Gathering the evidence: Cord gases and placental histology for births with low Apgar scores

Factors Associated with Apgar Score among Newborns Delivered by Cesarean Sections at Gandhi Memorial Hospital, Addis Ababa

BACKGROUND

Newborns can be assessed clinically using the Apgar score test to quickly and summarily assess the health of newborn physical condition immediately after delivery and to determine any immediate need for extra medical or emergency care. This study is aimed at assessing factors associated with Apgar score among newborns delivered by cesarean sections and factors associated with Apgar score.

METHOD

Institutional-based cohort study design was conducted. All eligible study participants were included. Training was given for data collectors and supervisors. Regular supervision and follow-up was made. Data was entered into Epi Info version 7 computer software by investigators and was transported to SPSS version 20 computer program for analysis. Bivariate and multivariate analysis was used to identify factors associated with Apgar score.

RESULT

A total 354 newborn babies were included into the study. Majority of baby had low Apgar score at one minute and high Apgar score at five minutes. About 30.2% of newborn baby had Apgar score below seven minutes. On the other hand, about 12.8% of all newborns had low Apgar score at five minutes. It had been found that those neonates who were born when skin incision to delivery time is greater than three minutes were about fourfolds more likely to have low Apgar score than those who were born when skin incision to delivery time is less than three minutes (AOR 3.645) (95% CI (0.116-26.421)).

CONCLUSION

Newborn babies have a low Apgar score at one minute as compared to five minutes. But low Apgar score at five minutes has long-term sequel. Therefore, it is very important to reduce factors associated with low Apgar score at both minutes.

Five and 10 minute Apgar scores and risks of cerebral palsy and epilepsy: population based cohort study in Sweden

OBJECTIVE

To investigate associations between Apgar score at five and 10 minutes across the entire range of score values (from 0 to 10) and risks of childhood cerebral palsy or epilepsy, and to analyse the effect of changes in Apgar scores from five to 10 minutes after birth in infants born ≥37 completed weeks.

DESIGN, SETTING, AND PARTICIPANTS

Population based cohort study in Sweden, including 1 213 470 non-malformed live singleton infants, born at term between 1999 and 2012. Data on maternal and pregnancy characteristics and diagnoses of cerebral palsy and epilepsy were obtained by individual record linkages of nationwide Swedish registries.

EXPOSURES

Apgar scores at five and 10 minutes.

MAIN OUTCOME MEASURE

Cerebral palsy and epilepsy diagnosed up to 16 years of age. Adjusted hazard ratios were calculated, along with 95% confidence intervals.

RESULTS

1221 (0.1%) children were diagnosed as having cerebral palsy and 3975 (0.3%) as having epilepsy. Compared with children with an Apgar score of 10 at five minutes, the adjusted hazard ratio for cerebral palsy increased steadily with decreasing Apgar score: from 1.9 (95% confidence interval 1.6 to 2.2) for an Apgar score of 9 to 277.7 (154.4 to 499.5) for an Apgar score of 0. Similar and even stronger associations were obtained between Apgar scores at 10 minutes and cerebral palsy. Associations between Apgar scores and epilepsy were less pronounced, but increased hazard ratios were noted in infants with a five minute Apgar score of 7 or less and a 10 minute Apgar score of 8 or less. Compared with infants with an Apgar of 9-10 at both five and 10 minutes, hazard ratios of cerebral palsy and epilepsy were higher among infants with a five minute Apgar score of 7-8 and a 10 minute Apgar score of 9-10.

CONCLUSION

Risks of cerebral palsy and epilepsy are inversely associated with five minute and 10 minute Apgar scores across the entire range of Apgar scores.

Cerebral palsy: causes, pathways, and the role of genetic variants

Cerebral palsy (CP) is heterogeneous with different clinical types, comorbidities, brain imaging patterns, causes, and now also heterogeneous underlying genetic variants. Few are solely due to severe hypoxia or ischemia at birth. This common myth has held back research in causation. The cost of litigation has devastating effects on maternity services with unnecessarily high cesarean delivery rates and subsequent maternal morbidity and mortality. CP rates have remained the same for 50 years despite a 6-fold increase in cesarean birth. Epidemiological studies have shown that the origins of most CP are prior to labor. Increased risk is associated with preterm delivery, congenital malformations, intrauterine infection, fetal growth restriction, multiple pregnancy, and placental abnormalities. Hypoxia at birth may be primary or secondary to preexisting pathology and international criteria help to separate the few cases of CP due to acute intrapartum hypoxia. Until recently, 1-2% of CP (mostly familial) had been linked to causative mutations. Recent genetic studies of sporadic CP cases using new-generation exome sequencing show that 14% of cases have likely causative single-gene mutations and up to 31% have clinically relevant copy number variations. The genetic variants are heterogeneous and require function investigations to prove causation. Whole genome sequencing, fine scale copy number variant investigations, and gene expression studies may extend the percentage of cases with a genetic pathway. Clinical risk factors could act as triggers for CP where there is genetic susceptibility. These new findings should refocus research about the causes of these complex and varied neurodevelopmental disorders.

Placental histology in clinically unexpected severe fetal acidemia at term

BACKGROUND

Fetal acidemia at birth is defined as a newborn condition wherein the cord blood pH value is less than 7.0. It could represent an association with newborn brain damage; therefore, it is important to investigate which conditions precipitate its occurrence. No extensive placental analysis has been performed in cases of acidotic newborns delivered from low-risk pregnancies.

AIMS

To study placental characteristics in cases with severe fetal acidemia.

STUDY DESIGN

Retrospective case-control study.

SUBJECT

34 cases, 102 controls.

OUTCOME MEASURES

Umbilical artery pH was measured at delivery from a doubly clamped portion of the cord. Placental characteristics were compared between cases with severe fetal acidemia (cord pH at birth <7.0) and controls (normal pH at birth) in term low-risk pregnancies.

RESULTS

Macroscopic placental and umbilical cord characteristics were comparable in cases and controls whereas histological characteristics exhibited differences: diffuse villous edema, increased number of syncytial knots and villous branching abnormalities significantly affected cases more frequently than controls. Diffuse villous edema is related to fetal vascularization and associated with an increase of venous pressure; in our low-risk population, it is conceivable that these changes of fetal flow and pressure occurred in labor during the alteration of fetal heart rate. An increased number of syncytial knots and villous branching abnormalities have been previously associated with chronic placental hypoxic condition; in our low-risk population they could reflect a clinically undetectable hypoxic situation that acted during pregnancy reducing fetal resources to bear labor and delivery.

CONCLUSIONS

Placental histology provides useful information related to fetal acidemia in low-risk term pregnancy.

Does aetiology of neonatal encephalopathy and hypoxic-ischaemic encephalopathy influence the outcome of treatment?

Neonatal encephalopathy, a clinical syndrome affecting term-born and late preterm newborn infants, increases the risk of perinatal death and long-term neurological morbidity, especially cerebral palsy. With the advent of therapeutic hypothermia, a treatment designed for hypoxic or ischaemic injury, associated mortality and morbidity rates have decreased. Unfortunately, only about one in eight neonates (95% confidence interval) who meet eligibility criteria for therapeutic cooling apparently benefit from the treatment. Studies of infants in representative populations indicate that neonatal encephalopathy is a potential result of a variety of antecedents and that asphyxial complications at birth account for only a small percentage of neonatal encephalopathy. In contrast, clinical case series suggest that a large proportion of neonatal encephalopathy is hypoxic or ischaemic, and trials of therapeutic hypothermia are specifically designed to include only infants exposed to hypoxia or ischaemia. This review addresses the differences, definitional and methodological, between infants studied and investigations undertaken, in population studies compared with cooling trials. It raises the question if there may be subgroups of infants with a clinical diagnosis of hypoxic-ischaemic encephalopathy (HIE) in whom the pathobiology of neonatal neurological depression is not fundamentally hypoxic or ischaemic and, therefore, for whom cooling may not be beneficial. In addition, it suggests approaches to future trials of cooling plus adjuvant therapy that may contribute to further improvement of care for these vulnerable neonates.

Placental pathology in full-term infants with hypoxic-ischemic neonatal encephalopathy and association with magnetic resonance imaging pattern of brain injury

OBJECTIVE

To investigate the relationship between placental pathology and pattern of brain injury in full-term infants with neonatal encephalopathy after a presumed hypoxic-ischemic insult.

STUDY DESIGN

The study group comprised full-term infants with neonatal encephalopathy subsequent to presumed hypoxia-ischemia with available placenta for analysis who underwent cerebral magnetic resonance imaging (MRI) within the first 15 days after birth. Macroscopic and microscopic characteristics of the placenta were assessed. The infants were classified according to the predominant pattern of brain injury detected on MRI: no injury, predominant white matter/watershed injury, predominant basal ganglia and thalami (BGT) injury, or white matter/watershed injury with BGT involvement. Maternal and perinatal clinical factors were recorded.

RESULTS

Placental tissue was available for analysis in 95 of 171 infants evaluated (56%). Among these 95 infants, 34 had no cerebral abnormalities on MRI, 27 had white matter/watershed injury, 18 had BGT injury, and 16 had white matter/watershed injury with BGT involvement. Chorioamnionitis was a common placental finding in both the infants without injury (59%) and those with white matter/BGT injury (56%). On multinomial logistic regression analysis, white matter/watershed injury with and without BGT involvement was associated with decreased placental maturation. Hypoglycemia was associated with an increased risk of the white matter/BGT injury pattern (OR,5.4; 95% CI, 1.4-21.4). The BGT injury pattern was associated with chronic villitis (OR, 12.7; 95% CI, 2.4-68.7). A placental weight <10th percentile appeared to be protective against brain injury, especially for the BGT pattern (OR, 0.1; 95% CI, 0.01-0.7).

CONCLUSION

Placental weight <10th percentile was mainly associated with normal cerebral MRI findings. Decreased placental maturation and hypoglycemia <2.0 mmol/L were associated with increased risk of white matter/watershed injury with or without BGT involvement. Chronic villitis was associated with BGT injury irrespective of white matter injury.

The association of cerebral palsy with birth asphyxia: a definitional quagmire

AIM

The aim of this study was to investigate whether current literature provides a useful body of evidence reflecting the proportion of cerebral palsy (CP) that is attributable to birth asphyxia.

METHOD

We identified 23 studies conducted between 1986 and 2010 that provided data on intrapartum risks of CP.

RESULTS

The proportion of CP with birth asphyxia as a precursor (case exposure rate) varied from less than 3% to over 50% in the 23 studies reviewed. The studies were heterogeneous in many regards, including the definitions for birth asphyxia and the outcome of CP.

INTERPRETATIONS

Current data do not support the belief, widely held in the medical and legal communities, that birth asphyxia can be recognized reliably and specifically, or that much of CP is due to birth asphyxia. The very high case exposure rates linking birth asphyxia to CP can probably be attributed to several factors: the fact that the clinical picture at birth cannot specifically identify birth asphyxia; the definition of CP employed; and confusion of proximal effects - results - with causes. Further research is needed.

Neurodiagnostic techniques in neonatal critical care

This article reviews recent advances in the neurodiagnostic tools available to clinicians practicing in neonatal critical care. The advent of induced mild hypothermia for acute neonatal hypoxic-ischemic encephalopathy in 2005 has been responsible for renewed urgency in the development of precise and reliable neonatal neurodiagnostic techniques. Traditional evaluations of bedside head ultrasounds, head computed tomography scans, and routine electroencephalograms (EEGs) have been upgraded in most tertiary pediatric centers to incorporate protocols for MRI, continuous EEG monitoring with remote bedside access, amplitude-integrated EEG, and near-infrared spectroscopy. Meanwhile, recent studies supporting the association between placental pathology and neonatal brain injury highlight the need for closer examination of the placenta in the neurodiagnostic evaluation of the acutely ill newborn. As the pursuit of more effective neuroprotection moves into the "hypothermia plus" era, the identification, evaluation, and treatment of the neurologically affected newborn in the neonatal intensive care unit has increasing significance.

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.