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

The aetiology of preterm birth and risks of cerebral palsy and cognitive impairment: A systematic review and meta-analysis

AIM

The associations between the aetiology of preterm birth and later neurodevelopmental outcomes are unclear. A systematic review and meta-analysis examined the existing evidence.

METHODS

The PubMed and Embase databases were searched for papers published in English from inception to 16 December 2020. We included original papers on the causes of preterm birth and the risks of cerebral palsy (CP) and suboptimal cognitive development. Two reviewers independently evaluated the studies and extracted the data.

RESULTS

The literature search yielded 5472 papers and 13 were selected. The aetiology of preterm birth was classified under spontaneous or medically indicated delivery. A meta-analysis was performed, comprising 104 902 preterm infants from 11 papers on CP. Preterm infants born after a medically indicated delivery had a lower CP risk than infants born after spontaneous delivery, with a pooled odds ratio of 0.59 (95% confidence interval 0.40-0.86). This result was robust in the subgroup and sensitivity analyses. Cognitive development was reported in three papers, which suggested that worse outcomes were associated with medically indicated deliveries.

CONCLUSION

The aetiology of preterm delivery may contribute to the risk of CP and cognitive delay. Further research is needed, using individual-level meta-analyses to adjust for possible confounders, notably gestational age.

Associations between the aetiology of preterm birth and mortality and neurodevelopment up to 11 years

AIM

To investigate how the aetiology of very preterm birth/very low birth weight is associated with mortality and later neurodevelopmental outcomes.

METHODS

Very preterm/very low-birth weight singletons were categorised based on the aetiology of preterm birth: spontaneous preterm birth (n = 47, 28.1%), preterm premature rupture of membranes (n = 56, 33.5%) or placental vascular pathology (n = 64, 38.3%). Mortality, cerebral palsy, severe cognitive impairment by 11 years of age (<2SD) and mean full-scale intelligence quotient at 11 years were studied in association with birth aetiology.

RESULTS

There was no difference in mortality or rate of cerebral palsy according to birth aetiologies. The rate of severe cognitive impairment was lower (4.9% vs. 15.3%) in the preterm premature rupture of the membrane group in comparison to the placental vascular pathology group (OR 0.2, 95% CI 0.03-0.9, adjusted for gestational age). At 11 years, there was no statistically significant difference in the mean full-scale intelligence quotient.

CONCLUSION

Placental vascular pathology, as the aetiology of very preterm birth/very low birth weight, is associated with a higher rate of severe cognitive impairments in comparison to preterm premature rupture of membranes, although there was no difference in the mean full-scale intelligence quotient at 11 years. The aetiology of very preterm birth/very low birth weight was not associated with mortality or the rate of cerebral palsy.

Risk factors of cerebral palsy in children: a systematic review and meta-analysis

BACKGROUND

This study aimed to explore the main risk factors for cerebral palsy in children by meta-analysis of the literature on the risk factors of cerebral palsy.

METHODS

We performed a literature search of the PubMed, EMBASE, Medline, and CENTRAL databases using the following search terms: ("cerebrl plsy" or "cerebrl plsis" or "infantile cerebral palsy") and ("risk factors"). Case-control or cohort studies of children with cerebral palsy and healthy children were included for meta-analysis. The Newcastle-Ottawa Scale (NOS) of case-control studies was used to evaluate the quality of the included studies. The Chi-square test was used to test the heterogeneity of the literature. This study used subgroup analysis and sensitivity analysis to identify sources of heterogeneity. If subgroup analyses and sensitivity analyses could not identify the source of heterogeneity, no pooling between study results was performed, and only individual study results were described. In this study, Egger's test was used to test for publication bias. The random-effects model was used when heterogeneity existed, and the fixed-effect model was applied when heterogeneity did not exist.

RESULTS

A total of 1,836 related articles were retrieved. After screening, 13 articles were included in the analysis, involving a total of 2,489 children with cerebral palsy and 4,782 children without cerebral palsy. None of the included articles achieved a NOS score of 9, four articles scored 8, eight articles scored 7, and one article scored 6. Meta-analysis showed that maternal hypertension during pregnancy, premature rupture of membranes, premature delivery and emergency cesarean section were risk factors for cerebral palsy in children, and there was no heterogeneity among the literatures and no publication bias.

CONCLUSIONS

This study identified gestational hypertension, preterm birth, premature rupture of membranes, and emergency cesarean section as risk factors for cerebral palsy in children through meta-analysis, providing a reference for risk monitoring and clinical intervention.

Cerebral palsy: Aetiology, pathophysiology and therapeutic interventions

Cerebral palsy (CP) is the most common non-progressive neurodevelopmental disorder in which the impairment of motor and posture functions occurs. This condition may be present in many different clinical spectra. Various aetiological and risk factors play a crucial role in the causation of CP. In various cases, the causes of CP may not be apparent. Interruption in the supply of oxygen to the fetus or brain asphyxia was considered to be the main causative factor explaining CP. Antenatal, perinatal, and postnatal factors could be involved in the origin of CP. Understanding its pathophysiology is also crucial for developing preventive and protective strategies. A major advancement in the brain stimulation techniques has emerged as a promising status in diagnostic and interventional approaches. This review provides a brief explanation about the various aetiological factors, pathophysiology, and recent therapeutic approaches in the treatment of cerebral palsy.

The spectrum of brain malformations and disruptions in twins

Twins have an increased risk for congenital malformations and disruptions, including defects in brain morphogenesis. We analyzed data on brain imaging, zygosity, sex, and fetal demise in 56 proband twins and 7 less affected co-twins with abnormal brain imaging and compared them to population-based data and to a literature series. We separated our series into malformations of cortical development (MCD, N = 39), cerebellar malformations without MCD (N = 13), and brain disruptions (N = 11). The MCD group included 37/39 (95%) with polymicrogyria (PMG), 8/39 (21%) with pia-ependymal clefts (schizencephaly), and 15/39 (38%) with periventricular nodular heterotopia (PNH) including 2 with PNH but not PMG. Cerebellar malformations were found in 19 individuals including 13 with a cerebellar malformation only and another 6 with cerebellar malformation and MCD. The pattern varied from diffuse cerebellar hypoplasia to classic Dandy-Walker malformation. Brain disruptions were seen in 11 individuals with hydranencephaly, porencephaly, or white matter loss without cysts. Our series included an expected statistically significant excess of monozygotic (MZ) twin pairs (22/41 MZ, 54%) compared to population data (482/1448 MZ, 33.3%; p = .0110), and an unexpected statistically significant excess of dizygotic (DZ) twins (19/41, 46%) compared to the literature cohort (1/46 DZ, 2%; p < .0001. Recurrent association with twin-twin transfusion syndrome, intrauterine growth retardation, and other prenatal factors support disruption of vascular perfusion as the most likely unifying cause.

Does low dose aspirin prescribed for risk of early onset preeclampsia reduce the prevalence of preterm prelabor rupture of membranes?

Background: Placental dysfunction, inflammation and degradation of fetal membranes has been hypothesized as a cause of preterm prelabor of rupture of membranes.Objective: To examine the effect of aspirin, an anti-inflammatory agent, on the prevalence of preterm prelabor rupture of membranes (PPRoMs).Methods: A retrospective analysis was conducted to examine the effect of aspirin on the prevalence of PPRoM. Aspirin (150 mg, nocte) was prescribed to women who were identified through a screening program at 11-13⁺⁶ weeks' gestation as being at high risk for developing early-onset preeclampsia. Women who were at low risk for developing preeclampsia did not receive aspirin. The prevalence of PPRoM was compared with an observational cohort.Results: In the observational cohort, there were 3027 women, including 32 (1.1%) cases of PPRoM. The prevalence of PPRoM in the high risk group was 3.1% (4/128) and was statistically significantly higher compared to the low risk group (1.0%) (28/2899). The relative risk was 3.02 (95% CI 1.2-7.7; p= .04). In the interventional cohort, there were 7280 women, with 114 (1.6%) cases of PPRoM. The prevalence of PPRoM in the high risk group who were treated with aspirin was 1.8% (14/766) compared to 1.5% (100/6516) in the low risk group (p= .54). The prevalence of PPRoM in high risk patients in the observational group (who did not receive aspirin) compared with the high risk patients in the interventional group (who were treated with aspirin) was not statistically significant (p= .31).Conclusions: PPRoM is significantly associated with a description of high risk for ePET; although, this algorithm is not a good screening tool for predicting PPRoM. Aspirin treatment of women deemed high risk for ePET is safe in the context of PPRoM and there may be some reduction in prevalence of PPRoM in treated high risk women; although, this study was not powered to demonstrate a small reduction in the prevalence of PPRoM. The findings merit further investigation through a larger prospective study with adequate sample size.

Risk factors for failure in the newborn hearing screen test in very preterm twins

BACKGROUND

We aimed to identify prenatal and postnatal risk factors associated with abnormal newborn hearing screen (NHS) results and subsequently confirmed sensorineural hearing loss (SNHL) in preterm twin neonates.

METHODS

Electronic medical records of 159 twin neonates who were born alive after ≤32 weeks were retrospectively reviewed for hearing loss in both ears. Histopathologic examination of the placenta was performed and clinical data, including method of conception and factors specific to twins, were retrieved from a computerized perinatal database. The main outcome measure was failure to pass the NHS test. The generalized estimation equations model was used for twins.

RESULTS

Thirty-two neonates (20.1%) had a "refer" result, and, on the confirmation test, permanent SNHL was identified in 4.4% (7/159) of all neonates. Neonates who had a "refer" result on the NHS test were more likely to be of lower birth weight, more likely to have been conceived with the use of in vitro fertilization (IVF), and more likely to have higher rates of intraventricular hemorrhage (IVH) and bronchopulmonary dysplasia. However, monochorionic placentation, death of the co-twin, or being born first was not associated with a "refer" result on the NHS test. Multivariable logistic regression revealed that conception after IVF and the presence of IVH were the only variables to be statistically significantly associated with "refer" on the NHS test. No parameters studied were found to be significantly different between the SNHL and no SNHL groups, probably because of the relatively small number of cases of SNHL.

CONCLUSION

In preterm twin newborns, IVF and the presence of IVH were independently associated with an increased risk of abnormal NHS results, whereas the factors specific to twins were not associated with abnormal NHS results.

[Epidemiology, risk factors and child prognosis: CNGOF Preterm Premature Rupture of Membranes Guidelines]

OBJECTIVES

To synthetize the available evidence regarding the incidence and risk factors of preterm premature rupture of membranes (PPROM). To describe the evolution of pregnancy, neonatal outcomes and the prognosis of infants born in a context of PPROM, according to the existence of an associated intrauterine infection and to the latency duration.

METHOD

Consultation of the Medline database, from 1980 to February 2018.

RESULTS

PPROM before 37 and before 34 weeks' gestation occur in 2-3% and <1% of pregnancies, respectively (LE2). Although many risk factors are identified, few are modifiable, and the vast majority of patients have no risk factors (LE2). Consequently, individual prediction of the risk of PPROM and primary prevention measures have not been shown to be effective and are not recommended in clinical practice (Grade B). Most women give birth within the week following PPROM (LE2). The main complications of PPROM are prematurity, intrauterine infection and obstetric and maternal complications (LE2). Latency duration and the frequency of complications decrease with increasing gestational age at PPROM (LE2). Neonatal prognosis is largely conditioned by gestational age at birth, with no apparent over-risk of poor outcomes linked to PPROM compared to other causes of preterm birth (LE2). In contrast, intrauterine infection is associated with an increased risk of in utero fetal death (LE3), necrotizing enterocolitis (LE1) and early-onset sepsis (LE2). The association of intrauterine infection with neurological morbidity remains controversial. Prolongation of latency, from gestational age at PPROM, is beneficial for the child (LE2).

CONCLUSION

PPROM is a major cause of prematurity and short- and long-term mortality and morbidity. Antenatal care is an important issue for obstetric and pediatric teams, aiming to reduce complications and adverse consequences for both mother and child.

Epigenome-wide analysis in newborn blood spots from monozygotic twins discordant for cerebral palsy reveals consistent regional differences in DNA methylation

Background

Cerebral palsy (CP) is a clinical description for a group of motor disorders that are heterogeneous with respect to causes, symptoms and severity. A diagnosis of CP cannot usually be made at birth and in some cases may be delayed until 2–3 years of age. This limits opportunities for early intervention that could otherwise improve long-term outcomes. CP has been recorded in monozygotic twins discordant for the disorder, indicating a potential role of non-genetic factors such as intrauterine infection, hypoxia-ischaemia, haemorrhage and thrombosis. The aim of this exploratory study was to utilise the discordant monozygotic twin model to understand and measure epigenetic changes associated with the development of CP.

Methods

We performed a genome-wide analysis of DNA methylation using the Illumina Infinium Human Methylation 450 BeadChip array with DNA from newborn blood spots of 15 monozygotic twin pairs who later became discordant for CP. Quality control and data preprocessing were undertaken using the minfi R package. Differential methylation analysis was performed using the remove unwanted variation (RUVm) method, taking twin pairing into account in order to identify CP-specific differentially methylated probes (DMPs), and bumphunter was performed to identify differentially methylated regions (DMRs).

Results

We identified 33 top-ranked DMPs based on a nominal p value cut-off of p < 1 × 10⁻⁴ and two DMRs (p < 1 × 10⁻³) associated with CP. The top-ranked probes related to 25 genes including HNRNPL, RASSF5, CD3D and KALRN involved in immune signalling pathways, in addition to TBC1D24, FBXO9 and VIPR2 previously linked to epileptic encephalopathy. Gene ontology and pathway analysis of top-ranked DMP-associated genes revealed enrichment of inflammatory signalling pathways, regulation of cytokine secretion and regulation of leukocyte-mediated immunity. We also identified two top-ranked DMRs including one on chromosome 6 within the promoter region of LTA gene encoding tumour necrosis factor-beta (TNF-β), an important regulator of inflammation and brain development. The second was within the transcription start site of the LIME1 gene, which plays a key role in inflammatory pathways such as MAPK signalling. CP-specific differential DNA methylation within one of our two top DMRs was validated using an independent platform, MassArray EpiTyper.

Conclusions

Ours is the first epigenome-wide association study of CP in disease-discordant monozygotic twin pairs and suggests a potential role for immune dysfunction in this condition.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0457-4) contains supplementary material, which is available to authorized users.

Twins and neurodevelopmental outcomes: the effect of IVF, fetal growth restriction, and preterm birth

This invited review aimed at presenting the evidence concerning neurodevelopmental outcomes, particularly cerebral palsy (CP), motor disability, cognitive impairment, mental retardation, any major disability, blindness and deafness in cases of twins, conceived after in vitro fertilization, presenting fetal/intrauterine growth restriction (FGR/IUGR) or being prematurely born. FGR/IUGR, prematurity and zygosity affect neurodevelopmental outcome; CP is higher in term infants, those presenting with FGR/IUGR, as well as in survivors of intrauterine co-twin death; cognitive ability of twins versus singletons mainly relates to confounding factors, as FGR/IUGR and prematurity, while evidence for differences in behavioral and psychiatric disorders between twins and singletons is limited. The impact of IVF per se has not been documented. Nevertheless, available literature, usually of heterogeneous and retrospective nature, diverges in the criteria for neurodevelopmental delay. Furthermore, differences in selection/exclusion criteria and small mixed cohorts, including the full range of complications, make comparison of the existing studies difficult. Future studies should focus in confirming the lack of IVF impact on twins' neurodevelopment and general health, in comparing long-term outcome of naturally conceived twins with those conceived following assisted reproduction techniques and in including evaluation of individual, longitudinal trajectories of growth, and development. In this respect, worldwide population-based registries will enable more precise description of neurodevelopmental outcomes among twins.

Childhood outcomes following preterm prelabor rupture of the membranes (PPROM): a population-based record linkage cohort study

OBJECTIVE

The objective of this study is to determine child health, development and educational outcomes for infants born following preterm prelabor rupture of the membrane (PPROM).

STUDY DESIGN

Population-based record linkage cohort study using data from NSW, Australia, 2001 to 2014.

RESULTS

Of 121 822 births at 20 to 37 weeks, 18 799 (15%) followed PPROM, 56 406 (46%) followed spontaneous labor and 46 617 (38%) were planned. Compared with infants of a similar gestational age born following spontaneous labor or planned delivery, exposure to PPROM did not increase the risk of childhood mortality, childhood hospitalization, developmentally vulnerable at school entry, low reading or numeracy scores. Median latency ranged from 12 days (interquartile range 3 to 37 days) at 25 weeks to 1 day (0 to 2 days) at 36 weeks. Longer latency and more advanced gestational age at birth were associated with better outcomes.

CONCLUSION

Infants born following PPROM are at no greater risk of adverse child health, development and education outcomes than those of similar gestational age born without PPROM.

[Epidemiology and risk factors of preterm birth]

OBJECTIVE

To synthesize the available evidence regarding the incidence and several risk factors of preterm birth. To describe neonatal outcomes according to gestational age and to the context of delivery.

MATERIALS AND METHODS

Consultation of the Medline database.

RESULTS

In 2010, 11% of live births (15 million babies) occurred before 37 completed weeks of gestation worldwide. About 85% of these births were moderate to late preterm babies (32-36 weeks), 10% were very preterm babies (28-31 weeks) and 5% were extremely preterm babies (<28 weeks). In France, premature birth concerns 60,000 neonates every year, 12,000 of whom are born before 32 completed weeks of gestation. Half of them are delivered after spontaneous onset of labor or preterm premature rupture of the membranes, and the other half are provider-initiated preterm births. Several maternal factors are associated with preterm birth, including sociodemographic, obstetrical, psychological, and genetic factors; paternal and environmental factors are also involved. Gestational age is highly associated with neonatal mortality and with short- and long-term morbidities. Pregnancy complications and the context of delivery also have an impact on neonatal outcomes.

CONCLUSION

Preterm birth is one of the leading cause of the under-five mortality and of neurodevelopmental impairment worldwide; it remains a major public health issue.

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.

Risk Factors for Intraventricular Hemorrhage in Preterm Infants Born at 34 Weeks of Gestation or Less Following Preterm Premature Rupture of Membranes

OBJECTIVE

The objective of this study is to identify possible perinatal risk factors related to intraventricular hemorrhage (IVH) in preterm infants born at 34 weeks of gestation or less following preterm premature rupture of membranes (pPROM).

METHODS

A total of 292 preterm infants born at 34 weeks of gestation or less following pPROM were enrolled in the study, while 155 newborns with incomplete data, especially those that lack histological examination of the placenta, maternal details, and neonatal characteristics, have been further excluded. Finally, data of 137 preterm infants were included in the analysis. All infants underwent ultrasonographic screening for IVH. Thirty-three infants with IVH were considered as cases and 104 infants without IVH were considered as controls. The association between risk factors and IVH was evaluated by univariate and multivariate logistic regression analyses.

RESULTS

The incidence of IVH in preterm infants born at 34 weeks of gestation or less following pPROM was 24.1%, while the incidence of maternal chorioamnionitis was 43.8%. By univariate analysis, gestational age, birth weight, asphyxia resuscitation, maternal chorioamnionitis, fetal distress, amniotic fluid index, and latency of the rupture of membranes to birth were found to be significantly different between the 2 groups. By logistic regression analysis, lower gestational age, low birth weight, asphyxia resuscitation, and maternal chorioamnionitis were found to be independent risk factors for IVH.

CONCLUSION

Lower gestational age, low birth weight, asphyxia resuscitation, and maternal chorioamnionitis are independent risk factors for IVH in preterm infants born at 34 weeks of gestation or less following pPROM.

Neonatal outcome of very preterm twins: policy of planned vaginal or cesarean delivery

OBJECTIVE

The objective of the study was to compare neonatal mortality and morbidity in very preterm twins with the first twin in cephalic presentation in hospitals with a policy of planned vaginal delivery (PVD) and those with a policy of planned cesarean delivery (PCD).

STUDY DESIGN

Women with preterm cephalic first twins delivered after preterm labor and/or premature preterm rupture of membranes from 26(0/7) to 31(6/7) weeks of gestation were identified from the databases of 6 perinatal centers and classified as PVD or PCD according to the center's management policy from 1999 to 2010. Severe neonatal morbidity was defined as any of the following: intraventricular hemorrhage grades 3-4, periventricular leukomalacia, necrotizing enterocolitis, bronchopulmonary dysplasia, and hospital death. The independent effect of the planned mode of delivery, defined by the center's management policy, was tested and quantified with a 2-level multivariable logistic regression.

RESULTS

The PVD group included 248 women, and the PCD group 63. Maternal characteristics did not differ between the 2 groups. The rate of vaginal delivery was 85.9% (213 of 248) vs 20.6% (13 of 63) (P < .001), and the rate of cesarean delivery for the second twin was 1.6% (4 of 248) vs 4.8% (3 of 63) (P = .13) for PVD and PCD. PVD had no independent effect on either newborn hospital mortality or severe neonatal composite morbidity.

CONCLUSION

A policy of planned vaginal delivery of very preterm twins with the first twin in cephalic presentation does not increase either severe neonatal morbidity or mortality.

Do very preterm twins and singletons differ in their neurodevelopment at 5 years of age?

OBJECTIVE

Twins have inconsistently shown poorer outcomes than singletons. Although a high proportion of twins are born very preterm, data are sparse on the long-term outcomes in very preterm twins. The objective of this study was to compare mortality and neurodevelopmental outcomes of very preterm singletons and twins and to study outcomes in relation to factors specific to twins.

DESIGN

Birth cohort study Etude Epidemiologique sur les Petits Ages Gestationnels (EPIPAGE).

SETTING

Nine regions in France.

PATIENTS

All very preterm live births occurring from 22 to 32 weeks of gestation in all maternity wards of nine French regions in 1997 (n=2773).

MAIN OUTCOMES MEASURES

Neurodevelopmental status, including cerebral palsy, and a cognitive assessment with the Kaufman Assessment Battery for Children, with scores on the Mental Processing Composite (MPC) scale, was available for 1732 and 1473 children at 5 years of age, respectively.

RESULTS

Among live births, twins had higher hospital mortality than singletons (adjusted (a)OR: 1.4 (95% CI 1.1 to 1.9)). Among survivors, there was no crude difference at 5 years between twins and singletons in the prevalence of cerebral palsy (8.0% vs 9.1%, respectively), MPC <70 (9.5% vs 11.1%) and mean MPC (94.6 vs 94.4). However, after adjustment for sex, gestational age, intrauterine growth restriction and social factors, twins were more likely to have lower MPC scores (mean difference: -2.4 (95% CI-4.8 to 0.01)). Live born twins had a higher risk of mortality when birth weight discordance was present (aOR:2.9 (95% CI 1.7 to 4.8)), but there were no differences in long-term outcomes.

CONCLUSIONS

Compared with very preterm singletons, twins had higher mortality, no difference with respect to severe deficiencies, but slightly lower MPC scores at 5 years.

[Increase in twin maternities and consequences on health]

OBJECTIVES

To describe trends in twin maternity rates, factors which contribute to these trends, and risks associated with twin maternities for mothers and children.

POPULATION AND METHOD

The review was done on population-based studies, preferably in France and the European Union.

RESULTS

The rate of twin maternities was 15.6 p 1000 in 2008 and it increased by about 80% between 1972 and 2006. This rise was explained mainly by advanced maternal age and the diffusion of fertility treatments. The major risks for twins were fetal and infant mortality, preterm delivery, small for gestational age, and cerebral palsy. The rate of preterm delivery (<37 weeks) was 44.3% in France in 2003, and the relative risk was 8.8 (95% CI: 7.8-10.0), when compared with single pregnancies. Maternal age and fertility treatments do not change very much the perinatal risk of twins.

CONCLUSION

Twin pregnancies are a high risk group which needs more intensive medical care than single pregnancies. The perinatal information system should be improved in France to monitor perinatal indicators according to the number of fetuses in a proper way.

Gait patterns in twins with cerebral palsy: similarities and development over time after multilevel surgery

To examine gait patterns and gait quality, 7 twins with cerebral palsy were measured preoperatively and after surgical intervention. The aim was to study differences and/or similarities in gait between twins, the influence of personal characteristics and birth conditions, and to describe the development of gait over time after single event multilevel surgery. A standardized clinical exam and a three-dimensional gait analysis were performed. Gait patterns were classified according to Sutherland and Davids, and the Gillette Gait Index was calculated as a global measure of the gait impairment. Next to subject characteristics at time of first measurement, and at time of birth, birth conditions were collected. Gait patterns were determined as crouch gait in 13 legs, as stiff gait in 6 legs and as jump gait in 8 legs. One leg showed a normal gait pattern. The knee flexion-extension angle correlated most constant with the knee flexion-extension angle of the contralateral leg (range 0.91-0.99). Correlations with the legs of the sibling showed variable correlations (range 0.44-0.99); with all other legs medium to high correlations of 0.73-0.91 were found. The Gillette Gait Index was found to initially decrease after surgical intervention. Similar correlations were found between twins or between legs for the gait pattern expressed by the knee flexion-extension angle, and the Gillette Gait Index improved after surgery. It seems that gait quality in twins with cerebral palsy is characterized predominantly by the traumatic disorder: genetic dispositions and personal characteristics only play a negligible role.

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.

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.

Neonatal arterial ischaemic stroke: obstetric issues

Perinatal arterial ischaemic stroke (PAIS) is increasingly recognised as an important cause of neurological morbidity in children. The aetiology remains unclear although perinatal risk factors have been identified from limited case series. Risk factors for PAIS in term infants are different from those in preterm infants. Maternal primiparity, infertility, cocaine use, prothrombotic disorders, prolonged rupture of membranes, abnormal cardiotocograph, instrumental deliveries and emergency caesarean sections are reported risk factors in term infants. Uncomplicated vaginal delivery and prelabour caesarean section are uncommon in cases of PAIS. The presence of multiple risk factors increases the odds of developing PAIS. For preterm babies, fetal heart abnormalities, twin-twin transfusion and hypoglycaemia are recognised risk factors. Larger cohort studies are required to elucidate further the multifactorial pathway to perinatal arterial stroke.

Twinning on the brain: the effect on neurodevelopmental outcomes

Twinning is currently considered a complex multifactorial trait. Few studies have explored how the unique genetic and environmental influences that create twinning affect phenotypes and outcomes. Previous data has shown that twins account for a significant proportion of preterm and low-birth-weight infants, who are at risk for long-term neurodevelopmental disabilities such as cerebral palsy and cognitive impairment. More recently, it has been postulated that even without these co-morbidities, twinning in and of itself may incur a neurodevelopmental disadvantage even among term newborns. The purpose of this review is to report primarily on neuromotor outcomes of twins compared to singletons. In addition, we describe specific environmental risk factors among twins which are associated with poorer outcomes. Several putative neurodevelopmental modulators are explored, including death of a co-twin, chorionicity, birth weight discordance, and twin-twin transfusion. By teasing out environmental influences that potentially influence neurocognitive outcomes, families can receive more specific counseling and developmental services can be provided to those twins at especially high risk.

Infant sex, obstetric risk factors, and 2-year neurodevelopmental outcome among preterm infants

AIM

To evaluate the effect of the interaction between fetal sex and obstetric variables on the risk of neurodevelopmental impairment among preterm infants.

METHOD

A cohort study of 394 male and 360 female surviving infants born at 24 to 33 completed weeks of gestational age. Neurological examination and cognitive assessment of the infants (Bayley Scales of Infant Development) were performed at 2 years corrected age.

RESULTS

Mean gestational age was 30.4 weeks (SD 2.4). Rates of mild and moderate-to-severe neurodevelopmental impairment were 14.6% (110/754) and 7% (53/754) respectively. In logistic analysis, male sex was associated with an increased risk of neurodevelopmental impairment (odds ratio 1.8, 95% confidence interval 1.21-2.68) compared with females. The excess risk of neurodevelopmental impairment associated with male sex was higher among preeclamptic than normotensive pregnancies (p for interaction=0.004), among infants who were either small for gestational age or delivered to a mother with preeclampsia (p for interaction=0.001) and in iatrogenic as opposed to spontaneous preterm birth or preterm premature rupture of membranes (p for interaction=0.035).

INTERPRETATION

The excess risk of neurodevelopmental impairment associated with male sex among preterm infants is modulated by obstetric risk factors.

Assessment of risk factors for survival of neonates born after second-trimester PPROM

OBJECTIVE

Assess fetal risk factors which impact survival of infants delivered after second-trimester PPROM.

STUDY DESIGN

Clinical records of 87 patients, who all had second-trimester rupture of membranes between 14+0 and 24+6 weeks of gestation treated January 1998 to July 2005 were reviewed regarding perinatal outcome. This study is based on 25 surviving infants.

RESULTS

13 of these 25 infants died in the hospital. Survivors had a higher birth weight (p=0.008) and higher Apgar scores after 5 min (p=0.005) than those infants dying. No differences in UA pH, the need of catecholamines and no association between histological verified chorioamnionitis and early onset sepsis were seen between survivors and nonsurvivors.

CONCLUSION

Higher gestational age at birth, higher birth weight, the absence of histologically verified chorioamnionitis and 5 min Apgar scores of >or= than 6 have positive prognostic value for survival of neonates delivered preterm after second-trimester PPROM.

Cystic periventricular leukomalacia in preterm infants: an analysis of obstetric risk factors

OBJECTIVE

To identify obstetric risk factors and to elucidate the effect of prolonged rupture of the membranes on the development of cystic periventricular leukomalacia (PVL) in preterm infants.

METHODS

A retrospective case-control study of 95 preterm infants with the diagnosis of PVL and 245 healthy controls matched for gestational age. A total of 52 antenatal, intrapartum and neonatal characteristics were studied by univariate methods and logistic regression.

RESULTS

Preterm premature rupture of membranes (PPROM) (odds ratio 2.1 [95% CI 1.3-3.4], P=.003), gestational age at PPROM (P=.025), prolonged rupture of membranes (P<.0001), administration of tocolytic agents (1.8 [1.1-3.0], P=.019) and antibiotics (1.9 [1.2-3.1], P=.008) were associated with PVL. The use of tocolytic agents >24 h (P=.008), prolonged latency between the increase in maternal leukocyte count and birth (P=.034), spontaneous onset of labor (1.8 [1.0-2.9], P=.026), vaginal delivery (1.7 [1.1-2.8], P=.029) and male gender (1.5 [1.0-2.0], P=.04) were found more frequently in PVL cases. Preeclampsia (0.4 [0.1-0.9], P=.034), hypertension at booking (P=.009), sonographic IUGR (P=.020), abnormal blood flow of the umbilical artery (P=.032) and cesarean section without labor (0.5 [0.3-0.8], P=.006) were found less frequently. In logistic regression analysis, prolonged rupture of the membranes (P=.748), preeclampsia (P=.973), the use of antibiotics (P=.617) and beta-sympathomimetic tocolytic agents (P=.563) lost statistical significance, whereas birth weight (P=.036) became significant.

CONCLUSION

PPROM and prolonged rupture of the membranes may provoke adverse effects on the neurodevelopmental outcome of the preterm fetus. These findings may have implications on the obstetric management of PPROM beyond 30 weeks of gestation. Cesarean section without labor was less likely associated with the diagnosis of PVL.

Neonatal and 5-Year Outcomes After Birth at 30–34 Weeks of Gestation

OBJECTIVE

To evaluate the rates of in-hospital death, neonatal complications, and 5-year outcomes of infants born at 30-34 weeks of gestation.

METHODS

In nine regions of France, all 2,020 stillbirths and live births at 30, 31, and 32 weeks in 1997 and all 457 births at 33 and 34 weeks in April and October 1997 were recorded. Survivors were evaluated at 5 years of age.

RESULTS

Increasing gestational age from 30 to 34 weeks was associated with progressive decreases in in-hospital mortality (from 8.1% to 0.4%) and neonatal complications (respiratory distress syndrome, 43.8% to 2.6%; maternofetal infections, 7.2% to 2.6%; and severe white matter injury, 5.5% to 1.3%). Although infants at 33 and 34 weeks of gestation rarely experienced necrotizing enterocolitis, bronchopulmonary dysplasia, or nosocomial infections, they still required endotracheal ventilation, antibiotics, or parenteral nutrition. At 5 years of age, older gestational age was associated with significant decreases in rates of cerebral palsy (6.3% at 30 weeks and 0.7% at 34 weeks) and mild to severe cognitive impairments (35.3% at 30 weeks and 23.9% at 34 weeks). In singletons, preterm rupture of membranes or preterm labor carried an increased risk of cerebral palsy but not of cognitive impairment.

CONCLUSION

Neonates born at 30-34 weeks experienced substantial morbidity and often required admission to neonatal intensive care units. These outcomes suggest that prolonging pregnancies beyond 34 weeks may be desirable whenever possible. Infants born at 30-34 weeks should be carefully monitored to ensure prompt detection and management of neurodevelopmental impairment.

Neonatal outcome in preterm monochorionic twins with twin-to-twin transfusion syndrome after intrauterine treatment with amnioreduction or fetoscopic laser surgery: comparison with dichorionic twins

OBJECTIVE

The purpose of this study was to compare neonatal outcome in preterm neonates after twin-to-twin transfusion syndrome (TTTS) that was treated by amnioreduction or fetoscopic laser surgery (FLS) and in dichorionic neonates who were matched for gestational age at birth.

STUDY DESIGN

Neonatal outcome was assessed in 137 TTTS preterm neonates who were treated primarily with either amnioreduction (n = 36) or FLS (n = 101) and compared with dichorionic twins (n = 242) who were delivered at our center at 24-34 weeks of gestation.

RESULTS

Adverse neonatal outcome (death or severe cerebral lesions) was more frequent in the amnioreduction group than in the FLS and dichorionic groups. Overall neonatal outcome was comparable in FLS and dichorionic infants. However, neonatal morbidity was higher in FLS neonates at <30 weeks of gestation that was related mainly to failed laser therapy.

CONCLUSION

In preterm TTTS cases, neonatal morbidity decreases independently with gestational age and after successful FLS. Neonatal morbidity that was specific of TTTS was higher in the amnioreduction group and in cases with failed laser therapy.

Antenatal and delivery risk factors and prevalence of cerebral palsy in Duzce (Turkey)

This cross-sectional study aimed at investigating the prevalence and the etiological factors of cerebral palsy (CP) and comparing them with normal population within the rural and urban areas of Duzce province. Of the 102 children with cerebral palsy, 98 were associated with antenatal and delivery risk factors. The mean crude prevalence of cerebral palsy was 1.1 per 1000 live births. The children with CP were compared with 530 control subjects. The mothers of the children with cerebral palsy were significantly younger than the mothers of children in control group, and they had less parity and abortion. Preeclampsia, premature rupture of membranes, home births, prolonged labor, and twin pregnancies were significantly more common in the mothers of children with cerebral palsy, where no significant differences were found between the groups in terms of breech delivery, rate of cesarean births, gestational diabetes, and hemorrhage in late pregnancy. Birth asphyxia, liqueur with meconium stained, prolonged jaundice and neonatal seizure were also significantly more common in the group with cerebral palsy. Of the children with cerebral palsy, 78% were born at term, 20% were born with gestational ages of 32-36 weeks, 2% were born with gestational ages of 30-31 weeks. Nine percent of those children had a birth weight of >or= 3000 g, 12.2% had a birth weight of 2500-2999 g, 33.7% had a birth weight of 1500-2499 g, and 5.1% had a birth weight of <or= 1500 g. The causes of low prevalence of cerebral palsy were due to insufficient neonatal care, resulting in low survival in preterm and low birth weight children, and poor postnatal care of children with cerebral palsy.

Magnesium sulphate given before very-preterm birth to protect infant brain: the randomised controlled PREMAG trial*

OBJECTIVE

To evaluate whether magnesium sulphate (MgSO(4)) given to women at risk of very-preterm birth would be neuroprotective in preterm newborns and would prevent neonatal mortality and severe white-matter injury (WMI).

DESIGN

A randomised study.

SETTING

Eighteen French tertiary hospitals. Population Women with fetuses of gestational age < 33 weeks whose birth was planned or expected within 24 hours were enrolled from July 1997 to July 2003 with follow up of infants until hospital discharge. METHODS Five hundred and seventy-three mothers were randomly assigned to receive a single 40-ml infusion of 0.1 g/ml of MgSO(4) (4 g) solution or isotonic 0.9% saline (placebo) over 30 minutes. This study is registered as an International Standard Randomised Controlled Trial, number 00120588.

MAIN OUTCOME MEASURES

The primary endpoints were rates of severe WMI or total mortality before hospital discharge, and their combined outcome. Analyses were based on intention to treat.

RESULTS

After 6 years of enrolment, the trial was stopped. Data from 688 infants were analysed. Comparing infants who received MgSO(4) or placebo, respectively, total mortality (9.4 versus 10.4%; OR: 0.79, 95% CI 0.44-1.44), severe WMI (10.0 versus 11.7%; OR: 0.78, 95% CI 0.47-1.31) and their combined outcomes (16.5 versus 17.9%; OR: 0.86, 95% CI 0.55-1.34) were less frequent for the former, but these differences were not statistically significant. No major maternal adverse effects were observed in the MgSO(4) group.

CONCLUSION

Although our results are inconclusive, improvements of neonatal outcome obtained with MgSO(4) are of potential clinical significance. More research is needed to assess the protective effect of MgSO(4) alone or in combination with other neuroprotective molecules.

The origins of cerebral palsy

PURPOSE OF REVIEW

Cerebral palsy is the most common and visible motor disability of childhood. Its aetiology remains a topic of hot debate between those who see it as a reflection of medical mismanagement of an avoidable complication and those who see its origins in the development of the fetal brain affected at many points along a causal pathway to damage. This review outlines the themes of research publications over the year 2004/2005.

RECENT FINDINGS

The review looks at recent findings relating to epidemiology, infection and inflammation, prematurity, multiple pregnancy, thrombophilias, genetics, placenta, neuroimaging and rescue therapies in cerebral palsy.

SUMMARY

Papers this year have helped clarify risk groups and identify some areas (e.g. the management of thrombophilias and the potential of induced hypothermia) with the potential to be rapidly introduced into clinical practice. In this enigmatic and multifactorial condition, however, progress remains slow. New tools such as magnetic resonance imaging are providing valuable insights into the lesions that result in cerebral palsy but the pathways to injury remain unclear. The future of cerebral palsy research lies in understanding the complex interactions of multiple factors on the road to cerebral palsy or in looking for final common pathways such as inflammation which may be amenable to manipulation.