An overview of mortality and sequelae of preterm birth from infancy to adulthood

Outcomes at age 2 years of infants < 28 weeks' gestational age born in Victoria in 2005

OBJECTIVE

To determine the survival rates and neurosensory outcomes of infants born at gestational age 22-27 weeks in the state of Victoria in 2005 and compare theses data with those for similar infants born in the 1990s.

STUDY DESIGN

This was a population-based study of all extremely preterm (22-27 weeks' gestational age) live births in Victoria in 2005 free of lethal anomalies and randomly selected term controls. Survival and quality-adjusted survival rates at age 2 years were determined relative to the controls, and results were compared with regional extremely preterm cohorts born in 1991-92 and 1997.

RESULTS

Of 270 very preterm live births in 2005, 172 (63.7%) survived to 2 years, not significantly different from the survival rate of 69.6% for those born in 1997. Rates of severe developmental delay and severe disability were lower than in the very preterm survivors born in 1997. Quality-adjusted survival rates in the extremely preterm cohorts rose from 42.1% in 1991-92 to 55.1% in 1997, but did not increase in 2005 (53.4%).

CONCLUSIONS

Survival rates for infants born at 22-27 weeks' gestational age have not increased since the late 1990s, but the neurosensory outcome in survivors has improved.

Prenatal low-dose aspirin and neurobehavioral outcomes of children born very preterm

OBJECTIVE

Low-dose aspirin (LDA) given during pregnancy may alter brain development in very preterm infants. We report the short- and long-term outcomes of very preterm infants according to LDA treatment.

PATIENTS AND METHODS

Data were from the Etude Epidemiologique des Petites Ages Gestationnels (EPIPAGE) cohort study, which included all infants born before 33 weeks of gestation in 9 French regions in 1997. This study was restricted to 656 children who were born to 584 women with an obstetric history of placental vascular disease or with chronic hypertension or renal or autoimmune diseases. The main outcome measures were mortality, cerebral lesions, and outcome at 5 years of age, which were measured by a diagnosis of cerebral palsy; behavioral difficulties, which were assessed with the Strength and Difficulties Questionnaire; and cognitive impairment, which was measured by the mental processing composite scale of the Kaufman Assessment Battery for Children (an IQ-equivalent measure of cognitive ability in 2 dimensions: sequential and simultaneous processing scores).

RESULTS

LDA treatment was administered to 125 of 584 (21%) mothers and was not significantly associated with mortality, cerebral lesions, cerebral palsy, or global cognitive impairment of the children at 5 years of age. The proportion of low simultaneous processing scores (<70) was lower in the group with LDA (7% vs 19% without LDA; P = .04). This association was not significant after adjustment for propensity score, prognostic factors, and social class (adjusted odds ratio [aOR]: 0.59 [95% confidence interval (CI): 0.17-2.06]). LDA treatment was associated with a reduction, at the limit of significance, in total behavioral difficulties (aOR: 0.44 [95% CI: 0.19-1.02]) and hyperactivity (aOR: 0.43 [95% CI: 0.17-1.05]).

CONCLUSIONS

LDA was not associated with adverse neonatal or long-term outcomes. Moreover, the results suggest that LDA may be associated with a reduction in neurobehavioral difficulties. More research is needed to assess the effects of aspirin alone or combined with other neuroprotective agents.

Recent advances in our understanding of protein and amino acid metabolism in the human fetus

PURPOSE OF REVIEW

Premature infants often suffer from suboptimal outcome, at least partially due to suboptimal nutrition. Gaining insight into human fetal amino acid metabolism might ultimately lead to an improved nutritional strategy for prematurely born infants. Our aim was, therefore, to discuss recent findings with regard to human fetal amino acid metabolism.

RECENT FINDINGS

Human fetal protein and amino acid metabolism can be studied in vivo using stable isotope techniques. To date, however, only a few studies employing these techniques have been performed. For one, it was shown in vivo that essential amino acids are transported at different rates across the human placenta. In addition, tyrosine appears not to be a conditionally essential amino acid in the fetus at term, as phenylalanine is hydroxylated into tyrosine at considerable rates. Furthermore, albumin is synthesized at very high rates at two-thirds of gestation; higher than prematurely born infants do at a neonatal intensive care unit. This could indicate that postnatal nutrition of very immature infants can be improved.

SUMMARY

Although technically challenging, more studies regarding human fetal amino acid metabolism should be performed. Premature infants could then benefit from this knowledge from new nutritional strategies.

Very preterm birth: who has access to antenatal corticosteroid therapy?

We describe the administration of antenatal corticosteroid therapy (ACT) for liveborn very preterm neonates in a population-based study. A total of 790 very preterm neonates (between 24 and 31 full weeks of gestation) were included in this regionally defined population of very preterm neonates in France. The main outcome measure was non-access to ACT. Data were analysed using logistic and polytomous models to control for neonatal and sociodemographic characteristics, mechanisms of very preterm birth and neonatal network organisation. As compared with level III, births in levels I-II maternity units were closely related to non-access to ACT (60.1% vs. 8.8%), but not to pregnancy follow-up (19.7% vs. 17.8%). Only 6.3% of very preterm neonates that benefited from antepartum referral did nor receive ACT. Births associated with rupture of membranes and gestational hypertension were significantly more often transferred to level-III units (73.8% and 68.3% respectively) than those due to maternal bleeding and spontaneous labour (57.0% and 50.7% respectively), and the neonates had a lower probability of not receiving ACT (8.5%, 11.5%, 23.0%, 31.2% respectively). Very preterm neonates referred in utero to a level-III unit came from a more favourable socio-economic environment. Non-access to ACT was more often observed in neonates born to 14- to 24-year-old mothers, smokers, of low socio-economic status, and preterm birth resulting from maternal bleeding or spontaneous labour. These data from a French regional study show that access to ACT is not only explained by practitioners' support of recommendations. In our population-based study, ACT access was related to socio-economic factors and to the mechanisms of very preterm birth. Improving the rate of access to ACT should take these organisational, medical and socio-economic dimensions into account.

An evidentiary review regarding the use of chronological and adjusted age in the assessment of preterm infants

PURPOSE

The evidence supporting the recommendation to use age adjustment when assessing the growth, motor, and global development of premature infants was explored. Following a comprehensive literature search, 16 articles that compared the use of adjusted and chronological age were reviewed.

CONCLUSIONS

The use of full age adjustment based on the degree of prematurity was supported for the assessment of premature infants for a minimum of 12 months adjusted age.

PRACTICE IMPLICATIONS

The use of adjusted age enhances the ability to accurately recognize genuine delays as opposed to perceived delays related to a child's gestational age at birth.

A Haptic Simulator for Training the Application of Range of Motion Exercise to Premature Infants

The range of motion exercise is an experimental therapy for improving bone and muscle growth in premature infants but little is known about the magnitude of pressures that must be applied to the limbs during this exercise to elicit a physiological benefit and novice caregivers currently must rely on subjective instruction to learn to apply appropriate pressures. The goal of this study was to quantify the pressures applied by experienced caregivers during application of this exercise and to create a haptic simulator that could be used to train novice caregivers such as parents to apply the same pressures. We quantified the pressure applied by two neonatal intensive care nurses (“experts”) to the wrists of nine newborn, premature infants of varying gestational ages using an infant blood pressure cuff modified to act as a finger pressure sensor. The experts applied statistically significant different pressures depending on gestational age but did not differ significantly between themselves in the pressure they applied. We then created a robotic simulator of the premature infant wrist and programmed it to respond with the measured pressure-angle properties of the actual infants’ wrists. The novice adult participants (n=19) used the simulator to learn to apply target pressures for simulated wrists that corresponded to three different gestational ages. Training with the simulator for 30 min allowed the participants to learn to apply pressures significantly more like those of the experts. The performance improvement persisted at a retention test several days later. These results quantify for the first time the pressures applied during assisted exercise, include novel observations about joint flexibility and maturation early in life and suggest a strategy for teaching exercise intervention teams to provide assisted exercise within a more reproducible range using haptic simulation technology.

Maternal ethnic ancestry and adverse perinatal outcomes in New York City

OBJECTIVE

We sought to examine the association between narrowly defined subsets of maternal ethnicity and birth outcomes.

STUDY DESIGN

We analyzed 1995-2003 New York City birth certificates linked to hospital discharge data for 949,210 singleton births to examine the multivariable associations between maternal ethnicity and preterm birth, subsets of spontaneous and medically indicated preterm birth, term small for gestational age, and term birthweight.

RESULTS

Compared with non-Hispanic whites, Puerto Ricans had an elevated odds ratio (1.9; 95% confidence interval, 1.9-2.0) for delivering at 32-36 weeks (adjusted for nativity, maternal age, parity, education, tobacco use, prepregnancy weight, and birth year). We found an excess of adverse outcomes among most Latino groups. Outcomes also varied within regions, with North African infants nearly 100 g (adjusted) heavier than sub-Saharan African infants.

CONCLUSION

The considerable heterogeneity in risk of adverse perinatal outcomes is obscured in broad categorizations of maternal race/ethnicity and may help to formulate etiologic hypotheses.

Maternal effects for preterm birth: a genetic epidemiologic study of 630,000 families

This study was undertaken to disentangle the maternal genetic from the fetal genetic effects for preterm birth and to study the possibility of these effects being explained by known risk factors. By cross-linking of the population-based Swedish Multigeneration and Medical Birth registers, 989,027 births between 1992 and 2004 were identified. Alternating logistic regression was applied to model the familial clustering with pairwise odds ratios (PORs), and covariates were included to evaluate if the familial aggregation was explained by exposure to shared risk factors. Generalized linear mixed models were used to estimate the contribution of genetic and environmental effects. Sisters of women who had a preterm delivery had themselves an increased odds of having a preterm delivery (POR = 1.8, 95% confidence interval: 1.5, 2.1), while there was no corresponding increase in odds in families joined by brothers (POR = 1.1, 95% confidence interval: 0.9, 1.4). Twenty-five percent of the variation in preterm birth was explained by maternal genetic factors, whereas fetal genetic factors only marginally influenced the variation in liability. The increased odds ratio between offspring of sisters was independent of maternal risk factors for preterm birth, suggesting that the relative importance of maternal effects is not explained by these well-known risk factors.

Long-term outcome of preterm infants and the role of neuroimaging

Preterm birth has been defined as one of the major public health problems of this decade, preterm neonates being at high risk for neurodevelopmental disabilities. As preterm survival rates increase, the next great imperative for perinatal medicine is to understand and prevent the serious adverse neurodevelopmental outcomes of preterm birth. The challenge for neonatologists and neurologists alike is identifying early markers of outcome in the prematurely born. This article reviews current trends in prevalence, mortality, and morbidity, and the present status of outcome data for cognitive and neurosensory neurodevelopmental dysfunctions in preterm infants. New neuroimaging modalities and analysis tools are contributing to the understanding of neurologic sequelae of preterm birth by providing microstructural evidence of injury sustained by the preterm brain.

The APPLe study: a randomized, community-based, placebo-controlled trial of azithromycin for the prevention of preterm birth, with meta-analysis

BACKGROUND

Premature birth is the major cause of perinatal mortality and morbidity in both high- and low-income countries. The causes of preterm labour are multiple but infection is important. We have previously described an unusually high incidence of preterm birth (20%) in an ultrasound-dated, rural, pregnant population in Southern Malawi with high burdens of infective morbidity. We have now studied the impact of routine prophylaxis with azithromycin as directly observed, single-dose therapy at two gestational windows to try to decrease the incidence of preterm birth.

METHODS AND FINDINGS

We randomized 2,297 pregnant women attending three rural and one peri-urban health centres in Southern Malawi to a placebo-controlled trial of oral azithromycin (1 g) given at 16-24 and 28-32 wk gestation. Gestational age was determined by ultrasound before 24 wk. Women and their infants were followed up until 6 wk post delivery. The primary outcome was incidence of preterm delivery, defined as <37 wk. Secondary outcomes were mean gestational age at delivery, perinatal mortality, birthweight, maternal malaria, and anaemia. Analysis was by intention to treat. There were no significant differences in outcome between the azithromycin group (n = 1,096) and the placebo group (n = 1,087) in respect of preterm birth (16.8% versus 17.4%), odds ratio (OR) 0.96, 95% confidence interval (0.76-1.21); mean gestational age at delivery (38.5 versus 38.4 weeks), mean difference 0.16 (-0.08 to 0.40); mean birthweight (3.03 versus 2.99 kg), mean difference 0.04 (-0.005 to 0.08); perinatal deaths (4.3% versus 5.0%), OR 0.85 (0.53-1.38); or maternal malarial parasitaemia (11.5% versus 10.1%), OR 1.11 (0.84-1.49) and anaemia (44.1% versus 41.3%) at 28-32 weeks, OR 1.07 (0.88-1.30). Meta-analysis of the primary outcome results with seven other studies of routine antibiotic prophylaxis in pregnancy (>6,200 pregnancies) shows no effect on preterm birth (relative risk 1.02, 95% confidence interval 0.86-1.22).

CONCLUSIONS

This study provides no support for the use of antibiotics as routine prophylaxis to prevent preterm birth in high risk populations; prevention of preterm birth requires alternative strategies.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN84023116

Indigenous newborn care

Infant mortality and morbidity disparities occur between non-Indigenous and Indigenous populations of Australia, Canada, New Zealand, and the United States. Neonatal mortality is due to high-risk births, which vary according to prevalence of the maternal risk factors of smoking, alcohol consumption, infection, and disorders of nutritional status, whereas postneonatal mortality is predominantly influenced by environmental factors. Aside from changing socioeconomic conditions, a continuum of maternal and child health care is likely to be the most effective measure in reducing these health disparities.

Visuospatial and verbal fluency relative deficits in 'complicated' late-preterm preschool children

BACKGROUND

Late-preterm children constitute a majority of all preterm deliveries (75%). Their immature brain development at birth has been associated with an increased risk for morbidities. Data have been sparse regarding neuropsychological outcomes in the preschool years.

AIM

To examine general cognition, attention/working memory, language, manual coordination/motor dexterity, visuomotor, visuospatial, and executive functions in preschoolers born late-preterm (LPT; 34-36 gestational weeks) who required NICU admission compared to term-born participants.

DESIGN

Single-center retrospective cohort study of 95 three-year-old children; 60 born LPT in 2004-2005 and admitted to the NICU compared to 35 healthy term-born participants born > or =37 gestational weeks and > or =2500 g.

RESULTS

LPT birth was associated with visuospatial (p=.005), visuomotor (p=.012), and executive function (noun [p=.018] and action-verb [p=.026] fluency) relative deficits, but not attention/working memory, receptive or expressive language, nonverbal reasoning, or manual coordination/dexterity deficit.

CONCLUSIONS

Late-preterm birth is likely to be associated with negative neuropsychological sequelae, although subtle and selective compared to effects reported for children born at an earlier gestational age. Visuospatial function appears to be especially vulnerable to disruption even at preschool age, and verbal fluency may be useful as an early predictor of executive dysfunction in childhood. Routine preschool neuropsychological evaluation is recommended to identify delay or deficit in LPT children preparing for school entry, and may highlight underlying vulnerable neural networks in LPT children.

Invited commentary: maternal effects in preterm birth--effects of maternal genotype, mitochondrial DNA, imprinting, or environment?

Preterm birth is an important public health problem. A wide range of risk factors has been investigated, of which the strongest established is a woman's previous history of preterm birth. In this issue of the Journal, Boyd et al. (Am J Epidemiol. 2009;170(11):1358-1364) and Svensson et al. (Am J Epidemiol. 2009;170(11):1365-1372), using data on singleton livebirths from national birth registers linked with multigeneration databases, found evidence that maternal genetic factors impact on the risk for preterm birth, whereas paternal and probably fetal genetic factors do not. Possible caveats include missing information, the range of maternal risk factors included in the analyses, possible misclassification of these risk factors, and possible vertical transmission of microbial flora or behaviors from mother to daughter. Weinberg and Shi (Am J Epidemiol. 2009;170(11):1373-1381) build on the evidence regarding potential mechanisms underlying the heritability of preterm birth from these 2 and other studies, to evaluate the comparative ability of different study designs to distinguish among these potential mechanisms. These studies have different strengths, and a portfolio of studies of different designs and with more detailed phenotyping than previously done will be needed to probe further the etiology of preterm birth and thereby provide tools for its control.

Risk of preterm delivery and other adverse perinatal outcomes in relation to maternal use of psychotropic medications during pregnancy

OBJECTIVE

The purpose of this study was to determine the association of maternal psychotropic medication use during pregnancy with preterm delivery and other adverse perinatal outcomes.

STUDY DESIGN

A cohort of 2793 pregnant women in Washington State was interviewed, and their medical files were abstracted. Logistic regression models were constructed to assess odds ratios for perinatal outcomes by use of psychotropic medications.

RESULTS

Maternal use of benzodiazepine during pregnancy was associated with an increased risk of preterm delivery (adjusted odds ratio, 6.79; 95% confidence interval, 4.01-11.5) and with increased risks of low birthweight, low Apgar score, neonatal intensive care unit admissions, and respiratory distress syndrome. Selective serotonin receptor inhibitors were associated with preterm deliveries only among women who started treatment after the first trimester.

CONCLUSION

Benzodiazepine was associated highly with preterm delivery and other adverse perinatal outcomes. Well-conducted cohort studies are warranted to draw conclusions about risks and benefits of psychotropic medication use during pregnancy.

Neurodevelopmental outcome of infants with unilateral or bilateral periventricular hemorrhagic infarction

OBJECTIVE

Periventricular hemorrhagic infarction (PVHI) is a major contributing factor to poor neurodevelopmental outcomes in preterm infants. We hypothesized that surviving infants with unilateral PVHI would have more favorable outcomes than those with bilateral PVHI.

METHODS

This was a multicenter, retrospective study of infants who were admitted to 3 NICUs in North Carolina from 1998 to 2004. The clinical course and late neuroimaging studies and neurodevelopmental outcomes of 69 infants who weighed <1500 g and had confirmed PVHI on early cranial ultrasonography were reviewed. A predictive model for Bayley Scales of Infant Development, Second Edition, Mental Developmental Index (MDI) <70 was constructed by using radiologic and clinical variables.

RESULTS

Infants with unilateral PVHI had higher median MDI (82 vs 49) and Psychomotor Developmental Index (53 vs 49) than infants with bilateral PVHI. Infants with unilateral PVHI were less likely to have severe cerebral palsy (adjusted odds ratio: 0.15 [95% confidence interval (CI): 0.05-0.45]) than infants with bilateral PVHI. Infants who had unilateral PVHI and developed periventricular leukomalacia and retinopathy of prematurity that required surgery had an increased probability of having MDI <70 compared with those without these complications (probability of MDI <70: 89% [95% CI: 0.64-1.00] vs 11% [95% CI: 0.01-0.28]).

CONCLUSIONS

Infants with unilateral PVHI had better motor and cognitive outcomes than infants with bilateral PVHI. By combining laterality of PVHI, periventricular leukomalacia, and retinopathy of prematurity it is possible to estimate the probability of having an MDI <70, which will assist clinicians when counseling families.

Late preterm birth is a risk factor for growth faltering in early childhood: a cohort study

BACKGROUND

Rates of preterm birth are increasing worldwide and this increase is mostly due to infants born between 34 and 36 weeks of gestational age, the so-called "late preterm" births. The aim of this study was to assess the effect of late preterm birth over growth outcomes, assessed when children were 12 and 24 months old.

METHODS

In 2004, all births taking place in Pelotas (Southern Brazil) were recruited for a cohort study. Late preterm (34/0-36/6 weeks of gestational age) and term children (37/0-42/6 weeks) were compared in terms of weight-for-age, length-for-age and weight-for-length z-scores. Weight-for-age, length-for-age and weight-for-length z-scores below -2 were considered, respectively, underweight, stunting and wasting. Singleton newborns with adequate weight for gestational age at birth, successfully followed-up either at 12 or 24 months of age were analyzed and adjusted odds ratios with 95% confidence intervals calculated through logistic regression.

RESULTS

3285 births were included, 371 of whom were late preterm births (11.3%). At 12 months, prevalence of underweight, stunting and wasting were, respectively, 3.4, 8.7 and 1.1% among late preterm children, against 1.0, 3.4 and 0.3% among term children. At 24 months, correspondent values were 3.0, 7.2 and 0.8% against 0.8, 2.9 and 0.4%. Comparing with the term children, adjusted odds of being underweighted among late preterm children was 2.57 times higher (1.27; 5.23) at 12 months and 3.36 times higher (1.56; 7.23) at 24; of being stunted, 2.35 (1.49; 3.70) and 2.30 (1.40; 3.77); and of being wasted, 3.98 (1.07; 14.85) and 1.87 (0.50; 7.01). Weight gain from birth to 12 and 24 months was similar in late preterm and term children, whereas length gain was higher in the former group in both periods.

CONCLUSION

Late preterm children grow faster than children born at term, but they are at increased risk of underweight and stunting in the first two years of life. Failure to thrive in the first two years may put them at increased risk of future occurrences of serious morbidity in late childhood and of chronic disease development in adult life.

[Very preterm birth: is maternal anesthesia a risk factor for neonatal intubation in the delivery room?]

OBJECTIVE

To assess the risk of tracheal intubation at birth in very premature neonates related to the type of maternal anesthesia in case of elective cesarean.

POPULATION AND METHODS

All 219 live-born very premature neonates (28-32 weeks of gestation), delivered after an elective cesarean in the 27 maternity wards of 2 French semi-rural neonatal networks. Eighty-three percent (182/219) were delivered in level III maternity wards in university hospitals.

RESULTS

Of the very preterm neonates, 33.3% (73/219) were intubated in the delivery room, either for respiratory distress syndrome or a low APGAR score. Very preterm neonates delivered after maternal general anesthesia were more often intubated than those delivered after spinal anesthesia (48.7% vs 25.2%; OR: 2.8; 95% CI: 1.8-5.1). The risk of intubation related to maternal general anesthesia remained statistically significant after an adjustment for gestational age, fetal growth retardation, respiratory distress syndrome, type of maternity ward, and a propensity score that took into account maternal sociodemographic characteristics and the causes of very preterm birth (aOR: 3.4; 95% CI: 1.4-8.2). The risk of intubation related to general anesthesia was lower after adjusting for the 5-min APGAR score (aOR: 2.8; 95% CI: 1.0-7.3).

CONCLUSION

Very preterm neonates delivered after cesarean with general anesthesia require tracheal intubation in the delivery room more often than those delivered with spinal anesthesia. This study cannot assess a causal link between anesthesia and the need for neonatal intubation. However, neonatologists have to be aware of the type of maternal anesthesia because it may interfere with the non-invasive ventilation support policy of the very preterm neonate.

Strain differences in behavioral and cellular responses to perinatal hypoxia and relationships to neural stem cell survival and self-renewal: Modeling the neurovascular niche

Premature infants have chronic hypoxia, resulting in cognitive and motor neurodevelopmental handicaps caused by suboptimal neural stem cell (NSC) repair/recovery in neurogenic zones (including the subventricular and the subgranular zones). Understanding the variable central nervous system repair response is crucial to identifying "at risk" infants and to increasing survival and clinical improvement of affected infants. Using mouse strains found to span the range of responsiveness to chronic hypoxia, we correlated differential NSC survival and self-renewal with differences in behavior. We found that C57BL/6 (C57) pups displayed increased hyperactivity after hypoxic insult; CD-1 NSCs exhibited increased hypoxia-induced factor 1alpha (HIF-1alpha) mRNA and protein, increased HIF-1alpha, and decreased prolyl hydroxylase domain 2 in nuclear fractions, which denotes increased transcription/translation and decreased degradation of HIF-1alpha. C57 NSCs exhibited blunted stromal-derived factor 1-induced migratory responsiveness, decreased matrix metalloproteinase-9 activity, and increased neuronal differentiation. Adult C57 mice exposed to hypoxia from P3 to P11 exhibited learning impairment and increased anxiety. These findings support the concept that behavioral differences between C57 and CD-1 mice are a consequence of differential responsiveness to hypoxic insult, leading to differences in HIF-1alpha signaling and resulting in lower NSC proliferative/migratory and higher apoptosis rates in C57 mice. Information gained from these studies will aid in design and effective use of preventive therapies in the very low birth weight infant population.

Randomized trial of a parenting intervention for very preterm infants: outcome at 2 years

OBJECTIVES

To determine the efficacy of a neonatal parenting intervention for improving development in very preterm infants.

STUDY DESIGN

A cluster-randomized, controlled trial with a cross-over design and washout period was conducted in 6 neonatal centers. Two hundred thirty-three babies <32 weeks' gestation were recruited (intervention = 112; control = 121). Intervention families received weekly Parent Baby Interaction Programme (PBIP) sessions during neonatal intensive care unit admission and up to 6 weeks after discharge. Control families received standard care. All 195 infants remaining in the study at 24 months' corrected age were assessed by psychologists blinded to group allocation.

RESULTS

There was no significant difference in Mental Development Index (-0.9 points; 95% CI, -5.0, 3.2) or Psychomotor Development Index (2.5; -3.3, 8.4) scores between the intervention and control groups and no significant effect of intervention on Mental Development Index or Psychomotor Development Index scores for subgroups dichotomized by gestational age (<28 weeks/> or =28 weeks), parity (1st/other child) or mother's cohabiting status (supported/unsupported).

CONCLUSIONS

There was no effect of PBIP on infant development at 2 years' corrected age. Parenting interventions may be better delivered after discharge or targeted for preterm infants with high biological and social risk.

Paradoxical stimulation of cyclooxygenase-2 expression by glucocorticoids via a cyclic AMP response element in human amnion fibroblasts

Human amnion fibroblasts produce abundant prostaglandins toward the end of gestation, which is one of the major events leading to parturition. In marked contrast to its well-described antiinflammatory effect, glucocorticoids have been shown to up-regulate cyclooxygenase-2 (COX-2) expression in human amnion fibroblasts. The mechanisms underlying this paradoxical induction of COX-2 by glucocorticoids have not been resolved. Using cultured human amnion fibroblasts, we found that the induction of COX-2 mRNA expression by cortisol was a glucocorticoid receptor (GR)-dependent process requiring ongoing transcription. Upon transfection of a COX-2 promoter-driven reporter gene into the amnion fibroblasts, cortisol stimulated the COX-2 promoter activity. This was abolished by mutagenesis of a cAMP response element (CRE) at -53 to approximately -59bp as well as by cotransfection of a plasmid expressing dominant-negative CRE-binding protein (CREB). The phosphorylation level of CREB-1 was significantly increased by cortisol treatment of the amnion fibroblasts, whereas the effect was attenuated either by the protein kinase A inhibitor H89 or the p38 -MAPK inhibitor SB203580. The induction of the COX-2 promoter activity and the phosphorylation of CREB-1 were also blocked by the GR antagonist RU486. Chromatin immunoprecipitation (ChIP) assay revealed that the binding of CREB-1 to the CRE of the COX-2 promoter was increased by cortisol treatment of the amnion fibroblasts. In conclusion, cortisol, via binding to GR, stimulated COX-2 expression by increasing phosphorylated CREB-1 binding to the CRE of the COX-2 gene. Cortisol may phosphorylate CREB-1 by activating either protein kinase A or p38-MAPK in the amnion fibroblasts.

Neonatal end-of-life decisions and bioethical perspectives

In the nineties the EURONIC project documented the staff views and practices regarding ethical decision-making in neonatal intensive care units of eight Western Europe countries: France, Germany, Great Britain, Italy, Luxembourg, Netherlands, Spain and Sweden. This paper reviews the changes occurred in the ethical and legal background of these countries, and discusses possible influences on neonatal care practices. To a certain extent, many of these changes appear to be in line with the neonatal physicians' views and attitudes previously documented by the EURONIC project, while some are not. Large differences persist within Western Europe on what constitutes appropriate neonatal end-of-life care.

Imaging biomarkers of outcome in the developing preterm brain

The neurodevelopmental disabilities of those who were born prematurely have been well described, yet the underlying alterations in brain development that lead to these changes remain poorly understood. Processes that are vulnerable to injury in the developing brain include maturation of oligodendrocyte precursors and genetically programmed changes in cortical connectivity; recent data have indicated that diffuse injury of the white matter accompanied by neuronal and axonal disruption is common in prematurely born infants. Recent advances in MRI include diffusion tensor imaging and sophisticated image analysis tools, such as functional connectivity, voxel-based morphometry, and mathematical morphology-based cortical folding strategies. These advanced techniques have shown that white matter structure is dependent on gestational age and have started to provide important information about the dynamic interactions between development, injury, and functional recovery in the preterm brain. Identification of early biomarkers for outcome could enable physicians and scientists to develop targeted pharmacological and behavioural therapies to restore functional connectivity.

Prenatal smoking cessation and the risk of delivering preterm and small-for-gestational-age newborns

OBJECTIVE

To examine the association between prenatal smoking cessation and delivery of a preterm or small-for-gestational-age (SGA) newborn in a large U.S. subpopulation using the revised (2003) birth certificate, which now assesses maternal smoking status by trimester.

METHODS

We analyzed a cohort of U.S.-resident, singleton births in the 11 states that used the revised birth certificate in 2005 (n=915,441). Self-reported maternal smoking status was categorized as "never smoked," "quit in the first trimester," "quit in the second trimester," and "smoked throughout" pregnancy (referent). Multinomial logistic regression was used to estimate adjusted odds ratios (aORs) for three outcomes (preterm non-SGA, term SGA, or preterm SGA newborns) by maternal smoking status. Analyses stratified by maternal age were also conducted.

RESULTS

Compared with women who smoked throughout pregnancy, first-trimester quitters reduced their odds of delivering a preterm non-SGA newborn by 31% (aOR 0.69, 95% confidence interval [CI] 0.65-0.74), a term SGA newborn by 55% (aOR 0.45, 95% CI 0.42-0.48), and a preterm SGA newborn by 53% (aOR 0.47, 95% CI 0.40-0.55), similar to nonsmokers. Second-trimester quitters also reduced their odds of delivering preterm non-SGA and term SGA newborns but to a lesser magnitude. When comparing first-trimester quitters with smokers in each age group, older mothers had generally lower odds of these outcomes than younger mothers.

CONCLUSION

Pregnant smokers who quit in the first trimester lowered their risk of delivering preterm and SGA newborns to a level similar to that of pregnant nonsmokers, and this benefit appeared to increase with maternal age. These findings reinforce current clinical guidance to encourage smoking cessation among pregnant smokers and serve as an additional incentive to quit.

LEVEL OF EVIDENCE

II.

Adrenomedullin promotes lung angiogenesis, alveolar development, and repair

Bronchopulmonary dysplasia (BPD) and emphysema are significant global health problems at the extreme stages of life. Both are characterized by alveolar simplification and abnormal distal airspace enlargement due to arrested development or loss of alveoli, respectively. Both lack effective treatments. Mechanisms that inhibit distal lung growth are poorly understood. Adrenomedullin (AM), a recently discovered potent vasodilator, promotes angiogenesis and has protective effects on the cardiovascular and respiratory system. Its role in the developing lung is unknown. We hypothesized that AM promotes lung angiogenesis and alveolar development. Accordingly, we report that lung mRNA expression of AM increases during normal alveolar development. In vivo, intranasal administration of the AM antagonist, AM22-52 decreases lung capillary density (12.4 +/- 1.5 versus 18 +/- 1.5 in control animals; P < 0.05) and impairs alveolar development (mean linear intercept, 52.3 +/- 1.5 versus 43.8 +/- 1.8 [P < 0.05] and septal counts 62.0 +/- 2.7 versus 90.4 +/- 3.5 [P < 0.05]) in neonatal rats, resulting in larger and fewer alveoli, reminiscent of BPD. This was associated with decreased lung endothelial nitric oxide synthase and vascular endothelial growth factor-A mRNA expression. In experimental oxygen-induced BPD, a model of arrested lung vascular and alveolar growth, AM attenuates arrested lung angiogenesis (vessel density, 6.9 +/- 1.1 versus 16.2 +/- 1.3, P < 0.05) and alveolar development (mean linear intercept, 51.9 +/- 3.2 versus 44.4 +/- 0.7, septal counts 47.6 +/- 3.4 versus 67.7 +/- 4.0, P < 0.05), an effect in part mediated by inhibition of apoptosis. AM also prevents pulmonary hypertension in this model, as assessed by decreased right ventricular hypertrophy and pulmonary artery medial wall thickness. Our findings suggest a role for AM during normal alveolar development. AM may have therapeutic potential in diseases associated with alveolar injury.

Early emergence of behavior and social-emotional problems in very preterm infants

OBJECTIVE

Children born very preterm are reported to have an increased frequency of social, emotional, and behavioral problems at school age compared with their peers born at term. The primary aim of this study was to compare social-emotional difficulties and competencies of very preterm and full-term children at 2 years' corrected age. In addition, the relation between perinatal variables and early behavior problems was also examined to help identify those very preterm children most at risk.

METHOD

At 2 years' corrected age, the parents of 188 very preterm (gestational age <30 weeks or birth weight <1,250 g) and 70 full-term (gestational age >or=37 weeks) children completed the Infant Toddler Social and Emotional Assessment to determine externalizing, internalizing, and dysregulation problems and social-emotional competencies. For the very preterm sample, extensive perinatal data were collected including sex, birth weight, gestational age, chronic lung disease, and postnatal steroids, as well as neonatal cerebral white matter abnormalities detected by magnetic resonance imaging.

RESULTS

The very preterm children at 2 years demonstrated significantly higher internalizing and dysregulation scores and lower competence scores than peers born at term. There was no significant difference in externalizing scores between groups. Female sex, lower birth weight z score, white matter abnormalities, and postnatal corticosteroids were significantly associated with lower competence scores in the very preterm group.

CONCLUSIONS

Very preterm children exhibit higher rates of behavior problems early in development, in particular internalizing and dysregulation problems and poorer competence.

Risk factors for preterm birth among opiate-addicted gravid women in a methadone treatment program

OBJECTIVE

Prior studies noted elevated preterm birth (PTB) rates among opiate-addicted women treated with methadone. We sought to determine the risk factors for PTB in this population.

STUDY DESIGN

We performed a retrospective cohort study of opiate-addicted gravid women treated with methadone who delivered a single neonate between 2000 and 2006. Variables evaluated as potential risk factors for PTB less than 37 weeks included medical and infectious comorbidities and "supplements to methadone" (illicit drugs and/or alcohol).

RESULTS

The overall PTB rate was 29.1% (75/258). No medical or infectious comorbidity was predictive of PTB. Among women abusing 0, 1, 2, or 3 or more supplements in addition to methadone, the PTB rate was 24.2% (reference), 25.5% (P = .50), 47.6% (P = .04), and 64.7% (P = .01), respectively.

CONCLUSION

The PTB rate among women on methadone (29.1%) is nearly 3 times the national average (11.1%), and those abusing 2 or more supplements to methadone are at further increased risk for PTB.

Airway delivery of mesenchymal stem cells prevents arrested alveolar growth in neonatal lung injury in rats

RATIONALE

Bronchopulmonary dysplasia (BPD) and emphysema are characterized by arrested alveolar development or loss of alveoli; both are significant global health problems and currently lack effective therapy. Bone marrow-derived mesenchymal stem cells (BMSCs) prevent adult lung injury, but their therapeutic potential in neonatal lung disease is unknown.

OBJECTIVES

We hypothesized that intratracheal delivery of BMSCs would prevent alveolar destruction in experimental BPD.

METHODS

In vitro, BMSC differentiation and migration were assessed using co-culture assays and a modified Boyden chamber. In vivo, the therapeutic potential of BMSCs was assessed in a chronic hyperoxia-induced model of BPD in newborn rats.

MEASUREMENTS AND MAIN RESULTS

In vitro, BMSCs developed immunophenotypic and ultrastructural characteristics of type II alveolar epithelial cells (AEC2) (surfactant protein C expression and lamellar bodies) when co-cultured with lung tissue, but not with culture medium alone or liver. Migration assays revealed preferential attraction of BMSCs toward oxygen-damaged lung versus normal lung. In vivo, chronic hyperoxia in newborn rats led to air space enlargement and loss of lung capillaries, and this was associated with a decrease in circulating and resident lung BMSCs. Intratracheal delivery of BMSCs on Postnatal Day 4 improved survival and exercise tolerance while attenuating alveolar and lung vascular injury and pulmonary hypertension. Engrafted BMSCs coexpressed the AEC2-specific marker surfactant protein C. However, engraftment was disproportionately low for cell replacement to account for the therapeutic benefit, suggesting a paracrine-mediated mechanism. In vitro, BMSC-derived conditioned medium prevented O(2)-induced AEC2 apoptosis, accelerated AEC2 wound healing, and enhanced endothelial cord formation.

CONCLUSIONS

BMSCs prevent arrested alveolar and vascular growth in part through paracrine activity. Stem cell-based therapies may offer new therapeutic avenues for lung diseases that currently lack efficient treatments.

New insights into nutrition and cognitive neuroscience

Nutrition can affect the brain throughout the life cycle, with profound implications for mental health and degenerative disease. Many aspects of nutrition, from entire diets to specific nutrients, affect brain structure and function. The present short review focuses on recent insights into the role of nutrition in cognition and mental health and is divided into four main sections. First, the importance of nutritional balance and nutrient interactions to brain health are considered by reference to the Mediterranean diet, energy balance, fatty acids and trace elements. Many factors modulate the effects of nutrition on brain health and inconsistencies between studies can be explained in part by differences in early environment and genetic variability. Thus, these two factors are considered in the second and third parts of the present review. Finally, recent findings on mechanisms underlying the actions of nutrition on the brain are considered. These mechanisms involve changes in neurotrophic factors, neural pathways and brain plasticity. Advances in understanding the critical role of nutrition in brain health will help to fulfil the potential of nutrition to optimise brain function, prevent dysfunction and treat disease.

Growth trajectories and intellectual abilities in young adulthood: The Helsinki Birth Cohort study

Slow childhood growth is associated with poorer intellectual ability. The critical periods of growth remain uncertain. Among 2,786 Finnish male military conscripts (1952-1972) born in 1934-1944, the authors tested how specific growth periods from birth to age 20 years predicted verbal, visuospatial, and arithmetic abilities at age 20. Small head circumference at birth predicted poorer verbal, visuospatial, and arithmetic abilities. The latter 2 measures were also associated with lower weight and body mass index (weight (kg)/height (m)(2)) at birth (for a 1-standard-deviation (SD) decrease in test score per SD decrease in body size > or = 0.05, P's < 0.04). Slow linear growth and weight gain between birth and age 6 months, between ages 6 months and 2 years, or both predicted poorer performance on all 3 tests (for a 1-SD decrease in test score per SD decrease in growth > or = 0.05, P's < 0.03). Reduced linear growth between ages 2 and 7 years predicted worse verbal ability, and between age 11 years and conscription it predicted worse performance on all 3 tests. Prenatal brain growth and linear growth up to 2 years after birth form a first critical period for intellectual development. There is a second critical period, specific for verbal development, between ages 2 and 7 years and a third critical period for all 3 tested outcomes during adolescence.

Meta-analysis of neurobehavioral outcomes in very preterm and/or very low birth weight children

OBJECTIVE

Sequelae of academic underachievement, behavioral problems, and poor executive function (EF) have been extensively reported for very preterm (<or=33 weeks' gestation) and/or very low birth weight (VLBW) (<or=1500 g) children. Great variability in the published results, however, hinders the field in studying underlying dysfunctions and developing intervention strategies. We conducted a quantitative meta-analysis of studies published between 1998 and 2008 on academic achievement, behavioral functioning, and EF with the aim of providing aggregated measures of effect size for these outcome domains.

METHODS

Suitable for inclusion were 14 studies on academic achievement, 9 studies on behavioral problems, and 12 studies on EF, which compared a total of 4125 very preterm and/or VLBW children with 3197 term-born controls. Combined effect sizes for the 3 outcome domains were calculated in terms of Cohen's d. Q-test statistics were performed to test homogeneity among the obtained effect sizes. Pearson's correlation coefficients were calculated to examine the impact of mean birth weight and mean gestational age, as well as the influence of mean age at assessment on the effect sizes for academic achievement, behavioral problems, and EF.

RESULTS

Combined effect sizes show that very preterm and/or VLBW children score 0.60 SD lower on mathematics tests, 0.48 SD on reading tests, and 0.76 SD on spelling tests than term-born peers. Of all behavioral problems stacked, attention problems were most pronounced in very preterm and/or VLBW children, with teacher and parent ratings being 0.43 to 0.59 SD higher than for controls, respectively. Combined effect sizes for parent and teacher ratings of internalizing behavior problems were small (<0.28) and for externalizing behavior problems negligible (<0.09) and not significant. Combined effect sizes for EF revealed a decrement of 0.57 SD for verbal fluency, 0.36 SD for working memory, and 0.49 SD for cognitive flexibility in comparison to controls. Mean age at assessment was not correlated with the strength of the effect sizes. Mathematics and reading performance, parent ratings of internalizing problems, teacher ratings of externalizing behavior, and attention problems, showed strong and positive correlations with mean birth weight and mean gestational age (all r values > 0.51).

CONCLUSIONS

Very preterm and/or VLBW children have moderate-to-severe deficits in academic achievement, attention problems, and internalizing behavioral problems and poor EF, which are adverse outcomes that were strongly correlated to their immaturity at birth. During transition to young adulthood these children continue to lag behind term-born peers.

Functioning at school age of moderately preterm children born at 32 to 36 weeks' gestational age

OBJECTIVE

To study outcome of low-risk moderately preterm birth between 32 and 36/7 weeks' gestation.

METHODS

377 Moderately preterm children (M: 34.7, SD: 1.2 complete weeks), without need for neonatal intensive care and without dysmaturity or congenital malformations, were compared with 182 term children and assessed at eight years (M: 8.9, SD: 0.54). School situation, IQ, sustained attention, behavior problems, and attention-deficit/hyperactivity characteristics were studied.

RESULTS

Special education was attended by 7.7% of the moderately preterm children, more than twice the rate of 2.8% in the general Dutch population of this age. Additional exploration for two preterm subgroups of 32 to 33 versus 34 to 36 weeks' gestation showed a need for special education in 9.7% versus 7.3% and a significant difference in grade retention for 30% versus 17%, respectively. Of the children attending mainstream primary schools, grade retention was found in 19% of the preterm versus 8% of the comparison children. Adjusting for maternal education, a group difference of 3 points was found in IQ. The preterm children needed more time for the sustained attention task. The preterm children had more behavior problems (specifically internalizing problems with 27% scoring above the borderline cut-off), as well as more attention-deficit/hyperactivity disorder characteristics (specifically attention deficits).

CONCLUSIONS

Cognitive and emotional regulation difficulties affect functioning of moderately preterm children, as school problems, a slightly lower IQ, attention and behavioral problems are found when they are compared with term-born children. Identification and monitoring of precursors of these problems at younger age is needed in view of prevention purposes.

Neurosensory disabilities at school age in geographic cohorts of extremely low birth weight children born between the 1970s and the 1990s

OBJECTIVE

To contrast the rates of neurosensory disabilities at age 8 years in extremely low birth weight (ELBW; birth weight 500 to 999 g) children born in the state of Victoria, Australia in 4 four distinct eras from the late 1970s to the late 1990s.

STUDY DESIGN

Study subjects were assessed at age 8 years. Results were compared among 4 ELBW cohorts (87 of 89 children born in 1979-1980, 206 of 212 born in 1985-1987, 224 of 241 born in 1991-1992, and 160 of 170 born in 1997), and between each of these ELBW cohorts and normal birth weight (NBW; birth weight > 2499 g) controls.

RESULTS

The survival rate for ELBW children rose from 25% for the 1979-1980 cohort to 73% for the 1997 cohort. No statistically significant differences in the disability rates were seen in the 4 eras; however, in the 1997 cohort, disability rates were significantly higher in the ELBW children compared with NBW controls: mild disability, 36.7% vs 9.8%; moderate disability, 10.1% vs 2.3%; and severe disability, 8.2% vs 0.6%.

CONCLUSIONS

The survival rate of ELBW children continues to rise over time. Despite this, however, the rates of disability in these vulnerable children at school age have remained stable and high relative to controls.

The global impact of pre-eclampsia and eclampsia

Over half a million women die each year from pregnancy related causes, 99% in low and middle income countries. In many low income countries, complications of pregnancy and childbirth are the leading cause of death amongst women of reproductive years. The Millennium Development Goals have placed maternal health at the core of the struggle against poverty and inequality, as a matter of human rights. Ten percent of women have high blood pressure during pregnancy, and preeclampsia complicates 2% to 8% of pregnancies. Preeclampsia can lead to problems in the liver, kidneys, brain and the clotting system. Risks for the baby include poor growth and prematurity. Although outcome is often good, preeclampsia can be devastating and life threatening. Overall, 10% to 15% of direct maternal deaths are associated with preeclampsia and eclampsia. Where maternal mortality is high, most of deaths are attributable to eclampsia, rather than preeclampsia. Perinatal mortality is high following preeclampsia, and even higher following eclampsia. In low and middle income countries many public hospitals have limited access to neonatal intensive care, and so the mortality and morbidity is likely to be considerably higher than in settings where such facilities are available. The only interventions shown to prevent preeclampsia are antiplatelet agents, primarily low dose aspirin, and calcium supplementation. Treatment is largely symptomatic. Antihypertensive drugs are mandatory for very high blood pressure. Plasma volume expansion, corticosteroids and antioxidant agents have been suggested for severe preeclampsia, but trials to date have not shown benefit. Optimal timing for delivery of women with severe preeclampsia before 32 to 34 weeks' gestation remains a dilemma. Magnesium sulfate can prevent and control eclamptic seizures. For preeclampsia, it more than halves the risk of eclampsia (number needed to treat 100, 95% confidence interval 50 to 100) and probably reduces the risk of maternal death. A quarter of women have side effects, primarily flushing. With clinical monitoring serious adverse effects are rare. Magnesium sulfate is the anticonvulsant of choice for treating eclampsia; more effective than diazepam, phenytoin, or lytic cocktail. Although it is a low cost effective treatment, magnesium sulfate is not available in all low and middle income countries; scaling up its use for eclampsia and severe preeclampsia will contribute to achieving the Millennium Development Goals.

Preterm and infection-driven preterm labor: the role of peroxisome proliferator-activated receptors and retinoid X receptor

Approximately 8% of births are complicated by preterm delivery. To improve neonatal outcomes, a greater understanding of the mechanisms surrounding preterm parturition is required. Peroxisome proliferator-activated receptors (PPARs) have been implicated in the regulation of labor at term where they exhibit anti-inflammatory properties. Thus, we hypothesize that dysregulation of PPAR expression and activity may be associated with preterm labor and infection-associated preterm labor. The aim of this study was to compare the expression and activity of PPARs and the expression of retinoid X-receptor α (RXRA) in gestational tissues from term and preterm deliveries, and from infection-associated preterm deliveries. Quantitative RT-PCR, western blotting and activity ELISA were used to study expression and DNA binding profiles. Compared with term, preterm parturition was associated with an increased expression of PPAR δ (PPARD; mRNA and protein), PPAR γ (PPARG; protein) and RXRA (protein) in the placenta and PPARD (mRNA and protein) and RXRA (mRNA) in the choriodecidua. There was, however, no change in preterm PPAR DNA binding activity compared with term. Preterm chorioamnionitis (CAM) demonstrated protein degradation in the choriodecidua and was associated with a decline in the mRNA expression of PPAR α (PPARA) and RXRA compared with uninfected preterm cases. PPAR DNA binding activity increased in the placenta (PPARD and PPARG) and decreased in the amnion (PPARA and PPARG) in association with preterm CAM. In conclusion, idiopathic preterm deliveries were associated with an increase in PPAR:RXR expression and preterm CAM was associated with a decrease in PPAR:RXR expression and tissue-specific alterations in transcriptional activity. The reasons for such dysregulation remain to be determined; however, the data are consistent with the hypothesis that PPARs may play a role in preterm labor and infection-complicated preterm deliveries.

Modeling premature brain injury and recovery

Premature birth is a growing and significant public health problem because of the large number of infants that survive with neurodevelopmental sequelae from brain injury. Recent advances in neuroimaging have shown that although some neuroanatomical structures are altered, others improve over time. This review outlines recent insights into brain structure and function in these preterm infants at school age and relevant animal models. These animal models have provided scientists with an opportunity to explore in depth the molecular and cellular mechanisms of injury as well as the potential of the brain for recovery. The endogenous potential that the brain has for neurogenesis and gliogenesis, and how environment contributes to recovery, are also outlined. These preclinical models will provide important insights into the genetic and epigenetic mechanisms responsible for variable degrees of injury and recovery, permitting the exploration of targeted therapies to facilitate recovery in the developing preterm brain.

[Repeat doses of prenatal corticosteroids for women at risk of preterm birth: a difficult consensus]

A single course of antenatal corticosteroids in women at risk of preterm delivery reduces the risk of neonatal mortality and morbidity. Recent experimental and clinical studies have stated early, medium and long term consequences of single or repeated courses of antenatal corticosteroids. Betamethasone and dexamethasone are the two molecules usually used. Benefits are observed until the first 24 hours after the first injection. Single-course corticosteroids are not effective in babies born more than 7 days after initial treatment. Benefits of corticosteroids were evaluated between 22 and 35 weeks of gestation. Antenatal exposure to single-course betamethasone might result in disruption on glucose metabolism in adult offspring. Weekly courses of prenatal corticosteroids therapy are not recommended. Repeat prenatal corticosteroids given to women at continuing risk of preterm birth 7 or more days after an initial course reduced the inherent respiratory complications of prematurity and improved health outcomes of preterm infants. However, adverse outcomes have been reported concerning cognitive development. Although repeat course may have short term benefits, whether there are effects on health into childhood and beyond must await later assessment. Long term data are needed to recommend repeated courses.

Prematurity is not associated with reduced insulin sensitivity in adulthood

BACKGROUND

In 2005, 12.7% of all babies were born preterm, and the incidence is rising. Nowadays, due to improved survival, an increasing number of children born preterm reach young adulthood. A recent report suggested lower insulin sensitivity in children born preterm, which may put them at risk for the development of type 2 diabetes. It is, however, still unknown whether this reduced insulin sensitivity persists into adulthood.

METHODS

We determined insulin sensitivity and beta-cell function with frequently sampled iv glucose tolerance tests in 305 young adults (aged 18-24 yr; 169 preterm and 136 term). Adult body composition was measured by dual energy x-ray absorptiometry. We investigated the effect of gestational age, size at birth, and adult body composition on insulin sensitivity.

RESULTS

In contrast to previous reports, we found no evidence that preterm birth has a deleterious effect on insulin sensitivity in young adulthood. Adult trunk fat and the use of oral contraceptives in women were the most important determinants of insulin insensitivity, independently of size at birth and duration of pregnancy.

CONCLUSION

Contrary to our hypothesis, preterm birth was not associated with reduced insulin sensitivity in young adulthood.

Hypoxic injury during neonatal development in murine brain: correlation between in vivo DTI findings and behavioral assessment

Preterm birth results in significant neurodevelopmental disability. A neonatal rodent model of chronic sublethal hypoxia (CSH), which mimics effects of preterm birth, was used to characterize neurodevelopmental consequences of prolonged exposure to hypoxia using tissue anisotropy measurements from diffusion tensor imaging. Corpus callosum, cingulum, and fimbria of the hippocampus revealed subtle, yet significant, hypoxia-induced modifications during maturation (P15-P51). Anisotropy differences between control and CSH mice were greatest at older ages (>P40) in these regions. Neither somatosensory cortex nor caudate putamen revealed significant differences between control and CSH mice at any age. We assessed control and CSH mice using tests of general activity and cognition for behavioral correlates of morphological changes. Open-field task revealed greater locomotor activity in CSH mice early in maturation (P16-P18), whereas by adolescence (P40-P45) differences between control and CSH mice were insignificant. These results may be associated with lack of cortical and subcortical anisotropy differences between control and CSH mice. Spatial-delayed alternation and free-swim tasks in adulthood revealed lasting impairments for CSH mice in spatial memory and behavioral laterality. These differences may correlate with anisotropy decreases in hippocampal and callosal connectivities of CSH mice. Thus, CSH mice revealed developmental and behavioral deficits that are similar to those observed in low birth weight preterm infants.

Fgfr1 is required for cortical regeneration and repair after perinatal hypoxia

Chronic postnatal hypoxia causes an apparent loss of cortical neurons that is reversed during recovery (Fagel et al., 2006). The cellular and molecular mechanisms underlying this plasticity are not understood. Here, we show that chronic hypoxia from postnatal days 3 (P3) to 10 causes a 30% decrease in cortical neurons and a 24% decrease in cortical volume. T-brain-1 (Tbr1)(+) and SMI-32(+) excitatory neuron numbers were completely recovered 1 month after the insult, but the mice showed a residual deficit in Parvalbumin(+) and Calretinin(+) GABAergic interneurons. In contrast, hypoxic mice carrying a disrupted fibroblast growth factor receptor-1 (Fgfr1) gene in GFAP+ cells [Fgfr1 conditional knock-out (cKO)], demonstrated a persistent loss of excitatory cortical neurons and a worsening of the interneuron defect. Labeling proliferating progenitors at P17 revealed increased generation of cortical NeuN(+) and Tbr1(+) excitatory neurons in wild-type mice subjected to hypoxic insult, whereas Fgfr1 cKO failed to mount a cortical neurogenetic response. Hypoxic wild-type mice also demonstrated a twofold increase in cell proliferation in the subventricular zone (SVZ) at P17 and a threefold increase in neurogenesis in the olfactory bulb (OB) at P48, compared with normoxic mice. In contrast, Fgfr1 cKO mice had decreased SVZ cell proliferation and curtailed reactive neurogenesis in the OB. Thus, the activation of FGFR-1 in GFAP+ cells is required for neuronal recovery after neonatal hypoxic injury, which is attributable in part to enhanced cortical and OB neurogenesis. In contrast, there is incomplete recovery of inhibitory neurons after injury, which may account for persistent behavioral deficits.

Activation of TLR3 in the trophoblast is associated with preterm delivery

PROBLEM

Toll-like receptors (TLRs) recognize conserved sequences on the surface of pathogens and trigger effector cell functions. Previously, we described the expression of TLR3 by human trophoblast and their ability to respond to (Poly[I:C]). Here we evaluate the effect of Poly[I:C] on mouse pregnancy and characterize the local and systemic response.

METHOD OF STUDY

C57B/6 wild type (wt) and TLR3 knockout (TLR3KO) mice were treated with Poly[I:C] at 16.5 dpc and pregnancy outcome recorded. Morphologic changes, cytokines and chemokines levels in blood and utero-placental tissue were determined. NF-kappaB pathway was evaluated in vivo and in vitro.

RESULTS

Poly[I:C] in C57B/6 wt mice caused preterm delivery within 24 hr (4.5 mg/kg). No effect was observed in TLR3KO mice. In addition, we observed local (placenta) and systemic (serum) response characterized by increased production of proinflammatory cytokines and chemokines. The NF-kappaB pathway was activated by Poly[I:C] in human and mice trophoblast cells.

CONCLUSION

We report that Poly[I:C] induces preterm delivery via TLR3-dependent manner. Furthermore, we demonstrate that the trophoblast is able to recognize Poly[I:C] through TLR3 and respond to viral infection, modulating the immune system at the feto-maternal interface.