Preterm birth and cerebral palsy. Predictive value of pregnancy complications, mode of delivery, and Apgar scores

Cerebral Palsy and Motor Impairment After Extreme Prematurity: Prediction of Diagnoses at Ages 2 and 10 Years

OBJECTIVE

To identify perinatal factors in children born extremely preterm (EP) that were associated with motor impairment (MI) at 2 and 10 years of age and develop a predictive algorithm to estimate the risk of MI during childhood.

STUDY DESIGN

Participants of the Extremely Low Gestational Age Newborns Study (ELGANS) were classified as: no MI, MI only at 2 years, MI only at 10 years, and MI at both 2 and 10 years, based on a standardized neurological examination at 2 and the Gross Motor Function Classification System (GMFCS) at 10 years of age. Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to develop the final predictive model.

RESULTS

Of the 849 study participants, 64 (7.5%) had a diagnosis of MI at both 2 and 10 years and 63 (7.4%) had a diagnosis of MI at 1 visit but not the other. Of 22 total risk factors queried, 4 variables most reliably and accurately predicted MI: gestational age, weight z-score growth trajectory during neonatal intensive care unit (NICU) stay, ventriculomegaly, and cerebral echolucency on head ultrasound. By selecting probability thresholds of 3.5% and 7.0% at ages 2 and 10, respectively, likelihood of developing MI can be predicted with a sensitivity and specificity of 71.2%/72.1% at age 2 and 70.7%/70.7% at age 10.

CONCLUSION

In our cohort, the diagnosis of MI at 2 years did not always predict a diagnosis of MI at 10 years. Specific risk factors are predictive of MI and can estimate an individual infant's risk at NICU discharge of MI at age 10 years.

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.

Decreasing cerebral palsy prevalence in multiple births in the modern era: a population cohort study of European data

Multiple births (twins or higher order multiples) are increasing in developed countries and may present higher risk for cerebral palsy (CP). However, few studies can reliably investigate trends over time because these outcomes are relatively rare.

OBJECTIVE

We pooled data from European CP registers to investigate CP birth prevalence and its trends among single and multiple births born between 1990 and 2008.

DESIGN

Population cohort study.

SETTING

12 population-based registers from the Surveillance of Cerebral Palsy in Europe collaboration.

PARTICIPANTS

4 446 125 single and multiple live births, of whom 8416 (0.19%) had CP of prenatal or perinatal origin.

MAIN OUTCOMES

CP diagnosis ascertained in childhood using harmonised methods; CP subtype; Motor impairment severity among CP cases.

RESULTS

The rate of multiple births increased from 1990. Multiples displayed higher risk for CP (RR=4.27, 95% CI 4.00 to 4.57). For singletons and multiples alike, risk for CP was higher among births of lower gestational age (GA) or birth weight (BW). However, CP birth prevalence declined significantly among very preterm (<32 weeks) and very low BW (<1500 g) multiples. Singletons and multiples with CP displayed similar severity of motor impairment.

CONCLUSIONS

Between 1990 and 2008, CP birth prevalence decreased steadily among multiples with low GA or BW. Furthermore, multiples with CP display similar profiles of severe motor impairment compared with CP singletons. Improvements in management of preterm birth since the 1990s may also have been responsible for providing better prospects for multiples.

A systematic review and meta-analysis of randomized controlled trials comparing 17-alpha-hydroxyprogesterone caproate versus placebo for the prevention of recurrent preterm birth

BACKGROUND

Preterm birth causes an increased risk for perinatal morbidity and mortality.

OBJECTIVE

To determine whether mid-trimester 17-alpha-hydroxyprogesterone caproate (17-OHPC) reduces the risk of recurrent preterm birth and adverse perinatal outcomes.

SEARCH STRATEGY

Systematic search to identify relevant studies published in different languages, registered after 2000, using appropriate MeSH terms.

SELECTION CRITERIA

Inclusion criteria were women between 16 and 26⁺⁶  weeks of pregnancy with history of preterm delivery in any pregnancy randomized to either 17-OHPC or placebo/no treatment.

DATA COLLECTION AND ANALYSIS

The number of preterm births and adverse outcomes in the 17-OHPC and placebo arms over the total number of patients in each randomized group were used to calculate the risk ratio (RR) by random-effects models using the Mantel-Haenszel method. Between-study heterogeneity was assessed using tau² , χ² (Cochrane Q), and I² statistics.

MAIN RESULTS

Four studies were included. There was a 29% (RR 0.71; 95% CI, 0.53-0.96; P=0.001), 26% (RR 0.74; 95% CI, 0.58-0.96; P=0.021), and 40% (RR 0.60; 95% CI, 0.42-0.85; P=0.004) reduction in recurrent preterm birth at <37, <35, and <32 weeks, respectively, in the 17-OHPC group compared with placebo. The reduction in neonatal death was 68% (RR 0.32; 95% CI, 0.15-0.66; P=0.002).

CONCLUSIONS

17-OHPC could reduce the risk of recurrent preterm birth at <37, <35, and <28 weeks and neonatal death.

PROSPERO

CDR42017082190.

Respiratory distress syndrome in moderately late and late preterm infants and risk of cerebral palsy: a population-based cohort study

OBJECTIVES

Infant respiratory distress syndrome (IRDS) is a known risk factor for intracerebral haemorrhage/intraventricular haemorrhage (ICH/IVH) and periventricular leucomalacia. These lesions are known to increase the risk of cerebral palsy (CP). Thus, we wanted to examine the long-term risk of CP following IRDS in moderately late and late preterm infants.

DESIGN

Population-based cohort study.

SETTING

All hospitals in Denmark.

PARTICIPANTS

We used nationwide medical registries to identify a cohort of all moderately and late preterm infants (defined as birth during 32-36 full gestational weeks) born in Denmark in 1997-2007 with and without hospital diagnosed IRDS.

MAIN OUTCOMES MEASURES

We followed study participants from birth until first diagnosis of CP, emigration, death or end of follow-up in 2014. We computed the cumulative incidence of CP before age 8 years and used Cox's regression analysis to compute HRs of IRDS, comparing children with IRDS to those without IRDS. HRs were adjusted for multiple covariates.

RESULTS

We identified 39 420 moderately late and late preterm infants, of whom 2255 (5.7%) had IRDS. The cumulative incidence of CP was 1.9% in infants with IRDS and 0.5% in the comparison cohort. The adjusted HR of CP was 2.0 (95% CI 1.4 to 2.9). The adjusted HR of CP was 12 (95% CI 4.5 to 34) in children with IRDS accompanied by a diagnosis of ICH/IVH. After restriction to children without diagnoses of perinatal breathing disorders other than IRDS, congenital heart disease and viral or bacterial infections occurring within 4 days of birth, the overall adjusted HR was 2.1 (95% CI 1.4 to 3.1).

CONCLUSIONS

The risk of CP was increased in moderately late and late preterm infants with IRDS compared with infants without IRDS born during the same gestational weeks.

Risk factors for cerebral palsy in PPROM and preterm delivery with intact membranes (.)

OBJECTIVE

Gestational age (GA) at delivery and spontaneous prematurity are independent risk factors for cerebral palsy (CP). The aim of this study is to investigate perinatal risk factors for CP in spontaneous preterm delivery.

METHODS

A retrospective cohort study of all single pregnancies complicated by spontaneous preterm labor (PTL) or PPROM with delivery at <34 weeks from January 2006 to December 2012 was performed. We compared demographic, obstetric, neonatal, and placental histology variables in cases of spontaneous preterm birth in reference to the development of CP. Statistical analysis included chi-square, one-way ANOVA and logistic regression analysis. p < 0.05 was considered significant.

RESULTS

Two hundred sixty-one women were included for this study. Of 249 survivors, 5 babies died during the first year of life, 52 did not fulfill the inclusion criteria for neurologic follow-up, and 24 were lost to follow up. Thus 168 infants in the study cohort underwent neurologic follow-up. We observed 26 cases of CP. Factors related to CP were lower GA at PROM (p = 0.007) and longer latency from PPROM to delivery (p = 0.002) in the PPROM group, lower GA at delivery (p < 0.001) and presence of funisitis (p <0.001) in the PTL group.

CONCLUSIONS

GA at membrane rupture in PPROM and GA at delivery in PTL are significantly associated with CP. A process leading to neurological damage may be initiated at the moment of membranes rupture in cases of PPROM and at the time of PTL in the group with intact membranes.

The effects of multiple pre- and perinatal risk factors on the occurrence of cerebral palsy. A Norwegian register based study

AIMS

To examine the effects of multiple risk factors on cerebral palsy (CP).

MATERIALS/METHODS

For 176,591 Norwegian infants born 1996-98 and surviving the early neonatal period, data on a number of potential pre- and perinatal risk factors (RFs) for CP were available in the Medical Birth Registry of Norway. For 241 children with CP detailed clinical data were available in the Norwegian CP registry.

RESULTS

In children born at term, 31% had no RF, and none had five or more, while in children born preterm, 9% had no RF in addition to prematurity (p < 0.001 vs. term), and 5% had five or more (p < 0.02 vs. term). In both groups, few children shared the same combination of RFs. Interdependent sequences were more often observed among children born preterm than at term (p < 0.001 vs. term). The most detrimental effect was observed for the combination of maternal disease and low 5-min Apgar score, registered in 11.2% of children with CP. The combination of maternal disease and premature birth had an interaction contrast ratio of 9.25 (CI: 3.56; 14.94), which may be consistent with biological interaction.

CONCLUSIONS

The majority of children with CP born at term most likely had an antenatal or single cause, suggesting individual susceptibility to an injury. The majority of children born preterm, had combinations or sequences of antenatal and perinatal risk factors as the most likely cause of CP.

Association of cerebral palsy with Apgar score in low and normal birthweight infants: population based cohort study

OBJECTIVES

To assess the association of Apgar score 5 minutes after birth with cerebral palsy in both normal weight and low birthweight children, and also the association with the cerebral palsy subdiagnoses of quadriplegia, diplegia, and hemiplegia.

DESIGN

Population based cohort study.

SETTING

The Medical Birth Registry of Norway was used to identify all babies born between 1986 and 1995. These data were linked to the Norwegian Registry of Cerebral Palsy in Children born 1986-95, which was established on the basis of discharge diagnoses at all paediatric departments in Norway.

POPULATION

All singletons without malformations born in Norway during 1986-95 and who survived the first year of life (n=543 064).

MAIN OUTCOME MEASURE

Cerebral palsy diagnosed before the age of 5 years.

RESULTS

988 children (1.8 in 1000) were diagnosed with cerebral palsy before the age of 5 years. In total, 11% (39/369) of the children with Apgar score of less than 3 at birth were diagnosed with cerebral palsy, compared with only 0.1% (162/179 515) of the children with Apgar score of 10 (odds ratio (OR) 53, 95% CI 35 to 80 after adjustment for birth weight). In children with a birth weight of 2500 g or more, those with an Apgar score of less than 4 were much more likely to have cerebral palsy than those who had an Apgar score of more than 8 (OR 125, 95% confidence interval 91 to 170). The corresponding OR in children weighing less than 1500 g was 5 (95% CI 2 to 9). Among children with Apgar score of less than 4, 10-17% in all birthweight groups developed cerebral palsy. Low Apgar score was strongly associated with each of the three subgroups of spastic cerebral palsy, although the association was strongest for quadriplegia (adjusted OR 137 for Apgar score <4 v Apgar score >8, 95% CI 77 to 244).

CONCLUSIONS

Low Apgar score was strongly associated with cerebral palsy. This association was high in children with normal birth weight and modest in children with low birth weight. The strength of the association differed between subgroups of spastic cerebral palsy. Given that Apgar score is a measure of vitality shortly after birth, our findings suggest that the causes of cerebral palsy are closely linked to factors that reduce infant vitality.

The role of perinatal and intrapartum risk factors in the etiologyof cerebral palsy in term deliveries in a Turkish population

OBJECTIVE

To investigate the relationship between cerebral palsy (CP) and perinatal and intrapartum risk factors and markers of birth asphyxia.

METHODS

This was a retrospective case-control study of 101 children with CP and 308 controls who were born at the Zeynep Kamil Hospital between 1990 and 2000. The roles of possible perinatal and intrapartum risk factors were investigated in CP development. Chi-square tests, Fisher's exact tests, Student t-tests, and regression analysis were used for statistical analysis (p < 0.05).

RESULTS

The only significant perinatal risk factor was neonatal weight of <2500 grams. The CP rate in the presence of solely intrapartum risk factors was estimated as 24.7% (n = 25). In 39.6% of cases, no risk factor could be identified. When regression analysis was performed, the following factors were significant: decreased beat-to-beat variability on electronic fetal monitoring (EFM) (p = 0.02), an Apgar score of <7 at 1 and 5 minutes (p = 0.02), and the necessity for neonatal intensive care unit admission (p < 0.0001).

CONCLUSION

Intrapartum risk factors were significantly more frequent in the CP group (p < 0.01). An increased cesarean section rate could not prevent CP, suggesting that the hypoxic insult that causes CP might be of chronic onset. The development of diagnostic tests to detect non-reassuring fetal status in its intrauterine life and interventions at appropriate times may decrease the CP rate.

Epidemiology of stillbirth and fetal central nervous system injury

The epidemiology of stillbirth and fetal central nervous system (CNS) injury is described with some emphasis on maternal and feto-placental risk factors. To maximize utility of the discussion and because it also represents the classical manifestation of fetal CNS injury, we have selected cerebral palsy (CP) to illustrate the epidemiologic aspects of injury to the fetal CNS in general. While trends in stillbirth rates have modestly decreased over time, those of CP seem to be increasing. Interestingly, both stillbirth and CP share traditional as well as emerging risk factors lending credence to the hypothesis that fetuses that would previously have been stillborn are increasingly surviving albeit with some form of morbidity. The existence of shared risk factors also suggests that in some cases of stillbirth fetal CNS injury precedes the in utero fetal demise. Pregnant women bearing these risk indicators represent potential candidates for appropriate and tailored protocols for antenatal fetal testing.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

A review of the Apgar score indicated that contextualization was required within the contemporary perinatal and neonatal care framework in different settings

OBJECTIVE

To triangulate the Apgar score by using a crossdisciplinary approach and highlighting the differences that exist between actual everyday practice and accepted standards of scoring in contrasting populations of the world.

STUDY DESIGN AND SETTING

Clinimetrics review of Apgar scoring.

RESULTS

The Apgar scoring has weighting problems, rigid categorization, redundancy and subjectivity in its variables. Poor inter-rater reliability and equivocal validity mark its use in the present milieu. The ceiling and floor effects further hamper the evaluative responsiveness of scoring. Moreover, despite some recent evidence in its favor, the Apgar score has poor calibration when used as an isolated criterion to predict mortality and long-term morbidity, particularly in preterms. Also, the vigor of resuscitation (nature and duration), in essence, is beyond the realm of the Apgar score in contemporary resuscitation guidelines. In developed nations, with rapidly decreasing age of viability, and alternative modes of childbearing, threats to Apgar are more ominous today than before. On the other hand, in developing countries, feasibility problems due to unattended home deliveries and barriers to effective scoring in the overburdened and understaffed hospitals cast doubts about its accuracy as a measure of neonatal well-being.

CONCLUSION

Use of the Apgar score definitely needs to be contextualized within the contemporary perinatal and neonatal care framework in different settings.

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.

Cerebral palsy registries

Cerebral palsy (CP) registers appear to be appropriate tools for answering questions regarding the prevalence and characteristics of this common childhood disability. Registers are population databases issuing from multiple sources, relying on a clear definition and inclusion and exclusion criteria of CP, and requiring a mix of skills with the collaboration of obstetricians, pediatricians, and epidemiologists. In Europe alone there are 18 different CP registers or population data collections on CP, and collaborative research efforts exist through a European network. Data collection on CP has also been done in Australia (register), the United States (surveys), and Canada (register). Beside monitoring trends, other public health contributions of CP registers might be to reduce the frequency of CP and to improve the quality of life of children with CP. CP registers are useful to clinicians by enabling them to identify subgroups of children requiring specific etiologic investigations, and also to provide more accurate information to the parents of children with CP.

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.

Comparison of neonatal outcome including cerebral palsy between abruptio placentae and placenta previa

OBJECTIVE

Our purpose was to evaluate the neonatal prognosis after abruptio placentae and placenta previa during pre-term gestation.

STUDY DESIGN

A case-control study was performed using a logistic regression model. A poor outcome was defined as neonatal death occurring before hospital discharge or a diagnosis of cerebral palsy.

RESULTS

A poor outcome was more frequent in cases of abruptio placentae (11/42, 26.2%) than in placenta previa (2/72, 2.8%) and pre-term labor (1/120, 0.8%). The difference was mainly due to the incidence of cerebral palsy. A significant association of abruptio placentae (odds ratio (OR) 61.0, 95% confidence interval (CI 3.4-1084), delivery at <31 weeks of gestation (OR 19.0, CI 2.8-128.8), and low Apgar score (<7) at 5min (OR 70.8, CI 16.5-304.9) with increased risk of poor outcome was found in the logistic regression model that controlled for confounding effects. In abruptio placentae, a low Apgar score (<7) at 5min (OR 19.8, CI 2.0-197.8) was associated with increased risk of poor outcome in the logistic regression model.

CONCLUSION

From the standpoint of poor perinatal outcome including cerebral palsy, abruptio placentae was the most significant clinical entity in pre-term gestation.

Muscle power development during the first year of life predicts neuromotor behaviour at 7 years in preterm born high-risk infants

The aim of the study was to find if neurological function during the first year of life could predict neuromotor behaviour at 7 years of age in children born preterm with a high risk. A follow-up study of neuromotor behaviour in 52 children at a mean age of 3, 6, 12 months (corrected age) and 7 years was performed. All children were born with a gestational age less than 32 weeks and/or a birthweight under 1500 g and the infants were categorised according to their medical history in the three highest categories of the 'Neonatal Medical Index' (NMI, from category I to V, from few to serious complications). In addition, neonatal cerebral ultrasound abnormalities were used to divide the infants further into the different NMI categories. At 3 and 6 months, the relationship between active and passive muscle power was measured in shoulders, trunk and legs and (a)symmetry between right and left was noted. The results at 3 and 6 months were ranged from 1 for optimal to 5 for poor muscle power regulation. At 12 months of age, a neurological examination was done with special emphasis on the assessment of postural control, spontaneous motility, hand function and elicited infantile reactions with special attention to (a)symmetry. Outcome at 12 months was expressed as percentage of the optimal score on each subcategory. At 7 years, the motor behaviour study based on Touwen's examination for minor neurological dysfunction was performed. This investigation focuses on different functions, such as hand function, quality of walking, posture, passive muscle tone, coordination and diadochokinesis. The outcome was expressed as percentage of the optimal score on the combined subcategories. The best prediction of neuromotor behaviour at 7 years was assessed with stepwise linear multiple regression, using as potential predictors perinatal factors and outcome of motor behaviour at the corrected age of 3, 6 and 12 months. At 7 years none of the children scored 100% on the combined subcategories, 15 children (29%) scored between 75% and 99%, whereas 15 children scored less than 50%. Neuromotor behaviour at 7 years could be predicted by the NMI categorisation and gender with a sensitivity of 92% (specificity 47%; positive and negative predictive value 81% and 70%). No direct relation was found between neuromotor behaviour and cerebral ultrasound classification only, days on the ventilator and/or continuous positive airway pressure, birthweight, gestational age and dysmaturity. The best predictor of neuromotor behaviour at 7 years was the combination of outcome of muscle power in shoulders and legs at 3 months and postural control at 12 months, taking into account the gender of the child (sensitivity 95%; specificity 40%; positive predictive value 80%; negative predictive value 75%).

Antenatal and intrapartum antecedents of cerebral palsy: a case-control study

AIM

To identify antenatal and intrapartum factors contributing to the aetiology of cerebral palsy (CP).

METHODS

A case-control study using moderate/severe cases of cerebral palsy identified from the Victorian Cerebral Palsy Register and two controls per case identified through the Victorian Perinatal Data Collection Unit.

RESULTS

A number of previously identified risk factors for CP were confirmed in our data. New observations were (in specific sub-groups): protective effects of mother's negative Rhesus status, cigarette smoking at the first visit and episiotomy and an increased risk of CP associated with an abnormal antenatal cardiotocograph.

CONCLUSIONS

Although the result of the deliberate investigation of specific aspects of the antenatal and intrapartum period identified from a pilot study, our new findings must be interpreted with caution as they were not all based on specific a priori hypotheses, although some had been examined by other investigators. We would encourage their evaluation in other data sets.

Cerebral palsy births in eastern Denmark, 1987--90: implications for neonatal care

The Cerebral Palsy Register in eastern Denmark has collected cases using a uniform data sampling procedure since birth year 1979. We have investigated changes in the rate of cerebral palsy, related to gestational age, mortality and perinatal risk factors in children born 1983--90. The total cerebral palsy birth prevalence decreased from 3.0 in the birth year period 1983--86 to 2.4 per 1000 live births (P < 0.01) in 1987--90, owing to a decrease among all preterm infants (29--19 per 1000, P < 0.001). The perinatal and early neonatal mortality in preterm infants was unchanged from 1983--86 to 1987--90. The rate of cerebral palsy in term infants was 1.5 per 1000 in all birth-year periods from 1979--90. Among the cerebral palsy infants, the proportion of very preterm babies treated with mechanical ventilation in the neonatal period decreased from 95% in 1983--86 to 61% in 1987--90 (P < 0.001), while the group treated with CPAP among the moderately preterm babies increased from 61% to 78% (P < 0.05). The significant decline in cerebral palsy rate in preterm infants born 1987--90 may be due to a change in treatment at the neonatal intensive care units using less mechanical ventilation, a hypothesis which needs further investigation.

Risk factors for cerebral palsy in very low-birthweight infants in the 1980s and 1990s

One-hundred twenty-nine very low-birthweight infants were treated in Newborn and Infant Care Department of Children's Memorial Health Institute between 1985 and 1994; 89 were taken to prospective neurodevelopmental care. The newborns were divided into two groups. Group I had 38 preterm infants born from 1985 to 1989 and followed up at 7 to 11 years of age. Group II had 51 very low-birthweight infants treated from 1990 to 1994 and followed up at 2 to 5 years of age. Complicated, multiple pregnancy, normal delivery, and extremely low birthweight were significantly more frequent in group II. Very low-birthweight infants were frequently born by cesarean section in severe asphyxia. Only four (7.8%) newborns received surfactant therapy. From 1990 to 1994, respiratory distress syndrome III and IV, and a longer respiratotherapy period were significantly more frequent. From 1985 to 1994, the frequency of sepsis, periventricular leukomalacia, and normal ultrasonography was constant. Intraventricular hemorrhage I, II, and IV were frequently present in the 1990s, and intraventricular hemorrhage III was frequent in the 1980s. Cerebral palsy was diagnosed in 11 (28.9%) children in group I and 18 (35.2%) in group II (not statistically different). Multiple and complicated pregnancy, cesarean section, severe asphyxia, and respiratory distress syndrome did not increase the risk of cerebral palsy in very low-birthweight infants. Periventricular leukomalacia has a more predictive value for cerebral palsy in these infants than did intraventricular hemorrhage.