Bayley-III Cognitive Composite Score Research Articles

Association between intermittent hypoxemia and neurodevelopmental outcomes in extremely premature infants: A single-center experience

ObjectiveTo describe the association between intermittent hypoxemic events (IHEs) and severe neurodevelopmental impairment (SNDI) or death in extremely premature infants. Study designRetrospective study of extremely premature infants 230/7–276/7 weeks gestational age (GA) and birthweight (BW) ≤1250 g (g) admitted to a level IV neonatal intensive care unit (NICU) from 2013 to 2017. IHEs, defined as events with SpO2 ≤ 80 % lasting 10 s to 5 min, were algorithmically identified using data extracted from bedside monitors at 2 s intervals (0.5 Hz). The primary outcome was SNDI at 18–24 months corrected age (CA), defined as a Bayley-III motor, language or cognitive composite score ≤69, or death before discharge while the secondary outcome was SNDI alone. We used mixed-effects regression models to evaluate the relationship between mean daily IHE rate per postnatal week of life for the first 12 weeks and the outcomes, and logistic regression models to assess the association between outcomes and summary measures of hypoxic burden for the entire NICU hospitalization. ResultsThe mortality rate was 7 % (18/249) during NICU hospitalization. Of 249 infants born during this time period, IHE and neurodevelopmental outcome data were fully available for 65 infants (mean GA 26 ± 1.4 weeks, mean birth weight (BW) 738 ± 199 g). The outcome of SNDI alone occurred in 34 % (22/65) with a majority demonstrating motor or language delay on the Bayley-III. Although mean daily IHE rate/week was not associated with SNDI or death, total IHE duration was associated with increased odds of SNDI (OR (95 % CI) 1.03 (1.01, 1.05), p = 0.008) in models adjusted for GA. ConclusionsIn a cohort of extremely premature infants 23–27 weeks GA, each hour of total IHE duration (SpO2 ≤ 80 %) was associated with a 2.7 % (0.7 %, 4.8 %) increase in the odds of SNDI at 18–24 months CA.

Lack of association between gestational age adjusted TSH percentiles and neurodevelopmental outcomes among preterm infants

Limited evidence exists on whether subclinical hypothyroidism suggested by mildly elevated TSH levels affect neurodevelopment and growth in preterm infants. The objective of this study was to determine the association between gestational age adjusted TSH percentiles and neurodevelopmental outcomes among preterm infants. Univariate linear regression analysis was conducted to determine, in infants born less than thirty-two weeks gestational age, the correlation between the TSH percentile on the last newborn screen and neurodevelopmental assessment scores and growth outcomes at eighteen to twenty-two months of corrected age. Seventy-four patients were enrolled in the study with a mean gestational age of 28.8 weeks. There was no correlation between the last TSH percentile value and Bayley-III cognitive composite score or other neurodevelopmental or growth outcomes. In a cohort of preterm infants, higher TSH percentiles suggesting potential subclinical hypothyroidism did not predict any adverse effect on neurodevelopmental or growth outcomes.

Neurodevelopmental Outcomes following Preterm Birth and the Association with Postmenstrual Age at Discharge.

This study aimed to (1) define the prevalence of motor, cognitive, and language delays in preterm infants born <32 weeks estimated gestational age (EGA); and (2) identify the relationship between the timing of discharge from the neonatal intensive care unit (NICU) and neurodevelopmental outcome in early childhood. This retrospective study of 172 preterm infants born <32 weeks EGA and hospitalized in a level-IV NICU captured medical factors, including timing of discharge, from the NICU stay. Standardized developmental testing at 1 to 2 years corrected age was conducted in the newborn follow-up clinic. At 1 to 2 years corrected age, the sample had an average Bayley Scales of Infant and Toddler Development (Bayley-III) cognitive composite score of 91.5 ± 17.4, language composite score of 84.5 ± 17.3, and motor composite score of 88.9 ± 18.4. Lower EGA at birth, necrotizing enterocolitis, patent ductus arteriosus, and oxygen requirement for >28 days were independently associated with higher postmenstrual age (PMA) at NICU discharge. Higher PMA at discharge was associated with poorer cognitive outcome [p < 0.001, β = -1.1 (-1.6, -0.7)], poorer language outcome [p = 0.049, β = -0.5 (-0.9, -0.003)], and poorer motor outcome [p <0.001, β = -1.0 (-1.5, -0.5)]. For every additional week of hospitalization, scores were an average of 1.1 points lower in cognitive, 1.0 point lower in motor, and 0.5 points lower in language domains of the Bayley-III assessment. Poorer cognitive, language, and motor outcomes were associated with longer hospitalization, even after controlling for medical risk factors known to be associated with poorer outcome. This provides further evidence for the potential role of the environment in impacting developmental outcomes of infants hospitalized in the NICU. · There are high rates of developmental impairment among preterm infants born <32 weeks at 1 year to 2 years.. · The longer the infant is exposed to the NICU environment, the higher the risk of neurodevelopmental challenges.. · These findings provide increased motivation for optimizing the early NICU environment..

Neurodevelopmental outcomes of preterm infants conceived by assisted reproductive technology

There have been concerns about the development of children conceived through assisted reproductive technology. Despite multiple studies investigating the outcomes of assisted conception, data focusing specifically on the neurodevelopmental outcomes of infants conceived through assisted reproductive technology and born preterm are limited. This study aimed to evaluate and compare the neurodevelopmental outcomes of preterm infants born at <29 weeks' gestation at 18 to 24 months' corrected age who were conceived through assisted reproductive technology and those who were conceived naturally. This retrospective cohort study included inborn, nonanomalous infants, born at <29 weeks' gestation between January 1, 2010, and December 31, 2016, who had a neurodevelopmental assessment at 18 to 24 months' corrected age at any of the 10 Canadian Neonatal Follow-Up Network clinics. The primary outcome was neurodevelopmental impairment at 18 to 24 months, defined as the presence of any of the following: cerebral palsy; Bayley-III cognitive, motor, or language composite score of <85; sensorineural or mixed hearing loss; and unilateral or bilateral visual impairment. Secondary outcomes included mortality, composite of mortality or neurodevelopmental impairment, significant neurodevelopmental impairment, and each component of the primary outcome. We compared outcomes between infants conceived through assisted reproductive technology and those conceived naturally, using bivariate and multivariable analyses after adjustment. Of the 4863 eligible neonates, 651 (13.4%) were conceived using assisted reproductive technology. Maternal age; education level; and rates of diabetes mellitus, receipt of antenatal corticosteroids, and cesarean delivery were higher in the assisted reproduction group than the natural conception group. Neonatal morbidity and death rates were similar except for intraventricular hemorrhage, which was lower in the assisted reproduction group (33% [181 of 546] vs 39% [1284 of 3318]; P=.01). Of the 4176 surviving infants, 3386 (81%) had a follow-up outcome at 18 to 24 months' corrected age. Multivariable logistic regression adjusting for gestational age, antenatal steroids, sex, small for gestational age, multiple gestations, mode of delivery, maternal age, maternal education, pregnancy-induced hypertension, maternal diabetes mellitus, and smoking showed that infants conceived through assisted reproduction was associated with lower odds of neurodevelopmental impairment (adjusted odds ratio, 0.67; 95% confidence interval, 0.52-0.86) and the composite of death or neurodevelopmental impairment (adjusted odds ratio, 0.67; 95% confidence interval, 0.54-0.84). Conception through assisted reproductive technology was associated with decreased odds of a Bayley-III composite cognitive score of <85 (adjusted odds ratio, 0.68; 95% confidence interval, 0.48-0.99) and composite language score of <85 (adjusted odds ratio, 0.67; 95% confidence interval, 0.50-0.88). Compared with natural conception, assisted conception was associated with lower odds of adverse neurodevelopmental outcomes, especially cognitive and language outcomes, at 18 to 24 months' corrected age among preterm infants born at <29 weeks' gestation. Long-term follow-up studies are required to assess the risks of learning disabilities and development of complex visual-spatial and processing skills in these children as they reach school age.

The long-term effect of prenatal progesterone treatment on child development, behaviour and health: a systematic review.

BackgroundProgesterone is widely used in prenatal care. However, long‐term effects of prenatal progesterone treatment on child development are unclear.ObjectivesTo evaluate long‐term outcomes in children after prenatal progesterone treatment.Search strategyMEDLINE, Embase and Cochrane Central Register of Controlled Trials from inception to 24 May 2020.Selection criteriaRandomised controlled trials (RCTs) reporting outcomes in children born to women who received progesterone treatment (compared with placebo or another intervention) during any trimester in pregnancy.Data collection and analysisTwo authors independently selected and extracted data. We used the Cochrane Risk of Bias tool for randomised trials and Quality In Prognosis Studies.Main resultsOf 388 papers, we included seven articles based on five RCTs, comprising 4222 measurements of children aged 6 months to 8 years. All studies compared progesterone to placebo in second and/or third trimester for the prevention of preterm birth. Meta‐analysis (two studies, n = 890 children) showed no difference in neurodevelopment as assessed by the Bayley‐III Cognitive Composite score at 2 years between children exposed to progesterone versus placebo (Standardised Mean Difference −0.04, 95% Confidence Interval −0.26 to 0.19), I 2 = 22%. Heterogeneity prohibited additional meta‐analyses. Other long‐term outcomes showed no differences.ConclusionsOur systematic review comprising a multitude of developmental measurements with a broad age range did not find evidence of benefit or harm in offspring prenatally exposed to progesterone treatment for the prevention of preterm birth. We identified an urgent need for follow‐up studies of prenatal progesterone administration in early pregnancy and effects in offspring beyond early childhood.Tweetable abstractProgesterone to prevent preterm birth: no effect on child development. Outcomes after first trimester progesterone are unclear.

Weight, length, and head circumference at 36 weeks are not predictive of later cognitive impairment in very preterm infants.

To assess diagnostic accuracy of 36-week anthropometric weight, length, and head circumference <10th and <3rd percentiles to predict preterm infant cognitive impairment. Cohort study of 898 preterm <30-week very-low-birth weight (<1500 g) infants. Anthropometric measures' accuracy to predict cognitive impairment (Bayley-III Cognitive Composite score) <80, 21-months corrected age (CA) and Wechsler Preschool and Primary Scale of Intelligence Quotient (intellectual outcomes) <70, 36-months CA, were determined using receiver operating characteristic (ROC) curves. Thirty-six-week weight, length or head circumference <10th or <3rd percentile did not predict cognitive impairment; areas under ROC curves were <0.6. Sensitivities and specificities for 10th and 3rd percentile cut points were all poor, with most not exceeding 70%, whether the Fenton 2013 or INTERGROWTH 2015 growth charts were used. Brain injury and low maternal education were better predictors of cognitive impairment. Preterm infant 36-week anthropometric measurements are not accurate predictors of cognitive impairment.

Predictive Value of the BSID-II and the Bayley-III for Early School Age Cognitive Function in Very Preterm Infants.

Objective:To compare the predictive validity of the Bayley Scales of Infant Development, Second Edition (BSID-II) and the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) for cognitive function at early school age in very preterm infants.Methods:Seventy-seven former preterm infants (born <32 weeks gestation and ≤2000 g) completed both the BSID-II and the Bayley-III at 2 years corrected age. Children enrolled at hospitals that perform follow-up beyond 2 years had cognitive assessments with the Wechsler Preschool and Primary Scale of Intelligence Fourth Edition (WPPSI-IV). Associations between Bayley and WPPSI scores were assessed using correlation coefficients, linear regression, and Bland-Altman plots.Results:Thirty-one of 45 eligible children were tested with the WPPSI-IV at 47 ± 11 months. Average BSID-II Mental Development Index (MDI) was 86 ± 19, Bayley-III Cognitive composite score was 101 ± 12 and WPPSI Full Scale IQ (FSIQ) was 96 ± 12. Correlation between MDI and FSIQ was 0.54 (P < .001); correlation between Bayley-III cognitive composite score and FSIQ was 0.31 (P = .03). Bayley-III language composite had a modestly stronger correlation with FSIQ than cognitive composite (correlation coefficient 0.39; P = .005). Linear regression models also demonstrated that BSID-II was more closely correlated with FSIQ than Bayley-III. This bias was consistent across the full range of scores.Conclusion:The BSID-II underestimated FSIQ and the Bayley-III overestimated FSIQ. Children at risk for impairment might be missed with the Bayley-III. As the Bayley-4 is introduced, clinicians and researchers should be cautious about interpretation of scores until performance of this new measure is fully understood.

Parental age effects on neonatal white matter development

ObjectiveAdvanced paternal age is associated with poor offspring developmental outcome. Though an increase in paternal age-related germline mutations may affect offspring white matter development, outcome differences could also be due to psychosocial factors. Here we investigate possible cerebral changes prior to strong environmental influences using brain MRI in a cohort of healthy term-born neonates. MethodsWe used structural and diffusion MRI images acquired soon after birth from a cohort (n = 275) of healthy term-born neonates. Images were analysed using a customised tract based spatial statistics (TBSS) processing pipeline. Neurodevelopmental assessment using the Bayley-III scales was offered to all participants at age 18 months. For statistical analysis neonates were compared in two groups, representing the upper quartile (paternal age ≥38 years) and lower three quartiles. The same method was used to assess associations with maternal age. ResultsIn infants with older fathers (≥38 years), fractional anisotropy, a marker of white matter organisation, was significantly reduced in three early maturing anatomical locations (the corticospinal tract, the corpus callosum, and the optic radiation). Fractional anisotropy in these locations correlated positively with Bayley-III cognitive composite score at 18 months in the advanced paternal age group. A small but significant reduction in total brain volume was also observed in in the infants of older fathers. No significant associations were found between advanced maternal age and neonatal imaging. ConclusionsThe epidemiological association between advanced paternal age and offspring outcome is extremely robust. We have for the first time demonstrated a neuroimaging phenotype of advanced paternal age before sustained parental interaction that correlates with later outcome.

Weight, Length, and Head Circumference Z-scores at 36 Weeks Are Not Accurate in Predicting Neurodevelopmental Impairment in Preterm Infants Less Than 30 Weeks Gestation (P11-062-19)

ObjectivesThe association between poor growth and neurodevelopmental impairment (NDI) among preterm infants is well-established whether due to inadequate nutrition, adverse events or both. The present study assessed the diagnostic accuracy of 36-week anthropometric measures, including corresponding < 10th and < 3rd percentile cut points to predict NDI in preterm infants. MethodsThis study included data from the PreM Growth Cohort Study for preterm infants < 30 weeks of gestational age (GA) and birth weights < 1500 grams. The accuracy with which measured weight, length and head circumference z-scores can predict cognitive impairment (Bayley-III Cognitive Composite score < 80) at 21 months corrected age (born in 2005–2014) and intellectual impairment (Wechsler Preschool and Primary Scale of Intelligence-3rd and 4th Edition (Intellectual test) score < 70) at 3-years corrected age (born in 2001–2014) was determined by the area under the receiver operating characteristic curve (AUROC). ResultsAt 21 months 98/621 (15.8%) of infants had low Bayley scores and 57/613 (9.3%) had low Intellectual test scores at 3 years. None of the AUROCs exceeded 0.6 and none were significantly different from 0.5. Sensitivities and specificities for the 10th and 3rd percentile cut points were equally poor, with most not exceeding 70% (Figures). The findings were similar between the Fenton 2013 and INTERGROWTH 2015 growth charts. The addition of morbidities increased the accuracy of predicting cognitive impairments except for infants with cerebral palsy, other morbidities had relatively marginal associations with impairment. ConclusionsPreterm infant measures of weight, length, and head circumference z-scores at 36 weeks, including corresponding < 10th and < 3rd percentile cut points, are not accurate as predictors of NDI. This study confirms previous findings that preterm infants show some “catch up” in weight relative to growth references between 37–44 weeks GA. ClinicalTrials.gov Identifier: NCT03064022 Funding SourcesCanadian Foundation for Dietetic Research. Supporting Tables, Images and/or Graphs▪▪

Does progesterone prophylaxis to prevent preterm labour improve outcome? A randomised double-blind placebo-controlled trial (OPPTIMUM).

Progesterone prophylaxis is widely used to prevent preterm birth but is not licensed and there is little information on long-term outcome. To determine the effect of progesterone prophylaxis in women at high risk of preterm birth on obstetric, neonatal and childhood outcomes. Double-blind, randomised placebo-controlled trial. Obstetric units in the UK and Europe between February 2009 and April 2013. Women with a singleton pregnancy who are at high risk of preterm birth because of either a positive fibronectin test or a negative fibronectin test, and either previous spontaneous birth at ≤ 34 weeks+0 of gestation or a cervical length of ≤ 25 mm. Fibronectin test at 18+0 to 23+0 weeks of pregnancy to determine risk of preterm birth. Eligible women were allocated (using a web-based randomisation portal) to 200 mg of progesterone or placebo, taken vaginally daily from 22+0 to 24+0 until 34+0 weeks' gestation. Participants, caregivers and those assessing the outcomes were blinded to group assignment until data collection was complete. There were three primary outcomes, as follows: (1) obstetric - fetal death or delivery before 34+0 weeks' gestation; (2) neonatal - a composite of death, brain injury on ultrasound scan (according to specific criteria in the protocol) and bronchopulmonary dysplasia; and (3) childhood - the Bayley-III cognitive composite score at 22-26 months of age. In total, 96 out of 600 (16%) women in the progesterone group and 108 out of 597 (18%) women in the placebo group had the primary obstetric outcome [odds ratio (OR) 0.86, 95% confidence interval (CI) 0.61 to 1.22]. Forty-six out of 589 (8%) babies of women in the progesterone group and 62 out of 587 (11%) babies of women in the placebo group experienced the primary neonatal outcome [OR 0.72, 95% CI 0.44 to 1.17]. The mean Bayley-III cognitive composite score of the children at 2 years of age was 97.3 points [standard deviation (SD) 17.9 points; n = 430] in the progesterone group and 97.7 points (SD 17.5 points; n = 439) in the placebo group (difference in means -0.48, 95% CI -2.77 to 1.81). Overall compliance with the intervention was 69%. There were no major harms, although there was a trend of more deaths from trial entry to 2 years in the progesterone group (20/600) than in the placebo group (16/598) (OR 1.26, 95% CI 0.65 to 2.42). In this study, progesterone had no significant beneficial or harmful effects on the primary obstetric, neonatal or childhood outcomes.The OPPTIMUM trial is now complete. We intend to participate in a comprehensive individual patient-level data meta-analysis examining women with a singleton pregnancy with a variety of risk factors for preterm birth. Current Controlled Trials ISRCTN14568373. This trial was funded by the Medical Research Council (MRC) and managed by the National Institute for Health Research (NIHR) on behalf of the MRC-NIHR partnership.

Comparison of Second and Third Editions of the Bayley Scales in Children With Suspected Developmental Delay.

ObjectiveTo compare the scores of the Bayley Scales of Infant Development second edition (BSID-II) and the third edition, Bayley-III, in children with suspected developmental delay and to determine the cutoff score for developmental delay in the Bayley-III.MethodsChildren younger than 42 months (n=62) with suspected developmental delay who visited our department between 2014 and 2015 were assessed with both the BSID-II and Bayley-III tests.ResultsThe mean Bayley-III Cognitive Language Composite (CLC) score was 5.8 points higher than the mean BSID-II Mental Developmental Index (MDI) score, and the mean Bayley-III Motor Composite (MC) score was 7.9 points higher than the mean BSID-II Psychomotor Developmental Index (PDI) score. In receiver operating characteristic (ROC) analysis of a BSID-II MDI score <70, Bayley-III CLC scores showed a cutoff of 78.0 (96.6% sensitivity and 93.9% specificity). In ROC analysis of a BSID-II PDI score <70, the Bayley-III MC score showed a cutoff of 80.ConclusionThere was a strong correlation between the BSID-II and Bayley-III in children with suspected developmental delay. The Bayley-III identified fewer children with developmental delay. The recommended cutoff value for developmental delay increased from a BSID-II score of 70 to a Bayley-III CLC score of 78 and Bayley-III MC score of 80.

Effect of Supplemental Donor Human Milk Compared With Preterm Formula on Neurodevelopment of Very Low-Birth-Weight Infants at 18 Months

For many very low-birth-weight (VLBW) infants, there is insufficient mother's milk, and a supplement of pasteurized donor human milk or preterm formula is required. Awareness of the benefits of mother's milk has led to an increase in use of donor milk, despite limited data evaluating its efficacy. To determine if nutrient-enriched donor milk compared with formula, as a supplement to mother's milk, reduces neonatal morbidity, supports growth, and improves neurodevelopment in VLBW infants. In this pragmatic, double-blind, randomized trial, VLBW infants were recruited from 4 neonatal units in Ontario, Canada, within 96 hours of birth between October 2010 and December 2012. Follow-up was completed in July 2015. Infants were fed either donor milk or formula for 90 days or to discharge when mother's milk was unavailable. The primary outcome was the cognitive composite score on the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) at 18 months' corrected age (standardized mean, 100 [SD, 15]; minimal clinically important difference, 5 points). Secondary outcomes included Bayley-III language and motor composite scores, growth, and a dichotomous mortality and morbidity index. Of 840 eligible infants, 363 (43.2%) were randomized (181 to donor milk and 182 to preterm formula); of survivors, 299 (92%) had neurodevelopment assessed. Mean birth weight and gestational age of infants was 996 (SD, 272) g and 27.7 (2.6) weeks, respectively, and 195 (53.7%) were male. No statistically significant differences in mean Bayley-III cognitive composite score (adjusted scores, 92.9 in donor milk group vs 94.5 in formula group; fully adjusted mean difference, -2.0 [95% CI, -5.8 to 1.8]), language composite score (adjusted scores, 87.3 in donor milk group vs 90.3 in formula group; fully adjusted mean difference, -3.1 [95% CI, -7.5 to 1.3]), or motor composite score (adjusted scores, 91.8 in donor milk group vs 94.0 in formula group; fully adjusted mean difference, -3.7 [95% CI, -7.4 to 0.09]) were observed between groups. There was no statistically significant difference in infants positive for the mortality and morbidity index (43% in donor milk group, 40% in formula group) or changes in growth z scores. Among VLBW infants, use of supplemental donor milk compared with formula did not improve neurodevelopment at 18 months' corrected age. If donor milk is used in settings with high provision of mother's milk, this outcome should not be considered a treatment goal. isrctn.org Identifier: ISRCTN35317141.

Transcriptomics of maternal and fetal membranes can discriminate between gestational-age matched preterm neonates with and without cognitive impairment diagnosed at 18-24 months.

BackgroundNeurocognitive impairment among children born preterm may arise from complex interactions between genes and the intra-uterine environment.Objectives(1) To characterize the transcriptomic profiles of chorioamniotic membranes in preterm neonates with and without neurocognitive impairment via microarrays and (2) to determine if neonates with neurocognitive impairment can be identified at birth.Materials/MethodsA retrospective case-control study was conducted to examine the chorioamniotic transcriptome of gestational-age matched very preterm neonates with and without neurocognitive impairment at 18–24 months’ corrected-age defined by a Bayley-III Cognitive Composite Score <80 (n = 14 each). Pathway analysis with down-weighting of overlapping genes (PADOG) was performed to identify KEGG pathways relevant to the phenotype. Select differentially expressed genes were profiled using qRT-PCR and a multi-gene disease prediction model was developed using linear discriminant analysis. The model’s predictive performance was tested on a new set of cases and controls (n = 19 each).Results 1) 117 genes were differentially expressed among neonates with and without subsequent neurocognitive impairment (p<0.05 and fold change >1.5); 2) Gene ontology analysis indicated enrichment of 19 biological processes and 3 molecular functions; 3)PADOG identified 4 significantly perturbed KEGG pathways: oxidative phosphorylation, Parkinson’s disease, Alzheimer’s disease and Huntington’s disease (q-value <0.1); 4) 48 of 90 selected differentially expressed genes were confirmed by qRT-PCR, including genes implicated in energy metabolism, neuronal signaling, vascular permeability and response to injury (e.g., up-regulation of SEPP1, APOE, DAB2, CD163, CXCL12, VWF; down-regulation of HAND1, OSR1)(p<0.05); and 5) a multi-gene model predicted 18–24 month neurocognitive impairment (using the ratios of OSR1/VWF and HAND1/VWF at birth) in a larger, independent set (sensitivity = 74%, at specificity = 83%).ConclusionsGene expression patterns in the chorioamniotic membranes link neurocognitive impairment in preterm infants to neurodegenerative disease pathways and might be used to predict neurocognitive impairment. Further prospective studies are needed.

Performance of 2-year-old children after early surgery for congenital heart disease on the Bayley Scales of Infant and Toddler Development, Third Edition

BackgroundPrevious research on developmental outcomes of infants with congenital heart disease (CHD) has shown delays in both cognitive and motor skills. AimsTo describe outcomes on the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III) for infants with CHD and to compare those findings to published results for similar samples of infants assessed on the 2nd edition of the Bayley Scales (BSID-II). Study designProspective cohort. Participants and outcome measuresOf 50 infants with CHD who participated in this longitudinal study (2006–2008) at the Royal Children's Hospital in Melbourne, Australia, 47 were assessed on the Bayley-III (median age=24.5months), administered by a psychologist or neonatologist. Although neither assessor was blind to the CHD diagnosis, they were unaware of results of previous developmental assessments conducted in this longitudinal study. ResultsFor the Bayley-III cognitive composite score, 17.0% of infants showed mild delays (1–2 SD below the mean), 2.1% had moderate delays (2–3 SD below the mean), and none had severe delays (greater than 3 SD below the mean). Motor composite scores showed mild delays in 10.9% of infants and moderate delays in 2.2%; none had severe motor delays. These findings differ from study results using the BSID-II in similar infants. ConclusionsThe Bayley-III may underestimate developmental delay in 2-year-old children with CHD when compared to results of similar children tested at 12–36months of age on the BSID-II.