Antepartum risk factors for newborn encephalopathy: the Western Australian case-control study

Antepartum and intrapartum factors preceding neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

To determine whether antepartum factors alone, intrapartum factors alone, or both in combination, are associated with term neonatal hypoxic-ischemic encephalopathy (HIE).

METHODS

A total of 405 infants ≥ 35 weeks' gestation with early encephalopathy, born between 1992 and 2007, were compared with 239 neurologically normal infants born between 1996 and 1997. All cases met criteria for perinatal asphyxia, had neuroimaging findings consistent with acute hypoxia-ischemia, and had no evidence for a non-hypoxic-ischemic cause of their encephalopathy.

RESULTS

Both antepartum and intrapartum factors were associated with the development of HIE on univariate analysis. Case infants were more often delivered by emergency cesarean delivery (CD; 50% vs 11%, P < .001) and none was delivered by elective CD (vs 10% of controls). On logistic regression analysis only 1 antepartum factor (gestation ≥ 41 weeks) and 7 intrapartum factors (prolonged membrane rupture, abnormal cardiotocography, thick meconium, sentinel event, shoulder dystocia, tight nuchal cord, failed vacuum) remained independently associated with HIE (area under the curve 0.88; confidence interval 0.85-0.91; P < .001). Overall, 6.7% of cases and 43.5% of controls had only antepartum factors; 20% of cases and 5.8% of controls had only intrapartum factors; 69.5% of cases and 31% of controls had antepartum and intrapartum factors; and 3.7% of cases and 19.7% of controls had no identifiable risk factors (P < .001).

CONCLUSIONS

Our results do not support the hypothesis that HIE is attributable to antepartum factors alone, but they strongly point to the intrapartum period as the necessary factor in the development of this condition.

A case-control study of hypoxic-ischemic encephalopathy in newborn infants at >36 weeks gestation

OBJECTIVE

The purpose of this study was to determine risk factors that are associated with hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

This was a case-control study that included newborn infants with HIE who were admitted to the hospital between January 2001 and December 2008. Two control newborn infants were chosen for each case. Logistic regression and classification and regression tree (CART) analysis that compared control infants and cases with grade 1 HIE and control infants and cases with grades 2 and 3 HIE was performed.

RESULTS

Two hundred thirty-seven cases (newborn infants with grade 1 encephalopathy, 155; newborn infants with grade 2 encephalopathy, 61; newborn infants with grade 3 encephalopathy, 21) and 489 control infants were included. Variables that were associated independently with HIE included higher grade meconium, growth restriction, large head circumference, oligohydramnios, male sex, fetal bradycardia, maternal pyrexia and increased uterine contractility. CART analysis ranked high-grade meconium, oligohydramnios, and the presence of obstetric complications as the most discriminating variables and defined distinct risk groups with HIE rates that ranged from 0-86%.

CONCLUSION

CART analysis provides information to help identify the time at which intervention in labor may be of benefit.

Evidence for therapeutic intervention in the prevention of cerebral palsy: hope from animal model research

Knowledge translation, as defined by the Canadian Institute of Health Research, is defined as the exchange, synthesis, and ethically sound application of knowledge--within a complex system of interactions among researchers and users--to accelerate the capture of the benefits of research through improved health, more effective services and products, and a strengthened healthcare system. The requirement for this to occur lies in the ability to continue to determine mechanistic actions at the molecular level, to understand how they fit at the in vitro and in vivo levels, and for disease states, to determine their safety, efficacy, and long-term potential at the preclinical animal model level. In this regard, particularly as it relates to long-term disabilities such as cerebral palsy that begin in utero, but only express their full effect in adulthood, animal models must be used to understand and rapidly evaluate mechanisms of injury and therapeutic interventions. In this review, we hope to provide the reader with a background of animal data upon which therapeutic interventions for the prevention and treatment of cerebral palsy, benefit this community, and increasingly do so in the future.

Understanding cardiotocographic patterns associated with intrapartum fetal hypoxia and neurologic injury

Widespread use of fetal heart rate monitoring for intrapartum fetal surveillance preceded our detailed understanding of the behaviour and regulation of the fetal cardiovascular system during labour. The fetal heart rate is sensitive to fetal hypoxaemia and hypoxia, but lacks specificity for fetal acidosis, the end point of unmitigated hypoxaemia and hypoxia. Original interpretations of fetal heart rate patterns equated decelerations to 'fetal distress' and mandated operative intervention. Since then, obstetricians have been trained to focus on the morphological appearances of fetal heart rate decelerations rather than to understand the underlying physiological mechanisms, how the fetus compensates and defends itself, and those patterns that suggest progressive loss of compensation. Consequently, operative interventions are commonly undertaken to 'rescue' fetuses that display benign signs of fetal heart rate adaption to events in labour. Failure to recognise abnormal fetal heart rate patterns remains the leading cause of avoidable brain injury and litigation. In this chapter the general characteristics of the fetal heart rate, the changes in fetal heart rate pattern that may occur during labour, and the patterns that suggest failure of the fetal compensatory mechanisms leading to injury are discussed.

Term neonatal encephalopathy antecedent cerebral palsy: a retrospective population-based study

OBJECTIVE

To compare the clinical profile of term-born cerebral palsy children with or without antecedent moderate to severe neonatal encephalopathy. We hypothesized that antecedent neonatal encephalopathy is associated with a spastic quadriparesis cerebral palsy clinical profile, a higher severity of functional motor impairment, and a greater number of associated comorbidities.

METHODS

Using the Quebec Cerebral Palsy Registry, neurologic subtype, Gross Motor Function Classification System stratification, and comorbidities were compared in children with cerebral palsy with and without antecedent neonatal encephalopathy. Differences between groups were evaluated using chi square analysis for categorical variables and student t test for continuous variables.

RESULTS

We identified 132 children with cerebral palsy born full term over a 4 year-interval (1999-2002 inclusive) within the Quebec Cerebral Palsy Registry, of which 44 (33%) had an antecedent neonatal encephalopathy. Spastic quadriplegia subtype of cerebral palsy and Gross Motor Function Classification System Level III-V (non-independent ambulation) were significantly associated with antecedent neonatal encephalopathy. The mean number of comorbidities experienced was not different in the two groups. Of five documented comorbidities, only severe communication difficulties were found to be associated (p < 0.05) with antecedent neonatal encephalopathy.

CONCLUSION

A pattern of increased neuromotor impairment, functional gross motor severity and possible communication difficulties was found in the 33% of children with cerebral palsy born at term and with a history of neonatal encephalopathy.

Optimizing the definition of intrauterine growth restriction: the multicenter prospective PORTO Study

OBJECTIVE

The objective of the Prospective Observational Trial to Optimize Pediatric Health in Intrauterine Growth Restriction (IUGR) (PORTO Study), a national prospective observational multicenter study, was to evaluate which sonographic findings were associated with perinatal morbidity and mortality in pregnancies affected by growth restriction, originally defined as estimated fetal weight (EFW) <10th centile.

STUDY DESIGN

Over 1100 consecutive ultrasound-dated singleton pregnancies with EFW <10th centile were recruited from January 2010 through June 2012. A range of IUGR definitions were used, including EFW or abdominal circumference <10th, <5th, or <3rd centiles, with or without oligohydramnios and with or without abnormal umbilical arterial Doppler (pulsatility index >95th centile, absent or reversed end-diastolic flow). Adverse perinatal outcome, defined as a composite outcome of intraventricular hemorrhage, periventricular leukomalacia, hypoxic ischemic encephalopathy, necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, and death was documented for all cases.

RESULTS

Of 1116 fetuses, 312 (28%) were admitted to neonatal intensive care unit and 58 (5.2%) were affected by adverse perinatal outcome including 8 mortalities (0.7%). The presence of abnormal umbilical Doppler was significantly associated with adverse outcome, irrespective of EFW or abdominal circumference measurement. The only sonographic weight-related definition consistently associated with adverse outcome was EFW <3rd centile (P = .0131); all mortalities had EFW <3rd centile. Presence of oligohydramnios was clinically important when combined with EFW <3rd centile (P = .0066).

CONCLUSION

Abnormal umbilical artery Doppler and EFW <3rd centile were strongly and most consistently associated with adverse perinatal outcome. Our data call into question the current definitions of IUGR used. Future studies may address whether using stricter IUGR cutoffs comparing various definitions and management strategies has implications on resource allocation and pregnancy outcome.

Why the term neonatal encephalopathy should be preferred over neonatal hypoxic-ischemic encephalopathy

The unresponsiveness of the full-term newborn is sometimes attributed to asphyxia, even when no severe physiologic disturbance occurred during labor and delivery. The controversy about whether to use the name "hypoxic-ischemic encephalopathy" or "newborn encephalopathy" has recently flared in publications directed toward pediatricians and neurologists. In this clinic opinion piece, I discuss the importance to obstetricians of this decision and explain why "newborn encephalopathy" should be the default term.

Neonatal outcomes after preterm birth by mothers' health insurance status at birth: a retrospective cohort study

Background

Publicly insured women usually have a different demographic background to privately insured women, which is related to poor neonatal outcomes after birth. Given the difference in nature and risk of preterm versus term births, it would be important to compare adverse neonatal outcomes after preterm birth between these groups of women after eliminating the demographic differences between the groups.

Methods

The study population included 3085 publicly insured and 3380 privately insured, singleton, preterm deliveries (32–36 weeks gestation) from Western Australia during 1998–2008. From the study population, 1016 publicly insured women were matched with 1016 privately insured women according to the propensity score of maternal demographic characteristics and pre-existing medical conditions. Neonatal outcomes were compared in the propensity score matched cohorts using conditional log-binomial regression, adjusted for antenatal risk factors. Outcomes included Apgar scores less than 7 at five minutes after birth, time until establishment of unassisted breathing (>1 minute), neonatal resuscitation (endotracheal intubation or external cardiac massage) and admission to a neonatal special care unit.

Results

Compared with infants of privately insured women, infants of publicly insured women were more likely to receive a low Apgar score (ARR = 2.63, 95% CI = 1.06-6.52) and take longer to establish unassisted breathing (ARR = 1.61, 95% CI = 1.25-2.07), yet, they were less likely to be admitted to a special care unit (ARR = 0.84, 95% CI = 0.80-0.87). No significant differences were evident in neonatal resuscitation between the groups (ARR = 1.20, 95% CI = 0.54-2.67).

Conclusions

The underlying reasons for the lower rate of special care admissions in infants of publicly insured women compared with privately insured women despite the higher rate of low Apgar scores is yet to be determined. Future research is warranted in order to clarify the meaning of our findings for future obstetric care and whether more equitable use of paediatric services should be recommended.

Prediction of intrapartum fetal compromise using the cerebroumbilical ratio: a prospective observational study

OBJECTIVE

To investigate the use of the fetal cerebroumbilical ratio to predict intrapartum compromise in appropriately grown fetuses.

STUDY DESIGN

A prospective observational study set at Queen Charlotte's and Chelsea hospital, London, UK. Fetal biometry and Doppler resistance indices were measured in 400 women immediately before established labor. Labor was then managed according to local protocols and guidelines, and intrapartum and neonatal outcome details recorded.

RESULTS

Infants delivered by cesarean section for fetal compromise had significantly lower cerebroumbilical ratios than those born by spontaneous vaginal delivery (1.52 vs 1.82, P ≤ .001). Infants with a cerebroumbilical ratio <10th percentile were 6 times more likely to be delivered by cesarean section for fetal compromise than those with a cerebroumbilical ratio ≥10th percentile (odds ratio, 6.1; 95% confidence interval, 3.03-12.75). A cerebroumbilical ratio >90th percentile appears protective of cesarean section for fetal compromise (negative predictive value 100%).

CONCLUSION

The fetal cerebroumbilical ratio can identify fetuses at high and low risk of a subsequent diagnosis of intrapartum compromise, and may be used to risk stratify pregnancies before labor.

Cooling for newborns with hypoxic ischaemic encephalopathy

BACKGROUND

Newborn animal studies and pilot studies in humans suggest that mild hypothermia following peripartum hypoxia-ischaemia in newborn infants may reduce neurological sequelae without adverse effects.

OBJECTIVES

To determine the effect of therapeutic hypothermia in encephalopathic asphyxiated newborn infants on mortality, long-term neurodevelopmental disability and clinically important side effects.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group as outlined in The Cochrane Library (Issue 2, 2007). Randomised controlled trials evaluating therapeutic hypothermia in term and late preterm newborns with hypoxic ischaemic encephalopathy were identified by searching the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2007, Issue 2), MEDLINE (1966 to June 2007), previous reviews including cross-references, abstracts, conferences, symposia proceedings, expert informants and journal handsearching. We updated this search in May 2012.

SELECTION CRITERIA

We included randomised controlled trials comparing the use of therapeutic hypothermia with standard care in encephalopathic term or late preterm infants with evidence of peripartum asphyxia and without recognisable major congenital anomalies. The primary outcome measure was death or long-term major neurodevelopmental disability. Other outcomes included adverse effects of cooling and 'early' indicators of neurodevelopmental outcome.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected, assessed the quality of and extracted data from the included studies. Study authors were contacted for further information. Meta-analyses were performed using risk ratios (RR) and risk differences (RD) for dichotomous data, and weighted mean difference for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

We included 11 randomised controlled trials in this updated review, comprising 1505 term and late preterm infants with moderate/severe encephalopathy and evidence of intrapartum asphyxia. Therapeutic hypothermia resulted in a statistically significant and clinically important reduction in the combined outcome of mortality or major neurodevelopmental disability to 18 months of age (typical RR 0.75 (95% CI 0.68 to 0.83); typical RD -0.15, 95% CI -0.20 to -0.10); number needed to treat for an additional beneficial outcome (NNTB) 7 (95% CI 5 to 10) (8 studies, 1344 infants). Cooling also resulted in statistically significant reductions in mortality (typical RR 0.75 (95% CI 0.64 to 0.88), typical RD -0.09 (95% CI -0.13 to -0.04); NNTB 11 (95% CI 8 to 25) (11 studies, 1468 infants) and in neurodevelopmental disability in survivors (typical RR 0.77 (95% CI 0.63 to 0.94), typical RD -0.13 (95% CI -0.19 to -0.07); NNTB 8 (95% CI 5 to 14) (8 studies, 917 infants). Some adverse effects of hypothermia included an increase sinus bradycardia and a significant increase in thrombocytopenia.

AUTHORS' CONCLUSIONS

There is evidence from the 11 randomised controlled trials included in this systematic review (N = 1505 infants) that therapeutic hypothermia is beneficial in term and late preterm newborns with hypoxic ischaemic encephalopathy. Cooling reduces mortality without increasing major disability in survivors. The benefits of cooling on survival and neurodevelopment outweigh the short-term adverse effects. Hypothermia should be instituted in term and late preterm infants with moderate-to-severe hypoxic ischaemic encephalopathy if identified before six hours of age. Further trials to determine the appropriate techniques of cooling, including refinement of patient selection, duration of cooling and method of providing therapeutic hypothermia, will refine our understanding of this intervention.

Endocrinology of parturition

The myometrium must remain relatively quiescent during pregnancy to accommodate growth and development of the feto-placental unit, and then must transform into a highly coordinated, strongly contracting organ at the time of labour for successful expulsion of the new born. The control of timing of labour is complex involving interactions between mother, fetus and the placenta. The timely onset of labour and delivery is an important determinant of perinatal outcome. Both preterm birth (delivery before 37 week of gestation) and post term pregnancy (pregnancy continuing beyond 42 weeks) are both associated with a significant increase in perinatal morbidity and mortality. There are multiple paracrine/autocrine events, fetal hormonal changes and overlapping maternal/fetal control mechanisms for the triggering of parturition in women. Our current article reviews the mechanisms for uterine distension and reduced contractions during pregnancy and the parturition cascade responsible for the timely and spontaneous onset of labour at term. It also discusses the mechanisms of preterm labour and post term pregnancy and the clinical implications thereof.

Neonatal seizures

Epileptic seizures are more frequent in the neonate than at any other time. The incidence of neonatal seizures (NNS) is estimated to be between 1.5 and 5.5/1000 living births, its onset being during the first week in 80% of cases. Mortality rate remains very high (20-45%). Not all paroxysmal manifestations are epileptic, and differential diagnosis remains an important challenge. Neonates may present with different types of seizures: clonic, tonic, myoclonic (axial, focal, erratic), epileptic spasms, and subtle seizures, including autonomic signs or automatisms. The main etiology is hypoxic-ischemic encephalopathy (40-45%) with a very early onset, and variable semiology including all seizure types. An EEG is necessary to recognize the seizures, and interictal tracing may help in assessing prognosis. Ischemic stroke is associated with seizures of early onset, being focal or unilateral. Interictal EEG is asymmetrical, with focal or unilateral patterns. Other etiologies less often linked to epileptic seizures must be looked for such as brain infection, metabolic disorders, chromosomal abnormalities, inborn errors of metabolism, brain malformations, and vitamin B6 dependency. Neonatal epilepsy syndromes may have favorable (benign familial neonatal seizures) or poor (early infantile encephalopathy with epilepsy, early myoclonic encephalopathy, and migrating partial seizures in infancy) prognosis.

Pathophysiology of cerebral palsy

Cerebral palsy (CP), defined as a group of nonprogressive disorders of movement and posture, is the most common cause of severe neurodisability in children. Understanding its physiopathology is crucial to developing some protective strategies. Interruption of oxygen supply to the fetus or brain asphyxia was classically considered to be the main causal factor explaining later CP. However several ante-, peri-, and postnatal factors could be involved in the origins of CP syndromes. Congenital malformations are rarely identified. CP is most often the result of environmental factors, which might interact with genetic vulnerabilities, and could be severe enough to cause the destructive injuries visible with standard imaging (i.e., ultrasonographic study or MRI), predominantly in the white matter in preterm infants and in the gray matter and the brainstem nuclei in full-term newborns. Moreover they act on an immature brain and could alter the remarkable series of developmental events. Biochemical key factors originating in cell death or cell process loss, observed in hypoxic-ischemic as well as inflammatory conditions, are excessive production of proinflammatory cytokines, oxidative stress, maternal growth factor deprivation, extracellular matrix modifications, and excessive release of glutamate, triggering the excitotoxic cascade. Only two strategies have succeeded in decreasing CP in 2-year-old children: hypothermia in full-term newborns with moderate neonatal encephalopathy and administration of magnesium sulfate to mothers in preterm labor.

Risk factors for birth asphyxia in an urban health facility in cameroon

OBJECTIVE

The World Health Organization (WHO) estimates that 4 million children are born with asphyxia every year, of which 1 million die and an equal number survive with severe neurologic sequelae. The purpose of this study was to identify the risk factors of birth asphyxia and the hospital outcome of affected neonates.

MATERIALS & METHODS

This study was a prospective case-control study on term neonates in a tertiary hospital in Yaounde, with an Apgar score of < 7 at the 5th minute as the case group, that were matched with neonates with an Apgar score of ≥ 7 at the 5th minute as control group. Statistical analysis of relevant variables of the mother and neonates was carried out to determine the significant risk factors.

RESULTS

The prevalence of neonatal asphyxia was 80.5 per 1000 live births. Statistically significant risk factors were the single matrimonial status, place of antenatal visits, malaria, pre-eclampsia/eclampsia, prolonged labor, arrest of labour, prolonged rupture of membranes, and non-cephalic presentation. Hospital mortality was 6.7%, that 12.2% of them had neurologic deficits and/or abnormal transfontanellar ultrasound/electroencephalogram on discharge, and 81.1% had a satisfactory outcome.

CONCLUSION

The incidence of birth asphyxia in this study was 80.5% per1000 live birth with a mortality of 6.7%. Antepartum risk factors were: place of antenatal visit, malaria during pregnancy, and preeclampsia/eclampsia. Whereas prolonged labor, stationary labor, and term prolonged rupture of membranes were intrapartum risk faktors. Preventive measures during prenatal visits through informing and communicating with pregnant women should be reinforced.

Antecedents of neonatal encephalopathy in the Vermont Oxford Network Encephalopathy Registry

BACKGROUND

Neonatal encephalopathy (NE) is a major predictor of death and long-term neurologic disability, but there are few studies of antecedents of NE.

OBJECTIVES

To identify antecedents in a large registry of infants who had NE.

METHODS

This was a maternal and infant record review of 4165 singleton neonates, gestational age of ≥ 36 weeks, meeting criteria for inclusion in the Vermont Oxford Network Neonatal Encephalopathy Registry.

RESULTS

Clinically recognized seizures were the most prevalent condition (60%); 49% had a 5-minute Apgar score of ≤ 3 and 18% had a reduced level of consciousness. An abnormal maternal or fetal condition predated labor in 46%; maternal hypertension (16%) or small for gestational age (16%) were the most frequent risk factors. In 8%, birth defects were identified. The most prevalent birth complication was elevated maternal temperature in labor of ≥ 37.5 °C in 27% of mothers with documented temperatures compared with 2% to 3.2% in controls in population-based studies. Clinical chorioamnionitis, prolonged membrane rupture, and maternal hypothyroidism exceeded rates in published controls. Acute asphyxial indicators were reported in 15% (in 35% if fetal bradycardia included) and inflammatory indicators in 24%. Almost one-half had neither asphyxial nor inflammatory indicators. Although most infants with NE were observably ill since the first minutes of life, only 54% of placentas were submitted for examination.

CONCLUSIONS

Clinically recognized asphyxial birth events, indicators of intrauterine exposure to inflammation, fetal growth restriction, and birth defects were each observed in term infants with NE, but much of NE in this large registry remained unexplained.

Neonatal encephalopathy: an inadequate term for hypoxic-ischemic encephalopathy

This Point of View article addresses neonatal encephalopathy (NE) presumably caused by hypoxia-ischemia and the terminology currently in wide use for this disorder. The nonspecific term NE is commonly utilized for those infants with the clinical and imaging characteristics of neonatal hypoxic-ischemic encephalopathy (HIE). Multiple magnetic resonance imaging studies of term infants with the clinical setting of presumed hypoxia-ischemia near the time of delivery have delineated a topography of lesions highly correlated with that defined by human neuropathology and by animal models, including primate models, of hypoxia-ischemia. These imaging findings, coupled with clinical features consistent with perinatal hypoxic-ischemic insult(s), warrant the specific designation of neonatal HIE.

Innate immune regulation by toll-like receptors in the brain

The innate immune system plays an important role in cerebral health and disease. In recent years the role of innate immune regulation by toll-like receptors in the brain has been highlighted. In this paper the expression of toll-like receptors and endogenous toll-like receptor ligands in the brain and their role in cerebral ischemia will be discussed. Further, the ability of systemic toll-like receptor ligands to induce cerebral inflammation will be reviewed. Finally, the capacity of toll-like receptors to both increase (sensitization) and decrease (preconditioning/tolerance) the vulnerability of the brain to damage will be disclosed. Studies investigating the role of toll-like receptors in the developing brain will be emphasized.

The customized fetal growth potential: a standard for Ireland

OBJECTIVE

To identify maternal and pregnancy-related physiological and pathological variables associated with fetal growth and birthweight in Ireland and to develop customized birthweight centile charts for the Irish population that will aid in appropriate identification and selection of growth-restricted fetuses requiring increased antenatal surveillance.

STUDY DESIGN

Prospectively collected outcome data of 11,973 consecutive ultrasound-dated singleton pregnancies between 2008 and 2009 from six maternity units in Ireland (Dublin, Galway, Limerick and Belfast) were included for analysis. Maternal weight and height at booking, parity and ethnicity were recorded and combined with birthweight, fetal gender and pregnancy outcomes. Coefficients were derived by backward multiple regression using a stepwise backward elimination approach.

RESULTS

A total of 11,973 ultrasound-dated singleton pregnancies were included in the analysis. Over 90% of women (n=10,850) were of Irish or European descent, 3.4% (n=407) were African or African Caribbean, 1.7% (n=208) were Indian; 42.2% (n=5057) were nulliparous, 32.8% (n=3923) had one previous delivery after 24 weeks' gestation, 15.6% (n=1872) had two previous deliveries and 9.4% (n=1121) had three or more previous deliveries. Mean term birthweight for a standard Irish mother was 3491 grams. Babies of all other ethnic origins were smaller than their Irish counterparts. African Caribbean, Bangladeshi, Indian and Pakistani babies were on average 237 g, 196 g, 181 g and 181 g lighter, respectively, when compared to the average Irish offspring. Pathological factors significantly affecting term birthweight were pre-gestational diabetes (+137 g; p<0.001), smoking (-225 g; p<0.001), pregnancy-induced hypertension (-37.6g; p=0.009) and maternal obesity (-41.6g; p=0.012).

CONCLUSION

Birthweight in this Irish maternity population is subject to similar influences to those observed in studies from the UK, Sweden, USA and Australasia. The derived coefficients can be used for customized assessment of fetal growth potential in Ireland. The implementation of these customized centile charts and their free online availability will aid clinicians in Ireland in the interpretation of fetal weight estimation.

Effects of hospital delivery during off-hours on perinatal outcome in several subgroups: a retrospective cohort study

Background

Studies have demonstrated a higher risk of adverse outcomes among infants born or admitted during off-hours, as compared to office hours, leading to questions about quality of care provide during off-hours (weekend, evening or night). We aim to determine the relationship between off-hours delivery and adverse perinatal outcomes for subgroups of hospital births.

Methods

This retrospective cohort study was based on data from the Netherlands Perinatal Registry, a countrywide registry that covers 99% of all hospital births in the Netherlands. Data of 449,714 infants, born at 28 completed weeks or later, in the period 2003 through 2007 were used. Infants with a high a priori risk of morbidity or mortality were excluded. Outcome measures were intrapartum and early neonatal mortality, a low Apgar score (5 minute score of 0–6), and a composite adverse perinatal outcome measure (mortality, low Apgar score, severe birth trauma, admission to a neonatal intensive care unit).

Results

Evening and night-time deliveries that involved induction or augmentation of labour, or an emergency caesarean section, were associated with an increased risk of an adverse perinatal outcome when compared to similar daytime deliveries. Weekend deliveries were not associated with an increased risk when compared to weekday deliveries. It was estimated that each year, between 126 and 141 cases with an adverse perinatal outcomes could be attributed to this evening and night effect. Of these, 21 (15-16%) are intrapartum or early neonatal death. Among the 3100 infants in the study population who experience an adverse outcome each year, death accounted for only 5% (165) of these outcomes.

Conclusion

This study shows that for infants whose mothers require obstetric interventions during labour and delivery, birth in the evening or at night, are at an increased risk of an adverse perinatal outcomes.

Can anomalies of fetal brain circulation be useful in the management of growth restricted fetuses?

Assessment of the fetal cerebral circulation provides important information on the hemodynamic changes associated with chronic hypoxia and intrauterine growth restriction. Despite the incorporation of new US parameters, the landmark for the fetal brain hemodynamic evaluation is still the middle cerebral artery. However, new vascular territories, such as the anterior and posterior cerebral arteries, might provide additional information on the onset of the brain sparing effect. The fractional moving blood volume estimation and three-dimensional power Doppler ultrasound indices are new techniques that seem to be promising in identifying cases at earlier stages of vascular deterioration; still, they are not available for clinical application and more information is needed on the reproducibility and advantages of three-dimensional power Doppler ultrasound blood flow indices. In the past, the brain sparing effect was considered as a protective mechanism; however, recent information challenges this concept. There is growing evidence of an association between brain sparing effect and increased risk of abnormal neurodevelopment after birth. Even in mild late-onset intrauterine growth restriction affected fetuses with normal umbilical artery blood flow, increased cerebral blood perfusion can be associated with a substantial risk of abnormal neuroadaptation and neurodevelopment during childhood.

The Vermont Oxford Neonatal Encephalopathy Registry: rationale, methods, and initial results

Background

In 2006, the Vermont Oxford Network (VON) established the Neonatal Encephalopathy Registry (NER) to characterize infants born with neonatal encephalopathy, describe evaluations and medical treatments, monitor hypothermic therapy (HT) dissemination, define clinical research questions, and identify opportunities for improved care.

Methods

Eligible infants were ≥ 36 weeks with seizures, altered consciousness (stupor, coma) during the first 72 hours of life, a 5 minute Apgar score of ≤ 3, or receiving HT. Infants with central nervous system birth defects were excluded.

Results

From 2006–2010, 95 centers registered 4232 infants. Of those, 59% suffered a seizure, 50% had a 5 minute Apgar score of ≤ 3, 38% received HT, and 18% had stupor/coma documented on neurologic exam. Some infants experienced more than one eligibility criterion. Only 53% had a cord gas obtained and only 63% had a blood gas obtained within 24 hours of birth, important components for determining HT eligibility. Sixty-four percent received ventilator support, 65% received anticonvulsants, 66% had a head MRI, 23% had a cranial CT, 67% had a full channel encephalogram (EEG) and 33% amplitude integrated EEG. Of all infants, 87% survived.

Conclusions

The VON NER describes the heterogeneous population of infants with NE, the subset that received HT, their patterns of care, and outcomes. The optimal routine care of infants with neonatal encephalopathy is unknown. The registry method is well suited to identify opportunities for improvement in the care of infants affected by NE and study interventions such as HT as they are implemented in clinical practice.

Spectral power differences in the brain activity of growth-restricted and normal fetuses

Using non-invasive fetal magnetoencephalography (fMEG), we investigated spontaneous brain activity in 28 fetuses diagnosed with intrauterine growth restriction (IUGR) and compared the results to 47 normal-growth fetuses. The fetal gestational age ranged from 28 to 39 weeks with post-natal recordings obtained on 17 of the IUGR fetuses. Power spectrum was computed and was divided into four frequency bands. A significant difference in the relative spectral power in delta, theta and beta bands (P<0.01) was observed only in the 28-32 week gestation age group with alpha band showing a similar trend (P=0.054). This observation suggests that growth restriction may have a more pronounced effect on the fetal brain in early gestation. Larger population studies could reveal the potential value of fMEG as an additional surveillance tool for growth-restricted fetuses.

Impact of therapeutic hypothermia on MRI diffusion changes in neonatal encephalopathy

OBJECTIVE

The objective of this work was to determine the impact of therapeutic hypothermia (TH) on the magnitude and time course of mean diffusivity (MD) changes following hypoxic-ischemic encephalopathy (HIE) in newborns.

METHODS

Cerebral MRI scans of infants undergoing whole body TH for HIE from 2007 to 2010 were retrospectively reviewed. The data were analyzed identically to a control group of newborns with HIE previously published, prior to the development of TH. Anatomic injury was defined on T1- and T2-weighted ("late") MRI obtained after the fifth day of life. Since MD values vary regionally, the ratios of MD values for injured and normal tissue were calculated for areas of injury. Normal values were obtained from corresponding brain regions of 12 infants undergoing TH who had no injury on MRI studies.

RESULTS

Twenty-three of 59 infants who underwent TH and MRI displayed cerebral injury on late MRI and were included in the study. MD ratios were decreased in all injured infants within the first 7 days of life. The return of MD to normal (pseudonormalization) occurred after the tenth day as compared to 6-8 days in the control group. Infants with severest injury demonstrated greater reduction in MD, but no difference in time to pseudonormalization.

CONCLUSION

TH slows the evolution of diffusion abnormalities on MRI following HIE in term infants.

Drug studies in newborns: a therapeutic imperative

Although some drugs have been developed for the neonate, drug development for the least mature and most vulnerable pediatric patients is lacking. Most of the drugs are off-label or off-patent and are empirically administered to newborns once efficacy has been demonstrated in adults and usefulness is suspected or demonstrated in the older pediatric population. Few drugs are approved by the Food and Drug Administration for use in this population. The factors that prevent the demonstration of efficacy and safety in the newborn are discussed and a change in the current approach for neonatal drug studies is suggested.

Perinatal risk factors for neonatal asphyxia in Vali-e-Asr hospital, Tehran-Iran

BACKGROUND

Asphyxia is a medical condition in which placental or pulmonary gas exchange is impaired or they cease all together, typically producing a combination of progressive hypoxemia and hypercapnea.

OBJECTIVE

In addition to regional differences in its etiology; it is important to know its risk factors.

MATERIALS AND METHODS

This is a case-control study, all neonates born from May 2002 to September 2005 in Vali-e-Asr Hospital were studied. 9488 newborns were born of which 6091 of the live patients were hospitalized in NICU. 546 newborns were studied as case and control group. 260 neonates (48%) were female and 286 neonates (52%) were male. Among the neonates who were admitted, 182 of them were diagnosed with asphyxia and twice of them (364 newborns) were selected as a control group. The variables consist of; gestational age, type of delivery, birth weight, prenatal care, pregnancy and peripartum complications and neonatal disorders.

RESULTS

Our studies showed that 35 (19.2%) patients had mild asphyxia, 107 (58.8%) had moderate asphyxia and 40 (22%) were diagnosed as severe asphyxia. Mean maternal age was 34.23±4.29yr; (range: 23-38 yr); and mean of parity was 2±1.2; (range: 1-8). Risk factors in our study included emergent Caesarian Section, preterm labor (<37w), low birth weight (<2500g), 5 minute Apgar (less than 6), need for resuscitation, nuchal cord, impaired Biophysical Profile, neonatal anemia, and maternal infertility.

CONCLUSION

All risk factors listed above play a role in asphyxia. The majority of these factors are avoidable by means of good perinatal care.

Perinatal morbidity and risk of hypoxic-ischemic encephalopathy associated with intrapartum sentinel events

OBJECTIVE

To examine perinatal morbidity and rate of hypoxic-ischemic encephalopathy in infants exposed to intrapartum sentinel events.

STUDY DESIGN

Retrospective cohort study from 2000-2005. Perinatal mortality, perinatal morbidity and rate of hypoxic-ischemic encephalopathy were compared in 3 groups of infants exposed to different risk factors for perinatal asphyxia (sentinel events, nonreassuring fetal status, elective cesarean section).

RESULTS

Five hundred eighty-six infants were studied. Perinatal mortality was 6% in the sentinel event group and 0.3% in the nonreassuring fetal status group (relative risk, 2.4; 95% confidence interval, 1.95-2.94). Perinatal morbidity was 2-6 times more frequent in infants exposed to sentinel events; the incidence of hypoxic-ischemic encephalopathy was 10%, compared with 2.5% in the nonreassuring fetal status group (relative risk, 1.93; 95% confidence interval, 1.49-2.52). No infant in the elective cesarean section group died, had perinatal morbidity, or developed encephalopathy.

CONCLUSION

Intrapartum sentinel events are associated with a high incidence of perinatal morbidity and hypoxic-ischemic encephalopathy.

Postterm pregnancy

Postterm pregnancy is a pregnancy that extends to 42 weeks of gestation or beyond. Fetal, neonatal and maternal complications associated with this condition have always been underestimated. It is not well understood why some women become postterm although in obesity, hormonal and genetic factors have been implicated. The management of postterm pregnancy constitutes a challenge to clinicians; knowing who to induce, who will respond to induction and who will require a caesarean section (CS). The current definition and management of postterm pregnancy have been challenged in several studies as the emerging evidence demonstrates that the incidence of complications associated with postterm pregnancy also increase prior to 42 weeks of gestation. For example the incidence of stillbirth increases from 39 weeks onwards with a sharp rise after 40 weeks of gestation. Induction of labour before 42 weeks of gestation has the potential to prevent these complications; however, both patients and clinicians alike are concerned about risks associated with induction of labour such as failure of induction and increases in CS rates. There is a strong body of evidence however that demonstrates that induction of labour at term and prior to 42 weeks of gestation (particularly between 40 & 42 weeks) is associated with a reduction in perinatal complications without an associated increase in CS rates. It seems therefore that a policy of induction of labour at 41 weeks in postterm women could be beneficial with potential improvement in perinatal outcome and a reduction in maternal complications.

"Every case of asphyxia can be used as a learning example". Conclusions from an analysis of substandard obstetrical care

AIM

To propose suggestions for improvements in care based on conclusions from studies on low Apgar scores and substandard care during labor.

SETTING AND PATIENTS

Studies on infants with low Apgar scores in a general obstetric population 2004-2006 and claims for financial compensation on the behalf of infants, based on the suspicion that substandard care in conjunction with childbirth has caused severe asphyxia or neonatal death in Sweden 1990-2005.

RESULTS

The most common flaws were related to insufficient fetal surveillance, defective interpretation of cardiotocography (CTG) tracings, not acting in a timely fashion on abnormal CTG, and the incautious use of oxytocin. Besides, in half of the infants a suboptimal mode of delivery added further trauma to the already asphyxiated infant. Additionally, resuscitation was unsatisfactory in many of these infants. The most critical flaw was defective compliance with the guidelines concerning ventilation and the early paging of skilled personnel in cases of imminent asphyxia or known complications during labor. In many case reports, the documentation of the neonatal resuscitation was insufficient to enable accurate and reliable evaluation.

CONCLUSIONS

Examples of proposed improvements in care during labor are the introduction of a permanent educational atmosphere with aside time for daily educational rounds and discussion, cooperation around the use of standardized terminology in CTG interpretation, the cautious use of oxytocin, and the routine paging of a pediatrician before birth in cases of complicated delivery or imminent asphyxia. The proposed interventions need to be evaluated in clinical trials in the future.

Antenatal suspicion of ischemic placental disease and coexistence of maternal and fetal placental disease: analysis of over 500 cases

OBJECTIVE

To investigate the antenatal suspicion of placental disease and the coexistence of maternal and fetal placental ischemic disease.

STUDY DESIGN

A prospective cohort study on normally formed singleton infants from 2000 to 2008 inclusive with placental ischemic disease.

RESULTS

Uteroplacental ischemia or fetoplacental thrombotic vasculopathy was identified in 511 of 74,857 births (7/1000 births). Four hundred fifty-nine cases met the inclusion criteria. Maternal and fetal placental vascular disease coexisted in 9.2% (n = 42) of cases. Placental ischemic disease was suspected antenatally in 70% (324/459). Maternal placental disease occurred in 40% (184/459) and 30% (140/459) had fetal pathology. The perinatal mortality rate was 12.7/1000. Antenatal suspicion of placental disease led to increased obstetric intervention and delivery of small-for-gestational age infants.

CONCLUSION

Maternal and fetoplacental vascular disease coexisted in 9.2%. Placental disease was suspected antenatally in 70% of cases and was associated with increased rates of obstetric intervention.

Head Ultrasound and MR imaging in the evaluation of neonatal encephalopathy: competitive or complementary imaging studies?

Magnetic resonance (MR) imaging is superior to ultrasonography (US) for the evaluation and prognostication of neonates with neonatal encephalopathy (NE). Nonetheless, US may provide important information early in the course of NE and can be used to document the evolution of lesions. This article provides an overview of useful findings in the US evaluation of infants with NE. Although many of the findings do not appear as conspicuous or as extensively as they do on MR imaging, recognition and familiarity with subtle head US abnormalities may allow head US to play an important complementary role to MR imaging in the evaluation of infants with NE.

The biological basis of injury and neuroprotection in the fetal and neonatal brain

A compromised intrauterine environment that delivers low levels of oxygen and/or nutrients, or is infected or inflammatory, can result in fetal brain injury, abnormal brain development and in cases of chronic compromise, intrauterine growth restriction. Preterm birth can also be associated with injury to the developing brain and affect the normal trajectory of brain growth. This review will focus on the effects that episodes of perinatal hypoxia (acute, chronic, associated with inflammation or as an antecedent of preterm birth) can have on the developing brain. In animal models of these conditions we have found that relatively brief (acute) periods of fetal hypoxemia can have significant effects on the fetal brain, for example death of susceptible neuronal populations (cerebellum, hippocampus, cortex) and cerebral white matter damage. Chronic placental insufficiency which includes fetal hypoxemia, nutrient restriction and altered endocrine status can result in fetal growth restriction and long-term deficits in neural connectivity in addition to altered postnatal function, for example in the auditory and visual systems. Maternal/fetal inflammation can result in fetal brain damage, particularly but not exclusively in the white matter; injury is more pronounced when associated with fetal hypoxemia. In the baboon, in which the normal trajectory of growth is affected by preterm birth, there is a direct correlation between a higher flux in oxygen saturation and a greater extent of neuropathological damage. Currently, the only established therapy for neonatal encephalopathy in full term neonates is moderate hypothermia although this only offers some protection to moderately but not severely affected brains. There is no accepted therapy for injured preterm brains. Consequently the search for more efficacious treatments continues; we discuss neuroprotective agents (erythropoietin, N-acetyl cysteine, melatonin, creatine, neurosteroids) which we have trialed in appropriate animal models. The possibility of combining hypothermia with such agents or growth factors is now being considered. A deeper understanding of causal pathways in brain injury is essential for the development of efficacious strategies for neuroprotection.

Incidence of and risk factors for neonatal respiratory depression and encephalopathy in rural Sarlahi, Nepal

OBJECTIVES

To characterize the incidence of, risk factors for, and neonatal morbidity and mortality associated with respiratory depression at birth and neonatal encephalopathy (NE) among term infants in a developing country.

METHODS

Data were collected prospectively in 2002-2006 during a community-based trial that enrolled 23 662 newborns in rural Nepal and evaluated the impact of umbilical-cord and skin cleansing on neonatal morbidity and mortality rates. Respiratory depression at birth and NE were defined on the basis of symptoms from maternal reports and study-worker observations during home visits.

RESULTS

Respiratory depression at birth was reported for 19.7% of live births, and 79% of cases involved term infants without congenital anomalies. Among newborns with probable intrapartum-related respiratory depression (N = 3465), 112 (3%) died before their first home visit (presumed severe NE), and 178 (5%) eventually developed symptoms of NE. Overall, 629 term infants developed NE (28.1 cases per 1000 live births); 2% of cases were associated with congenital anomalies, 25% with infections, and 28% with a potential intrapartum event. The incidence of intrapartum-related NE was 13.0 cases per 1000 live births; the neonatal case fatality rate was 46%. Infants with NE more frequently experienced birth complications and were male, of multiple gestation, or born to nulliparous mothers.

CONCLUSIONS

In Sarlahi, the incidence of neonatal respiratory depression and NE, associated neonatal case fatality, and morbidity prevalence are high. Action is required to increase coverage of skilled obstetric/neonatal care in this setting and to evaluate long-term impairments.

Placental infarction identified by macroscopic examination and risk of cerebral palsy in infants at 35 weeks of gestational age and over

OBJECTIVE

We sought to investigate whether placental infarction determined by macroscopic examination was associated with risk of cerebral palsy (CP).

STUDY DESIGN

This was a population-based study of macroscopic placental infarcts in singletons>35 weeks' gestational age, in 158 perinatal deaths, 445 infants with CP, and 491 controls matched with CP cases for gestational age.

RESULTS

Placental infarcts were recorded in 2.0% of controls, 4.4% of deaths (relative risk [RR], 2.2; 95% confidence interval [CI], 0.8-5.6]), 5.2% of infants with CP (P<.05, RR, 2.5; 95% CI, 1.2-5.3), and 8.4% with spastic quadriplegic CP (P=.0026; RR, 4.4; 95% CI, 1.8-10.6). In children with CP, unlike controls, placental infarction was associated with reduced fetal growth, older maternal age, more prior miscarriages, and poor neonatal condition, but not with maternal preeclampsia.

CONCLUSION

Placental infarction identified by macroscopic examination was associated with increased risk of CP and the CP subtype, spastic quadriplegic CP. Antecedents of placental infarction differed in children with CP compared with control children.

The placenta and neurologic and psychiatric outcomes in the child: study design matters

Much information exists about functions of the human placenta and about potential mechanisms by which the placenta may influence human health or disease, including developmental disorders of brain. Recent studies indicate a high frequency of placental pathology in infants with developmental brain disorders, or with risk factors for such disorders. However, most clinical studies of the association of placental features with adverse neurologic or psychiatric outcome have substantial methodologic limitations. We discuss issues of study design as they relate to studies of the placenta and human brain disorders. In addition to the need for further consensus on procedures and terminology for placental evaluation, there are a number of special features that make clinical studies of the association of placental features with neurologic and psychiatric disorders especially difficult: most such disorders are not diagnosed until months or years after the majority of placentas have been discarded; these disorders are individually uncommon, so that prospective studies - needed to provide denominator data to enable estimation of risks - will require very large sample sizes; the administrative structures required to relate features of the placenta with clinical outcome will be complicated and costly. We offer some suggestions concerning study design in the face of these practical difficulties. Systematic and methodologically rigorous exploration of the role of the placenta in human developmental brain disorders has scarcely begun. A new generation of studies, difficult but potentially enormously rewarding, will be needed for clinical investigations of the placenta and fetal brain development.

Perinatal death and neurological damage as a sequential chain of poor outcome

OBJECTIVE

We investigated the risk factors of perinatal death and neurological damage.

METHODS

Perinatal death and neurological damage were retrospectively investigated using a population-based study of 108 024 deliveries from 1998 to 2007. Main factors studied were asphyxia, growth restriction and preterm delivery < 34 weeks of gestation, since these three factors were most often associated with poor prognosis. The impact of each factor was identified by multiple regression analyses.

RESULTS

There were 459 perinatal deaths (4.3/1000) and 220 neurological damages (2.0/1000). Preterm delivery accounted for 50% of perinatal deaths and neurological damage, whereas it constituted 2.6% of total births. Multiple regression analyses showed that prematurity < 34 weeks (10-fold), asphyxia (10-fold) and growth restriction (2-fold) were independent and significant risk factors associated with poor outcomes, and that the magnitude was similar throughout the three consecutive critical events of fetal death, neonatal death and neurological damage.

CONCLUSIONS

Prematurity < 34 weeks, asphyxia and growth restriction are independent and persistent risk factors from perinatal death to neurological damage.

Treatment advances in neonatal neuroprotection and neurointensive care

Knowledge of the nature, prognosis, and ways to treat brain lesions in neonatal infants has increased remarkably. Neonatal hypoxic-ischaemic encephalopathy (HIE) in term infants, mirrors a progressive cascade of excito-oxidative events that unfold in the brain after an asphyxial insult. In the laboratory, this cascade can be blocked to protect brain tissue through the process of neuroprotection. However, proof of a clinical effect was lacking until the publication of three positive randomised controlled trials of moderate hypothermia for term infants with HIE. These results have greatly improved treatment prospects for babies with asphyxia and altered understanding of the theory of neuroprotection. The studies show that moderate hypothermia within 6 h of asphyxia improves survival without cerebral palsy or other disability by about 40% and reduces death or neurological disability by nearly 30%. The search is on to discover adjuvant treatments that can further enhance the effects of hypothermia.

Migraine and preterm birth

OBJECTIVE

To investigate whether maternal migraine was associated with preterm birth.

STUDY DESIGN

Case-control sample within a population-based study of risk factors for cerebral palsy (CP). Infants without CP were matched for gestational age with those with CP. Maternal migraine was self-identified at first prenatal visit, most in the first trimester.

RESULT

Infants without CP born to women with migraine had a higher rate of preterm birth (odds ratio (OR)=3.5, 95% confidence interval (CI) 1.5, 8.5), as did infants who died in the perinatal period (OR=7.3, 95% CI 0.98, 54), the difference marginal for nominal statistical significance. In all outcome groups, infants of women with migraine had a higher observed rate of suboptimal intrauterine growth. In term infants, the rate of maternal migraine was higher in those with CP than in controls (OR=2.18, 95% CI 0.92, 5.25). Pre-eclampsia was reported more frequently in women with migraine who gave birth to a child with CP or a perinatal death, particularly in those born preterm; OR=5.1 (1.3, 20) and OR=2.9 (1.1, 7.6), respectively, but not in women giving birth to a control whether term or preterm.

CONCLUSION

Maternal migraine, as self-reported early in pregnancy, was associated with preterm birth in survivors without CP and in infants who died in the perinatal period. The combination of maternal migraine and pre-eclampsia was associated with CP and perinatal death. The association of maternal migraine with outcomes of pregnancy warrants further study.