Preterm birth and risk of epilepsy in Swedish adults

Underlying Disorders in Children With Infection-Related Acute Encephalopathy

BACKGROUND

Various factors contribute to the development of infection-related acute encephalopathy (AE) in children, such as infectious agents and chronic underlying disorders. We studied underlying disorders in children with AE to identify predisposing factors of AE.

METHODS

We investigated underlying disorders or past histories in patients with two types of AE from the database in the Tokai area of Japan between 2009 and 2022: 204 patients with AE with reduced subcortical diffusion (AED) and 137 with clinically mild encephalopathy with a reversible splenial lesion (MERS). We compared them with 89 patients with acute disseminated encephalomyelitis (ADEM) to clarify the specific disorders in the two AE types.

RESULTS

The prevalence of underlying disorders in AED (34%, 70 patients) was significantly higher than that in ADEM (12%, 11 patients) (P < 0.01). The prevalence of underlying disorders in MERS was 23% (32 patients). The underlying disorders included seizure disorders, premature birth, genetic/congenital disorders, and endocrine/renal diseases. In patients with seizure disorders in AED, five patients (18%) had Dravet syndrome and four (15%) had West syndrome, whereas none with MERS had these syndromes. Twenty-five (12%) of 204 patients with AED, three (2%) with MERS, and one (1%) with ADEM were preterm or low birth weight.

CONCLUSIONS

The high prevalence of seizure disorders suggests that seizure susceptibility is an important predisposing factor in AED. Premature birth also has an impact on the development of AED. Caution is required regarding the development of AE in patients with chronic seizure disorders or premature birth.

Accelerated Aging and the Life Course of Individuals Born Preterm

Individuals born preterm have shorter lifespans and elevated rates of chronic illness that contribute to mortality risk when compared to individuals born at term. Emerging evidence suggests that individuals born preterm or of low birthweight also exhibit physiologic and cellular biomarkers of accelerated aging. It is unclear whether, and to what extent, accelerated aging contributes to a higher risk of chronic illness and mortality among individuals born preterm. Here, we review accelerated aging phenotypes in adults born preterm and biological pathways that appear to contribute to accelerated aging. We highlight biomarkers of accelerated aging and various resiliency factors, including both pharmacologic and non-pharmacologic factors, that might buffer the propensity for accelerated aging among individuals born preterm.

Preterm or early term birth and risk of attention-deficit/hyperactivity disorder: a national cohort and co-sibling study

PURPOSE

To examine risks of attention-deficit/hyperactivity disorder (ADHD) in preterm and early term birth survivors, and potential sex-specific differences.

METHODS

A national cohort study was conducted of all 4061,795 singletons born in Sweden in 1973-2013 who survived infancy, followed up for ADHD identified from nationwide diagnoses and medications through 2018. Poisson regression was used to compute prevalence ratios (PRs), adjusting for sociodemographic and perinatal factors. Co-sibling analyses assessed for confounding by unmeasured shared familial (genetic or environmental) factors.

RESULTS

ADHD prevalences by gestational age at birth were 12.1% for extremely preterm (22-27 weeks), 7.0% for moderately preterm (28-33 weeks), 5.7% for late preterm (34-36 weeks), 6.1% for all preterm (<37 weeks), 5.2% for early term (37-38 weeks), and 4.5% for full-term (39-41 weeks). Adjusted PRs comparing extremely preterm, all preterm, or early term versus full-term, respectively, were 2.35 (95% CI, 2.15-2.57), 1.28 (1.25-1.31), and 1.12 (1.10-1.13) among males, and 2.46 (2.17-2.78), 1.24 (1.20-1.28), and 1.08 (1.06-1.10) among females (P < .001 for each). These associations were virtually unchanged after controlling for shared familial factors. Both spontaneous and medically indicated preterm birth were associated with ADHD (adjusted PRs, 1.21; 95% CI, 1.18-1.24; and 1.39; 1.34-1.43, respectively).

CONCLUSIONS

In this large cohort, preterm and early term birth were associated with increased risks of ADHD in males and females, independently of covariates and shared familial factors.

Mendelian randomization approach shows no causal effects of gestational age on epilepsy in offspring

BACKGROUND

Observational studies have suggested that gestational age was associated with the risk of epilepsy later in life. However, it remains unclear whether the association is of a causal nature.

METHODS

Two-sample Mendelian randomization (MR) was performed to assess the causal effect of fetal gestational age on epilepsy. Genome-wide association studies (GWAS) summary statistics of gestational duration, early preterm birth, preterm birth, and postterm birth were from the Early Growth Genetics (EGG) Consortium. GWAS summary-level data on epilepsy were obtained from the International League Against Epilepsy Consortium (ILAEC) and FinnGen Consortium. The inverse-variance weighted (IVW) was applied as the primary method to calculate estimates, which were further validated using other sensitivity analyses.

RESULTS

There was not yet strong evidence of causal associations between gestational age and epilepsy of ILAEC (early preterm birth: odds ratio [OR]=1.01, 95% CI: 0.99-1.03, P = 0.441; preterm birth: OR=1.01, 95% CI: 0.96-1.07, P = 0.617; postterm birth: OR=0.96, 95% CI: 0.89-1.04, P = 0.357; gestational duration: OR=0.90, 95% CI: 0.75-1.07, P = 0.214). Similar results were obtained in the replication stage using epileptic samples from the FinnGen Consortium. Finally, a meta-analysis of the causal estimates from the ILAEC and FinnGen Consortium showed consistent results. No obvious pleiotropy was found throughout the MR study.

CONCLUSIONS

The present study indicated that gestational age, either preterm birth or postterm birth, might not be causally associated with the risk of epilepsy. Further studies are warranted to evaluate the potential mechanisms underlying the epidemiological relationship between preterm birth and epilepsy.

Perinatal adversities and risk of epilepsy after traumatic brain injury: A Danish nationwide cohort study

Objectives

Traumatic brain injury (TBI) and perinatal adversities such as low gestational age at birth, low birth weight, low Apgar, and being born small for gestational age are well‐established risk factors for epilepsy. We examined whether perinatal adversities modified the risk of epilepsy after TBI in a nationwide cohort study of Danish singletons born from 1982 to 2011.

Materials and Methods

We categorized perinatal adversities as a composite measure of preterm delivery, low birth weight, low Apgar score, or being born small for gestational age. Cox regression and competing risk regression were used to estimate the risk of epilepsy after TBI according to such perinatal adversities. The study included 1,715,095 singletons (51.1% males). The mean age at end of follow‐up was 19.3 years (Interquartile range [IQR] = 12.1–26.3). During follow‐up, 85,636 persons (58.2% males) sustained a TBI and 18,064 developed epilepsy (50.7% males), of whom 1329 persons had a preceding TBI.

Results

The hazard ratio (HR) of epilepsy in persons with perinatal adversities was 1.19 (95% confidence interval [CI] 1.15–1.24), compared to persons without. The HR of epilepsy in persons with TBI was 2.31 (95% CI 2.18–2.45) compared to persons without TBI, but this risk was not modified by perinatal adversities (p = 0.2460).

Conclusions

Perinatal adversities and TBI both increased the risk of epilepsy, but the risk of epilepsy after TBI was not modified by these perinatal adversities.

The effect of gestational age on major neurodevelopmental disorders in preterm infants

BACKGROUND

Preterm infants have an increased risk of neurodevelopmental disorders. We established a direct quantitative comparison of the association between the degree of prematurity and three different neurodevelopmental disorders.

METHODS

In this cohort study, we combined data from 995,498 children in the Danish Medical Birth Register, from birth years 1997-2013, with information on cerebral palsy, epilepsy, and special educational needs. We estimated the gestational week-specific prevalence and risk for each of the disorders.

RESULTS

The risk ratio of cerebral palsy at gestational weeks 21-24, compared to term birth, was more than ten times higher than for the two other disorders. The prevalence of epilepsy and special educational needs declined almost parallel, with 9.2% (4.6%-13.5%) and 12.5% (11.2%-13.7%), respectively, per week of gestation toward term birth. Cerebral palsy did not decline similarly: from gestational weeks 21-24 until week 29 the prevalence declined insignificantly by 0.6% (-11.1%-11.0%) per week; whereas from week 29 until term, the prevalence declined markedly by 36.7% (25.9%-45.9%) per week.

CONCLUSIONS

The prevalence and risk of cerebral palsy are affected differently by the degree of prematurity compared with epilepsy and special educational needs, possibly reflecting important differences in cerebral pathophysiology.

IMPACT

For each week of gestation toward term birth, there was a clear log-linear decline in the prevalence of early childhood epilepsy and special educational needs. In contrast, the risk of cerebral palsy was high at the earliest gestational age, and the prevalence did not decline significantly until gestational week 29, from where it declined notably by nearly 40% for each week of gestation until term birth. Our results indicate important differences in the pathophysiological processes that associate preterm birth with these three neurodevelopmental disorders.

An overview of adult health outcomes after preterm birth

Preterm birth (gestational age < 37 completed weeks) has increased in prevalence in most countries in the past 20 years and now affects nearly 11% of all births worldwide. Because of treatment advances introduced in the 1970s-1980s, >95% of preterm infants who receive modern neonatal and pediatric care now survive into adulthood. The earliest birth cohorts to benefit from those advances are now in their 4th and 5th decades of life. A growing number of large cohort studies have investigated the long-term health sequelae in adulthood. Evidence has consistently shown that adult survivors of preterm birth have increased risks of chronic disorders involving various organ systems, including cardiovascular, endocrine/metabolic, respiratory, renal, neurodevelopmental, and psychiatric disorders, which either persist from childhood into adulthood or sometimes first manifest in adulthood. These disorders also lead to moderately (30% to 50%) increased mortality risks during early to mid-adulthood among persons born preterm compared with full-term, and even higher risks among those born at the earliest gestational ages. However, the majority of persons born preterm have low absolute risks of these outcomes and good self-reported quality of life in adulthood. Priorities for future research include the assessment of long-term health sequelae of preterm birth in racially and economically diverse populations, additional follow-up of existing cohorts into older adulthood, elucidation of outcomes by preterm birth subtype (e.g., different underlying causes) to improve risk stratification, and identification of protective factors that will support the long-term health trajectory and well-being of preterm-born adults.

Cortical Gray Matter Injury in Encephalopathy of Prematurity: Link to Neurodevelopmental Disorders

Preterm-born infants frequently suffer from an array of neurological damage, collectively termed encephalopathy of prematurity (EoP). They also have an increased risk of presenting with a neurodevelopmental disorder (e.g., autism spectrum disorder; attention deficit hyperactivity disorder) later in life. It is hypothesized that it is the gray matter injury to the cortex, in addition to white matter injury, in EoP that is responsible for the altered behavior and cognition in these individuals. However, although it is established that gray matter injury occurs in infants following preterm birth, the exact nature of these changes is not fully elucidated. Here we will review the current state of knowledge in this field, amalgamating data from both clinical and preclinical studies. This will be placed in the context of normal processes of developmental biology and the known pathophysiology of neurodevelopmental disorders. Novel diagnostic and therapeutic tactics required integration of this information so that in the future we can combine mechanism-based approaches with patient stratification to ensure the most efficacious and cost-effective clinical practice.

Preterm birth and mortality in adulthood: a systematic review

Preterm birth (gestational age < 37 weeks) has a worldwide prevalence of nearly 11%, and >95% of preterm infants who receive modern neonatal and pediatric care now survive into adulthood. However, improved early survival has been accompanied by long-term increased risks of various chronic disorders, prompting investigations to determine whether preterm birth leads to higher mortality risks in adulthood. A systematic review identified eight studies with a total of 6,594,424 participants that assessed gestational age at birth in relation to all-cause or cause-specific mortality at any ages ≥18 years. All six studies that included persons born in 1967 or later reported positive associations between preterm birth and all-cause mortality in adulthood (attained ages, 18-45 years). Most adjusted relative risks ranged from 1.2 to 1.6 for preterm birth, 1.1 to 1.2 for early term birth (37-38 weeks), and 1.9 to 4.0 for extremely preterm birth (22-27 weeks), compared with full-term birth (variably defined but including 39-41 weeks). These findings appeared independent of sociodemographic, perinatal, and maternal factors (all studies), and unmeasured shared familial factors in co-sibling analyses (assessed in four studies). Four of these studies also explored cause-specific mortality and reported associations with multiple causes, including respiratory, cardiovascular, endocrine, and neurological. Two smaller studies based on an earlier cohort born in 1915-1929 found no clear association with all-cause mortality but positive associations with selected cause-specific mortality. The overall evidence indicates that premature birth during the past 50 years is associated with modestly increased mortality in early to mid-adulthood.

Pregnancy and Epilepsy: a Korean Tertiary Epilepsy Center Review

BACKGROUND

Pregnancy in women with epilepsy (WWE) is known to have a higher risk for fetal development complications, which may include congenital malformations. Unfortunately, information pertaining to pregnancy in WWE is difficult to obtain because there are considerable ethical issues preventing these studies from being conducted on pregnant women. Therefore, this study investigated the pregnancies of Korean WWE in a tertiary epilepsy center to observe data resulting from the outcome of the pregnancies.

METHODS

This was a retrospective study of 48 pregnant WWE who were treated at the regional tertiary epilepsy center. All records of hospital visits before and after the period of pregnancy were analyzed to obtain information about the seizures as well as pregnancy-related outcomes, including the status of the newborns' conditions.

RESULTS

The subject group consisted of 31 (63.3%) with partial epilepsy, 6 (12.5%) with generalized epilepsy, and 11 (22.9%) with unclassified epilepsy. There were 27 subjects who took one antiepileptic drug (AED), and 12 who took two AEDs. The most commonly used drug was lamotrigine (29.8%). Of the 48 WWE involved in the study, 31 underwent caesarian sections and 17 opted for natural birth. Thirty-nine (81.3%) delivered at full-term, but 9 (18.7%) delivered at preterm. Compared to full-term infants, pre-mature infants showed lower birth weight, smaller head circumference, shorter height, and lower 1-minute Apgar scores, but seizure frequencies of the mothers did not differ.

CONCLUSION

In WWE, epilepsy classification, number of AEDs taken, and frequency of seizures are not significantly correlated with delivery and fetal condition. This data could be used as a clinical reference for physicians to provide useful information to WWE if they are concerned about their pregnancies.

Medication Utilization at School Age for Children Born Preterm

We explored medication use by children born preterm at 5-8 years of age. Compared with children born at full term, children born preterm had higher medication use that included most therapeutic classifications. Although asthma and chronic lung disease influenced use, prematurity remained an independent risk factor.

Incidence of epilepsy in children born prematurely and small for gestational age at term gestation: A population-based cohort study

AIM

This study assessed the incidence of epilepsy in preterm infants and those small for gestational age (SGA) at term and identified risk factors associated with higher epilepsy incidence in these children.

METHODS

We enrolled children (from 2000 to 2010) who were premature (n = 21 474) or SGA (n = 2206); we then included a matched control cohort (n = 94 720). Cox regression was used to assess the epilepsy risk in preterm and SGA children. To determine the associated factors for epilepsy, the preterm and SGA infants were divided into six groups according to the common complications related to brain development and were separated into three subgroups based on birthweight (BW).

RESULTS

The cumulative incidence of epilepsy was significantly higher in preterm or SGA children than in the control group. The overall incidence densities (per 1000 person-years) of epilepsy were: 0.37 in the control, 2.96 in the preterm, 2.90 in the SGA, 15.9 in the preterm with cerebral haemorrhage, 14.6 in the SGA with cerebral haemorrhage, 6.92 in the preterm with asphyxia, 3.82 in the SGA with asphyxia, 14.3 in the preterm with congenital brain anomalies, and 25.4 in the SGA with congenital brain anomalies cohorts. Infants with BW < 1000 g had a higher incidence of epilepsy than those with BW ≥2500 g.

CONCLUSIONS

Preterm and SGA infants had an increased risk of epilepsy in childhood, and the incidence of epilepsy increased with decreasing BW. Several perinatal factors (e.g. intracranial haemorrhage, birth asphyxia and congenital brain anomalies) are associated with a higher incidence of later epilepsy.

Updates on an At-Risk Population: Late-Preterm and Early-Term Infants

The American Academy of Pediatrics published a clinical report on late-preterm (LPT) infants in 2007 that was largely based on a summary of a 2005 workshop convened by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, at which a change in terminology from "near term" to "late preterm" was proposed. This paradigm-shifting recommendation had a remarkable impact: federal agencies (the Centers for Disease Control and Prevention), professional societies (the American Academy of Pediatrics and American College of Obstetricians and Gynecologists), and organizations (March of Dimes) initiated nationwide monitoring and educational plans that had a significant effect on decreasing the rates of iatrogenic LPT deliveries. However, there is now an evolving concern. After nearly a decade of steady decreases in the LPT birth rate that largely contributed to the decline in total US preterm birth rates, the birth rate in LPT infants has been inching upward since 2015. In addition, evidence revealed by strong population health research demonstrates that being born as an early-term infant poses a significant risk to an infant's survival, growth, and development. In this report, we summarize the initial progress and discuss the potential reasons for the current trends in LPT and early-term birth rates and propose research recommendations.

Prevalence of Survival Without Major Comorbidities Among Adults Born Prematurely

IMPORTANCE

Preterm birth has been associated with cardiometabolic, respiratory, and neuropsychiatric disorders in adulthood. However, the prevalence of survival without any major comorbidities is unknown.

OBJECTIVE

To determine the prevalence of survival without major comorbidities in adulthood among persons born preterm vs full-term.

DESIGN, SETTING, AND PARTICIPANTS

National cohort study of all 2 566 699 persons born in Sweden from January 1, 1973, through December 31, 1997, who had gestational age data and who were followed up for survival and comorbidities through December 31, 2015 (ages 18-43 years).

EXPOSURES

Gestational age at birth.

MAIN OUTCOMES AND MEASURES

Survival without major comorbidities among persons born extremely preterm (22-27 weeks), very preterm (28-33 weeks), late preterm (34-36 weeks), or early term (37-38 weeks), compared with full-term (39-41 weeks). Comorbidities were defined using the Adolescent and Young Adult Health Outcomes and Patient Experience (AYA HOPE) Comorbidity Index, which includes conditions that commonly manifest in adolescence or young adulthood, including neuropsychiatric disorders; and the Charlson Comorbidity Index (CCI), which includes major chronic disorders predictive of mortality in adulthood. Poisson regression was used to determine prevalence ratios and differences, adjusted for potential confounders.

RESULTS

In this study population, 48.6% were female, 5.8% were born preterm, and the median age at end of follow-up was 29.8 years (interquartile range, 12.6 years). Of all persons born preterm, 54.6% were alive with no AYA HOPE comorbidities at the end of follow-up. Further stratified, this prevalence was 22.3% for those born extremely preterm, 48.5% for very preterm, 58.0% for late preterm, 61.2% for early term, and 63.0% for full-term. These prevalences were significantly lower for earlier gestational ages vs full-term (eg, adjusted prevalence ratios: extremely preterm, 0.35 [95% CI, 0.33 to 0.36; P < .001]; all preterm, 0.86 [95% CI, 0.85 to 0.86; P < .001]; adjusted prevalence differences: extremely preterm, -0.41 [95% CI, -0.42 to -0.40; P < .001]; all preterm, -0.09 [95% CI, -0.09 to -0.09; P < .001]). Using the CCI, the corresponding prevalences were 73.1% (all preterm), 32.5% (extremely preterm), 66.4% (very preterm), 77.1% (late preterm), 80.4% (early term), and 81.8% (full-term) (adjusted prevalence ratios: extremely preterm, 0.39 [95% CI, 0.38 to 0.41; P < .001]; all preterm, 0.89 [95% CI, 0.89 to 0.89; P < .001]; adjusted prevalence differences: extremely preterm, -0.50 [95% CI, -0.51 to -0.49; P < .001]; all preterm, -0.09 [95% CI, -0.09 to -0.09; P < .001]).

CONCLUSIONS AND RELEVANCE

Among persons born preterm in Sweden between 1973 and 1997, the majority survived to early to mid-adulthood without major comorbidities. However, outcomes were worse for those born extremely preterm.

Do premature and postterm birth increase the risk of epilepsy? An updated meta-analysis

BACKGROUND

Many studies have reported that premature birth is associated with a higher incidence of epilepsy, and postterm birth also increases the risk of epilepsy. The effects of different gestational ages (GAs) on epilepsy have become a research hotspot, but the findings of these studies remain controversial, and no systematic review has been performed until now.

OBJECTIVE

The aim of this study was to evaluate the impact of different GAs on the incidence of epilepsy.

DATA SOURCES

The main databases, including PubMed, Medline, Embase, Cochrane Library, and Web of Science, were searched using the terms "preterm/premature/early/postterm/postmature/late/delayed delivery/birth", "gestational age", and "epilepsy/seizure" for eligible studies published up to April 1, 2019. The search was limited to English-language articles.

STUDY SELECTION

Observational studies investigating the association between epilepsy and premature or postterm birth were included in this meta-analysis. We only selected studies that had clearly reported GA and the occurrence of epilepsy.

DATA EXTRACTION AND ANALYSIS

Two reviewers independently extracted the data. The quality of the included studies was examined in accordance with the Newcastle-Ottawa criteria, and the heterogeneity and publication bias were tested. We used sensitivity and subgroup analyses to determine the source of heterogeneity. A logistic randomized-effects model was used to assess the collected data when I² ≥ 50%.

MAIN OUTCOMES

The primary outcome was the odds ratio (OR) of epilepsy.

RESULTS

The research included eleven eligible studies with a total of 4,513,577 participants. Studies involving premature birth showed that the risk of epilepsy was 2.16 times higher in the premature birth group (<37 weeks) than in the full-term birth group (≥37 weeks) (OR [99% confidence interval [CI]] = 2.16 [1.80, 2.58]; P < 0.001). Those born before 32 weeks were associated with an increased occurrence of epilepsy when compared with those born at 32-36 weeks (OR [99% CI] = 2.73 [1.90, 3.94]; P < 0.001). However, the difference in the incidence of epilepsy between postterm children (41 weeks or more) and full-term children (37-40 weeks) was not statistically significant (OR [99% CI] = 1.05 [0.98, 1.12]; P = 0.067).

CONCLUSIONS

Preterm birth was closely associated with a higher risk of epilepsy throughout childhood that persisted into adulthood, and the association became stronger as GA decreased, while there was no significant difference in the risk of developing epilepsy between postterm and full-term offspring.

Antecedents of epilepsy and seizures among children born at extremely low gestational age

OBJECTIVE

To identify specific risk factors for epilepsy for individuals born extremely preterm.

STUDY DESIGN

In a prospective cohort study, at 10-year follow-up, children were classified as having epilepsy or seizures not associated with epilepsy. We evaluated for association of perinatal factors using time-oriented, multinomial logistic regression models.

RESULTS

Of the 888 children included in the study, 66 had epilepsy and 39 had seizures not associated with epilepsy. Epilepsy was associated with an indicator of low socioeconomic status, maternal gestational fever, early physiologic instability, postnatal exposure to hydrocortisone, cerebral white matter disease and severe bronchopulmonary dysplasia. Seizure without epilepsy was associated with indicators of placental infection and inflammation, and hypoxemia during the first 24 postnatal hours.

CONCLUSIONS

In children born extremely preterm, epilepsy and seizures not associated with epilepsy have different risk profiles. Though both profiles included indicators of infection and inflammation, the profile of risk factors for epilepsy included multiple indicators of endogenous vulnerability.

Gestational age at birth and mortality from infancy into mid-adulthood: a national cohort study

BACKGROUND

Breakthroughs in the treatment of preterm birth approximately 40 years ago have enabled a generation of preterm survivors to now reach mid-adulthood. Understanding their health sequelae is essential for guiding their long-term care. We did a study to examine preterm birth in relation to mortality into mid-adulthood.

METHODS

A national cohort study was done of all 4 296 814 singleton livebirths in Sweden between 1973 and 2015, who were followed up for mortality through Dec 31, 2017 (maximum age 45 years). Cox regression was used to examine gestational age at birth in relation to all-cause and cause-specific mortality, and cosibling analyses assessed for potential confounding by shared familial (genetic or environmental) factors.

FINDINGS

In 103·5 million person-years of follow-up, 43 916 (1·0%) deaths were reported. Gestational age at birth was inversely associated with mortality from infancy to mid-adulthood. Relative to full-term birth (39-41 weeks), the adjusted hazard ratios for mortality associated with gestational age at birth were: 66·14 (95% CI 63·09-69·34) for extremely preterm (22-27 weeks), 8·67 (8·32-9·03) for very preterm (28-33 weeks), 2·61 (2·52-2·71) for late preterm (34-36 weeks), and 1·34 (1·30-1·37) for early term (37-38 weeks), from birth to age 45 years; and 2·04 (0·92-4·55) for extremely preterm, 1·48 (1·17-1·87) for very preterm, 1·22 (1·07-1·39) for late preterm, and 1·16 (1·08-1·25) for early term, at ages 30-45 years. Preterm birth accounted for more deaths among males than females (additive interaction p<0·001). Multiple underlying causes were identified, including congenital anomalies; respiratory, endocrine, cardiovascular, and neurological diseases; cancer; and external causes. Cosibling analyses suggested that the observed associations were not due to shared genetic or environmental factors in families.

INTERPRETATION

Preterm and early term birth should be recognised as chronic conditions that require long-term follow-up for adverse health sequelae in adulthood.

FUNDING

National Heart, Lung, and Blood Institute at the National Institutes of Health.

Association of perinatal factors of epilepsy in very low birth weight infants, using a nationwide database in Japan

OBJECTIVE

To determine clinical features of very low birth weight infants (VLBWIs) who had developed epilepsy by age 3 years.

STUDY DESIGN

Multicenter cohort study using the Neonatal Research Network of Japan database. We analyzed clinical variables of 8431 VLBWIs who had recorded data of neurological sequelae at age 3 years. Logistic regression identified the association between variables and development of epilepsy.

RESULT

One hundred and forty-three (1.7%) infants developed epilepsy, 683 (8.1%) showed cerebral palsy (CP), and 1114 (13.2%) had psychomotor delay. Epilepsy was associated with history of sepsis [adjusted odds ratio (AOR) 3.23], severe intraventricular hemorrhage (IVH; AOR 5.13), and cystic periventricular leukomalacia (PVL; AOR 12.7). Severe IVH and cystic PVL were also frequently associated with CP and psychomotor delay.

CONCLUSION

Severe IVH and cystic PVL are strongly associated with development of epilepsy, as well as other neurological sequelae, and are potential critical therapeutic targets.

Delayed myelination and neurodevelopment in male seizure-prone versus seizure-resistant rats

OBJECTIVE

Aberrant myelination and developmental delay have been reported in epilepsy. However, it is unclear whether these are linked to intrinsic mechanisms that support a predisposition toward seizures and the development of epilepsy. Thus, we compared rates of myelination and neurodevelopment in male rats selectively bred for enhanced susceptibility to kindling epileptogenesis (FAST) with male rats bred for resistance (SLOW).

METHODS

Myelin-specific gene expression was compared in the brainstem, cerebellum, and cerebral hemisphere of FAST and SLOW rats on postnatal days (PNDs) 5, 11, 17, 23, and 90 to determine strain-specific myelination rates. Myelin protein levels were also compared at PNDs 5 and 23 in the brainstem. Relative rates of neurodevelopment were evaluated between PNDs 5 and 21 using physical growth landmarks and neuromotor tests including righting reflex, cliff avoidance, negative geotaxis, and locomotor activity.

RESULTS

Myelin-specific mRNA expression was significantly down-regulated in FAST rats on PNDs 5 and 11 in all 3 brain structures, indicating relatively delayed myelination. Likewise, corresponding protein levels were significantly lower in FAST brainstem on PND 5. Developmental delay was evident in the FAST strain such that only 9% of FAST pups, compared to 81% of SLOW, had open eyes by PND 13, locomotor activity was significantly reduced between PNDs 12 and 16, and neuromotor task acquisition was delayed between PNDs 5 and 10.

SIGNIFICANCE

Relative delays in myelination and neurodevelopment co-occurred in the seizure-prone FAST strain in the absence of seizures. These findings suggest these symptoms are not seizure-induced and may be mechanistically linked to an underlying pathophysiology supporting a predisposition toward developing epilepsy.

Structured Spontaneity: Building Circuits in the Human Prenatal Brain

Early brain activity is crucial for neurogenesis and the development of brain networks. However, it has been challenging to localize regions in the developing human brain that contribute to spontaneous waves of neuronal activity. Recently, Arichi and colleagues reported that the temporal and heteromodal insular cortices have a central role in propagating these neural instructional signals.

Health Services Use by Late Preterm and Term Infants From Infancy to Adulthood: A Meta-analysis

CONTEXT

Late-preterm infants born at 34 to 36 weeks' gestation have increased risks of various health problems. Health service utilization (HSU) of late-preterm infants has not been systematically summarized before.

OBJECTIVES

To summarize the published literature on short- and long-term HSU by late-preterm infants versus term infants from infancy to adulthood after initial discharge from the hospital.

DATA SOURCES

We searched Medline, Embase, the Cumulative Index to Nursing and Allied Health Literature, and PsycINFO.

STUDY SELECTION

Cohort and case-control studies that compared HSU (admissions, emergency department visits, etc) between late-preterm infants and term infants were included.

DATA EXTRACTION

Data extracted included study design, setting, population, HSU, covariates, and effect estimates.

RESULTS

Fifty-two articles were included (50 cohort and 2 case-control studies). Meta-analyses with random effect models that used the inverse-variance method found that late-preterm infants had higher chances of all-cause admissions than term infants during all the time periods. The magnitude of the differences decreased with age from the neonatal period through adolescence, with adjusted odds ratios from 2.34 (95% confidence intervals 1.19-4.61) to 1.09 (1.05-1.13) and adjusted incidence rate ratios from 2.62 (2.52-2.72) to 1.14 (1.11-1.18). Late-preterm infants had higher rates of various cause-specific HSU than term infants for jaundice, infection, respiratory problems, asthma, and neurologic and/or mental health problems during certain periods, including adulthood.

LIMITATIONS

Considerable heterogeneity existed and was partially explained by the variations in the adjustment for multiple births and gestational age ranges of the term infants.

CONCLUSIONS

Late-preterm infants had higher risks for all-cause admissions as well as for various cause-specific HSU during the neonatal period through adolescence.

Anthropometric Indices in Children With Refractory Epilepsy

OBJECTIVE

We aimed to assess the effect of body mass index (BMI) on reducing the risk of refractory seizure due to lipoid tissue factors.

MATERIALS & METHODS

This matched case-control study, consisted of cases (Patients with refractory epilepsy) and controls (Healthy children) referred to 17 Shahrivar Hospital, Guilan University of Medical Sciences, Guilan, Iran during 2013-2014. Data were gathered by a form including demographic characteristics, type of epilepsy, predominant time of epilepsy, therapeutic approach, frequency of epilepsy, time of disease onset and anthropometric indices. We measured anthropometric indices and transformed them into Z-scores. Data were reported by descriptive statistics (mean and standard deviation) and analyzed by Pearson correlation coefficient, paired t test and multinomial regression analysis test using SPSS 19.

RESULTS

There was no significant difference between sex groups regarding anthropometric indices. Generalized and focal types of epilepsies were noted on 57.5% and 38.75% of patients, respectively. Daytime epilepsies happened in 46.25% of patients and 33.75% noted no predominant time for epilepsies. Clinicians indicated poly-therapy for the majority of patients (92.5%). The most common onset times for epilepsies were 36-72 months for 32.5% of patients. Lower onset time indicated lower frequency of refractory epilepsies. Although, there was significant difference between Zheight and predominant time of epilepsies but no significant relation was found between types of epilepsies and frequency of epilepsies with anthropometric indices. Using multivariate regression analysis by backward LR, Zweight and birth weight were noted as the predicting factors of refractory epilepsies.

CONCLUSION

This effect may be because of leptin. Therefore, researchers recommend further investigations regarding this issue in children with epilepsy.

Postnatal Erythropoietin Mitigates Impaired Cerebral Cortical Development Following Subplate Loss from Prenatal Hypoxia-Ischemia

Preterm birth impacts brain development and leads to chronic deficits including cognitive delay, behavioral problems, and epilepsy. Premature loss of the subplate, a transient subcortical layer that guides development of the cerebral cortex and axonal refinement, has been implicated in these neurological disorders. Subplate neurons influence postnatal upregulation of the potassium chloride co-transporter KCC2 and maturation of γ-amino-butyric acid A receptor (GABAAR) subunits. We hypothesized that prenatal transient systemic hypoxia-ischemia (TSHI) in Sprague-Dawley rats that mimic brain injury from extreme prematurity in humans would cause premature subplate loss and affect cortical layer IV development. Further, we predicted that the neuroprotective agent erythropoietin (EPO) could attenuate the injury. Prenatal TSHI induced subplate neuronal loss via apoptosis. TSHI impaired cortical layer IV postnatal upregulation of KCC2 and GABAAR subunits, and postnatal EPO treatment mitigated the loss (n ≥ 8). To specifically address how subplate loss affects cortical development, we used in vitro mechanical subplate ablation in slice cultures (n ≥ 3) and found EPO treatment attenuates KCC2 loss. Together, these results show that subplate loss contributes to impaired cerebral development, and EPO treatment diminishes the damage. Limitation of premature subplate loss and the resultant impaired cortical development may minimize cerebral deficits suffered by extremely preterm infants.

The contribution of genetic and environmental factors to the duration of pregnancy

This review describes how improvements in biometric-genetic studies of twin kinships, half-sibships, and cousinships have now demonstrated a sizeable fetal genetic and maternal genetic contribution to the spontaneous onset of labor. This is an important development because previous literature for the most part reports only an influence of the maternal genome. Current estimates of the percent of variation that is attributable to fetal genetic factors range from 11-35%; the range for the maternal genetic contribution is 13-20%. These same studies demonstrate an even larger influence of environmental sources over and above the influence of genetic sources and previously identified environmental risk factors. With these estimates in hand, a major goal for research on pregnancy duration is to identify specific allelic variation and environmental risk to account for this estimated genetic and environmental variation. A review of the current literature can serve as a guide for future research efforts.

Risk factors and scoring system as a prognostic tool for epilepsy after neonatal seizures

BACKGROUND

Neonatal seizures may cause irreversible changes to the immature brain and. A scoring system for early prognostic information could be a useful clinical tool. The aim of the study was to analyze risk factors for epilepsy after neonatal seizures, to validate Garfinkle's scoring system, and to analyze whether a new scoring system is feasible.

METHODS

A retrospective study of 176 newborns (59.1% boys, 40.9% girls, 70.5% term, 29.5% preterm; mean birth weight 2820 g), admitted to the Department of Neonatology, Division of Pediatrics, University Medical Centre, Ljubljana, because of neonatal seizures (clinical and/or neurophysiological), was performed. Epilepsy rate between 2 and 12 years of follow-up was 18.1%. Five independent predictors from Garfinkle's study and other known predictors were entered into hierarchical binary logistic regression models and analyzed through four steps to identify independent predictors of epilepsy. We tested whether any of the predictors was an effect modifier.

RESULTS

Of five potential predictors from Garfinkle's score, electroencephalograph background findings and etiology were predictive. Etiologies, gestation, mode of delivery, duration of seizures, and other risk factors at birth were found to be independent predictors. Duration of seizures has a different effect on prognosis depending on the gestational age.

CONCLUSION

Gestational age determines the association between duration of seizures and epilepsy. Scoring systems to predict development of epilepsy after neonatal seizures need to limit interaction between important predictor variables.

Fetal and maternal genes' influence on gestational age in a quantitative genetic analysis of 244,000 Swedish births

Although there is increasing evidence that genetic factors influence gestational age, it is unclear to what extent this is due to fetal and/or maternal genes. In this study, we apply a novel analytical model to estimate genetic and environmental contributions to pregnancy history records obtained from 165,952 Swedish families consisting of offspring of twins, full siblings, and half-siblings (1987-2008). Results indicated that fetal genetic factors explained 13.1% (95% confidence interval (CI): 6.8, 19.4) of the variation in gestational age at delivery, while maternal genetic factors accounted for 20.6% (95% CI: 18.1, 23.2). The largest contribution to differences in the timing of birth were environmental factors, of which 10.1% (95% CI: 7.0, 13.2) was due to factors shared by births of the same mother, and 56.2% (95% CI: 53.0, 59.4) was pregnancy specific. Similar models fit to the same data dichotomized at clinically meaningful thresholds (e.g., preterm birth) resulted in less stable parameter estimates, but the collective results supported a model of homogeneous genetic and environmental effects across the range of gestational age. Since environmental factors explained most differences in the timing of birth, genetic studies may benefit from understanding the specific effect of fetal and maternal genes in the context of these yet-unidentified factors.

Risk of cerebral palsy and childhood epilepsy related to infections before or during pregnancy

BACKGROUND AND AIM

Maternal infections during pregnancy have been associated with several neurological disorders in the offspring. However, given the lack of specificity for both the exposures and the outcomes, other factors related to infection such as impaired maternal immune function may be involved in the causal pathway. If impaired maternal immune function plays a role, we would expect infection before pregnancy to be associated with these neurological outcomes.

METHODS/PRINCIPAL FINDINGS

The study population included all first-born singletons in Denmark between January 1 1982 and December 31 2004. We identified women who had hospital-recorded infections within the 5 year period before pregnancy, and women who had hospital-recorded infections during pregnancy. We grouped infections into either infections of the genitourinary system, or any other infections. Cox models were used to estimate adjusted hazard ratios (aHRs) with 95% confidence interval (CI). Maternal infection of the genitourinary system during pregnancy was associated with an increased risk of cerebral palsy (aHR = 1.63, 95% CI: 1.34-1.98) and epilepsy (aHR = 1.27, 95% CI: 1.13-1.42) in the children, compared to children of women without infections during pregnancy. Among women without hospital-recorded infections during pregnancy, maternal infection before pregnancy was associated with an increased risk of epilepsy (aHR = 1.35, 95% CI: 1.21-1.50 for infections of the genitourinary system, and HR = 1.12, 95% CI: 1.03-1.22 for any other infections) and a slightly higher risk of cerebral palsy (aHR = 1.20, 95% CI: 0.96-1.49 for infections of the genitourinary system, and HR = 1.23, 95% CI: 1.06-1.43 for any other infections) in the children, compared to children of women without infections before (and during) pregnancy.

CONCLUSIONS

These findings indicate that the maternal immune system, maternal infections, or factors related to maternal immune function play a role in the observed associations between maternal infections before pregnancy and cerebral diseases in the offspring.

An overview of risk factors for poor neurodevelopmental outcome associated with prematurity

BACKGROUND

Preterm birth is a major cause of neonatal mortality and morbidity. While advances in medical care have improved the survival of preterm infants, neurodevelopmental problems persist in this population. This article aims to review factors associated with their neurodevelopmental outcomes.

DATA SOURCES

English language studies of neurodevelopmental outcomes in preterm infants were retrieved from PubMed. A total of 100 related publications were included.

RESULTS

Early gestational age and birth weight are the most significant predictors of poor long-term neurological outcome. Structural changes of the brain, infection, male gender and neonatal intensive care unit course are also important factors affecting eventual outcome. Other complex biological and socio-economic factors, which extend from prenatal through postnatal periods, up through and including adulthood, also affect the trajectory of brain development in preterm infants.

CONCLUSIONS

Neurodevelopmental problems continue to affect the preterm population. There is a critical need for collaboration among geneticists, obstetricians, pediatricians, and neuroimaging and rehabilitation experts to determine early predictive factors and neuroprotective therapies to properly treat or prevent poor neurodevelopmental outcomes in these infants.

Risks associated with delivering infants 2 to 6 weeks before term--a review of recent data

BACKGROUND

There is an increasing trend towards delivery before 39 weeks of gestational age. The short- and long-term effects of early delivery on the infant have only recently received scientific attention.

METHODS

Selective review of the literature

RESULTS

Delivery at any time before 39 weeks is associated with significantly higher infant mortality and with an increase of the risk of impairments after birth from 8% to 11%. The increase in risks of various kinds is disproportionately more pronounced the earlier the child is delivered. For example, the risk of needing respiratory support or artificial ventilation after birth increases from 0.3% with delivery at 39-41 weeks of gestational age to 1.4% at 37 weeks and 10% at 35 weeks, while the risk of death or neurological complications increases from 0.15% at 39-41 weeks of gestation to 0.66% at 35 weeks. Delivery at 34.0 to 36.6 weeks of gestation also has long-term effects. Compared to delivery at term, the frequency of cerebral palsy rises threefold, from 0.14% to 0.43%; the risk of death in early adulthood rises by about half, from 0.046 to 0.065%; and the risk of dependence on government benefits in early adulthood also rises by about half, from 1.7% to 2.5%.

CONCLUSION

Studies from the USA have shown that the number of medically indicated deliveries before 39 weeks can be lowered by 70% to 80% through consistently applied measures for quality improvement. If similar results could be achieved in Germany, the iatrogenic complications of delivery would become less common in this country as well.

Gestational age at birth and risk of gastric acid-related disorders in young adulthood

PURPOSE

Preterm birth is associated with gastric acid-related disorders in infancy, but no investigators have examined this association beyond early childhood. We used antisecretory medication data to explore whether preterm birth is associated with gastric acid-related disorders in young adulthood.

METHODS

We conducted a national cohort study of 626,811 individuals born in Sweden in 1973 to 1979, followed up for antisecretory (proton pump inhibitor and H2-receptor antagonist) medication prescriptions from all outpatient and inpatient pharmacies nationwide from 2005 to 2009 (ages 25.5-37.0 years). We excluded individuals with congenital anomalies, and examined potential confounding by other comorbidities identified on the basis of oral anti-inflammatory or corticosteroid medication prescription.

RESULTS

Gestational age at birth was inversely associated with antisecretory medication prescription in young adulthood. Adjusted odds ratios for ≥1 antisecretory medication prescription/year were 3.38 (95% confidence interval [95% CI], 1.73-6.62) for individuals born at 22-27 weeks, 1.38 (95% CI, 1.19-1.60) for those born at 28-34 weeks, and 1.19 (95% CI, 1.06-1.32) for those born at 35-36 weeks, relative to those born full-term (37-42 weeks). Exclusion of individuals who were prescribed oral anti-inflammatory or corticosteroid medications (≥1/year) had little effect on these results.

CONCLUSIONS

These findings suggest that low gestational age at birth may be independently associated with an increased risk of gastric acid-related disorders in young adulthood.