Association of Growth During Infancy with Neurodevelopment and Obesity in Children Born Very Preterm: The Environmental Influences on Child Health Outcomes Cohort.

OBJECTIVE: To evaluate associations between change in weight z score after neonatal intensive care unit (NICU) discharge and neurodevelopmental outcomes and obesity at 12-48 months of age among individuals born very preterm. STUDY DESIGN: This secondary analysis used data from infants born very preterm participating in the Environmental influences on Child Health Outcomes cohort (n = 1400). Growth during infancy was calculated as change in weight z score between NICU discharge and follow-up at a mean of 27 months of age. Very low weight gain was defined as a change in weight z score <-1.67; very high weight gain was a change in weight z score >1.67. Neurodevelopmental outcomes included the Bayley Scales of Infant and Toddler Development, Child Behavior Checklist 1.5-5 years, and Modified Checklist for Autism in Toddlers. Multivariable linear regression was used to estimate associations between increase in weight z score and neurodevelopmental outcomes. RESULTS: Very low weight gain between NICU discharge and follow-up (experienced by 6.4% of participants) was associated with lower scores on cognitive (adjusted mean difference: -4.26; 95% CI: -8.55, -0.04) and language (adjusted mean difference: -4.80; 95% CI: -9.70, -0.11) assessments. Very high weight gain (experienced by 13.6% of participants) was associated with an increased obesity risk (adjusted relative risk: 6.20; 95% CI: 3.99, 9.66) but not with neurodevelopmental outcomes. CONCLUSIONS: Very high weight gain in the first 12-48 months after NICU discharge was associated with a higher risk of obesity at follow-up; very low weight gain was associated with lower scores on cognitive and language assessments.

Neurodevelopmental and behavioral outcomes of very preterm infants: latent profile analysis in the Environmental influences on Child Health Outcomes (ECHO) Program.

BACKGROUND: Very preterm infants are at high risk for neurodevelopmental impairments. We used a child-centered approach (latent profile analysis [LPA]) to describe 2-year neurobehavioral profiles for very preterm infants based on cognitive, motor, and behavioral outcomes. We hypothesized that distinct outcome profiles would differ in the severity and co-occurrence of neurodevelopmental and behavioral impairment. METHODS: We studied children born <33 weeks' gestation from the Environmental influences on Child Health Outcomes Program with at least one neurobehavioral assessment at age 2 (Bayley Scales of Infant and Toddler Development, Child Behavior Checklist, Modified Checklist for Autism in Toddlers, cerebral palsy diagnosis). We applied LPA to identify subgroups of children with different patterns of outcomes. RESULTS: In 2036 children (52% male; 48% female), we found four distinct neurobehavioral profiles. Most children (~85%) were categorized into one of two profiles characterized by no/mild neurodevelopmental delay and a low prevalence of behavioral problems. Fewer children (~15%) fell into one of two profiles characterized by severe neurodevelopmental impairments. One profile consisted of children (5%) with co-occurring neurodevelopmental impairment and behavioral problems. CONCLUSION: Child-centered approaches provide a comprehensive, parsimonious description of neurodevelopment following preterm birth and can be useful for clinical and research purposes. IMPACT: Most research on outcomes for children born very preterm have reported rates of impairment in single domains. Child-centered approaches describe profiles of children with unique combinations of cognitive, motor, and behavioral strengths and weaknesses. We capitalized on data from the nationwide Environmental influences on Child Health Outcomes Program to examine these profiles in a large sample of children born <33 weeks gestational age. We found four distinct neurobehavioral profiles consisting of different combinations of cognitive, motor, and behavioral characteristics. This information could aid in the development of clinical interventions that target different profiles of children with unique developmental needs.

Associations between neighborhood characteristics and child well-being before and during the COVID-19 pandemic: A repeated cross-sectional study in the Environmental influences on Child Health Outcomes (ECHO) program.

The corona virus disease (COVID-19) pandemic disrupted daily life worldwide, and its impact on child well-being remains a major concern. Neighborhood characteristics affect child well-being, but how these associations were affected by the pandemic is not well understood. We analyzed data from 1039 children enrolled in the Environmental influences on Child Health Outcomes Program whose well-being was assessed using the Patient-Reported Outcomes Measurement Information System Global Health questionnaire and linked these data to American Community Survey (ACS) data to evaluate the impacts of neighborhood characteristics on child well-being before and during the pandemic. We estimated the associations between more than 400 ACS variables and child well-being t-scores stratified by race/ethnicity (non-Hispanic white vs. all other races and ethnicities) and the timing of outcome data assessment (pre-vs. during the pandemic). Network graphs were used to visualize the associations between ACS variables and child well-being t-scores. The number of ACS variables associated with well-being t-scores decreased during the pandemic period. Comparing non-Hispanic white with other racial/ethnic groups during the pandemic, different ACS variables were associated with child well-being. Multiple ACS variables representing census tract-level housing conditions and neighborhood racial composition were associated with lower well-being t-scores among non-Hispanic white children during the pandemic, while higher percentage of Hispanic residents and higher percentage of adults working as essential workers in census tracts were associated with lower well-being t-scores among non-white children during the same study period. Our study provides insights into the associations between neighborhood characteristics and child well-being, and how the COVID-19 pandemic affected this relationship.

Environmental influences on child health outcomes: cohorts of individuals born very preterm.

The National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) Program was designed to address solution-oriented research questions about the links between children's early life environment and their risks of pre-, peri-, and post-natal complications, asthma, obesity, neurodevelopmental disorders, and positive health. Children born very preterm are at increased risk for many of the outcomes on which ECHO focuses, but the contributions of environmental factors to this risk are not well characterized. Three ECHO cohorts consist almost exclusively of individuals born very preterm. Data provided to ECHO from cohorts can be used to address hypotheses about (1) differential risks of chronic health and developmental conditions between individuals born very preterm and those born at term; (2) health disparities across social determinants of health; and (3) mechanisms linking early-life exposures and later-life outcomes among individuals born very preterm. IMPACT: The National Institutes of Health's Environmental Influences on Child Health Outcomes Program is conducting solution-oriented research on the links between children's environment and health. Three ECHO cohorts comprise study participants born very preterm; these cohorts have enrolled, to date, 1751 individuals born in 14 states in the U.S. in between April 2002 and March 2020. Extensive data are available on early-life environmental exposures and child outcomes related to neurodevelopment, asthma, obesity, and positive health. Data from ECHO preterm cohorts can be used to address questions about the combined effects of preterm birth and environmental exposures on child health outcomes.

Prenatal and perinatal factors associated with neonatal neurobehavioral profiles in the ECHO Program.

BACKGROUND: Single-cohort studies have identified distinct neurobehavioral profiles that are associated with prenatal and neonatal factors based on the NICU Network Neurobehavioral Scale (NNNS). We examined socioeconomic, medical, and substance use variables as predictors of NNNS profiles in a multi-cohort study of preterm and term-born infants with different perinatal exposures. METHODS: We studied 1112 infants with a neonatal NNNS exam from the Environmental influences on Child Health Outcomes (ECHO) consortium. We used latent profile analysis to characterize infant neurobehavioral profiles and generalized estimating equations to determine predictors of NNNS profiles. RESULTS: Six distinct neonatal neurobehavioral profiles were identified, including two dysregulated profiles: a hypo-aroused profile (16%) characterized by lethargy, hypotonicity, and nonoptimal reflexes; and a hyper-aroused profile (6%) characterized by high arousal, excitability, and stress, with low regulation and poor movement quality. Infants in the hypo-aroused profile were more likely to be male, have younger mothers, and have mothers who were depressed prenatally. Infants in the hyper-aroused profile were more likely to be Hispanic/Latino and have mothers who were depressed or used tobacco prenatally. CONCLUSIONS: We identified two dysregulated neurobehavioral profiles with distinct perinatal antecedents. Further understanding of their etiology could inform targeted interventions to promote positive developmental outcomes. IMPACT: Prior research on predictors of neonatal neurobehavior have included single-cohort studies, which limits generalizability of findings. In a multi-cohort study of preterm and term-born infants, we found six distinct neonatal neurobehavioral profiles, with two profiles being identified as dysregulated. Hypo- and hyper-aroused neurobehavioral profiles had distinct perinatal antecedents. Understanding perinatal factors associated with dysregulated neurobehavior could help promote positive developmental outcomes.

Rapid Whole-Genomic Sequencing and a Targeted Neonatal Gene Panel in Infants With a Suspected Genetic Disorder.

Importance: Genomic testing in infancy guides medical decisions and can improve health outcomes. However, it is unclear whether genomic sequencing or a targeted neonatal gene-sequencing test provides comparable molecular diagnostic yields and times to return of results. Objective: To compare outcomes of genomic sequencing with those of a targeted neonatal gene-sequencing test. Design, Setting, and Participants: The Genomic Medicine for Ill Neonates and Infants (GEMINI) study was a prospective, comparative, multicenter study of 400 hospitalized infants younger than 1 year of age (proband) and their parents, when available, suspected of having a genetic disorder. The study was conducted at 6 US hospitals from June 2019 to November 2021. Exposure: Enrolled participants underwent simultaneous testing with genomic sequencing and a targeted neonatal gene-sequencing test. Each laboratory performed an independent interpretation of variants guided by knowledge of the patient's phenotype and returned results to the clinical care team. Change in clinical management, therapies offered, and redirection of care was provided to families based on genetic findings from either platform. Main Outcomes and Measures: Primary end points were molecular diagnostic yield (participants with ≥1 pathogenic variant or variant of unknown significance), time to return of results, and clinical utility (changes in patient care). Results: A molecular diagnostic variant was identified in 51% of participants (n = 204; 297 variants identified with 134 being novel). Molecular diagnostic yield of genomic sequencing was 49% (95% CI, 44%-54%) vs 27% (95% CI, 23%-32%) with the targeted gene-sequencing test. Genomic sequencing did not report 19 variants found by the targeted neonatal gene-sequencing test; the targeted gene-sequencing test did not report 164 variants identified by genomic sequencing as diagnostic. Variants unidentified by the targeted genomic-sequencing test included structural variants longer than 1 kilobase (25.1%) and genes excluded from the test (24.6%) (McNemar odds ratio, 8.6 [95% CI, 5.4-14.7]). Variant interpretation by laboratories differed by 43%. Median time to return of results was 6.1 days for genomic sequencing and 4.2 days for the targeted genomic-sequencing test; for urgent cases (n = 107) the time was 3.3 days for genomic sequencing and 4.0 days for the targeted gene-sequencing test. Changes in clinical care affected 19% of participants, and 76% of clinicians viewed genomic testing as useful or very useful in clinical decision-making, irrespective of a diagnosis. Conclusions and Relevance: The molecular diagnostic yield for genomic sequencing was higher than a targeted neonatal gene-sequencing test, but the time to return of routine results was slower. Interlaboratory variant interpretation contributes to differences in molecular diagnostic yield and may have important consequences for clinical management.

NICU-based stress response and preterm infant neurobehavior: exploring the critical windows for exposure.

BACKGROUND: Exposure to maternal stress in utero negatively impacts cognitive and behavioral outcomes of children born at term. The neonatal intensive care unit (NICU) can be stressful for preterm infants during a developmental period corresponding to the third trimester of gestation. It is unknown whether stress in the NICU contributes to adverse neurodevelopment among NICU graduates. The aim was to examine the association between salivary cortisol and early neurodevelopment in preterm infants. METHODS: We examined the association between cortisol levels during the NICU hospitalization and subsequent performance on the NICU Network Neurobehavioral Scales (NNNS), estimating time-specific associations and considering sex differences. RESULTS: Eight hundred and forty salivary cortisol levels were measured from 139 infants. Average cortisol levels were inversely associated with NNNS Regulation scores for both male and female infants (ß = -0.19; 95% CI: -0.44, -0.02). Critical developmental windows based on postmenstrual age were identified, with cortisol measured <30 weeks PMA positively associated with Habituation and Lethargy scores (ß = 0.63-1.04). Critical developmental windows based on chronological age were identified, with cortisol measured in the first week of life inversely associated with Attention score (ß = -1.01 for females; -0.93 for males). CONCLUSIONS: Stress in the NICU at specific developmental time points may impact early preterm infant neurodevelopment. IMPACT: Stress in the neonatal intensive care unit can impact the neurodevelopmental trajectory of premature infants. The impact of stress is different at different points in development. The impact of stress is sexually dimorphic.

Trajectories of depressive symptoms among mothers of preterm and full-term infants in a national sample.

To examine postpartum depressive symptom trajectories from birth to age 5 and their risk factors in a national sample of mothers of preterm and full-term infants. The racially and ethnically diverse sample comprised 11,320 maternal participants (Mage = 29; SD = 5.9) in the Environmental influences on Child Health Outcomes (ECHO) Program in the USA with data on newborn gestational age at birth (≥ 22 weeks) and maternal depression symptoms during the first 5 years following childbirth. Growth mixture models determined the number and trajectory of postpartum depression classes among women in the preterm and full-term groups, and we examined predictors of class membership. Five trajectories described depressive symptoms for both groups; however, notable differences were observed. One in 5 mothers of preterm infants developed clinically relevant depressive symptoms over time compared with 1 in 10 mothers of full-term infants. Among women who delivered preterm compared with those who delivered full-term, symptoms were more likely to increase over time and become severe when offspring were older. Distinct subgroups describe mothers' depressive symptom trajectories through 5 years following childbirth. Mild to moderate depressive symptoms may onset or persist for many women beyond the initial postpartum period regardless of newborn gestational age at birth. For women with preterm infants, initially mild symptoms may increase to high levels of severity during the preschool and toddler years.

Clinical validation of the Neonatal Infant Stressor Scale with preterm infant salivary cortisol.

BACKGROUND: Preterm infants face unique stress states in early life. Early-life stress has been associated with changes in cortisol reactivity and behavioral abnormalities later in childhood in non-preterm populations. The Neonatal Infant Stressor Scale (NISS) has been used to estimate infant stress in the neonatal intensive care unit (NICU) but has not been biomarker validated. The relationship between NISS scores and salivary cortisol is unknown. The aim of this study is to test the association between NISS scores and salivary cortisol in the NICU Hospital Exposures and Long-Term Health (NICU-HEALTH) preterm birth cohort. METHODS: Three hundred and eighty-six salivary cortisol specimens were collected from 125 NICU-HEALTH participants during the NICU hospitalization. NISS scores were calculated to represent the infant's experience in the 6 hours prior to specimen collection. Adjusted mixed-effect regression models were used to assess the association between each NISS score and salivary cortisol. RESULTS: Acute and total NISS scores were significantly associated with salivary cortisol level (P = 0.002 and 0.05, respectively). The chronic NISS score was not associated with salivary cortisol levels. Caffeine treatment and postmenstrual age of the infant were important covariates in all models. CONCLUSION: Acute and total NISS score are associated with salivary cortisol level in hospitalized moderately preterm infants.

The association of prenatal exposure to intensive traffic with early preterm infant neurobehavioral development as reflected by the NICU Network Neurobehavioral Scale (NNNS).

INTRODUCTION: Traffic-related air pollution has been shown to be neurotoxic to the developing fetus and in term-born infants during early childhood. It is unknown whether there is an increased risk of adverse neurobehavioral outcome in preterm infants exposed to higher levels of air pollution during the fetal period. OBJECTIVE: To assess the association between prenatal exposure to traffic-related air pollution on early preterm infant neurobehavior. METHODS: Air pollution exposure was estimated by two methods: density of major roads and density of vehicle-miles traveled (VMT), each at multiple buffering areas around residential addresses. We examined the association between prenatal exposure to traffic-related air pollution and performance on the Neonate Intensive Care Unit (NICU) Network Behavioral Scale (NNNS), a measure of neurobehavioral outcome in infancy for 240 preterm neonates enrolled in the NICU-Hospital Exposures and Long-Term Health cohort. Linear regression analysis was conducted for exposure and individual NNNS subscales. Latent profile analysis (LPA) was applied to classify infants into distinct NNNS phenotypes. Multinomial logistic regression analysis was conducted between exposure and LPA groups. Covariates included gestational age, birth weight z-score, post-menstrual age at NNNS assessment, socioeconomic status, race, delivery type, maternal smoking status, and medical morbidities during the NICU stay. RESULTS: Among all 13 NNNS subscales, hypotonia was significantly associated with VMT (104 vehicle-mile/km2) in 150 m (ß = 0.01, P-value<0.001), 300 m (ß = 0.01, P-value = 0.003), and 500 m (ß = 0.01, P-value = 0.002) buffering areas, as well as with road density in a 500 m buffering area (ß = 0.03, P-value = 0.03). We identified three NNNS phenotypes by LPA. Among them, high density of major roads within 150 m, 300 m, and 500 m buffers of the residential address was significantly associated with the same phenotype (P < 0.05). CONCLUSION: Prenatal exposure to intensive air pollution emitted from major roads may impact early neurodevelopment of preterm infants. Motor development may be particularly sensitive to air pollution-related toxicity.

A framework for assessing the impact of chemical exposures on neurodevelopment in ECHO: Opportunities and challenges.

The Environmental influences on Child Health Outcomes (ECHO) Program is a research initiative funded by the National Institutes of Health that capitalizes on existing cohort studies to investigate the impact of early life environmental factors on child health and development from infancy through adolescence. In the initial stage of the program, extant data from 70 existing cohort studies are being uploaded to a database that will be publicly available to researchers. This new database will represent an unprecedented opportunity for researchers to combine data across existing cohorts to address associations between prenatal chemical exposures and child neurodevelopment. Data elements collected by ECHO cohorts were determined via a series of surveys administered by the ECHO Data Analysis Center. The most common chemical classes quantified in multiple cohorts include organophosphate pesticides, polychlorinated biphenyls, polybrominated diphenyl ethers, environmental phenols (including bisphenol A), phthalates, and metals. For each of these chemicals, at least four ECHO cohorts also collected behavioral data during infancy/early childhood using the Child Behavior Checklist. For these chemicals and this neurodevelopmental assessment (as an example), existing data from multiple ECHO cohorts could be pooled to address research questions requiring larger sample sizes than previously available. In addition to summarizing the data that will be available, the article also describes some of the challenges inherent in combining existing data across cohorts, as well as the gaps that could be filled by the additional data collection in the ECHO Program going forward.

Long-Term Outcomes of Small for Gestational Age Twins Born at 34 Weeks or Later.

OBJECTIVE: This article aims to compare long-term neurodevelopmental and health outcomes of twins born at 34 weeks or later, based on the presence of small for gestational age (SGA). STUDY DESIGN: This study is a mail-based survey of twin gestations delivered by a single practice. We compared twins with and without SGA delivered at ≥34 weeks. There were two primary outcomes for this study: a composite of major adverse outcomes (death; cerebral palsy; necrotizing enterocolitis; chronic renal, heart, or lung disease) and a composite of minor adverse outcomes (learning disability, speech therapy, occupational therapy, physical therapy). Regression analysis was performed to control for clustering of outcomes within twin pairs. RESULTS: A total of 712 children were included. Comparing twins with birthweights <10% to ≥10%, there were no significant differences in rates of composite major morbidities (3.2 vs. 1.4%, p = 0.109) or composite minor morbidities (43.6 vs. 39.3%, p = 0.279). Comparing twins with birthweights <5% to ≥5%, the rates of major morbidities were low in both groups, but significantly higher in the group with birthweights <5% (4.4 vs. 1.6%, p = 0.046). There were no significant differences seen in the composite minor morbidities (46.7 vs. 39.7%, p = 0.134). Twins with birthweights <5% were significantly more likely to have childhood cardiac disease (2.9 vs. 0.7%, p = 0.041). CONCLUSION: Twins with SGA <10% born at ≥34 weeks have similar long-term neurodevelopmental and health outcomes compared with twins with normal birthweights. Birthweight less than 5th percentile is associated with an increased risk of major morbidity, specifically cardiac disease, but the absolute risk is low.

Toddler temperament and prenatal exposure to lead and maternal depression.

BACKGROUND: Temperament is a psychological construct that reflects both personality and an infant's reaction to social stimuli. It can be assessed early in life and is stable over time Temperament predicts many later life behaviors and illnesses, including impulsivity, emotional regulation and obesity. Early life exposure to neurotoxicants often results in developmental deficits in attention, social function, and IQ, but environmental predictors of infant temperament are largely unknown. We propose that prenatal exposure to both chemical and non-chemical environmental toxicants impacts the development of temperament, which can itself be used as a marker of risk for maladaptive neurobehavior in later life. In this study, we assessed associations among prenatal and early life exposure to lead, mercury, poverty, maternal depression and toddler temperament. METHODS: A prospective cohort of women living in the Mexico City area were followed longitudinally beginning in the second trimester of pregnancy. Prenatal exposure to lead (blood, bone), mercury, and maternal depression were assessed repeatedly and the Toddler Temperament Scale (TTS) was completed when the child was 24 months old. The association between each measure of prenatal exposure and performance on individual TTS subscales was evaluated by multivariable linear regression. Latent profile analysis was used to classify subjects by TTS performance. Multinomial regression models were used to estimate the prospective association between prenatal exposures and TTS performance. RESULTS: 500 mother-child pairs completed the TTS and had complete data on exposures and covariates. Three latent profiles were identified and categorized as predominantly difficult, intermediate, or easy temperament. Prenatal exposure to maternal depression predicted increasing probability of difficult toddler temperament. Maternal bone lead, a marker of cumulative exposure, also predicted difficult temperament. Prenatal lead exposure modified this association, suggesting that joint exposure in pregnancy to both was most toxic. CONCLUSIONS: Maternal depression predicts difficult temperament and concurrent prenatal exposure to maternal depression and lead predicts a more difficult temperament phenotype in 2 year olds. The role of temperament as an intermediate variable in the path from prenatal exposures to neurobehavioral deficits and other health effects deserves further study.

Developmental Milestones.

• On the basis of observational studies (level C), preterm birth is a leading cause of neurodevelopmental disabilities in children, and the degree of neurodevelopmental disability is inversely correlated with gestational age at birth. When comparing performance of preterm children to developmental norms, "corrected age" or age from due date rather than birth date should be used for the first 24 to 36 months. • On the basis of observational studies (level C), clinicians should pay specific attention to sensory function in children born preterm because the incidence of visual and hearing impairments is higher in preterm than term children. Due to the elevated risk of cognitive and behavioral disabilities, clinicians caring for children born preterm should be vigilant when performing developmental assessments to improve outcomes. • On the basis of observational studies (level C), early identification of developmental delays allows for referral to therapeutic services, and children referred for early intervention are more likely to make gains in developmental milestones.

Impact of hospital-based environmental exposures on neurodevelopmental outcomes of preterm infants.

PURPOSE OF REVIEW: Over 300,000 infants are hospitalized in a neonatal intensive care unit (NICU) in the United States annually during a developmental period critical to later neurobehavioral function. Environmental exposures during the fetal period and infancy have been shown to impact long-term neurobehavioral outcomes. This review summarizes evidence linking NICU-based environmental exposures to neurodevelopmental outcomes of children born preterm. RECENT FINDINGS: Preterm infants experience multiple exposures important to neurodevelopment during the NICU hospitalization. The physical layout of the NICU, management of light and sound, social interactions with parents and NICU staff, and chemical exposures via medical equipment are important to long-term neurobehavioral outcomes in this highly vulnerable population. SUMMARY: Existing research documents NICU-based exposure to neurotoxic chemicals, aberrant light, excess sound, and restricted social interaction. In total, this creates an environment of co-existing excesses (chemicals, light, sound) and deprivation (touch, speech). The full impact of these co-exposures on the long-term neurodevelopment of preterm infants has not been adequately elucidated. Research into the importance of the NICU from an environmental health perspective is in its infancy, but could provide understanding about critical modifiable factors impacting the neurobehavioral health of hundreds of thousands of children each year.

Incidences and sociodemographics of specific congenital heart diseases in the United States of America: an evaluation of hospital discharge diagnoses.

Current estimates of the incidence of congenital heart disease (CHD) are derived from small clinical studies and metaanalyses. For the true incidence of CHD in the United States of America to be estimated, a single large representative population must be analyzed. All the data in this study were derived from the Nationwide Inpatient Sample database. The study determined the overall and lesion-specific incidences of CHD diagnoses among all birth hospitalizations in 2008, stratified by race, gender, socioeconomic status, and hospital geographic location. The study identified 13,093 CHD diagnoses among 1,204,887 birth hospitalizations, yielding an incidence of 10.8 per 1,000, with a predominance of mild lesions and septal defects. Atrial septal defect (ASD) and pulmonic stenosis were more common among females, whereas aortic stenosis, coarctation of the aorta, hypoplastic left heart syndrome, and d-transposition of great arteries were more common among males. No racial difference was observed in the overall CHD incidence. However, isolated patent ductus arteriosus (PDA) and ventricular septal defects (VSDs) were more common among Caucasians, whereas ASDs were more common among Hispanics. The incidences of CHD diagnoses were similar for all socioeconomic classes except the lowest socioeconomic class, which had a significantly lower CHD incidence. There was no geographic or seasonal variation in CHD incidence. This study demonstrated the incidence of echocardiographically confirmed CHD diagnosis to be 10.8 per 1,000 live births, marked by a high proportion of mild cardiac lesions and isolated PDAs. The high incidence of isolated PDAs in this study may be explained by the inclusion of only CHD diagnoses during birth hospitalization.