Preeclampsia, preterm delivery and infant cerebral palsy

Maternal age as a risk factor for cerebral palsy

The relationship between maternal age and the occurrence of cerebral palsy is still highly controversial. The aim of the study was to examine the effect of maternal age on the risk of CP development, taking into account all significant risk factors and the division into single, twin, full-term, and pre-term pregnancies.

The survey covered 278 children with CP attending selected educational institutions in Poland. The control group consisted of data collected from the medical records of 435 children born at Limanowa county hospital, Poland. The analyses included socio-economic factors, factors related to pregnancy and childbirth, and factors related to the presence of comorbidities and diseases in the child. Constructed logistic regression models were used for statistical analyses.

For all age categories included in the estimated models (assessing the effect of demographic factors on the development of CP), only the category of ≤24 years of age (in the group of all children) was significant. It was estimated that in this mother’s age category, the risk of CP is lower (OR 0.6, 95% CI: 0.3–1.0) in comparison to mothers aged 25-29 (p = 0.03). However, estimation with the use of a complex logistic regression model did not show any significant effect of maternal age on the incidence of CP in groups from different pregnancies types.

It became apparent that maternal age is a weak predictor of CP, insignificant in the final logistic regression model. It seems correct to assume that the studies conducted so far, showing a significant effect of maternal age in this respect, may be associated with bias in the estimators used to assess the risk of CP due to the fact that other important risk factors for CP development were not included in the research.

Preeclampsia and Neurodevelopmental Outcomes: Potential Pathogenic Roles for Inflammation and Oxidative Stress?

Preeclampsia (PE) is a common and serious hypertensive disorder of pregnancy that occurs in approximately 3-5% of first-time pregnancies and is a well-known leading cause of maternal and neonatal mortality and morbidity. In recent years, there has been accumulating evidence that in utero exposure to PE acts as an environmental risk factor for various neurodevelopmental disorders, particularly autism spectrum disorder and ADHD. At present, the mechanism(s) mediating this relationship are uncertain. In this review, we outline the most recent evidence implicating a causal role for PE exposure in the aetiology of various neurodevelopmental disorders and provide a novel interpretation of neuroanatomical alterations in PE-exposed offspring and how these relate to their sub-optimal neurodevelopmental trajectory. We then postulate that inflammation and oxidative stress, two prominent features of the pathophysiology of PE, are likely to play a major role in mediating this association. The increased inflammation in the maternal circulation, placenta and fetal circulation in PE expose the offspring to both prenatal maternal immune activation-a risk factor for neurodevelopmental disorders, which has been well-characterised in animal models-and directly higher concentrations of pro-inflammatory cytokines, which adversely affect neuronal development. Similarly, the exaggerated oxidative stress in the mother, placenta and foetus induces the placenta to secrete factors deleterious to neurons, and exposes the fetal brain to directly elevated oxidative stress and thus adversely affects neurodevelopmental processes. Finally, we describe the interplay between inflammation and oxidative stress in PE, and how both systems interact to potentially alter neurodevelopmental trajectory in exposed offspring.

Mediators of the association between pre-eclampsia and cerebral palsy: population based cohort study

OBJECTIVE

To test the hypothesis that pre-eclampsia is a risk factor for cerebral palsy mediated through preterm birth and being born small for gestational age.

DESIGN

Population based cohort study.

SETTING

Clinical data from the Norwegian Cerebral Palsy Registry were linked with perinatal data prospectively recorded by the Medical Birth Registry of Norway.

PARTICIPANTS

All singleton babies who survived the neonatal period during 1996-2006 (849 children with cerebral palsy and 616,658 control children).

MAIN OUTCOME MEASURES

Cerebral palsy and cerebral palsy subtypes.

RESULTS

Children exposed to pre-eclampsia had an excess risk of cerebral palsy (unadjusted odds ratio 2.5, 95% confidence interval 2.0 to 3.2) compared with unexposed children. Among children born at term (≥ 37 weeks), exposure to pre-eclampsia was not associated with an excess risk of cerebral palsy in babies not born small for gestational age (1.2, 0.7 to 2.0), whereas children exposed to pre-eclampsia and born small for gestational age had a significantly increased risk of cerebral palsy (3.2, 1.5 to 6.7). Non-small for gestational age babies born very preterm (<32 weeks) and exposed to pre-eclampsia had a reduced risk of cerebral palsy compared with unexposed children born at the same gestational age (0.5, 0.3 to 0.8), although the risk was not statistically significantly reduced among children exposed to pre-eclampsia and born small for gestational age (0.7, 0.4 to 1.3). Exposure to pre-eclampsia was not associated with a specific cerebral palsy subtype.

CONCLUSIONS

Exposure to pre-eclampsia was associated with an increased risk of cerebral palsy, and this association was mediated through the children being born preterm or small for gestational age, or both. Among children born at term, pre-eclampsia was a risk factor for cerebral palsy only when the children were small for gestational age.

Uncovering the complex relationship between pre-eclampsia, preterm birth and cerebral palsy

Pre-eclampsia is a leading cause of preterm birth, which is strongly associated with cerebral palsy (CP). However, there is controversy about whether pre-eclampsia is associated with increased risk of CP. We evaluated the association between pre-eclampsia and CP in 122,476 mother-child pairs insured by the South Carolina Medicaid programme, with births between 1996 and 2002. Prenatal billing records were linked to the children's Medicaid billing records after birth until December 2008. The odds of CP were modelled using logistic regression with generalised estimating equations. There were 337 children (0.28%) diagnosed with CP by at least two different health care providers, and 4226 (3.5%) women were diagnosed with pre-eclampsia at least twice during pregnancy. Children whose mothers had pre-eclampsia were almost twice as likely to have CP compared with children of mothers without pre-eclampsia [odds ratio (OR)=1.94, 95% confidence interval (CI) 1.25, 2.97]. The association was only significant for pre-eclampsia diagnosed prior to 37 weeks' gestation. Full term (gestational age ≥ 37 weeks) infants whose mothers were diagnosed with pre-eclampsia prior to 37 weeks had increased odds of CP compared with full term children whose mothers did not have pre-eclampsia (OR=3.41, 95% CI 1.40, 8.31). Preterm infants whose mothers had pre-eclampsia were at significantly increased risk of CP compared with full term infants whose mothers did not have pre-eclampsia (OR=5.88, 95% CI 3.40, 10.17). The greatest risk for CP was in preterm infants whose mothers did not have pre-eclampsia (OR=8.12, 95% CI 6.49, 10.17 compared with full term infants without exposure to pre-eclampsia). We conclude that pre-eclampsia with onset before 37 weeks' gestation is a significant risk factor for CP. Some of the association is probably attributable to high risk of preterm birth because of early pre-eclampsia, while a 'direct' effect of pre-eclampsia on fetal brain development also seems likely.

Utilization of health care services of pregnant women complicated by preeclampsia in Ontario

OBJECTIVE

To assess the utilization of health care services by pregnant women affected by preeclampsia (PE).

DESIGN

Population-based study.

SETTING

Perinatal partnership hospitals in Ontario.

POPULATION

Obstetric deliveries in 2005 Canadian province of Ontario (about 95% of births).

METHODS

For each PE case, four subjects without PE matched by age, parity, plurality, and hospital at childbirth were chosen as the controls. We compared the utilization of intra-partum care services and infant outcomes between the two groups. We also estimated the extra costs to the health care system in Ontario for caesarean delivery and caring of extremely low birth weight infants attributable to PE during the neonatal period and in the first 2 years of life.

MAIN OUTCOME MEASURES

Cesarean delivery, hospital stay, extremely low birth weight infants, cost.

RESULTS

Of the 120,611 obstetric deliveries included in this analysis, 1240 (1.3%) were diagnosed with PE. Patients with PE and matched controls were similar in maternal age, parity, and other demographic characteristics. Compared with study subjects without PE, those with PE had increased uses of spinal anesthesia, maternal transfer, Cesarean delivery, labour induction, neonatal transfer, newborn resuscitation, longer hospital stay for childbirth, and higher rates of preterm births and low birth weight. The extra costs to the health care system for cesarean delivery and caring of extremely low-birth-weight infants attributable to PE during the neonatal period and in the first 2 years of life in Ontario were $0.5 millions, 3.1 millions, and $5.1 million per year, respectively, if we use the reported PE rate in this database.

CONCLUSION

PE is associated with substantially increased costs to the health care system.

Prematurity or immaturity?

Birth in the human is particularly difficult compared with that in the other primates. Bipedalism has evolved over the past 6 or 7 million years, and has resulted in a small pelvis, adapted to the upright posture. In recent millennia, the increasing size of the fetal head at birth has made childbirth difficult. Haig has suggested that the mother and fetus do not have identical interests; the baby benefits from being large at birth, while it is easier for the mother to deliver a small baby. Many of the 500 000 maternal deaths per year around the world are due to obstructed labour, especially in Africa. Even in London, black African women have the highest caesarean section rates. Black African babies are on average smaller than white European babies, due mainly to earlier delivery. In a 13-year study of births in North West Thames, African babies were 2.5 times more likely to be born between 24 and 31 weeks inclusive than white European babies. Between 33 and 38 weeks of gestation, black African babies behaved in a more mature way, are more likely to pass meconium and have jaundice, but less likely to have respiratory problems leading to admission to the special care baby unit. Preterm black African babies have lower gestation-specific perinatal mortality than white European babies, while at term and beyond the reverse is true. Preterm birth may have evolved partly as a response to disproportion.

Morbidity and development in childhood of infants born after temporising treatment of early onset pre-eclampsia

OBJECTIVE

To assess morbidity and development in childhood of infants born after temporising management of severe early onset pre-eclampsia.

DESIGN

Cohort study with matched controls.

SETTING

University centre for high risk obstetrics.

SAMPLES

Three groups of neonates matched for gender and year of birth: one born after temporising treatment of severe early onset (<32 weeks) pre-eclampsia with an average delay of delivery of two weeks (n= 193); one born at the duration of pregnancy [1 week] of the pre-eclamptic mother on admission (control group I, n = 192); and one born at the same gestational age [1 week] as the infant of the pre-eclamptic mother (control group II, n= 189).

METHOD

Follow up at four years of age or more using medical records and questionnaires.

MAIN OUTCOME MEASURES

The presence of various morbidities including mental retardation, cerebral palsy, motor skill problems, visual handicap, hearing loss, speech and language problems, education level and acute or chronic respiratory problems.

RESULTS

Median follow up of seven years (range 4-12) was achieved in 159 infants in the study group (83%), 122 in control group I (64%) and 110 in control group II (58%). Missing data analysis showed no differences in neonatal characteristics and morbidity between infants with and without follow up in the study group. All major and minor handicaps were less frequent in the study group than in control group I but statistical significance was reached only for acute and chronic respiratory disorders in the study group (13.8%) compared with control group I (27%).

CONCLUSION

Average delay of delivery of two weeks with temporising management in severe early onset pre-eclampsia is associated with a reduced risk of respiratory disorders in childhood.

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.

Can obstetric care provide further improvement in the outcome of preterm infants?

Reducing the incidence of cerebral damage in preterm infants has become a major objective of perinatal medicine. Recent studies have shown that intrapartum hypoxia is implicated in only 10% of cases, whereas prenatal factors are significantly linked with such damage. The main risk factors associated with cerebral palsy are preterm birth, multiple pregnancy, intrauterine infection, serious hypoxaemic and haemodynamic disorders and, possibly, thrombophilic disorders. Recent progress in recognition of the pathogenesis of cerebral white matter damage has underlined the roles of cytokines, including interleukins 1 and 6 and tumour necrosis factor alpha (TNFalpha), and of a massive release of glutamate, which leads to the excitotoxic cascade. Three measures have had demonstrable benefits in improving neonatal outcome in preterm infants: a policy of prenatal transfers to tertiary level care units, antenatal corticosteroid therapy, and administration of antibiotics to women with preterm premature rupture of membranes. The influence of tocolysis is usually considered to be relatively minor, but further studies in very preterm pregnancies may be required. The recent development of tocolytics without major adverse effects will probably facilitate such studies. The mode of delivery of early preterm infants is another important area of controversy. Recent studies have suggested that a policy of elective caesarean section in PPROM and in the case of breech presentation of fetuses weighing less than 1000-1500 g would be beneficial. Lastly, in vitro and animal studies have shown that several pharmacological agents can prevent white matter disease by interacting with cytokine and the excitotoxic cascade. This will probably constitute an important area of research in the future.

The pulmonary paradox in premature infants: in-utero infected lungs do better than those with accelerated maturation

AIMS

To document, and explain, the pulmonary paradox whereby despite relative lung immaturity, preterm infants exposed to amniotic infection (AI) have better postnatal pulmonary function than those exposed to preeclampsia (PE).

METHODS

Lung maturation was characterized in 65 preterm perinatal deaths [AI (n=40) and PE (n=25)] and postnatal respiratory function in 100 preterm survivors [AI (n=50) and PE (n=50)].

RESULTS

At autopsy, lung architecture was in advance of gestational age in 5% of AI infants versus 40% of PE infants (P<0.001). In survivors, the groups were similar in age and Apgar scores. At birth, 40% of the AI group required continuous positive airway pressure or mechanical ventilation versus 24% of the PE group (NS). However, 24 hours later, only 1 AI infant had deteriorated compared to 40% of PE infants (P<0.05).

CONCLUSIONS

Accelerated morphologic lung maturation in preterm PE infants does not translate into improved postnatal respiratory function. Most likely, this is due to a relative lack of surfactant, ascribable to low stimulant cytokine and high TNF-alpha levels. An intrauterine history supplemented by an antenatal cytokine profile could identify an increased exogeneous surfactant need in preterm infants exposed to PE.

Severe umbilical cord inflammation-a predictor of periventricular leukomalacia in very low birth weight infants

Chorioamnionitis has been associated with periventricular leukomalacia (PVL) in very low birth weight (VLBW) infants. We examined the association between the pathological severity of chorioamnionitis and PVL in VLBW infants. Thirty-four VLBW infants with PVL and 34 control infants matched for gestational age without a diagnosis of PVL or intraventricular hemorrhage were obtained from the Women and Infants' Hospital of Rhode Island's Neonatal Follow-up Clinic database. Placental samples, including the amnion/chorion, chorionic plate, and umbilical cord, were examined microscopically. Statistical analysis included Mantel-Haenszel chi-square, and Student's t-test. Severe inflammation in the umbilical cord was observed in 53% of infants with PVL and 32% without PVL (p<0.05). Severe umbilical cord inflammation is one of the risk factors associated with the development of PVL in VLBW infants.

Labor and delivery factors in brain damage, disabling cerebral palsy, and neonatal death in low-birth-weight infants

OBJECTIVE

We assessed the relationships between active labor and neonatal death, neonatal brain damage, and disabling cerebral palsy in low-birth-weight infants.

STUDY DESIGN

A population-based cohort of 961 infants with birth weights of 580 to 2000 g and gestational ages >or=26 completed weeks. Neonatal brain damage was assessed by ultrasound scanning in the first weeks of life; disabling cerebral palsy was assessed at 2 years of age (corrected for gestational age).

RESULTS

After being controlled for possible confounders, active labor was associated significantly with an increased risk of parenchymal echodensities/lucencies and/or ventricular enlargement (odds ratio, 2.3; 95% CI, 1.2-4.5) but not with germinal matrix/intraventricular hemorrhage (odds ratio, 1.3; 95% CI, 0.8-2.1), neonatal death (odds ratio, 1.8; 95% CI, 0.8-4.0), or disabling cerebral palsy (odds ratio, 1.6; 95% CI, 0.7-3.7). In vertex presentations only, active labor was associated with a nearly 4-fold increase in risk of neonatal death (odds ratio, 3.8; 95% CI, 1.3-10.9). In nonvertex presentations only, active labor was associated strongly with parenchymal echodensities/lucencies and/or ventricular enlargement (odds ratio, 4.3; 95% CI, 1.2-15.6) and disabling cerebral palsy (odds ratio, 8.2; 95% CI, 1.4-49.9).

CONCLUSION

The only adverse outcome that was associated consistently with active labor was parenchymal echodensities/lucencies and/or ventricular enlargement. Fetal presentation modified the relationships between active labor and adverse outcomes. Delivery mode (whether vaginal or cesarean delivery) was not associated with any of the outcomes that were evaluated.

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.

Cerebral palsy in very preterm infants: new epidemiological insights

The focus of this review is on new insights from recent epidemiological research on cerebral palsy in preterm infants. These include: 1) a better understanding of issues related to diagnosis and classification; 2) new information about the brain abnormalities underlying cerebral palsy in preterm infants; and 3) a better understanding of biological mechanisms that may underlie previously described epidemiological associations. Ongoing efforts to improve the diagnosis and classification of cerebral palsy have been enhanced by findings from serial examinations of cohorts of very preterm infants. Cranial ultrasonography through the anterior fontanelle of very preterm infants has provided information about grossly evident brain damage, found in about one-half of preterm infants who develop cerebral palsy. Insights into the pathophysiologic basis for certain epidemiologic associations have come from studies of experimental brain damage in animals and clinical studies of neurologic disorders in adults. Much of the current epidemiological research into the causes of cerebral palsy in preterm infants has focused on two potential mechanisms of brain damage. One mechanism involves insufficient cerebral perfusion; the other, cytokine-mediated damage, potentially triggered by events such as maternal infection (e.g., intrauterine or periodontal infection), neonatal infection (e.g., sepsis and necrotizing enterocolitis), and neonatal oxygen- or ventilator-induced lung injury. In addition to the preterm infant's increased exposure to such damaging factors, the high frequency of cerebral palsy in these infants might be due, in part, to insufficient levels of developmentally regulated protective substances, such as thyroid hormone and glucocorticoids. Models of causation currently are being investigated using recently developed methods for quantifying, with small quantities of blood, biomolecules that are suspected to either promote or protect against brain damage in the neonate. Clinical investigations now under way can be expected to identify strategies to be tested in clinical trials that could lower the risk of cerebral palsy in very preterm infants.

Adverse and beneficial effects of tocolytic therapy

In addition to questions raised about the efficacy of many tocolytics, appropriate concern has been voiced about the safety of these potent drugs. Although some degree of risk for adverse effects with drugs promising a strong therapeutic effect can be accepted, caution needs to be exercised when benefits are marginal or unproven. Unfortunately, some of the tocolytics, most notably the betamimetics and magnesium sulfate, have been found to have considerable potential for adverse maternal cardiovascular and respiratory effects. Although less clearly established, the use of indomethacin appears to be associated with increased fetal and neonatal risks. Concerning magnesium sulfate, in addition to the well-known maternal effects, the accumulating evidence showing an increased frequency of adverse outcomes in the fetus and neonate has led to the recommendations to abandon its use entirely as a tocolytic. Given the limitations of our current state of knowledge, nifedipine would appear to be among the more efficacious and safer tocolytics available to use when properly indicated.

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.

Advances in prevention and treatment of cerebral palsy

In recent years there have been a number of advances in understanding of predisposing and protective factors in the development of cerebral palsy in infants. Multiple gestation births, maternal infection, and maternal and fetal thrombophilic conditions all predispose to the development of CP in the infant. Opportunities for prevention of CP may develop from an improved understanding of these factors and their mechanisms of operation. Similar progress has been made in the evaluation of treatments for CP and the effects of these treatments on the individual's impairment, function, and disability. Selective posterior rhizotomy and Botulinum toxin A are now widely used in the treatment of spasticity. The challenge remains to determine how effectively these promising interventions can alter long-term function and quality of life outcomes in children and adults with CP.

Cerebral white matter damage in the preterm infant: pathophysiology and risk factors

Based on clinical, epidemiologic, and experimental studies, the aetiology of white matter damage, specifically periventricular leukomalacia (PVL), is multifactorial and involves pre- and perinatal factors possibly including genetic factors, hypoxic-ischaemic insults, infection, excess cytokines, free radical production, increased excitatory amino acid release, and trophic factor deficiencies. The article summarizes research findings about the aetiology of white matter damage and cerebral palsy in preterm infants. The information is organized according to specific antecedents, for which we present epidemiological and neurobiological data. The most important prenatal factor appears to be intrauterine infection. We discuss the evidence supporting the hypothesis that the foetal inflammatory response contributes to neonatal brain injury and later developmental disability. We recently established an animal model of excitotoxic lesions in the developing mouse brain. Brain damage was induced by intra-cortical injections of ibotenate, a glutamatergic agonist. When administered on post-natal day 5 ibotenate induced the formation of white matter cysts. Our animal model could be used to further explore the mechanisms involved in the formation of PVL. Potentially preventive strategies will be discussed.

Antecedents of cerebral palsy in very low-birth weight infants

Research from the last two decades provides directions for efforts to prevent CP in VLBW infants. The pathogenesis of CP seems to involve factors operating both during pregnancy and in the neonatal period. The most important prenatal factor appears to be intrauterine infection. Perinatal infection and other risk factors, such as the death of a co-twin, placental abruption, and cerebral ischemia, could trigger a cytokine cascade resulting in damage to the developing brain. The low frequency of intrauterine infection in mothers with preeclampsia might explain the apparent protective effect of this disorder. If the brain damage attributed to intrauterine infection and other risk factors involves cytokines as intermediates, then blockade of the proinflammatory cascade or promotion of endogenous inhibitors might prevent CP. Other potentially preventive strategies include corticosteroids given to mothers (but not those given to neonates) and thyroid hormone.

Causes of cerebral palsy

Risk factors for cerebral palsy in term or near-term children include intrauterine exposure to infection or inflammation and disorders of coagulation. Interruption of the oxygen supply during birth contributes approximately 6% of spastic cerebral palsy. Low Apgar score, need for resuscitation, and seizures are nonspecific indicators of neonatal illness that do not identify cause. Although not entirely consistent, current evidence suggests that in utero infection may predispose very preterm and more mature infants to cerebral palsy and that antenatal exposure to steroids may be somewhat protective. Recognition of a broader set of causal possibilities encourages hope for new strategies for the prevention of cerebral palsy.

Maternal infection, fetal inflammatory response, and brain damage in very low birth weight infants. Developmental Epidemiology Network Investigators

Echolucent images (EL) of cerebral white matter, seen on cranial ultrasonographic scans of very low birth weight newborns, predict motor and cognitive limitations. We tested the hypothesis that markers of maternal and feto-placental infection were associated with risks of both early (diagnosed at a median age of 7 d) and late (median age = 21 d) EL in a multi-center cohort of 1078 infants <1500 x g. Maternal infection was indicated by fever, leukocytosis, and receipt of antibiotic; fetoplacental inflammation was indicated by the presence of fetal vasculitis (i.e. of the placental chorionic plate or the umbilical cord). The effect of membrane inflammation was also assessed. All analyses were performed separately in infants born within 1 h of membrane rupture (n = 537), or after a longer interval (n = 541), to determine whether infection markers have different effects in infants who are unlikely to have experienced ascending amniotic sac infection as a consequence of membrane rupture. Placental membrane inflammation by itself was not associated with risk of EL at any time. The risks of both early and late EL were substantially increased in infants with fetal vasculitis, but the association with early EL was found only in infants born > or =1 after membrane rupture and who had membrane inflammation (adjusted OR not calculable), whereas the association of fetal vasculitis with late EL was seen only in infants born <1 h after membrane rupture (OR = 10.8; p = 0.05). Maternal receipt of antibiotic in the 24 h just before delivery was associated with late EL only if delivery occurred <1 h after membrane rupture (OR = 6.9; p = 0.01). Indicators of maternal infection and of a fetal inflammatory response are strongly and independently associated with EL, particularly late EL.

The changing role of magnesium sulphate therapy

Magnesium sulphate is not an effective tocolytic. Magnesium sulphate therapy was also linked to preterm neonatal deaths in one study, which was stopped before completion. Other studies suggest a possible neuroprotective effect of magnesium. Both of these issues require further study. Magnesium sulphate is clearly the drug of choice to prevent recurrent eclampsia and to treat severe pre-eclampsia.