Intrauterine growth in children with cerebral palsy

Apgar Score and Risk of Cerebral Palsy in Preterm Infants: A Population-Based Cohort Study

A low Apgar score is associated with increased risk of cerebral palsy (CP) in term infants, while such association remains controversial in preterm neonates. The objective of this study was to assess association between 5-minute Apgar scores and CP in different subcategories of preterm birth based on gestational age. The Slovenian National Perinatal Information System was used to identify singleton children without congenital malformations live-born at 22 to 37 weeks of gestation between 2002 and 2010. Data were linked to the Slovenian Registry of Cerebral Palsy in children born between 2002 and 2010. CP was diagnosed at a minimum of 5 years of age. Of 11,924 children included, 241 (2.0%) died before discharge and 153 (1.3%) were diagnosed with CP. Five-minute Apgar scores <7 were significantly associated with higher risk of death or CP (compared with scores ≥9) at all preterm gestations. CP alone was associated with Apgar scores <7 only at moderately or late preterm gestation (32-36 weeks) (adjusted relative risk [aRR]: 8.27; 95% confidence interval [CI]: 1.87-36.64 for scores 0-4 and aRR: 4.96; 95% CI 1.89-13.06 for scores 5-6). In conclusion, a low 5-minute Apgar score was associated with combined outcome of neonatal death or CP in all preterm births, while in surviving preterm infants at >32 weeks a low 5-minute Apgar score was associated with CP.

Neurodevelopmental outcome at the age of 4 years according to the planned mode of delivery in term breech presentation: a nationwide, population-based record linkage study

PURPOSE

To evaluate whether a trial of planned vaginal breech labor affects neurologic development in children.

METHODS

This is a nationwide, Finnish, population-based record linkage study. An odds ratio with 95% confidence intervals was used to estimate the relative risk that a child delivered by planned vaginal breech labor would be diagnosed with adverse neurodevelopmental outcome (cerebral palsy, epilepsy, intellectual disability, sensor neural developmental outcome, hyperactivity, speech and language problems) at the age of 4 years. The reference group were children born by planned cesarean section.

RESULTS

During a study period of 7 years, 8374 infants were delivered in breech position. Among them, 3907 (46.7%) had an attempted labor and 4467 (53.3%) infants were delivered by planned cesarean section. There were no differences in the neurodevelopmental outcome. In the planned vaginal labor group, 133 (3.4%) children had an abnormal neurodevelopmental outcome at the age of 4 years compared to 142 (3.2%) in the planned cesarean section group.

CONCLUSION

The absolute risk of abnormal neurological outcome in breech deliveries at term was low, regardless of planned mode of birth. Planned vaginal breech labor did not increase the risk for abnormal neurological outcome compared to planned cesarean section.

SGA as a Risk Factor for Cerebral Palsy in Moderate to Late Preterm Infants: a System Review and Meta-analysis

Small for gestational age (SGA) is an established risk factor for cerebral palsy (CP) in term infants. However, there is conflicting data on the association between SGA and CP in moderate to late preterm infants. The aim of the article was to explore the relationship between SGA and CP in the moderate to late preterm infants and its strength by meta-analysis. We performed a system search in OVID (EMBASE and MEDLINE) and WANFANG from inception to May 2016. The study-specific risk estimates were pooled using the random-effect model. A total of seven studies were included in the meta-analysis, consisting of three cohort and four case-control studies. A statistically significant association was found between SGA and CP in moderate to late premature infants (OR: 2.34; 95% CI: 1.43-3.82). The association were higher in the several subgroups: 34-36 week gestational age (OR: 3.47; 95% CI: 1.29-9.31), SGA < 2SDs (OR: 3.48; 95% CI: 1.86-6.49), and malformation included in CP (OR: 3.00; 95% CI: 1.71-5.26). In moderate to late premature infants, SGA is a convenient and reliable predictor for CP. More studies are needed to explore the underlying mechanisms between SGA and CP association.

Prolonged Mild Hypoxia Alters Fetal Sheep Electrocorticogram Activity

OBJECTIVE

To assess the effects of prolonged mild hypoxemia on fetal brain electrocorticogram (ECoG) in late gestation.

STUDY DESIGN

Fetal and maternal catheters were placed under general anesthesia and animals allocated at random to receive intratracheal maternal administration of either nitrogen (n = 8) or compressed air (n = 8). Five days after surgery (125 days' gestational age), nitrogen infusion was adjusted to reduce fetal brachial artery PO2 by 25%. The targeted decrease in fetal oxygenation was maintained for 5 days while fetal ECoG activity and fetal and maternal cardiovascular variables were continuously recorded. Data are presented as mean +/- SEM and were analyzed by two-way analysis of variance (ANOVA) or two-sample t test.

RESULTS

Nitrogen infusion decreased fetal Po2 by 26% (20.5 +/- 1.7 versus 14.3 +/- 0.8) without changing fetal PCO2 or pH. Mild fetal hypoxemia was associated with fetal tachycardia and increased fetal blood pressure (P < .05). Fetal ECoG in hypoxic fetuses showed a significant decrease in the time spent in high voltage (HV) (P < .05) and an increase in the time spent in low voltage (LV) and in the number of low voltage events (P < .05). Also, a significant decrease in the proportion of 1-4 Hz and an increase in the proportion of 13-20 Hz frequencies was observed in LV events without a significant change in the frequency profile of HV events (P < .05).

CONCLUSION

Prolonged mild hypoxemia significantly altered fetal homeostasis as reflected by the sustained tachycardia and increased blood pressure. Fetal ECoG activity was affected significantly in a qualitatively and quantitative manner by mild prolonged hypoxemia.

Early onset preeclampsia and cerebral palsy: a double hit model?

BACKGROUND

Cerebral palsy (CP) is a late sequel of pregnancy, and the role of preeclampsia is debatable.

OBJECTIVE

The aims of this study were to determine the association between preeclampsia and cerebral palsy and to determine the risk factors for the development of cerebral palsy in these patients.

STUDY DESIGN

A retrospective population-based cohort study was designed that included 229,192 singleton pregnancies. The study population was divided into 2 groups: (1) patients with preeclampsia (n = 9749) and (2) normotensive gestations (n = 219,443). Generalized Estimating Equation multiple logistic regression models were performed to study the associations among preeclampsia, small for gestational age, gestational age at delivery, and the risk factors for the development of cerebral palsy in neonates of women with preeclampsia.

RESULTS

The rate of cerebral palsy was double in patients with preeclampsia than in the normotensive group (0.2% vs 0.1%; P = .015); early onset preeclampsia and small for gestational age were independent risk factors for the subsequent development of cerebral palsy (odds ratio, 8.639 [95% confidence interval, 4.269-17.480]; odds ratio, 2.737 [95% confidence interval, 1.937-3.868], respectively). A second model was conducted to determine the risk factors for the development of cerebral palsy in women with preeclampsia. Birth asphyxia, complications of prematurity, and neonatal infectious morbidity, but not small for gestational age or gestational age at delivery, were independent risk factors for the development of cerebral palsy.

CONCLUSION

In a comparison with normal pregnant women, the rate of cerebral palsy is double among patients with preeclampsia, especially those with early-onset disease. Early-onset preeclampsia is an independent risk factor for cerebral palsy. Among women with preeclampsia, the presence of neonatal infectious morbidity, birth asphyxia, and complications of prematurity are independent risk factors for the development of cerebral palsy, which further supports the role of a multi-hit model in the pathogenesis of this syndrome.

When is birthweight at term (≥37 weeks' gestation) abnormally low? A systematic review and meta-analysis of the prognostic and predictive ability of current birthweight standards for childhood and adult outcomes

BACKGROUND

Health outcomes throughout the life course have been linked to fetal growth restriction and low birthweight. A variety of measures exist to define low birthweight, with a lack of consensus regarding which predict adverse outcome.

OBJECTIVES

To evaluate the relationship between birthweight standards and childhood and adult outcomes in term-born infants (≥37 weeks' gestation).

SEARCH STRATEGY

MEDLINE (1966-January 2011), EMBASE (1980-January 2011), and the Cochrane Library (2011:1) and MEDION were included.

SELECTION CRITERIA

Studies comprising live term-born infants (gestation ≥37 completed weeks), with weight or other anthropometric measurements recorded at birth along with childhood and adult outcomes.

DATA COLLECTION AND ANALYSIS

Data were extracted to populate 2 × 2 tables relating birthweight standard with outcome, and meta-analysis was performed where possible.

MAIN RESULTS

Fifty-nine articles (2 600 383 individuals) were selected. There was no significant relationship between birthweight <2.5 kg (odds ratio [OR] 0.98, 95% confidence intervals [CI] 0.87-1.10) and composite measure of childhood morbidity. Weight <10th centile on the population nomogram showed a small association (OR 1.49, 95% CI 1.02-2.19) for the same outcome. There was no significant association between either of the above measures and adult morbidity. The relationship between other measures and individual outcomes varied.

AUTHOR'S CONCLUSIONS

The association between low birthweight, by any definition, and childhood and adult morbidity was inconsistent. None of the current standards of low birthweight was a good predictor of adverse outcome.

Intrauterine growth restriction and cerebral palsy

Intrauterine growth restriction (IUGR) can be described as condition in which fetus fails to reach his potential growth. It is common diagnosis in obstetrics, and carries an increased risk of perinatal mortality and morbidity. Moreover, IUGR has lifelong implications on health, especially on neurological outcome. There is a need for additional neurological assessment during monitoring of fetal well-being, in order to better predict antenatally which fetuses are at risk for adverse neurological outcome. Studies have revealed that the behavior of the fetus reflects the maturational processes of the central nervous system (CNS). Hence, ultrasound investigation of the fetal behavior can give us insight into the integrity and functioning of the fetal CNS. Furthermore, investigations carried out using modern method, four-dimensional (4D) sonography, have produced invaluable details of fetal behavior and its development, opening the door to a better understanding of the prenatal functional development of the CNS. Based on previous observations and several years of investigation, our reaserch group has proposed a new scoring system for the assessment of fetal neurological status by 4D sonography named Kurjak antenatal neurodevelopmental test (KANET). The value of KANET in distinguishing fetal brain and neurodevelopmental alterations due to the early brain impairment in utero is yet to be assessed in large population studies. However, preliminary results are very encouraging.

Atypical fetal voice processing in preeclamptic pregnancy

OBJECTIVE

To compare fetal heart rate (HR) response to the mother's voice in pregnancies complicated by preeclampsia with those of fetuses in uneventful, normotensive pregnancies.

METHOD

Fifty fetuses (n = 22, preeclampsia; n = 28, uneventful, normotensive pregnancies) between 32 and 40 weeks gestational age were recruited. Each fetus was presented with a 2-min no-sound baseline period followed by a 2-min voice period during which an audio recording of his/her mother reading a story was played through a loud speaker over the maternal abdomen at an average of 95 dBA followed by a 2-min no-voice offset period. HR was recorded continuously.

RESULTS

Fetuses in the preeclamptic group showed no response to the mother's voice when it was played. In comparison, fetuses in the uneventful, normotensive group responded to the mother's voice with a HR increase.

CONCLUSION

Fetuses in pregnancies complicated by preeclampsia show atypical auditory processing of the mother's voice. Such atypical responding may reflect a delay in auditory system maturation, functional elevation of sensorineural threshold, or decreased thyroid hormone.

Cerebral palsy and restricted growth status at birth: population-based case-control study

OBJECTIVE

To evaluate the association between growth status at birth and subsequent development of cerebral palsy in preterm and term infants.

DESIGN

Population-based case-controlled study.

SETTING

Cerebral palsy register in Western Sweden. Subjects Cohort of 334 singletons born between 1983 and 1990, with cerebral palsy diagnosed from age 4, and 668 singletons matched for gestation, gender and delivery unit.

METHOD

Growth status at birth was determined using small for gestational age (SGA) categories, with customised birthweight percentiles (SGAcust) based on the Swedish population.

MAIN OUTCOME MEASURES

Proportion of babies that were SGAcust, comparing cases and controls in three gestational age categories: early preterm (24-33 weeks), late preterm (34-36 weeks) and term (37+ weeks).

RESULTS

Of the 334 children with cerebral palsy, 87 (26.6%) were born early preterm, 27 (8.1%) late preterm and 218 (66%) at term. Children who had been born at term were more likely to have been SGA <1st customised percentile (SGAcust1) than their matched controls (OR 6.6, 95% CI 2.3-18.6). In contrast, children with cerebral palsy born preterm were not more likely to have been SGAcust1 (OR 0.9, 95% CI 0.4-1.9), and this applied to early preterm as well as late preterm births. For less severely small babies (SGA between 1st and 5th customised percentiles), the association with cerebral palsy remained significant for term births (OR 5.2, 95% CI 2.7-10.1) but was again not significant for preterm births.

CONCLUSIONS

Term singletons with severely SGA birthweights had a five- to seven-fold risk of developing cerebral palsy compared with gestational age-matched infants with birthweights within normal limits. For children born preterm, SGA was not more likely to be present in cases than in controls. These findings support the concept of cerebral palsy as a multifactorial condition and highlight the importance of antenatal surveillance of fetal growth.

Low birth weight, prematurity, and paternal social status: impact on the basic competence test in Taiwanese adolescents

OBJECTIVE

To investigate whether birth weight and paternal education may have independent and interactive effects on the learning achievement of adolescents.

STUDY DESIGN

We linked birth weights, gestational ages (term or preterm) and paternal education of a 4-year birth cohort to the Basic Competence Test (BCT) scores in Mandarin, mathematics and science for junior high school students age 15 to 16 years. The study groups comprised infants with term low birth weight (TLBW; n = 33 507), preterm normal birth weight (PNBW; n =19 905), and preterm low birth weight (PLBW; n = 25 840), as well as randomly selected term infants with normal birth weight (TNBW; n = 83 756). Paternal education levels were categorized.

RESULTS

Compared with the TNBW adolescents, the TLBW adolescents consistently showed larger deficits in mean scores for Mandarin (beta = -2.36), mathematics (beta = -2.89), and science (beta = -2.11). The corresponding significant deficit scores for the PLBW adolescents were -1.93, -2.80, and -1.92. The deficit scores were very small for the PNBW adolescents. Paternal education was inversely associated with scores of all 3 groups. Lower paternal education level tended to worsen the negative impact of low birth weight on BCT scores.

CONCLUSIONS

Both lower birth weight and lower paternal education exert an independent and interactive effect on adolescent learning achievement.

The influence of gestational age on severity of impairment in spastic cerebral palsy

OBJECTIVE

To investigate the association between severity of impairment and gestational age in unilateral and bilateral spastic cerebral palsy, and to determine whether the influence of gestational age is independent of deviations from optimal birth weight.

STUDY DESIGN

The study group was a United Kingdom cohort of 4772 cases of spastic cerebral palsy born between 1960 and 1997, with information on birth demographics and severity of impairment. Generalized additive models were used to determine the proportions of cases severely impaired, by gestational age, and to determine whether gestational age or deviations from optimal birth weight better predicts severity of impairment.

RESULTS

For unilateral spastic cerebral palsy, the proportions of severe impairments did not vary with gestational age. In contrast, for bilateral spastic cerebral palsy, the proportions of severe motor or cognitive impairments increased with increasing gestational age (e.g., from 20% to 50% between weeks 30 and 40 for cognitive impairment). For spastic cerebral palsy, gestational age is at least as good as deviation from optimal birth weight in predicting severity.

CONCLUSIONS

The severity of impairment increases with increasing gestational age in bilateral spastic cerebral palsy. This suggests differing etiologies in term and preterm infants and supports the theory that the developing brain is better able to compensate after a cerebral insult.

Mild chronic hypoxia modifies the fetal sheep neural and cardiovascular responses to repeated umbilical cord occlusion

We have shown that 5 days of mild hypoxia has significant effects on fetal ECoG activity, heart rate and blood pressure. We now studied if mild prolonged hypoxemia had an adverse effect on the fetal cardiovascular and neural responses to repeated cord occlusion and on the magnitude of neuronal damage. Fetal and maternal catheters were placed at 120 days' gestation and animals allocated at random to receive intratracheal maternal administration of nitrogen (n=8) or compressed air in controls (n=7). Five days after surgery, nitrogen infusion was adjusted to reduce fetal brachial artery pO(2) by 25%. After 5 days of chronic hypoxemia, the umbilical cord was completely occluded for 5 min every 30 min for a total of four occlusions. Data are presented as mean+/-SEM and were analyzed by two-way ANOVA or two-sample t-test. Nitrogen infusion decreased fetal pO(2) by 26% (20.5+/-1.7 vs. 14.3+/-0.8 mm Hg) without changing fetal pCO(2) or pH. Pre-existing hypoxia fetuses had a greater terminal fall in heart rate in occlusions II, III and IV, and also had a more severe terminal hypotension in the final occlusion. Pre-existing hypoxia was associated with a greater fall in spectral edge frequency during occlusions from 14.4+/-0.9 Hz to 6.9+/-0.4 Hz vs. 13.6+/-1.64 Hz to 10.6+/-0.77 Hz in controls, p<0.05. In addition, during the three-day post-occlusion period, the contribution of theta and alpha band frequencies to total ECoG activity was significantly lower in the pre-existing hypoxia fetuses (p<0.05). These effects were associated with increased neuronal loss in the striatum (p<0.05). In summary, the cardiovascular and neural response indicates a detrimental effect of pre-existing mild hypoxia on fetal outcome following repeated umbilical cord occlusions.

The assessment of fetal behavior of growth restricted fetuses by 4D sonography

AIM

To find out whether the quantity of fetal facial expression and quality of body movements can be used as an additional diagnostic criterion for prenatal brain impairment in fetuses with growth restriction.

SUBJECT AND METHODS

A prospective study was conducted in 50 uncomplicated healthy women as control group with reliably dated pregnancies and 50 pregnant women with a growth restricted fetus as study group in the third trimester of pregnancy. 4D ultrasound observation is specially designed to assess whether functional brain impairment and fetal growth restriction had prenatally occurred by the utilization of several behavioral patterns.

RESULTS

The median value of all movement patterns in the normal fetuses differed from fetuses with intrauterine growth restriction (IUGR). Statistical evaluation revealed significant differences in the distribution of the movements between these groups (P<0.05). We noted a tendency that IUGR fetuses have less behavioral activity than normal fetuses in all observed movement patterns. Correlation reached statistical significance between normal and IUGR fetuses in the third trimester in hand to head, hand to face and head retroflexion. Statistically significant differences could be shown in the distribution of the median values of observation over the five qualitative categories of head and hand movements (P<0.05).

CONCLUSIONS

Recent data on IUGR fetuses obtained by 4D sonography are stimulating and might result in a more effective strategy to assess development before birth. The results of this study may encourage future use of 4D ultrasound for quantitative and qualitative assessment of fetal behavior as possible indicators of the neurological condition in IUGR fetuses.

Auditory processing deficits in growth restricted fetuses affect later language development

An increased risk for language deficits in infants born growth restricted has been reported in follow-up studies for more than 20 years, suggesting a relation between fetal auditory system development and later language learning. Work with animal models indicate that there are at least two ways in which growth restriction could affect the development of auditory perception in human fetuses: a delay in myelination or conduction and an increase in sensorineural threshold. Systematic study of auditory function in growth restricted human fetuses has not been reported. However, results of studies employing low-risk fetuses delivering as healthy full-term infants demonstrate that, by late gestation, the fetus can hear, sound properties modulate behavior, and sensory information is available from both inside (e.g., maternal vascular) and outside (e.g., noise, voices, music) of the maternal body. These data provide substantive evidence that the auditory system is functioning and that environmental sounds are available for shaping neural networks and laying the foundation for language acquisition before birth. We hypothesize that fetal growth restriction affects auditory system development, resulting in atypical auditory information processing in growth restricted fetuses compared to healthy, appropriately-grown-for-gestational-age fetuses. Speech perception that lays the foundation for later language competence will differ in growth restricted compared to normally grown fetuses and be associated with later language abilities.

Regional metabolic status of the E-18 rat fetal brain following transient hypoxia/ischemia

Increasing evidence indicates that fetal metabolic stress may result in a variety of post-natal perturbations during brain development. The goal of the study was to determine the duration of hypoxia/ischemia that would elicit a demonstrable regional depression of metabolism in the fetal brain and further to examine several end-points to determine if the metabolic stress affects the developing brain. The uterine artery and uterine branch of the ovarian artery were occluded with aneurysm clamps for a period of 45 min, the clips removed and the metabolites in five regions of the perinatal brain were measured at 0, 2 and 6 h of reflow. Regional P-creatine, ATP and glucose levels were significantly depleted at the end of the 45 min occlusion. The levels of glycogen and glutamate at the end of the occlusion indicated a decreasing trend which was not significant. The concentration of citrate remained essentially unchanged at the end of the occlusion. To ensure that the insult was not lethal to the tissue, the recovery of the metabolites was examined at 2 and 6 h of reflow and generally the concentrations of the high-energy phosphates and glucose were normal or near-normal by 6 h of reperfusion in the five regions of the brain examined. The changes in the metabolites indicate that 45 min of hypoxia/ischemia is an appropriate model for studying neonatal development after fetal metabolic stress.

Cerebral palsy in a term population: risk factors and neuroimaging findings

OBJECTIVE

The purpose of this work was to study risk factors and neuroimaging characteristics of cerebral palsy in term and near-term infants.

PATIENTS AND METHODS

Among a cohort of 334,339 infants > or = 36 weeks' gestation born at Kaiser Permanente Medical Care Program in northern California in 1991-2003, we identified infants with cerebral palsy and obtained clinical data from electronic and medical charts. Risk factors for cerebral palsy among infants with different brain abnormalities were compared using polytomous logistic regression.

RESULTS

Of 377 infants with cerebral palsy (prevalence: 1.1 per 1000), 273 (72%) received a head computed tomography or MRI. Abnormalities included focal arterial infarction (22%), brain malformation (14%), and periventricular white matter abnormalities (12%). Independent risk factors for cerebral palsy were maternal age > 35, black race, and intrauterine growth restriction. Intrauterine growth restriction was more strongly associated with periventricular white matter injury than with other neuroimaging findings. Nighttime delivery was associated with cerebral palsy accompanied by generalized brain atrophy but not with cerebral palsy accompanied by other brain lesions.

CONCLUSIONS

Cerebral palsy is a heterogeneous syndrome with focal arterial infarction and brain malformation representing the most common neuroimaging abnormalities in term and near-term infants. Risk factors for cerebral palsy differ depending on the type of underlying brain abnormality.

Cerebral Palsy and the Application of the International Criteria for Acute Intrapartum Hypoxia

OBJECTIVE

To apply objective criteria for the identification of acute intrapartum hypoxia in a cohort of cerebral palsy cases and to identify other cerebral palsy-related pathologies.

METHODS

A cohort of all 235 neonates with cerebral palsy from a single Australian tertiary care center born between 1986 and 2003. Cases were identified from the South Australian Cerebral Palsy Register. Maternal and pediatric case notes were audited with application of the 2003 American College of Obstetricians and Gynecologists/American Academy of Pediatrics criteria to identify acute intrapartum hypoxia.

RESULTS

Data were available for analysis in 213 cases (91%). Major antenatal or pediatric cerebral palsy-related pathologies were identified in 98.1% of all these cases. An isolated acute intrapartum hypoxic event was defined as likely in only 2 of the 46 neonates born at term and none born preterm. Neonatal nucleated red blood cell counts were often high in neonates born preterm and following antenatal pathologies.

CONCLUSION

Cerebral palsy was seldom preceded by acute intrapartum hypoxia but antenatal cerebral palsy-related pathologies are often detectable. The objective American College of Obstetricians and Gynecologists/American Academy of Pediatrics criteria are useful to audit cerebral palsy causation and exclude primary intrapartum hypoxia.

LEVEL OF EVIDENCE

II-3.

Cerebral palsy and intrauterine growth

When birth weight for gestation is used as a surrogate for intrauterine growth, the prevalence of cerebral palsy varies continuously in a reversed J shape, with steep increases in the risk for infants lighter and heavier than the optimum size. Patterns of size-at-birth specific risk for cerebral palsy differ between male and female infants, as do the patterns for more severe versus milder cases. Although these excess risks with abnormal size at birth imply antenatal precursors, it is not clear whether or how intrauterine growth is involved in any of the suspected causal pathways resulting in cerebral palsy. The implication for clinicians is that serial measures of in utero growth may provide an important indicator of fetal health.

Current concepts in intrauterine growth restriction

Regulation of fetal growth is multifactorial and complex. Diverse factors, including intrinsic fetal conditions as well as maternal and environmental factors, can lead to intrauterine growth restriction (IUGR). The interaction of these factors governs the partitioning of nutrients and rate of fetal cellular proliferation and maturation. Although IUGR is probably a physiologic adaptive response to various stimuli, it is associated with distinct short- and long-term morbidities. Immediate morbidities include those associated with prematurity and inadequate nutrient reserve, while childhood morbidities relate to impaired maturation and disrupted organ development. Potential long-term effects of IUGR are debated and explained by the fetal programming hypothesis. In formulating a comprehensive approach to the management and follow-up of the growth-restricted fetus and infant, physicians should take into consideration the etiology, timing, and severity of IUGR. In addition, they should be cognizant of the immediate perinatal response of the growth-restricted infant as well as the childhood and long-term associated morbidities. A multi disciplinary approach is imperative, including early recognition and obstetrical management of IUGR, assessment of the growth-restricted newborn in the delivery room, possible monitoring in the neonatal intensive care unit, and appropriate pediatric follow-up. Future research is necessary to establish effective preventive, diagnostic, and therapeutic strategies for IUGR, perhaps affecting the health of future generations.

Neuronal migration is transiently delayed by prenatal exposure to intermittent hypoxia

BACKGROUND

Neonatal neurodevelopment is influenced by a variety of external factors, although the mechanisms responsible are poorly understood. Prenatal hypoxia, from physiological or chemical sources, can have no discernible effect, or can result in a broad spectrum of abnormalities.

METHODS

To mimic some of the maternal effects of smoking, we developed a model that investigates the effects of intermittent hypoxia (IH), with or without concurrent nicotine in timed pregnant Sprague-Dawley rats.

RESULTS

We found no significant differences between litter sizes or birthweight of pups from any treatment group, but animals exposed to IH (with or without nicotine) showed long term diminished body weights. Animals subjected to IH consistently showed a transient delay in neuronal migration early in the postpartum period, which was amplified by concurrent nicotine administration. We observed increased c-Abl protein levels in animals from the IH treatment groups. Multiple proteins involved in the intricate control of neuronal migration were also altered in response to this treatment, primarily the downstream targets of c-Abl: Cdk5, p25, and the cytoskeletal elements neurofilament H and F-actin and catalase. Catalase activity and protein levels, already elevated in response to IH, were further amplified by simultaneous nicotine exposure.

CONCLUSIONS

This new model provides a novel system for investigating the effects of low grade IH in the developing brain and suggests that concurrent nicotine further aggravates many of the deleterious effects of IH.

Paediatric consequences of fetal growth restriction

The evidence for outcome following fetal growth restriction (FGR) has previously been inferred from studies, based on babies who were born small for gestational age (SGA). Great care is required when evaluating studies in this area due to a number of potential confounders. It does appear, however, that FGR is associated with an increased risk of poor neurological outcome. This includes an increased risk of cerebral palsy in babies greater than 32 weeks' gestation. Below 32 weeks, the effects of prematurity appear to negate the effects of FGR. FGR is also associated with cognitive deficit and behaviour problems. Babies with poor prenatal head growth appear to have a worse cognitive outcome. However, the role of 'fetal brain sparing' remains unclear, as impaired cognitive outcome is still evident in babies with appropriate head growth. Recent studies, which have identified FGR more accurately using fetal growth standards, have found an increased incidence of major intracranial injury and other adverse neonatal outcomes, which had previously been thought to occur less frequently in FGR babies. FGR is also associated with poor postnatal growth. The majority of children with FGR demonstrate catch-up growth in the first 2 years of life. Children who fail to demonstrate catch-up growth have a high risk of long-term growth problems. There is evidence of impaired growth hormone activity in some children with FGR who have persistent poor growth in the postnatal period.

Antenatal risk factors for cerebral palsy

Two of every 1000 live-born children develop cerebral palsy (CP). The aetiology of CP is often unclear and because CP is a symptom complex rather than a disease, clinically defined at 4-5 years of age, it is not surprising that there are considerable problems associated with epidemiological studies of its aetiology. The only reason for the CP concept is that it emanates from an insult to a growing, developing brain and a dynamic clinical picture from static pathology. Evidence suggests that 70-80% of CP cases are due to prenatal factors and that birth asphyxia plays a relatively minor role (<10%). Some antenatal risk factors are repeatedly observed to be related to CP: low gestational age, male gender, multiple gestation, intrauterine viral infections and maternal thyroid abnormalities. Recently, intrauterine infection/inflammation with a maternal response (consisting of chorioamnionitis) and a fetal inflammatory response (consisting of funicitis or elevated interleukin-6 in fetal plasma) has been found to be related to white matter injury and CP. Some risk factors are associated with CP at all gestational ages whereas others mostly affect term or preterm infants, e.g. intrauterine growth restriction seems to be a risk factor in term infants. There also seems to be an association between autoimmune and coagulation disorders and CP.

Reflections on the occurrence and significance of antepartum fetal asphyxia

This chapter documents the growing evidence of the occurrence and significance of antepartum fetal asphyxia. Perinatal mortality studies demonstrate that the majority of fetal deaths, including those due to asphyxia, occur in the antepartum period. Epidemiological studies of cerebral palsy conclude that a minority of cases of cerebral palsy are due to intrapartum fetal asphyxia and implicate antenatal events, including asphyxia. Cordocentesis studies have confirmed that antepartum fetal asphyxia occurs in the growth-restricted fetus and might contribute to the increase of stillbirths and cerebral palsy in these children. Blood gas and acid-base studies in the immature fetus have demonstrated the increased prevalence of fetal asphyxia, and particularly of moderate or severe asphyxia, of which the majority might occur in the antepartum period. The ultimate determination of the prevalence and significance of antepartum fetal asphyxia requires the development of a non-invasive specific measure of fetal asphyxia.

Cerebral palsy and intrauterine growth in single births: European collaborative study

BACKGROUND

Cerebral palsy seems to be more common in term babies whose birthweight is low for their gestational age at delivery, but past analyses have been hampered by small datasets and Z-score calculation methods.

METHODS

We compared data from ten European registers for 4503 singleton children with cerebral palsy born between 1976 and 1990 with the number of births in each study population. Weight and gestation of these children were compared with reference standards for the normal spread of gestation and weight-for-gestational age at birth.

FINDINGS

Babies of 32-42 weeks' gestation with a birthweight for gestational age below the 10th percentile (using fetal growth standards) were 4-6 times more likely to have cerebral palsy than were children in a reference band between the 25th and 75th percentiles. In children with a weight above the 97th percentile, the increased risk was smaller (from 1.6 to 3.1), but still significant. Those with a birthweight about 1 SD above average always had the lowest risk of cerebral palsy. A similar pattern was seen in those with unilateral or bilateral spasticity, as in those with a dyskinetic or ataxic disability. In babies of less than 32 weeks' gestation, the relation between weight and risk was less clear.

INTERPRETATION

The risk of cerebral palsy, like the risk of perinatal death, is lowest in babies who are of above average weight-for-gestation at birth, but risk rises when weight is well above normal as well as when it is well below normal. Whether deviant growth is the cause or a consequence of the disability remains to be determined.

Changing metabolic and energy profiles in fetal, neonatal, and adult rat brain

The regional energy status and the availability of metabolic substrates during brain development are important, since a variety of fetal metabolic insults have been increasingly implicated in the evolution of neonatal brain disorders. The response of the brain to a metabolic insult is determined, in large part, by the ability to utilize the various substrates for intermediary metabolism in order to maintain energy stores within the tissue. To ascertain if metabolic conditions of the fetal brain make it more or less vulnerable to a stress, the high-energy phosphates and glucose-related compounds were examined in five regions of the embryonic day 18 (E-18) fetal brain. Glucose and glycogen levels in the E-18 fetal brain were generally higher in the cerebellum and its neuroepithelium than in the hippocampus, cerebral cortex, and its neuroepithelium. Regional lactate and high-energy phosphate concentrations were essentially the same in the five regions. Subsequently, the metabolic profile was examined in the cerebral cortex and striatum from E-18, postpartum day 7 (P-7) and adult rats. At the various stages of development, there were only minimal differences in the high-energy phosphate levels in the striatum and cortex. Glucose levels, the primary substrate in the adult brain, were essentially unchanged throughout development. In contrast, lactate was significantly elevated by 6- and 2-fold over those in the adult brain in the E-18 and P-7 striatum and cortex, respectively. Another alternative substrate, beta-hydroxybutyrate, was also significantly elevated at E-18 and increased more than 2-fold at P-7, but was barely detectable in the adult cortex and striatum. Finally, glucose and lactate levels were examined in cerebrospinal fluid, blood, and brain from the E-18 brain to determine if a gradient among the compartments exists. The levels of both lactate and glucose exhibited a concentration gradient in the E-18 fetus: blood > cerebrospinal fluid > brain parenchyma. The results indicate that energy state in the fetal brain is comparable to that in the neonates and the adults, but that the availability of alternative substrates for intermediary metabolism change markedly with development. The age-dependent substrate specificity for intermediary metabolism could affect the response of the fetal brain to a metabolic insult.

The epidemiology and causes of cerebral palsy

Cerebral palsy is the commonest physical disability in childhood, occurring in 2.0 to 2.5 per 1000 live births. Although the total number of children with cerebral palsy has remained stable or increased slightly since 1970, there has been a consistent rise in the proportion of cerebral palsy associated with preterm and very preterm births. Known causes of cerebral palsy--whether prenatal, perinatal or postnatal--must be distinguished from risk factors or associations. Much is known about such risk factors which, alone or in combination, may indirectly result in cerebral palsy. Causes and risk factors implicated in cerebral palsy are discussed in detail, together with directions for future research.

Perinatal outcomes in monoamniotic gestations

OBJECTIVE

A comprehensive review of monoamniotic twin gestations reported between 1990 and 2002 was performed to estimate current perinatal mortality and morbidity rates, as well as the predictive value of an antenatal diagnosis of cord entanglement for poor obstetric outcomes.

METHOD

A Medline literature review using the search term 'monoamniotic' and limited to articles published in the English language between 1990 and 2002 was performed.

RESULTS

A total of 133 continuing, non-conjoined twin monoamniotic pregnancies with delivery information were identified. Perinatal loss per 2-week interval was relatively constant at 2-4% from 15 to 32 weeks. However, of the 131 fetuses reaching 33 weeks, the percentage loss significantly increased to 11.0% at 33-35 weeks and 21.9% at 36-38 weeks compared to that at 30-32 weeks. Overall perinatal mortality was 23.3%. Of all losses, 61.2% involved both twins and 38.8% involved only one fetus. Cord entanglements were documented antenatally in 22.6% of reports. There was a statistically significant decrease in the average number of neonatal intensive care unit days for non-anomalous neonates (10.6 +/- 7.7 vs. 32.6 +/- 32.0), average gestational age at the time of delivery (30.4 +/- 7.6 vs. 32.6 +/- 4.1), as well as a decrease in the prevalence of total (8.3% vs. 27.7%) and non-anomalous (7.0% vs. 21.6%) perinatal mortality in pregnancies with an antenatal diagnosis of cord entanglement compared to those without the antenatal diagnosis of cord entanglement. The presence of fetal anomalies was associated with a 42.9% perinatal mortality rate.

CONCLUSIONS

Contrary to previous reports, there is a significant increase in the incidence of perinatal loss beyond 32 weeks among monoamniotic twins, suggesting that delivery after corticosteroid therapy should be strongly considered at this gestational age.

Prolonged mild fetal hypoxia up-regulates type I nitric oxide synthase expression in discrete areas of the late-gestation fetal sheep brain

OBJECTIVE

Our purpose was to study the effects of prolonged mild hypoxemia on type I nitric oxide synthase (NOS) messenger RNA, protein, and enzymatic activity in the fetal sheep brain.

STUDY DESIGN

Pregnant sheep were randomly allocated to receive maternal nitrogen (n = 8) or compressed air (controls, n = 5) to reduce fetal brachial artery PO(2) by 25% for 5 days. Type I NOS mRNA (determined by ribonuclease protection assay) protein (determined by Western blot) and enzymatic activity (determined by citrulline assay) were measured in the hippocampus, striatum, cerebellum, and frontal cortex. Data are presented as mean +/- SEM and were compared by means of one-way analysis of variance or two-sample t test.

RESULTS

The reduction in maternal inspired oxygen concentration decreased fetal PO(2) by 26% and oxygen content by 25% without an associated change in PCO(2) or pH. Fetal hypoxemia increased type I NOS mRNA by threefold in the striatum and by 2-fold in the frontal cortex and cerebellum, but it did not change mRNA expression in the hippocampus (P <.05). Type I NOS protein and catalytic activity increased only in the striatum (P <.05).

CONCLUSION

Prolonged mild hypoxemia has a differential effect on type I NOS mRNA in fetal sheep brain areas. Type I NOS protein and catalytic activity significantly increased only in the striatum. Our data suggest that fetal type I NOS gene expression is regulated at transcriptional, post-transcriptional, and translational levels.

Cognitive development of term small for gestational age children at five years of age

AIM

To assess the relative significance for cognitive development of small for gestational age, parental demographic factors, and factors related to the child rearing environment.

METHODS

IQ of a population based cohort of 338 term infants who were small for gestational age (SGA) and without major handicap, and a random control sample of 335 appropriate for gestational age (AGA) infants were compared at 5 years of age.

RESULTS

The mean non-verbal IQ was four points lower, while the mean verbal IQ was three points lower for the children in the SGA group. The results were not confounded by parental demographic or child rearing factors. However, parental factors, including maternal non-verbal problem solving abilities, and child rearing style, accounted for 20% of the variance in non-verbal IQ, while SGA versus AGA status accounted for only 2%. The comparable numbers for verbal IQ were 30 and 1%. Furthermore, we found no evidence that the cognitive development of SGA children was more sensitive to a non-optimal child rearing environment than that of AGA children. Maternal smoking at conception was associated with a reduction in mean IQ comparable to that found for SGA status, and this effect was the same for SGA and AGA children. The cognitive function of asymmetric SGA was comparable to that of symmetric SGA children.

CONCLUSIONS

Our findings indicate that child cognitive development is strongly associated with parental factors, but only marginally associated with intrauterine growth retardation.

Outcome after intrapartum asphyxia in term infants

Investigatory techniques, particularly magnetic resonance (MR) imaging and spectroscopy, performed in the early neonatal period on infants suspected of intrapartum asphyxia i.e. abnormal fetal heart recording, poor cord gases, low Apgar scores and the need for resuscitation, or with neonatal encephalopathy or seizures, have allowed a much better understanding of the patterns of brain injury and the biochemical processes that follow these events. It is usually possible to distinguish these patterns from those seen in other, often confounding, diagnoses. This has allowed far more precision about the timing of insults and in the prediction of particularly motor, feeding and visual outcome and to some extent intellectual outcome. Long-term neurological and psychometric follow-up of infants in whom detailed perinatal clinical histories and examination, haematological and biochemical investigation and MR brain scans are obtained will allow even more accurate prediction of outcome in the future. Such studies also help to validate standardized neonatal and infant clinical neurological examinations, making them useful tools to predict outcome.

The relation of breech presentation at term to cerebral palsy

OBJECTIVE

To examine the relation between breech delivery and cerebral palsy, considering the influence of intrauterine growth, low Apgar score at birth, and mode of delivery.

DESIGN

Register-based, case-control study.

POPULATION

A cohort of infants with cerebral palsy born between 1979 and 1986 in East Denmark, identified by linkage of the cerebral palsy register with the national birth register. Discharge letters from births of breech infants with cerebral palsy were reviewed.

MAIN OUTCOME MEASURES

Presentation, mode of delivery, gestational age, birthweight, Apgar score, type of cerebral palsy, severity of handicap.

RESULTS

Breech presentation at term was associated with a borderline significantly higher risk of cerebral palsy than vertex presentation (OR 1.56; 95% CI 0.9-2.4). Breech presentation infants more often had a lower Apgar score (< 7 at 5 minutes) and were smaller for gestational age (SGA < 2 SD) than were those with vertex presentation; infants with a low Apgar score, or who were small for gestational age, had a higher risk of cerebral palsy. After stratification by being small for gestational age the risk of cerebral palsy was not related to presentation. There were no differences between breech and vertex infants with cerebral palsy in terms of low Apgar score, being small for gestational age, mode of delivery, and severity of the handicap. Breech presentation infants were more often classified as diplegic (77.8% versus 42.3% in cephalic infants).

CONCLUSION

The risk of cerebral palsy among term breech presentation infants does not seem to be related to mode of delivery, but is more likely linked to a higher rate of being small for gestational age in breech infants.

Racial differences in birthweight for gestational age and infant mortality in extremely-low-risk US populations

Using national data, we develop and contrast the birth-weight percentiles for gestational age by infants of extremely-low-risk (ELR) White and African-American women and examine racial differences in the proportion of small-for-gestational-age (SGA) births. We then scrutinise racial variations in infant mortality rates of the infants of ELR women. We further compare the infant mortality rates of infants at or below the 10th percentile of birthweight for gestational age of each race group to determine whether infants with similar restricted fetal growth have comparable risks of subsequent mortality. Single live births, 34-42 weeks' gestation, to White and African-American US-resident mothers were selected from the 1990-91 US Linked Live Birth--Infant Death File (n = 4,360,829). Extremely-low-risk mothers were defined as: married, aged 20-34 years, 13+ years of education, multiparae, with average parity for age, adequate prenatal care, vaginal delivery, and no reports of medical risk factors, tobacco use or alcohol use during pregnancy. Marked racial variation in birthweight percentiles by gestational age was evident. Compared with ELR White mothers, the risk of an SGA infant was 2.64 times greater for ELR African-American mothers and the risk of infant mortality was 1.61 times greater. For the ELR group, the infant mortality rates of African-American and White infants at or below the 10th percentile of birthweight for gestational age of their respective maternal race group were essentially identical after controlling for gestational age. In conclusion, race differences in fetal growth patterns remained after controlling for risk status. Efforts to remove racial disparities in infant mortality will need to develop aetiological pathways that can explain why African-Americans have relatively higher rates of preterm birth and higher infant mortality rates among term and non-SGA infants.

Diet during pregnancy and the risk of cerebral palsy

The role of maternal diet in the development of the fetal brain has not been adequately explored. Marine n-3 fatty acids have, however, been proposed to be important for brain development. The present case-control study aimed to investigate the relationship between dietary intake during pregnancy and the occurrence of cerebral palsy (CP) in the offspring. Children with CP (n 109), born between 1984 and 1988 to mothers residing in the Greater Athens area, were identified at any time in 1991 or 1992 through institutions delivering care and rehabilitation. Successful nutritional interviews were conducted with ninety-one of these children. Controls were chosen among the neighbours of the CP cases or were healthy siblings of children with neurological diseases other than CP, seen by the same neurologists as the children with CP. A total of 278 control children were chosen, and 246 of them were included in the nutritional study. Guardians of all children were interviewed in person on the basis of a questionnaire covering obstetric, perinatal socioeconomic and environmental variables. A validated semiquantitative food-frequency questionnaire of 111 food items was used to estimate maternal dietary intake during pregnancy. Statistical analysis was done by modelling the data through logistic regression. Food groups controlling for energy intake were alternatively and simultaneously introduced in a core model containing non-nutritional confounding variables. Consumption of cereals (mostly bread) and fish intake were inversely associated with CP (P < 0.05 and P < 0.09 respectively) whereas consumption of meat was associated with increased risk (P < 0.02). A protective effect of fish consumption and a detrimental effect of meat intake have been suggested on the basis of earlier work and appear to be biologically plausible. If corroborated by other studies, these results could contribute to our understanding of the nutritional influences on fetal brain development.

Preeclampsia, preterm delivery and infant cerebral palsy

OBJECTIVE

To evaluate the association between preeclampsia and cerebral palsy among preterm infants.

STUDY DESIGN

A cohort study of 345 singleton preterm (24 to 33 weeks gestation) infants delivered at an institution where no mothers received magnesium sulphate. We investigated the relationship of preeclampsia to the development of infant cerebral palsy (spastic quadriplegia, hemiplegia or diplegia) at two years' corrected age. Potential confounders were controlled for by politomous logistic regression analysis.

RESULTS

The prevalence of cerebral palsy in surviving infants from normotensive and preeclamptic pregnancies was 13.4% (38/284) and 3.3% (2/61), respectively (P=0.026 by Fisher exact test). After control for potential confounders (gestational age, infant gender, birthweight standard deviation score, mode of delivery), the likelihood of infant cerebral palsy was reduced by preeclampsia (odds ratio 0.16, 95% confidence interval=0.04-0.74 for infants from preeclamptic versus normotensive pregnancies being palsied).

CONCLUSION

Among preterm infants, the protective effect of preeclampsia against cerebral palsy is manifest in the absence of magnesium sulphate utilization.

Prenatal determinants of motor disorders

Cerebral palsies (CP) are the commonest childhood motor disorders, originating in early childhood as a result of interference in the developing brain. Identifying prenatal factors in CP is a challenge because there is a considerable period of time (years) between the causal event(s) and diagnosis. Four fascinating "natural" situations provided a unique opportunity to identify and measure prenatal exposures in relation to motor disorders, thus establishing the unequivocal role of some factors. However, the majority of studies determining adverse reproductive effects of environmental factors require a retrospective case-control approach, which present considerable problems. Studies based on the Western Australian CP register suggest that prenatal factors singly or in complex sequences are more common as causes than those occurring perinatally or postnatally. In future, better diagnosis of motor disorders, use of sophisticated scientific techniques to identify markers of neuronal development and the accurate linkage of these findings to clinical patterns of motor dysfunction are required.

Morbidity during the first year of life in small for gestational age infants

Postneonatal morbidity during infancy was studied in 284 small for gestational age (SGA) and 359 non-SGA term infants. None of these babies had congenital malformations and they were born to para 1 and para 2 mothers. SGA infants had an increased risk (OR: 1.7, 95% confidence interval: 1.1-2.6) of being admitted to hospital compared with non-SGA infants. The principal cause was respiratory tract infections. Increased hospitalisation among SGA infants was a factor only if the mother was a smoker-that is, smoked cigarettes at the time of conception. Among subgroups of SGA babies, there was an increased risk for infants of non-repeaters (women without a previous SGA child) (OR: 2.4, 95% CI: 1.4-3.8) and for infants with symmetric (OR: 2.0, 95% CI: 1.2-3.3) body proportions compared with non-SGA infants. The results suggest that, beginning in early pregnancy, growth retardation may have long term consequences for subsequent infant morbidity, particularly if the mother is smoker.

Risk factors for cerebral palsy: a case-control study in Greece

The purpose of this study was to investigate the relation between a series of maternal, antenatal, perinatal, socioeconomic and environmental variables and the occurrence of cerebral palsy (CP) in a setting different from those in which previous analytic epidemiologic studies had been undertaken. The study was of case-control design and included 103 children with cerebral palsy born between 1984 and 1988 and residents of the Greater Athens area at any time during 1991 and 1992. Controls were chosen among the neighbors of the index case or were healthy siblings of children with neurological diseases other than CP seen by the same neurologists as the children with CP; a total of 254 control children were eventually included. Statistical analysis was done by modeling the data through unconditional logistic regression. Statistically significant (p < 0.05) risk factors of potential causal importance were: twin membership (OR = 10.2), gestational age (OR = 0.5 per 4 weeks), birth weight conditional on gestational age (OR = 0.9 per 100 g), congenital malformations (OR = 7.5), unhealthy placenta (OR = 6.6), placenta previa (6 cases, no controls), abnormal amniotic fluid (OR = 3.6), head circumference more than 36 cm (OR = 9.0), general anesthesia during labor (OR = 4.3), forceps delivery (OR = 6.8), and birth trauma (OR = 11.5). Among children with no identifiable prenatal risk factors there was no excess prevalence of one or more perinatal risk factors in CP cases compared to controls, which implies that the latter factors impart their effect through interactions with co-existing prenatal or other risk factors.

Intrauterine growth and gestational age in preterm infants with cerebral palsy

In a case-control study, gestational age and intrauterine growth of 191 preterm singleton infants 1971-82 with cerebral palsy were compared to all preterm live-born singletons in Denmark in 1982 (N = 2203). The distribution of gestational age among preterm cases was slightly bimodal with maximum values at 29 and 32 weeks. The risk for cerebral palsy was highest in the infants with gestational age 28-30 weeks (OR = 5.6 (4.0-7.8), 95% confidence interval). Birth weight deviation, in the 34-36 weeks infants, expressed as the number of standard deviations from the mean birth weight for gestational age, was more negative in cases than in controls (P < 0.001). The frequency of small for gestational age (SGA) was 13% in cases and 9% in controls (OR = 1.5 (0.96-2.3), 95% confidence interval). The odds for cerebral palsy being SGA, was lower in 28-30 weeks (OR = 0.22 (0.06-0.86), 95% confidence interval), the same in 31-33 weeks (OR = 0.83 (0.35-2.0), 95% confidence interval) and higher in 34-36 weeks (OR = 5.2 (2.9-9.5), 95% confidence interval). In conclusion, preterm infants with cerebral palsy are born earlier than other preterm infants. Small for gestational age is associated with cerebral palsy in preterm infants only above 33 weeks.

Antenatal antecedents of moderate and severe cerebral palsy

Aetiological relationships between cerebral palsy, preterm birth, small-for-gestational-age (SGA) birth and selected feto-maternal factors were investigated in a case-control study of all moderate and severe cerebral palsy cases born in Western Australia between 1980 and 1986 (n = 215). Cases were individually matched to three controls of the same gender and plurality born in the same year. Two of the controls were matched to the index cases for gestational age, one of which was also matched for birthweight. Pre-eclampsia and urinary tract infections were not significantly associated with cerebral palsy. The significant association of antepartum haemorrhage with cerebral palsy was accounted for by its associations with preterm birth. Congenital malformations and non-cerebral palsy neurological disorder were significantly associated with cerebral palsy; these associations were only partially accounted for by adjusting for preterm birth and small-for-gestational-age birth. This study shows that some of the risk of cerebral palsy associated with the antenatal antecedents of some common feto-maternal factors is mediated through preterm birth, confirming the importance of interrelationships between antenatal antecedents in the aetiology of some cerebral palsy. Perinatal and post-neonatal causes now account for only around 20% of all cerebral palsy. Future reductions in cerebral palsy incidence may therefore depend on acquiring greater knowledge of inter-relationships between antenatal antecedents.

Bilateral spastic cerebral palsy--a collaborative study between southwest Germany and western Sweden. III: Aetiology

In this third report from the collaborative study of children with bilateral spastic cerebral palsy born between 1975 and 1986, aetiology was analysed. Evidence for a prenatal aetiology increased with gestational age, whereas evidence for a peri-/neonatal aetiology decreased. The largest subgroup, the leg-dominated subtype, showed the same distribution of aetiology as the total group. A prenatal aetiology was found mainly among term and moderately preterm children with a four-limb-dominated subtype; a peri-/neonatal aetiology among very preterm children with a three- or four-limb-dominated subtype or among term children with a dyskinetic-spastic subtype. The findings support the hypothesis generated from the authors' epidemiological results of a peri-/neonatal aetiology being predominant among preterm, and a prenatal aetiology among term, children with bilateral spastic cerebral palsy.

Placental insights into neurodevelopmental and other childhood diseases

Deficient information regarding placental pathology has compromised epidemiological investigations of cerebral palsy, mental retardation, and other diseases. This article reviews light microscopic signs of low placental blood flow, fetal nucleated red blood cells, villitis (villous inflammatory lesions), chorangiosis (placental villous capillary hypervascularity), meconium staining, and chorioamnionitis. These findings can be used with data of birth weight, head circumference, and length to document the duration of fetal disease. The article includes pathophysiological considerations; for example, chorioamnionitis and fetal meconium discharge may cause autacoids to produce fetal hypoperfusion of the fetal brain and other vital organs.

Birth-weight ratio and cerebral palsy

The birth-weight ratio, a convenient measure of fetal growth, has been used to assess the importance of antecedent and perinatal factors in a retrospective analysis of 605 cases of congenital cerebral palsy. All had been seen by the author at a special clinic over a period of three decades. The ratio (normally 1) is high in the very premature, falls in the middle of the third trimester, then begins to rise again at term. Abnormalities of pregnancy, or a history of maternal pregnancy-losses, depress the ratio perceptibly. In both singletons and twins, there is no significant relationship between a low ratio and the severity of the clinical condition, and presumably the extent of the brain damage. The findings suggest that growth retardation is an association and not a cause of perinatal vascular-anoxic lesions.

Hypoxic-hemodynamic pathogenesis of brain lesions in the newborn

For more than a century two opposing views on the pathogenetic mechanisms and the timing of the origin of cerebral palsy (CP) have prevailed: the idea first formulated by Little attributing CP to "difficult deliveries" has been opposed by the view by Freud recognizing fetal influences, and the issue seems to be unsettled. The present review seeks to bridge the gap by recognizing that late prenatal or perinatal hypoxic-hemodynamic insult is a dominating final common path in the pathogenesis of static encephalopathies during development, in particular in premature infants. In turn, however, such lesions are determined by early genetic and environmental influences. The pathogenesis of static encephalopathy should therefore be seen as a chain of events, with its origin before gestation.

Clinical associations of prenatal ischaemic white matter injury

Neuropathological examinations were carried out at necropsy on 274 cases of intrauterine death or neonatal death at or before three days after birth. Fifty six (20.4%) subjects had evidence of prenatal ischaemic brain damage. On review of the maternal case notes to ascertain antenatal clinical associations there was an increased incidence of intrauterine growth retardation, either based on birth weight for gestational age (odds ratio (OR) 2.0; 95% confidence interval (CI) 1.1 to 3.7) or diagnosed antenatally (OR 2.7; 95% CI 1.3 to 5.6). Oligohydramnios was also more common (OR 2.9; 95% CI 1.2 to 7.0). The association of intrauterine growth retardation and white matter damage remained after excluding fetuses with a major congenital anomaly (OR 2.4; 95% CI 1.1 to 5.1). The findings suggest that chronic intrauterine hypoxia may be associated with damage to cerebral white matter among fetuses and infants who die. The relation between ischaemic white matter damage and cerebral palsy among survivors remains speculative.

The aetiology of cerebral palsy

I have attempted to give an overview of the latest thoughts on the aetiology of the cerebral palsies. These motor disabilities are of continuing interest and their prevalence is rising, particularly in low birth weight preterm singletons and multiple births. The likely multiplicity of causes demands intelligent investigation probably in collaborative population data bases. Ultrasound and other scans may provide better data on both site and timing of neonatal brain damage. However these are more likely to have been done on cerebral palsied children who were preterm than on those born at term. There are currently no clear preventive messages except those relating to postnatal cerebral palsy or encouraging strategies to reverse the increases in multiple births. The challenges now are to obtain better data on the antenatal factors and on causal sequences which may be important. The Little Foundation is seeking to encourage such collaborative studies. Other suggestions from our workshop [14] included attempting to follow up those infants who have been participants in large randomised controlled trials (such as those evaluating surfactant) to the age when they can be confidently diagnosed as having cerebral palsy. If antenatal data have been collected on them they may form the basis for a cohort analysis relating risk to cerebral palsy occurrence, as well as to answer questions about whether the intervention influenced cerebral palsy occurrence.