Some risk factors for cerebral palsy in very premature infants: importance of premature rupture of membranes and monochorionic twin placentation

Current approach to cerebral palsy

This teaching review aims to provide an overview of the current approach to children with cerebral palsy (CP), retrieving the best available evidence and summarizing existing knowledge in the field of CP in children. We also highlight areas where more research is needed and novel strategies for diagnosing and treating cerebral palsy. CP includes a group of permanent disorders of movement and posture that cause activity limitation. Multiple risk factors, occurring preconceptionally, prenatally, perinatally, or postneonatally, are involved in the pathogenesis of CP, with the prenatal ones accounting for 80-90 % of cases. Due to its heterogeneity, CP has various classifications, but usually is classified based on clinical findings and motor impairment. Standardized function classification systems have been developed to address inconsistencies in previous classifications. The combination of clinical assessment and validated predictive tools is recommended for an early diagnosis, which is important for early intervention and prevention of secondary impairments. The therapeutic regimen in CP involves prevention and management of the motor and associated problems. It includes the enhancement of motor performance, the enrichment of cognition and communication skills, the prevention of secondary impairments, and the support of parents and caregivers. The care of CP children demands a multidisciplinary approach focused on improving motor skills, reducing comorbidities, enhancing the quality of life, and prolonging survival.

Cerebral palsy and related neuromotor disorders: Overview of genetic and genomic studies

Cerebral palsy (CP) is a debilitating condition characterized by abnormal movement or posture, beginning early in development. Early family and twin studies and more recent genomic investigations clearly demonstrate that genetic factors of major effect contribute to the etiology of CP. Most copy number variants and small alterations of nucleotide sequence that cause CP arise as a result of de novo mutations, so studies that estimate heritability on basis of recurrence frequency within families substantially underestimate genetic contributions to the etiology. At least 4% of patients with typical CP have disease-causing CNVs, and at least 14% have disease-causing single nucleotide variants or indels. The rate of pathogenic genomic lesions is probably more than twice as high among patients who have atypical CP, i.e., neuromotor dysfunction with additional neurodevelopmental abnormalities or malformations, or with MRI findings and medical history that are not characteristic of a perinatal insult. Mutations of many different genetic loci can produce a CP-like phenotype. The importance of genetic variants of minor effect and of epigenetic modifications in producing a multifactorial predisposition to CP is less clear. Recognizing the specific cause of CP in an affected individual is essential to providing optimal clinical management. An etiological diagnosis provides families an "enhanced compass" that improves overall well-being, facilitates access to educational and social services, permits accurate genetic counseling, and, for a subset of patients such as those with underlying inherited metabolic disorders, may make precision therapy that targets the pathophysiology available. Trio exome sequencing with assessment of copy number or trio genome sequencing with bioinformatics analysis for single nucleotide variants, indels, and copy number variants is clinically indicated in the initial workup of CP patients, especially those with additional malformations or neurodevelopmental abnormalities.

The Prenatal Environment in Twin Studies: A Review on Chorionicity

A literature search was conducted to identify articles examining the association of chorionicity (e.g., whether twins share a single chorion and thus placenta or have separate chorions/placentas) and genetics, psychiatry/behavior, and neurological manifestations in humans twins and higher-order multiples. The main aim was to assess how frequently chorionicity has been examined in relation to heritability estimates, and to assess which phenotypes may be most sensitive to, or affected by, bias in heritability estimates because of chorionicity. Consistent with the theory that some chorionicity effects could lead to overestimation and others to underestimation of heritability, there were instances of each across the many phenotypes reviewed. However, firm conclusions should not be drawn since some of the outcomes were only examined in one or few studies and often sample sizes were small. While the evidence for bias due to chorionicity was mixed or null for many outcomes, results do, however, consistently suggest that heritability estimates are underestimated for measures of birth weight and early growth when chorionicity is not taken into account.

Presence of an umbilical artery notch in monochorionic/monoamniotic twins

OBJECTIVE

To examine the association between an umbilical artery notch and fetal deterioration in monochorionic/monoamniotic (MC/MA) twins.

METHODS

Six MC/MA twin pregnancies were admitted at 24-28 weeks of gestation for close fetal surveillance until elective delivery at 32 weeks or earlier in the presence of signs of fetal deterioration. Ultrasound (US) examinations were performed twice weekly. The presence of cord entanglement, umbilical artery notch, abnormal Doppler parameters, a non-reassuring fetal heart rate pattern, or an abnormal fetal biophysical profile were evaluated.

RESULTS

Umbilical cord entanglement was observed on US in all pregnancies. The presence of an umbilical artery notch was noted in four out of six pregnancies and in two of them an umbilical artery notch was seen in both twins. The umbilical artery pulsatility index was normal in all fetuses. Doppler parameters of the middle cerebral artery and ductus venosus, fetal biophysical profile and fetal heart rate monitoring remained normal until delivery in all pregnancies. All neonates experienced morbidity related to prematurity; however, all were discharged home in good condition.

CONCLUSION

The presence of an umbilical artery notch and cord entanglement, without other signs of fetal deterioration, are not indicative of an adverse perinatal outcome.

Cerebral palsy

The syndrome of cerebral palsy encompasses a large group of childhood movement and posture disorders. Severity, patterns of motor involvement, and associated impairments such as those of communication, intellectual ability, and epilepsy vary widely. Overall prevalence has remained stable in the past 40 years at 2-3·5 cases per 1000 livebirths, despite changes in antenatal and perinatal care. The few studies available from developing countries suggest prevalence of comparable magnitude. Cerebral palsy is a lifelong disorder; approaches to intervention, whether at an individual or environmental level, should recognise that quality of life and social participation throughout life are what individuals with cerebral palsy seek, not improved physical function for its own sake. In the past few years, the cerebral palsy community has learned that the evidence of benefit for the numerous drugs, surgery, and therapies used over previous decades is weak. Improved understanding of the role of multiple gestation in pathogenesis, of gene environment interaction, and how to influence brain plasticity could yield significant advances in treatment of the disorder. Reduction in the prevalence of post-neonatal cerebral palsy, especially in developing countries, should be possible through improved nutrition, infection control, and accident prevention.

An update on the prevalence of cerebral palsy: a systematic review and meta-analysis

AIMS

The aim of this study was to provide a comprehensive update on (1) the overall prevalence of cerebral palsy (CP); (2) the prevalence of CP in relation to birthweight; and (3) the prevalence of CP in relation to gestational age.

METHOD

A systematic review and meta-analysis was conducted and reported, based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement. Population-based studies on the prevalence of CP in children born in 1985 or after were selected. Statistical analysis was carried out using computer package R, version 2.14.

RESULTS

A total of 49 studies were selected for this review. The pooled overall prevalence of CP was 2.11 per 1000 live births (95% confidence interval [CI] 1.98-2.25). The prevalence of CP stratified by gestational age group showed the highest pooled prevalence to be in children weighing 1000 to 1499g at birth (59.18 per 1000 live births; 95% CI 53.06-66.01), although there was no significant difference on pairwise meta-regression with children weighing less than 1000g. The prevalence of CP expressed by gestational age was highest in children born before 28 weeks' gestation (111.80 per 1000 live births; 95% CI 69.53-179.78; p<0.0327).

INTERPRETATION

The overall prevalence of CP has remained constant in recent years despite increased survival of at-risk preterm infants.

Neurodevelopmental outcomes of twins

In population-based studies, the prevalence of neurodevelopmental disability is consistently higher in twins than singletons. This is largely because birth weight and gestational age (GA) distributions of twin births are shifted to the left when compared with singleton births, and lower birth weight and lower GA are associated with increased risk of neurodevelopmental disability. From a pathophysiologic perspective, a question of interest is whether neurodevelopmental outcomes of twins differ from singletons after controlling for covariates. If significant differences in outcomes persist, this would suggest that the twining process itself or something intrinsic to shared life in the womb may be responsible for observed differences. From a clinical perspective, when counseling parents at risk for preterm delivery of twins, it is useful to understand how twin outcomes compare relative to singleton outcomes at the same birth weight or GA. The purpose of this review is to examine the long-term neurodevelopmental outcomes of twins compared with singletons with control for important covariates.

Evaluating 2 Year Outcome in Twins ≤ 30 Weeks Gestation at Birth: A Regional Perinatal Unit's Experience

With improved technology in assisted reproductive medicine, there has been an absolute increase in the numbers of twin pregnancies with an associated increase in perinatal mortality and morbidity. This increase in perinatal mortality and morbidity is largely due to a higher incidence of delivering preterm as compared to singletons. Twin pregnancies have their unique complications that include abnormal placental communication and discordant growth which are associated with perinatal mortality and morbidity. The objectives of this study were two-fold: i) to determine if the morbidity/mortality outcome at 18–24 months corrected age seen in a cohort of twins born between 24–30 weeks gestation was significantly different as compared to singleton preterm infants of the same gestation; and ii) to determine and evaluate any differences between monochorionic (MC) and dichorionic (DC) twins. Twins 24–30 weeks gestation at birth born between 01/01/97–30/06/99 were identified and prospectively followed to 18–24 months corrected age (c.a.). They were matched with a singleton infant of the same gender and within 1 week of the same gestation. Obstetrical, neonatal and neurodevelopmental data were gathered and analyzed. The primary outcome was death or the presence of a severe neurodevelopmental deficit at 18–24 months corrected age. Of the 56 sets of twins identified, 52 sets were followed prospectively with 101 infants available for matching. In this cohort, twin pregnancies had a lower incidence of pregnancy-induced hypertension and premature rupture of membranes than singletons (p < 0.05). The two groups were comparable in neonatal characteristics. The incidence of death or severe disability was 29.7% in twins vs. 22.8% in singletons (p = 0.337, Fisher's exact test). The major area of deficit was in the cognitive category for both groups, 9.9% vs. 7.9% respectively. MC twins made up 35.6%; DC twins 64.4%. Twin to twin transfusion syndrome (TTTS) occurred in 6.9%. Discordant growth occurred more frequently in MC pregnancies (p = 0.016). MC twins tended to be more premature, lower in birth weight, and experience neonatal morbidity in the form of patent ductus arteriosus and sepsis (p < 0.05) as compared to DC twins. However, the primary outcome of death or severe neurodevelopmental deficit at 18–24 months c.a. was not significantly different between the two groups, 38.9% (MC) vs. 24.6% (DC), (p = 0.173, Fisher's exact test). Neurodevelopmental morbidity or mortality in twins with TTTS was 42%. Mortality and severe neurodevelopmental morbidity were not significantly higher in twins as compared to singletons in this cohort. However, the trend is slightly higher in twins, which may have clinical significance. Though not statistically significant, the incidence of 38.9% in adverse outcome with MC twins may be clinically significant. With the number of twins steadily increasing, further monitoring is required to determine future directions in intervention and research. Early recognition of monochorionicity remains essential to optimize care and neurodevelopment for these infants.

Developmental outcome of very low birth weight infants in a developing country

Background

Advances in neonatal care allow survival of extremely premature infants, who are at risk of handicap. Neurodevelopmental follow up of these infants is an essential part of ongoing evaluation of neonatal care. The neonatal care in resource limited developing countries is very different to that in first world settings. Follow up data from developing countries is essential; it is not appropriate to extrapolate data from units in developed countries. This study provides follow up data on a population of very low birth weight (VLBW) infants in Johannesburg, South Africa.

Methods

The study sample included all VLBW infants born between 01/06/2006 and 28/02/2007 and discharged from the neonatal unit at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH). Bayley Scales of Infant and Toddler Development Version 111 (BSID) 111 were done to assess development. Regression analysis was done to determine factors associated with poor outcome.

Results

178 infants were discharged, 26 were not available for follow up, 9 of the remaining 152 (5.9%) died before an assessment was done; 106 of the remaining 143 (74.1%) had a BSID 111 assessment. These 106 patients form the study sample; mean birth weight and mean gestational age was 1182 grams (SD: 197.78) and 30.81 weeks (SD: 2.67) respectively. The BSID (111) was done at a median age of 16.48 months. The mean cognitive subscale was 88.6 (95% CI: 85.69 - 91.59), 9 (8.5%) were < 70, mean language subscale was 87.71 (95% CI: 84.85 - 90.56), 10 (9.4%) < 70, and mean motor subscale was 90.05 (95% CI: 87.0 - 93.11), 8 (7.6%) < 70. Approximately one third of infants were identified as being at risk (score between 70 and 85) on each subscale. Cerebral palsy was diagnosed in 4 (3.7%) of babies. Factors associated with poor outcome included cystic periventricular leukomalacia (PVL), resuscitation at birth, maternal parity, prolonged hospitalisation and duration of supplemental oxygen. PVL was associated with poor outcome on all three subscales. Birth weight and gestational age were not predictive of neurodevelopmental outcome.

Conclusion

Although the neurodevelopmental outcome of this group of VLBW infants was within the normal range, with a low incidence of cerebral palsy, these results may reflect the low survival of babies with a birth weight below 900 grams. In addition, mean subscale scores were low and one third of the babies were identified as "at risk", indicating that this group of babies warrants long-term follow up into school going age.

Integrated review of cytokines in maternal, cord, and newborn blood: part II-- associations with early infection and increased risk of neurologic damage in preterm infants

A growing body of literature supports the relationship of maternal inflammation with preterm birth and adverse neonatal outcomes, including infection and central nervous system (CNS) dysfunction. Mediators of inflammation, most notably proinflammatory cytokines, have been implicated as having an association with and perhaps playing a causal role in the pathogenesis, leading to adverse neonatal outcomes. Even though the association of cytokines with early adverse neonatal outcomes has been actively pursued as a line of research, there has been little integration of diverse findings across studies. Therefore, the purpose of this systematic review was to appraise and classify empirical evidence from human studies for the association of cytokine levels in blood (serum, plasma, or cells; maternal, cord, or neonatal) with two adverse early outcomes in preterm infants: early infection and increased risk of neurologic damage. The review revealed that the proinflammatory cytokines most frequently linked with sepsis are in the interleukin (IL) 1 family as well as tumor necrosis factor alpha (TNF-alpha) and IL-6. The proinflammatory cytokines most frequently linked to neurologic insult in the reviewed studies were IL-1beta, IL-6, and IL-8. In all cases where IL-1beta was studied, the levels were increased when there was neurologic insult. A better understanding of the relationship of these inflammatory substances with these adverse conditions is needed for the future development of maternal and neonatal biobehavioral nursing research.

Clinical Risk Index for Babies score for the prediction of neurodevelopmental outcomes at 3 years of age in infants of very low birthweight

AIM

In this study, we evaluated the Clinical Risk Index for Babies - revised (CRIB-II) score as a predictor of long-term neurodevelopmental outcomes in preterm infants at 36 months' corrected age.

METHOD

CRIB-II scores, which include birthweight, gestational age, sex, admission temperature, and base excess, were recorded prospectively on all infants weighing 1250g or less admitted to the neonatal intensive care unit (NICU). The sensitivity and specificity of CRIB-II scores to predict poor outcomes were examined using receiver operating characteristic curves, and predictive accuracy was assessed using the area under the curve (AUC), based on the observed values entered on a continuous scale. Poor outcomes were defined as death or major neurodevelopmental disability (cerebral palsy, neurosensory hearing loss requiring amplification, legal blindness, severe seizure disorder, or cognitive score >2SD below the mean for adjusted age determined by clinical neurological examination and on the Wechsler Preschool and Primary Scale of Intelligence, Bayley Scales of Infant Development, or revised Leiter International Performance Scale).

RESULTS

Of the 180 infants admitted to the NICU, 155 survived. Complete follow-up data were available for 107 children. The male:female ratio was 50:57 (47-53%), median birthweight was 930g (range 511-1250g), and median gestational age was 27 weeks (range 23-32wks). Major neurodevelopmental impairment was observed in 11.2% of participants. In a regression model, the CRIB-II score was significantly correlated with long-term neurodevelopmental outcomes. It predicted major neurodevelopmental impairment (odds ratio [OR] 1.57, bootstrap 95% confidence interval [CI] 1.26-3.01; AUC 0.84) and poor outcome (OR 1.46; bootstrap 95% CI 1.31-1.71, AUC 0.82) at 36 months' corrected age.

INTERPRETATION

CRIB-II scores of 13 or more in the first hour of life can reliably predict major neurodevelopmental impairment at 36 months' corrected age (sensitivity 83%; specificity 84%).

Long-term neurodevelopmental outcome of monochorionic and matched dichorionic twins

BACKGROUND

Monochorionic (MC) twins are at increased risk for perinatal mortality and serious morbidity due to the presence of placental vascular anastomoses. Cerebral injury can be secondary to haemodynamic and hematological disorders during pregnancy (especially twin-to-twin transfusion syndrome (TTTS) or intrauterine co-twin death) or from postnatal injury associated with prematurity and low birth weight, common complications in twin pregnancies. We investigated neurodevelopmental outcome in MC and dichorionic (DC) twins at the age of two years.

METHODS

This was a prospective cohort study. Cerebral palsy (CP) was studied in 182 MC infants and 189 DC infants matched for weight and age at delivery, gender, ethnicity of the mother and study center. After losses to follow-up, 282 of the 366 infants without CP were available to be tested with the Griffiths Mental Developmental Scales at 22 months corrected age, all born between January 2005 and January 2006 in nine perinatal centers in The Netherlands. Due to phenotypic (un)alikeness in mono-or dizygosity, the principal investigator was not blinded to chorionic status; perinatal outcome, with exception of co-twin death, was not known to the examiner.

FINDINGS

Four out of 182 MC infants had CP (2.2%) - two of the four CP-cases were due to complications specific to MC twin pregnancies (TTTS and co-twin death) and the other two cases of CP were the result of cystic PVL after preterm birth - compared to one sibling of a DC twin (0.5%; OR 4.2, 95% CI 0.5-38.2) of unknown origin. Follow-up rate of neurodevelopmental outcome by Griffith's test was 76%. The majority of 2-year-old twins had normal developmental status. There were no significant differences between MC and DC twins. One MC infant (0.7%) had a developmental delay compared to 6 DC infants (4.2%; OR 0.2, 95% 0.0-1.4). Birth weight discordancy did not influence long-term outcome, though the smaller twin had slightly lower developmental scores than its larger co-twin.

CONCLUSIONS

There were no significant differences in occurrence of cerebral palsy as well as neurodevelopmental outcome between MC and DC twins. Outcome of MC twins seems favourable in the absence of TTTS or co-twin death.

Neuroimaging of neonatal encephalopathies

Neonatal brain disorders consist of a wide chapter including brain malformations, hypoxic-ischemic encephalopathy (HIE), intracranial infections, perinatal trauma and metabolic encephalopathy. We will focus here on HIE, intracranial infections (especially materno-fetal infection with or without prolonged and/or premature rupture of membranes) and metabolic encephalopathy, those three conditions being the most frequent so far in our experience. Neonatal stroke is also analyzed. Moreover minor perinatal events might be superimposed on an already damaged (infective, edematous, metabolically abnormal or maldeveloped) brain, highlighting the main role and potential benefits of neuroimaging during the neonatal period. The different methods of brain imaging are thus reported with their advantages and disadvantages.

Monochorionic diamniotic infants without twin-to-twin transfusion syndrome

BACKGROUND

Monochorionic-diamniotic twins (MoDi) occur in 0.3% of all pregnancies. Twin-to-twin transfusion syndrome (TTS) that occurs in 20% of MoDi pregnancies is associated with high perinatal morbidity and mortality. MoDi twins without TTS are more frequent (80%) but have been scarcely reported.

OBJECTIVE

To study perinatal morbidity and mortality of 74 MoDi twin sets without TTS and to compare it to that of 38 sets of MoDi twins with TTS.

METHODS

Chorionicity was determined by gender and placental examination. Gestational age (GA) was set by sonography and pediatric examination. TTS was diagnosed clinically and by sonography, discordance was defined by twins birth weight difference > or =20%, and fetal growth restriction was determined by using a twin-specific nomogram.

RESULTS

MoDi twin pregnancies without and with TTS were similar in demographics, live births, history of preeclampsia, fetal distress and cesarean delivery. They were different (p<0.01) in discordant pregnancies (36 and 79%), GA at delivery (32 and 29 weeks) intrauterine growth restriction (39 and 89%) and neonatal mortality (12 and 36%). Concordant (47 sets) and discordant (27 sets) MoDi twins without TTS were clinically similar.

CONCLUSIONS

MoDi twins without TTS have high rates of birth weight discordance, fetal growth restriction, fetal distress, prematurity and cesarean delivery. Although their perinatal mortality is low, the reported occurrence and the short- and long-term impacts of fetal and neonatal morbidities warrants attention.

Monochorionic twin pregnancies

The monochorionic placenta should be considered a developmental malformation and, as such, represents one of the most common birth defects. Great strides are being made to unravel the progression of nature's successful attempt at human cloning through fission. Critical to any strategy to reduce the perinatal morbidity and mortality associated with monochorionic placentas is early detection. Intense surveillance in at risk pregnancies will provide a better understanding of their natural progression, improve the prognosis with early intervention, and ultimately provide the key to prevent many of the complications unique to the monochorionic placenta.

Prenatal Risk Factors for Cerebral Palsy in Very Preterm Singletons and Twins

OBJECTIVE

To identify the main prenatal risk factors for cerebral palsy in very preterm singletons and twins.

METHODS

The data were from the Epipage study, which included all very preterm children (< 33 weeks) born in 1997 in 9 regions of France. The analysis included 1,954 children for whom a medical questionnaire was completed at the age of 2 years (83% of the surviving children). The risk factors studied were pregnancy complications and specific factors in twins (type of placenta and death of cotwin). Logistic regression analysis was carried out for singletons and generalized estimating equation models used for twins.

RESULTS

The proportion of cerebral palsy was 8% in singletons and 9% in twins. For singletons, spontaneous preterm labor (adjusted odds ratio [OR] 3.4, 95% confidence interval [CI] 1.7-6.7), preterm premature rupture of membranes (PPROM) with short latency (adjusted OR 4.9, 95% CI 2.0-11.8), and prolonged PPROM (adjusted OR 2.7, 95% CI 1.4-5.3) were associated with a higher risk of cerebral palsy than was hypertension. No such link was found between these pregnancy complications and cerebral palsy in twins. For twins, a monochorionic placenta (OR 1.9, 95% CI 1.0-3.6) increased the risk of cerebral palsy, but the OR became nonsignificant after adjustment (OR 1.7, 95% CI 0.8-3.4).

CONCLUSION

In very preterm singletons, spontaneous preterm labor and PPROM increased the risk of cerebral palsy compared with hypertension.

Do multiple gestations raise the risk of cerebral palsy?

There is an increased risk of CP in multiple as compared with singleton pregnancies, and the higher the number of fetuses the greater is the prevalence of CP. Although LBW and preterm birth are the most significant risk factors for CP, the disadvantage of twins is apparent near term. Moreover, the excessive risk is not only the result of over-representation of multiples among premature babies, but seems to be associated with circumstances that are unique to the twinning process. The risk of CP should be acknowledged not only when a multiple pregnancy is diagnosed, but also when counseling infertility patients in whom iatrogenic multiple pregnancies are an actual risk.

Why is it important to diagnose chorionicity and how do we do it?

Because the monochorionic (MC) placenta is designed for a singleton fetus, and might not provide adequate physiological support for twins, obstetric problems are more frequent in MC than dichorionic (DC) twins. Problems arise because asymmetric cord insertions cause growth discordance as a result of unequal sharing of placental tissue. Approximately 95% of MC twin placentas contain interfetal vascular connections of some kind, sometimes in several combinations. Such connections can cause twin-twin transfusion syndrome and twin reversed arterial perfusion. The survivor can also suffer damage if the co-twin dies spontaneously or from inappropriate methods of selective termination. These complications are progressive and often advanced by 18 weeks gestation. Monoamniotic twins carry greater risks than diamniotic twins, especially entangled cords. MC twins are often discordant for congenital anomalies. Diagnosis of MC twinning is optimal in the first trimester. Optimal management of these MC twin disorders is not yet established; long-term follow-up studies are unsatisfactory. In clinical practice, chorionicity is not always determined in the first trimester.

Preterm twin gestation and cystic periventricular leucomalacia

OBJECTIVE

To identify risk factors for the development of cystic periventricular leucomalacia (PVL) in twin gestation.

DESIGN

Retrospective case-control study.

SETTING

Tertiary care university hospital, Department of Paediatrics, Division of Neonatology, Graz, Austria.

PATIENTS

Preterm twin gestations with one sibling having developed cystic PVL, diagnosed by ultrasound scans, compared with their co-twins without PVL, in hospital between 1988 and 2000.

MAIN OUTCOME MEASURES

Perinatal and postnatal risk factors for the development of PVL.

RESULTS

Eighteen preterm twin gestations were included. Monochorionicity was evident in 47% of the pregnancies, and twin to twin transfusion syndrome occurred in two cases (11%). Fetal distress correlated inversely with PVL (15% v 53%, p = 0.019, relative risk (RR) = 2.057, 95% confidence interval (CI) = 1.067 to 3.968). Hypocarbia with Pco(2) levels below 30 mm Hg (4 kPa) was diagnosed in 29% of the cases compared with 6% of the controls (p = 0.038, RR = 1.944, 95% CI = 1.113 to 3.396). There were no significant differences between groups with regard to premature rupture of the membranes, early onset infection, respiratory distress syndrome, mechanical ventilation, arterial hypotension, persistent ductus arteriosus, and hyperbilirubinaemia. Asphyxia was only evident in three controls. Three infants died and another three were lost to follow up. None of the cases compared with 62% of the controls were diagnosed as having developed normally (p < 0.001), and 14 cases (82%) compared with two controls (15%) developed cerebral palsy (p < 0.001).

CONCLUSION

Hypocarbia was the only risk factor strongly associated with cystic PVL. The general outcome of the infants was poor.

Fetal brain injury

Improvements in MRI techniques widen the indications for fetal brain imaging and fetal brain injury represents the third indication of fetal brain magnetic resonance imaging (MRI) after the evaluation of suspected central nervous system (CNS) malformations and ventricular dilatation. Optimal MR imaging technique is necessary in order to collect as much data as possible about the fetal brain. Diffusion images can be used routinely in addition to the standard protocol of fetal brain MRI that consists of T1 and T2 weighted images of the fetal brain. Monovoxel proton magnetic resonance spectroscopy can also be performed in utero, but this technique is still more part of research protocol than of routine clinical protocol. Fetal brain injury includes hypoxia-ischemia, congenital infections (especially toxoplasmosis and cytomegalovirus infections), brain damage due to malformation such as vascular brain malformation and heart malformation, pregnancies at risk of fetal brain damage, and even inherited metabolic diseases, especially mitochondrial diseases. MRI findings in fetal brain injury consist of acute or chronic lesions that can be seen alone or in combination. Acute response of the fetal brain is less commonly seen than the chronic response compared to the brain response encountered in the postnatal period.

Fetal brain infections

INTRODUCTION

Congenital infections can cause severe brain damage. As a result, it is very important to identify them early in their course so that treatment can be administered to the mother, if possible. The role of imaging is to determine the presence, if any, and the extent of brain damage in the infected fetus. Although MRI is most commonly used as an adjunct to sonography, when clinical suspicion is high in the setting of a normal ultrasound or to better define abnormalities detected by ultrasound, MRI is routinely used in toxoplasmosis seroconversion to definitively rule out brain lesions, even when the ultrasound scan is considered normal. MRI is also used serially throughout the pregnancy to check for the development of brain abnormalities; medical treatment results in excellent clinical outcome if the brain is normal.

DISCUSSION

This article describes the indications, techniques, and findings that will allow proper use of fetal MRI in the setting of congenital infections.

MR imaging of acquired fetal brain disorders

INTRODUCTION

Acquired fetal brain disorders represent the third indication of fetal brain MRI, after ventricular dilatation and malformations of the central nervous system.

DISCUSSION

MRI is an adequate imaging technique for evaluating fetal brain damage. Fetal brain response to brain injury may be acute, chronic or a combination of acute and chronic. An acute response is not as common in the fetal brain as in the postnatal period. A chronic response or the combination of chronic and acute response are the most common responses of the fetal brain to injury, whatever its origin. MRI also provides the natural history of acquired fetal brain lesions with regard to the stage of development.

Myocardial hypertrophy of the recipient twins in twin-to-twin transfusion syndrome and cerebral palsy

OBJECTIVES

This study was performed to determine risk factors for cerebral palsy (CP) in monochorionic twins, especially with twin-to-twin transfusion syndrome (TTTS).

METHODS

In 33 pathologically confirmed monochorionic pregnancies, we analyzed the incidence of cardiovascular and neurological complications.

RESULTS

Seventeen cases were diagnosed as TTTS. Myocardial hypertrophy was detected in seven recipient twins of TTTS, but not found in the donor twins of TTTS or in non-TTTS. CP developed in six out of 29 in TTTS and one out of 32 in non-TTTS. In TTTS, all the cases with CP were seen in the recipient twins. The development of CP was significantly associated with cardiovascular complications such as myocardial hypertrophy and hydropic changes.

CONCLUSIONS

Myocardial hypertrophy found in the recipient twins in TTTS seems to be a risk for developing CP later on, which may have implications in understanding the pathogenesis of CP.

[Neurodevelopmental outcome of premature infants born at less than 33 weeks of gestational age and not cerebral palsy at the age of 5 years]

AIM

To appreciate the impact of prematurity, fetal hypotrophy and familial environment on the neurodevelopmental performances of very premature infants without cerebral palsy at the age of five years.

POPULATION AND METHODS

We followed a regional cohort of 171 very premature infants (< or = 32 weeks of gestation) until they were five years of age. Cognitive functions were tested with the WPPSI test and the development quotient was assessed by the ability to draw a "bonhomme". Twenty-two premature infants suffered from cerebral palsy diagnosed before the age of two years. Another infant had a moderate diplegia at the five-year examination. We had no information for 16 prematures (9.3% of survivors). Twenty-eight premature infants were considered as having no severe disability on phone or mailed contact, and another child had a severe isolated mental retardation. We examined 104/148 infants, and 96/148 survivors without cerebral palsy passed the tests. The cognitive functions of these premature infants are compared to the performances of a control group made up of 108 children born at term > or = 37 weeks, matched for birthplace and single or twin characteristics of the pregnancy.

RESULTS

The values of the different quotients are significantly decreased in the preterm group. The global IQ and the performance IQ are 0.8 SD, verbal IQ is 0.5 SD and the development quotient is 0.4 SD below the values observed in the control group. A performance IQ less than -2 SD for the mean of the control group is observed three times more than in the controls (13.5% vs 3.7%, P < 0.01). Multiple linear regression shows that prematurity explains, independent of hypotrophy and socioeconomic environment, 8% of the variation of the performance IQ (P < 0.01), 2% of the variation of the verbal IQ and 2% of the development quotient (P < 0.05).

CONCLUSION

The five-year neurologic outcome of the children born prematurely in this regional study is similar to the results observed in regional studies conducted in Europe: 13.4% of the survivors have cerebral palsy, and the cognitive functions of the children with no cerebral palsy are significantly lower than the term control group. Other risk factors such as hypotrophy, which modulates the developmental quotient, and the socioeconomic status, which modulates the verbal IQ, are underlined.

Role of the fetus in perinatal infection and neonatal brain damage

Increasing evidence supports the view that infants exposed to perinatal infection are at increased risk for brain injury. We suggest that elevated cytokines in the amniotic fluid or in the fetal circulation be viewed as a humoral expression and that inflammatory cells in chorionic plate or umbilical cord blood vessel walls be viewed as a morphologic expression of the fetal inflammatory response. We discuss the evidence supporting the hypothesis that the fetal inflammatory response contributes to neonatal brain injury and later developmental disability. Little support has been found for a maternal contribution. Intervention should be designed with the fetus in mind.

Developmental outcome of neonatal intensive care: what questions are we asking?

Recent neonatal intensive care outcome studies are asking more focused research questions and incorporating, at least implicitly, pathogenetic models. A few have grappled with the complex issues of health-related quality of life and functional outcomes and the many factors that affect these outcomes. The need to evaluate high-risk obstetrics is increasingly recognized. Studies of risk factors for neurodevelopmental outcomes provide valuable insights into mechanisms of and recovery from central nervous system injury. Ongoing study of the efficacy and effectiveness of interventions must continue amid concern about availability of family and developmental support for increasing numbers of survivors of high-risk obstetric and neonatal intensive care.

[For what reasons is the neurologic status of very premature infants altered between 1 and 2 years in a follow-up study? The contribution of a Frache-Comté region study]

BACKGROUND

The purpose of this population-based study was firstly to compare the neuro-developmental outcome at one and two years of very preterm infants, and secondly, to identify the risk factors for a misdiagnosis of cerebral impairment at the age of one year.

POPULATION AND METHODS

The preterm cohort included 203 infants born between 25 and 32 weeks of gestational age in the region of Franche-Comté (France) during a two-year period. The control group included 196 full-term infants born in the same maternity wards. Neuro-developmental assessments were performed by pediatricians or physicians, both at one and two years of age, on 94% (161/171) surviving preterms and 89% (173/195) full-terms.

RESULTS

There is a fair correlation between the two neurological evaluations of the control group (170/173, 98% have the same classification at the age of one and two). There is a weak correlation (kappa = 0.37) between the two neurological evaluations of the preterm group. Sixteen preterms (10%) had been classified more abnormal at one year than they were at two years. The presence of a broncho-pulmonary dysplasia, linked to male sex and extreme prematurity, was statistically linked to this first kind of misclassification. Seventeen preterms (10%) had been considered more normal at one year than they were at two years. The presence of a diplegia, family precariousness and the examination at one year of age by a general practitioner were statistically linked to this second kind of misclassification.

CONCLUSION

This prospective population-based study identifies structural situations (bronchopulmonary dysplasia linked to extreme prematurity) and environmental situations (family precariousness, examiner's qualifications) linked to a misclassification of the neurological status of one-year-old former preterm infants.