospitalization rates varied between seasons (min: 1.26% in 2010–2011; max: 1.48% in 2012–2013; p<0.001). Except omphalocele, the following conditions were associated with an increased risk for bronchiolitis hospitalization: solid organ (9.052; 95% CI, 4.664–17.567) and stem cell transplants (6.012; 95% CI, 3.441–10.503), muscular dystrophy (4.002; 95% CI, 3.1095–5.152), cardiomyopathy (3.407; 95% CI, 2.613–4.442), HS-CHD (3.404; 95% CI, 3.153–3.675), congenital lung disease and/or bronchial abnormalities, Down syndrome, congenital tracheoesophageal fistula, diaphragmatic hernia, pulmonary hypertension, chromosomal abnormalities other than Down syndrome, hemodynamically non-significant CHD, congenital abnormalities of nervous system, cystic fibrosis, cleft palate, cardiovascular disease occurring during perinatal period, and BPD.

Conclusion

Besides prematurity, BPD, and HS–CHD, eighteen underlying conditions were associated with a significant increased risk for bronchiolitis hospitalization in a nationwide population.

Foetal growth restriction is associated with poor reading and spelling skills at eight years to 10 years of age

AIM

Foetal growth restriction (FGR) is associated with communication problems, which might lead to poor literacy skills. The reading and spelling skills of eight- to 10-year-old FGR children born at 24-40 gestational weeks were compared with those of their gestational age-matched, appropriately grown (AGA) peers.

METHODS

A prospectively collected cohort of 37 FGR and 31 AGA children was recruited prenatally at a Finnish tertiary care centre during 1998-2001. The children's reading and spelling skills were assessed using standardised tests for Finnish-speaking second and third graders.

RESULTS

Significantly more children performed below the 10th percentile normal values for reading and spelling skills in the FGR group than in the AGA group. At nine years of age, the FGR children had significantly poorer performance in word reading skills and reading fluency, reading accuracy and reading comprehension than the AGA controls. No between-group differences were detected at eight years of age.

CONCLUSION

FGR is associated with poor performance in reading and spelling skills. A third of the FGR children performed below the 10th percentile normal values at nine years of age. These results indicate a need to continuously evaluate linguistic and literacy skills as FGR children age to ensure optimal support.

Variation in term birthweight across European countries affects the prevalence of small for gestational age among very preterm infants

AIM

This study assessed the prevalence of small for gestational age (SGA) among very preterm (VPT) infants using national and European intrauterine references.

METHODS

We generated country-specific and common European intrauterine growth references for 11 European countries, according to Gardosi's approach and Hadlock's foetal growth model, using national data on birthweights by sex. These references were applied to the Effective Perinatal Intensive Care in Europe (EPICE) cohort, which comprised 7766 live VPT births without severe congenital anomalies under 32 weeks of gestation in 2011-2012, to estimate the prevalence of infants with SGA birthweights, namely those below the 10th percentile.

RESULTS

The SGA prevalence was 31.8% with country-specific references and 34.0% with common European references. The European references yielded a 10-point difference in the SGA prevalence between countries with lower term birthweights (39.9%) - Portugal, Italy and France - and higher term birthweights, namely Denmark, the Netherlands, Sweden (28.9%; p < 0.001). This was not observed with country-specific references, where the respective figures were 32.4% and 33.9% (p = 0.34), respectively.

CONCLUSION

One-third of VPT infants were SGA according to intrauterine references. Common European references showed significant differences in SGA prevalence between countries with high and low-term birthweights.

Impact of fetal growth restriction on neurodevelopmental outcome at 2 years for extremely preterm infants: a single institution study

AIM

We evaluated the impact of fetal growth restriction on neurodevelopmental outcomes at 2 years corrected age for infants born before 27 weeks gestational age.

METHOD

Data on infants born before 27 weeks gestational age between 1999 and 2008 (n=463), admitted to a tertiary neonatal unit in Paris, were used to compare neurological outcomes at 2 years for infants with birthweight lower than the 10th centile and birthweight of at least the 10th centile, using intrauterine reference curves. Outcomes were cerebral palsy (CP) and the Brunet-Lézine assessment of cognitive development, which provides age-corrected overall and domain-specific (global and fine motor skills, language and social interaction) developmental quotients. Models were adjusted for perinatal and social factors.

RESULTS

Seventy-two percent of infants were discharged alive. Eighty-three percent (n=268) were evaluated at 2 years. Six percent had CP. Fetal growth restriction was not associated with the risk of CP. After adjustment, children with a birthweight lower than the 10th centile had a global developmental quotient 4.7 points lower than those with birthweight of at least the 10th centile (p<0.001); differences were greatest for fine motor and social skills (-4.7, p=0.053 and -7.3, p<0.001 respectively).

INTERPRETATION

In extremely preterm children, fetal growth restriction was associated with poorer neurodevelopmental outcomes at 2 years, but not with CP.

Country-Specific vs. Common Birthweight-for-Gestational Age References to Identify Small for Gestational Age Infants Born at 24-28 weeks: An International Study

BACKGROUND

Controversy exists as to whether birthweight-for-gestational age references used to classify infants as small for gestational age (SGA) should be country specific or based on an international (common) standard. We examined whether different birthweight-for-gestational age references affected the association of SGA with adverse outcomes among very preterm neonates.

METHODS

Singleton infants (n = 23 788) of 24(0) -28(6) weeks' gestational age in nine high-resource countries were classified as SGA (<10th centile) using common and country-specific references based on birthweight and estimated fetal weight (EFW). For each reference, the adjusted relative risk (aRR) for the association of SGA with composite outcome of mortality or major morbidity was estimated.

RESULTS

The percentage of infants classified as SGA differed slightly for common compared with country specific for birthweight references [9.9% (95% CI 9.5, 10.2) vs. 11.1% (95% CI 10.7, 11.5)] and for EFW references [28.6% (95% CI 28.0, 29.2) vs. 24.6% (95% CI 24.1, 25.2)]. The association of SGA with the composite outcome was similar when using common or country-specific references for the total sample for birthweight [aRRs 1.47 (95% CI 1.43, 1.51) and 1.48 (95% CI 1.44, 1.53) respectively] and for EFW references [aRRs 1.35 (95% CI 1.31, 1.38) and 1.39 (95% CI 1.35, 1.43) respectively].

CONCLUSION

Small for gestational age is associated with higher mortality and morbidity in infants born <29 weeks' gestational age. Although common and country-specific birthweight/EFW references identified slightly different proportions of SGA infants, the risk of the composite outcome was comparable.

Intrauterine Growth Restriction, Head Size at Birth, and Outcome in Very Preterm Infants

OBJECTIVES

To determine whether small head circumference (HC) or birth weight (BW) or both are associated with neonatal and long-term neurologic outcome in very preterm infants.

STUDY DESIGN

All 2442 live births from the 1997 Epipage study between 26 and 32 weeks of gestational age in 9 regions of France were analyzed. A total of 1395 were tested at age 5 years for cognitive performance and 1315 with school performance reports at age 8 years. Symmetric growth restriction (SGR) was defined by HC and BW <20th percentile and in the same percentile range, and asymmetric growth restriction by at least 1 of HC and BW <20th percentile and the other in a higher decile range. There were 2 forms of asymmetric growth restriction: head growth restriction (HGR) and weight growth restriction (WGR). Appropriate for gestational age was defined by both BW and HC >20th percentile.

RESULTS

Compared with appropriate for gestational age, SGR was significantly associated with neonatal mortality (aOR 2.99, 95% CI 1.78-5.03), moderate and severe cognitive deficiency (aOR 1.65, 95% CI 1.01-2.71 and aOR 2.61, 95% CI 1.46-4.68, respectively), and poor school performance (aOR 1.79; 95% CI 1.13-2.83). HGR was significantly associated with severe cognitive deficiency (aOR 2.07, 95% CI 1.15-3.74). WGR was not significantly associated with cognitive or school performance despite higher rates of neonatal morbidity.

CONCLUSIONS

SGR in preterm infants was associated with neonatal mortality and impaired cognitive and school performance. The outcome of asymmetric growth restriction differed according to HC. HGR was associated with impaired cognitive function; WGR was not.

Transcriptomic analysis of human placenta in intrauterine growth restriction

BACKGROUND

Intrauterine growth restriction (IUGR) is a frequent complication of pregnancy defined as a restriction of fetal growth. The objective of this work was to improve the knowledge on the pathophysiology of IUGR using a genome-wide method of expression analysis.

METHODS

We analyzed differentially expressed genes in pooled placental tissues from vascular IUGR (four pools of three placentas) and normal pregnancies (four pools of three placentas) using a long nucleotide microarray platform (Nimblegen). We first did a global bioinformatics analysis based only on P value without any a priori. We secondly focused on "target" genes among the most modified ones. Finally, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed on an extended panel of tissue samples (n = 62) on selected "target".

RESULTS

We identified 636 modified genes among which 206 were upregulated (1.5 and higher; P < 0.05). Groups of patients were classified unambiguously. Genes involved in mitochondrial function and oxidative phosphorylation were decreased affecting three out of five complexes of the respiratory chain of the mitochondria, and thus energy production and metabolism. Among the most induced genes, we identified LEP, IGFBP1, and RBP4.

CONCLUSION

Complementary studies on the role and function of LEP, IGFBP1, and RBP4 in IUGR pathophysiology and also in fetal programming remain necessary.

A modified prenatal growth assessment score for the evaluation of fetal growth in the third trimester using single and composite biometric parameters

OBJECTIVE

To define modified Prenatal Growth Assessment Scores (mPGAS) for single and composite biometric parameters and determine their reference ranges in normal fetuses.

METHODS

Nine anatomical parameters (ap) were measured and the weight estimated (EWTa, EWTb) in a longitudinal study of 119 fetuses with normal neonatal growth outcomes. Expected third trimester size trajectories, obtained from second trimester Rossavik size models, were used in calculating Percent Deviations (% Dev's) and their age-specific reference ranges in each fetus. The components of individual % Dev's values outside their reference ranges, designated +iapPGAS, -iapPGAS, were averaged to give +apPGAS and -apPGAS values for the 3rd trimester. The +iapPGAS and -iapPGAS values for different combinations of ap (c1a (HC, AC, FDL, ThC, EWTa), c1b (HC, AC, FDL, ThC, EWTb), c2 (ThC, ArmC, AVol, TVol), c3 (HC, AC, FDL, EWTa)) were then averaged to give +icPGAS and -icPGAS values at different time points or at the end of the third trimester (+cPGAS, -cPGAS). Values for iapPGAS, ic1bPGAS, and ic2PGAS were compared to their respective apPGAS or cPGAS reference ranges.

RESULTS

All mPGAS values had one 95% range boundary at 0.0%. Upper boundaries of 1D +apPGAS values ranged from 0.0% (HC) to +0.49% (ThC) and were +0.06%, +2.3% and +1.8% for EWT, AVol and TVol, respectively. Comparable values for -apPGAS were 0.0% (BPD, FDL, HDL), to -0.58% (ArmC), -0.13% (EWT), -0.8% (AVol), and 0.0% (TVol). The +cPGAS, 95% reference range upper boundaries varied from +0.36% (c1b) to +0.89% (c2). Comparable values for -cPGAS lower boundaries were -0.17% (c1b) to -0.43% (c2).

CONCLUSIONS

The original PGAS concept has now been extended to individual biometric parameters and their combinations. With the standards provided, mPGAS values can now be tested to see if detection of different types of third trimester growth problems is improved.

Prevalence of small-for-gestational-age and its mortality risk varies by choice of birth-weight-for-gestation reference population

Background

We use data from rural Nepal and South India to compare the prevalence of small-for-gestational-age (SGA) and neonatal mortality risk associated with SGA using different birth-weight-for-gestation reference populations.

Methods

We identified 46 reference populations in low-, middle-, and high-income countries, of which 26 met the inclusion criteria of being commonly cited and having numeric 10^th percentile cut points published. Those reference populations were then applied to populations from two community-based studies to determine SGA prevalence and its relative risk of neonatal mortality.

Results

The prevalence of SGA ranged from 10.5% to 72.5% in Nepal, and 12.0% to 78.4% in India, depending on the reference population. Females had higher rates of SGA than males using reference populations that were not sex specific. SGA prevalence was lowest when using reference populations from low-income countries. Infants who were both preterm and SGA had much higher mortality risk than those who were term and appropriate-for-gestational-age. Risk ratios for those who are both preterm and SGA ranged from 7.34–17.98 in Nepal and 5.29–11.98 in India, depending on the reference population.

Conclusions

These results demonstrate the value of a common birth-weight-for-gestation reference population that will facilitate comparisons of SGA prevalence and mortality risk across research studies.

Invited commentary: the incremental value of customization in defining abnormal fetal growth status

Reference tools based on birth weight percentiles at a given gestational week have long been used to define fetuses or infants that are small or large for their gestational ages. However, important deficiencies of the birth weight reference are being increasingly recognized. Overwhelming evidence indicates that an ultrasonography-based fetal weight reference should be used to classify fetal and newborn sizes during pregnancy and at birth, respectively. Questions have been raised as to whether further adjustments for race/ethnicity, parity, sex, and maternal height and weight are helpful to improve the accuracy of the classification. In this issue of the Journal, Carberry et al. (Am J Epidemiol. 2013;178(8):1301-1308) show that adjustment for race/ethnicity is useful, but that additional fine tuning for other factors (i.e., full customization) in the classification may not further improve the ability to predict infant morbidity, mortality, and other fetal growth indicators. Thus, the theoretical advantage of full customization may have limited incremental value for pediatric outcomes, particularly in term births. Literature on the prediction of short-term maternal outcomes and very long-term outcomes (adult diseases) is too scarce to draw any conclusions. Given that each additional variable being incorporated in the classification scheme increases complexity and costs in practice, the clinical utility of full customization in obstetric practice requires further testing.