A longitudinal study of differences in electroencephalographic activity among breastfed, milk formula-fed, and soy formula-fed infants during the first year of life

Background

The extent to which adequate nutrition from infant diets differentially influence developmental outcomes in healthy infants has not been determined.

Aim

To compare the effects of the major infant diets on the development of brain electrical activity during infancy.

Study design

Scalp EEG signals (124 sites) recorded from the same infants during quiet wakefulness at 3, 6, 9, and 12 months.

Subjects

Healthy, full-term infants (40/group; gender matched) either breastfed (BF) or fed milk formula (MF) or soy formula (SF) through the first 6 months.

Outcome measures

Power spectral values for frequencies in the 0.1-30 Hz range.

Results

Significant diet-related differences were present across frequency bands and included effects that were time- [peaks in 0.1-3 Hz at 6 (MF,SF) and 9 months (BF); 3-6 Hz at 6 months (MF, SF > BF); increases in 6-9 Hz from 3 to 6 months (MF > BF) and from 6 to 9 months (MF > SF)] and gender-related (9-12 Hz and 12-30 Hz: at 9 months BF > MF, SF boys, and MF > SF girls).

Conclusions

The development of brain electrical activity during infancy differs between those who are breastfed compared with those fed either milk or soy formula, but is generally similar for formula-fed groups. These variations in EEG activity reflect diet-related influences on the development of brain structure and function that could put infants on different neurodevelopmental trajectories along which cognitive and brain function development will proceed.     

Circulating adipocyte fatty acid binding protein levels in healthy preterm infants: Positive correlation with weight gain and total-cholesterol levels

Background

Adipocyte fatty acid binding protein (a-FABP) has been suggested to play an important role in the pathogenesis of metabolic syndrome. Preterm infants are at risk for the later development of insulin resistance, and, possibly, other components of metabolic syndrome.

Aim

To determine circulating levels of a-FABP in preterm infants and examine possible associations of a-FABP with metabolic indices (serum lipids, glucose, and insulin levels, and homeostasis model assessment index of insulin resistance [HOMA-IR]), levels of leptin and adiponectin, anthropometric parameters and weight gain.

Study design

Prospective cohort study.

Subjects

55 healthy preterm (mean [SD] gestational age 32.8 [1.8] weeks) and 23 fullterm infants (reference group).

Outcome measures

Serum a-FABP, lipids, glucose, insulin, leptin and adiponectin levels at 31.9 [10.4] days of life.

Results

Serum a-FABP levels did not differ significantly between preterm and fullterm infants. A-FABP levels correlated positively with total-cholesterol [total-C] in both preterm and fullterm infants (β = 0.33; p = 0.01 and β = 0.33; p = 0.04, respectively). In addition to total-C, weight gain correlated independently with a-FABP levels in preterm infants (β = 0.36, p = 0.01).

Conclusions

An association between a-FABP levels and indices of insulin resistance was not present in infants studied. As the development of insulin resistance in children born prematurely is possibly associated with weight gain in early postnatal life, follow-up of our study population is necessary to demonstrate whether a-FABP levels, shown to correlate with weight gain in preterm infants, are a predictive marker for the later development of insulin resistance in these infants.     

Nucleated red blood cells and early EEG: predicting Sarnat stage and two year outcome

Aims

Hypoxic Ischaemic Encephalopathy (HIE) causes characteristic changes of the electroencephalogram (EEG), and a raised Nucleated Red Blood Cell (NRBC) count compared to controls. We wished to examine whether combining these markers could improve their ability to predict HIE severity in the first 24 h.

Methods

Term infants with HIE were recruited. NRBC count and continuous multi-channel EEG were recorded within the first 24 h. Neurological assessment was carried out at 24 months. A control population with NRBC counts in the first 24 h was recruited.

Results

44 infants with HIE and 43 control infants were recruited. Of the HIE population 39 completed a 2 year follow-up. The median NRBC count differed significantly between the controls and those with HIE (3/100 WBC [range of 0-11] vs 12.3/100 WBC [0-240]) (p < 0.001). Within the HIE population the median NRBC count was significantly greater in infants with moderate/severe HIE than mild (16/100 WBC [range of 0-240] vs 8/100 WBC [1-23]) (p = 0.016), and among infants with abnormal outcome compared to normal (21.3/100 WBC [1-239.8] vs 8.3/100 WBC [0-50])(p = 0.03).The predictive ability of EEG changed with time post-delivery, therefore results are given at both 12 and 24 h of age. At both time points the combined marker had a stronger correlation than EEG alone; with HIE severity (12 h: r = 0.661 vs r = 0.622), (24 h: r = 0.645 vs r = 0.598), and with outcome at 2 years (12 h: r = 0.756 vs r = 0.652), (24 h: r = 0.802 vs r = 0.746).

Conclusion

Combining early EEG and NRBC count to predict HIE severity and neurological outcome, improved the predictive ability of either in isolation.     

Quantitative analysis of maturational changes in EEG background activity in very preterm infants with a normal neurodevelopment at 1 year of age

Background

The electroencephalographic (EEG) background pattern of preterm infants changes with postmenstrual age (PMA) from discontinuous activity to continuous activity. However, changes in discontinuity have been investigated by visual analysis only.

Aim

To investigate the maturational changes in EEG discontinuity in healthy preterm infants using an automated EEG detection algorithm.

Study design

Weekly 4 h EEG recordings were performed in preterm infants with a gestational age (GA) < 32 weeks and normal neurological follow-up at 1 year. The channel C3-C4 was analyzed using an algorithm which automatically detects periods of EEG inactivity (interburst intervals). The interburst-burst ratio (IBR, percentage of EEG inactivity during a moving time window of 600 s) and mean length of the interburst intervals were calculated. Using the IBR, discontinuous background activity (periods with high IBR) and continuous background activity (periods with low IBR) were automatically detected and their mean length during each recording was calculated. Data were analyzed with regression and multivariate analysis.

Results

79 recordings were performed in 18 infants. All recordings showed a cyclical pattern in EEG discontinuity. With advancing PMA, IBR (R² = 0.64; p < 0.001), interburst interval length (R² = 0.43; p < 0.001) and length of discontinuous activity (R² = 0.38; p < 0.001) decreased, while continuous activity increased (R² = 0.50; p < 0.001). Multivariate analysis showed that all EEG discontinuity parameters were equally influenced by GA and postnatal age.

Conclusion

Analyzing EEG background activity in preterm infants is feasible with an automated algorithm and shows maturational changes of several EEG derived parameters. The cyclical pattern in IBR suggests brain organisation in preterm infant.     

Perinatal cerebral insults alter auditory event-related potentials

Background

Auditory event-related potentials (AERPs) can be used as indices of neural information processing. Altered AERPs have been reported in children and young adults with frontal lobe infarction.

Aim

To test the hypothesis that perinatal brain injury affects cortical auditory processing.

Methods

We assessed AERPs at term, 6 and 12 months of age in preterm infants [n = 9, median gestational age (GA) 27.9, range 23.9-30.0 wk], term infants with perinatal intracerebral hemorrhage (ICH) [n = 5, GA 40.3, range 37.4-42.3 wk], and term infants with perinatal asphyxia [n = 4, GA 39.4, range 37.9-40.3 wk]. Healthy preterm (n = 16) and term infants (n = 22) served as controls. A harmonic tone of 500-Hz frequency was used as standard and of 750-Hz as deviant stimulus. Mean AERP amplitudes were calculated over 100 ms periods from 50 to 350 ms. The developmental outcome was followed until 2 years of age.

Results

The term ICH (p = 0.012) and asphyxia (p = 0.0016) group had smaller or more negative responses to the deviant, resulting in smaller or more negative MMR amplitudes than those of the controls. The preterm ICH group did not differ significantly from their preterm born controls. MMR varied in all patient groups and was not associated with adverse outcome.

Conclusion

AERP alterations suggest that perinatal cerebral insults affect cortical auditory processing.     

Standardization of the Alberta infant motor scale in full-term Greek infants: Preliminary results

Background

The Alberta Infant Motor Scale (AIMS) is a norm-referenced test that assesses the spontaneous motor performance of infants from birth through independent walking (0-18 months). This scale has been utilized for clinical and research purposes in various countries, however, whether the initial standardization in Canadian infants is also representative of other countries' populations has been questioned.

Aim

To assess whether the AIMS needs new reference values for Greek infants.

Methods

A cohort of 424 healthy full-term infants (250 boys and 174 girls), aged between 7 days and 18 months, derived from various areas of the Prefecture of Attica and from all socio-economic classes to ensure a true representation, was studied. The AIMS-scores of Greek infants were compared with the norm-referenced values of the original Canadian population reported by Piper and Darrah.

Results

The mean AIMS-scores did not differ significantly between Greek and Canadian infants at any age level from birth to 18 months, except for the 2-<3 month of age when higher scores were observed in Greek infants (p = 0.02). There was no significant difference in AIMS-values corresponding to the 5th and 90th percentile between Greek and Canadian infants. Inter-rater reliability was excellent in our study population [ICC: 0.99 (95% CI: 0.99-0.99)].

Conclusion

In healthy full-term Greek infants, gross motor maturity assessed by the AIMS during the first 18 months of age, seems to follow a similar course to that of Canadian infants.     

Early assessment of visual function in preterm infants: How early is early?

Background

Several studies reported on various aspects of visual function at term age and in the first months after birth but less has been reported in preterm infants before they reach termequivalent age.

Aims

To assess the suitability of a battery of tests of visual function for use in infants born at < 33 weeks gestation (GA) and assessed before 34 weeks post-menstrual age (PMA); to evaluate the distribution of the findings according to GA, and to compare the data with those previously published on preterm infants assessed at 35 weeks PMA.

Study design

Cross-sectional study.

Subjects

Sixty-four preterm infants with a GA < 33 weeks were studied.

Outcome measures

We used a battery of visual function tests previously validated at 35 and 40 weeks PMA in low-risk preterm infants. All the infants in this current study underwent the same assessment before 34 weeks PMA.

Results

Before 31 weeks PMA most infants could not be reliably assessed because of clinical instability, whilst after 31 weeks PMA most infants could be assessed and they showed progressive maturation in their responses with PMA. Some items (spontaneous ocular motility, horizontal tracking, tracking a coloured stimulus, and ocular fixation) showed similar results at 32-33 weeks PMA to those found in low-risk preterm at 35 weeks PMA. Ocular movements to a target and arc tracking were the items with the most immature responses.

Conclusions

Our results provide further evidence that a structured assessment of visual function can be used in clinical routine and for research purposes in infants as young as 31 weeks PMA.     

Maternal anxiety is related to infant neurological condition, paternal anxiety is not

Background

Parental anxiety and stress may have consequences for infant neurological development.

Aims

To study relationships between parental anxiety or well-being and infant neurological development approximately one year after birth.

Study design

Longitudinal study of a birth cohort of infants born to subfertile couples. Subjects: 206 parent-child dyads.

Outcome measures

Infant neurology was assessed with the Touwen Infant Neurological Examination (TINE) at 10 months and a developmental questionnaire at 12 months. Parental measures included trait anxiety measured by the State-Trait Anxiety Inventory (STAI) and well-being measured by the General Health Questionnaire (GHQ).

Results

Maternal trait anxiety was associated with a less optimal neurological condition (r_s = − 0.19, p < 0.01) of the infant. This association persisted after adjusting for confounders and results were confirmed by the outcome of the developmental questionnaire. Paternal trait anxiety and parental well-being were not related to the infant's neurodevelopmental outcome.

Conclusions

Infants of mothers with high trait anxiety have an increased vulnerability to develop a non-optimal nervous system. The association may be mediated in part by early programming of monoaminergic systems. Future research should include an exploration of specific windows of vulnerability to maternal anxiety.     

A comparison of executive function in very preterm and term infants at 8 months corrected age

Background

Executive function (EF) emerges in infancy and continues to develop throughout childhood. Executive dysfunction is believed to contribute to learning and attention problems in children at school age. Children born very preterm are more prone to these problems than their full-term peers.

Aim

To compare EF in very preterm and full-term infants at 8 months after expected date of delivery.

Subjects

37 very preterm infants without identified disabilities, and 74 gender and age matched healthy full-term infants. The very preterm infants were all ≤ 32 weeks gestation and < 1250 g birthweight.

Outcome measures

EF tasks which measured working memory, inhibition of distraction, and planning at 8 months after expected date of delivery.

Results

The very preterm infants performed significantly more poorly than the full-term infants on all measures of executive function. No significant differences were found between very preterm and full-term infants on any of potentially confounding variables of, infant temperament, maternal education, family income and maternal psychological wellbeing. Very preterm infants had significantly lower scores on the Mental Development Index (MDI) and Psychomotor Development Index (PDI) on the Bayley Scales of Infant Development (BSID II), however when this was partialled out the differences in EF scores remained. Medical complications, lower birthweight and lower gestation age were all found to adversely affect the performance of very preterm infants on executive function tasks.

Conclusion

Very preterm infants performed more poorly than full-term infants on measures of EF. Further follow up studies are required to investigate whether EF measures in infancy can predict learning and attention outcome at school age.     

Amplitude-integrated electroencephalographic activity is suppressed in preterm infants with high scores on illness severity

Background

The neonatal acute physiology score, SNAP-II, reflects the severity of illness in newborns. In term newborns, amplitude integrated EEG (aEEG), is depressed following asphyxia. In preterm infants aEEG is discontinuous, and therefore more difficult to assess compared to term infants.

Aims

Our first aim was to investigate whether assessing aEEG amplitudes by calculating amplitude centiles was consistent with assessment by pattern recognition. Our second aim was to investigate whether the aEEGs of preterm infants were influenced by SNAP-II.

Study Design and Subjects

We recorded aEEGs in 38 infants with a mean gestational age of 29.7 weeks (26.0-31.8 weeks) during the first five days of life. The mean recording time was 130 min. The aEEGs were assessed by pattern recognition, by calculating Burdjalov score, and by calculating the mean values of the 5th, 50th, and 95th centiles of the aEEG amplitudes. Illness severity was determined within the first 24 h.

Results

We assessed 151 recordings and found strong correlations between the 5th and 50th amplitude centiles and the Burdjalov scores (r = 0.71, p < 0.001 and r = 0.47, p < 0.001, respectively). The 5th and 50th amplitude centiles correlated with SNAP-II (r = − 0.34, p < 0.0001 and r = − 0.27, p = 0.001). These correlations were the strongest on the first day of life (r = − 0.55, p = 0.005 and r = − 0.47, p = 0.018, respectively). The 5th and the 50th amplitude centiles were best predicted by gestational age, SNAP-II, and low blood pressure.

Conclusions

Severe illness as measured by the SNAP-II, and low blood pressure had a negative influence on the aEEGs of preterm infants.     

A patient care system for early 3.0 Tesla magnetic resonance imaging of very low birth weight infants

Background

Very low birth weight (VLBW) infants (weight < 1500 g) are increasingly cared for without prolonged periods of positive pressure ventilation (PPV).

Aims

To develop a system for 3.0 T magnetic resonance (MR) image acquisition from VLBW infants who are not receiving PPV, and to test the clinical stability of a consecutive cohort of such infants.

Design

Seventy VLBW infants whose median weight at image acquisition was 940 g (590-1490) underwent brain MR imaging with the developed care system as participants in research. Twenty infants (29%) received nasal continuous positive airway pressure (nCPAP), 28 (40%) received supplemental oxygen by nasal cannulae, and 22 (31%) breathed spontaneously in air during the MR examination.

Results

There were no significant adverse events. Seventy-six percent had none or transient self-correcting oxygen desaturations. Desaturations that required interruption of the scan for assessment were less common among infants receiving nCPAP (2/20) or breathing spontaneously in air (2/22), compared with those receiving nasal cannulae oxygen (13/28), p = 0.003. Sixty-four (91%) infants had an axillary temperature ≥ 36 °C at completion of the scan (lowest 35.7 °C), There was no relationship between weight (p = 0.167) or use of nCPAP (p = 0.453) and axillary temperature < 36 °C. No infant became hyperthermic.

Conclusion

VLBW infants who do not require ventilation by endotracheal tube can be imaged successfully and safely at 3.0 T, including those receiving nCPAP from a customised system.     

Low Apgar score without acidosis may indicate neuromuscular disorder

Objective

We hypothesized that in term infants low Apgar score with normal umbilical artery pH (UApH) indicates prenatal damage to the neuromuscular system.

Study design

Retrospective database search of 42,117 liveborn infants born 1993—-2005. Medical record analysis of 3104 term infants with cardiorespiratory maladaptation referred for special neonatal care. Focus on infants with UApH > 7.00 and 5-min Apgar < 6 (group A, n = 74), UApH < 7.00 and 5-min Apgar > 5 (group B, n = 49), and UApH < 7.00 and 5-min Apgar < 6 (group C, n = 14).

Results

Incidence of 5-min Apgar score < 6 was 0.50% in term infants. Mean (SD) UApH was 7.262 (0.075, P = 0.075); incidence of UApH < 7.00 was 0.30% in term infants. Nucleated red blood cells were elevated without differences in all three groups. Parental consanguinity was present in 39 of the 137 maladapted infants. In groups A/B/C, 10/18/2 infants were small for gestational age (P = 0.002 for A vs B) and in 16/1/0 neuromuscular anomalies were identified (P = 0.004 for A vs B). Eight of the 17 anomalies had been suspected prenatally. Logistic regression proved neuromuscular disorder the only independent variable discriminating between groups A and B.

Conclusions

Neuromuscular problems are the cause rather than the result of maladaptation. For unexplained low Apgar score, especially without acidosis, meticulous examination of the infant including brain imaging and EEG is justified.     

Soluble receptor for advanced glycation end products (sRAGE) in tracheobronchial aspirate fluid and cord blood of very low birth weight infants with chorioamnionitis and funisitis

Background

A systemic fetal inflammatory response, reflected by histological funisitis is associated with pulmonary morbidity and increased mortality after premature birth. The receptor for advanced glycation end products (RAGE) is a membrane-bound multiligand receptor with a key role in inflammation. Soluble RAGE (sRAGE) is created by alternative mRNA splicing or shedding of the receptor's extracellular domain and can inhibit RAGE-activation.

Aims

To assess the association of funisitis with airway and systemic concentrations of sRAGE in very premature infants.

Methods

Forty-two ventilated infants (gestational age: 27.4 ± 1.8 weeks, birth weight: 1017 ± 229 g [mean ± SD]) were studied. sRAGE concentrations were measured in tracheobronchial aspirate fluid (TAF) on days of life 1, 3, 5, 7 and 10 and in umbilical cord serum of 28 infants by ELISA. The secretory component for IgA (SC) served as reference protein in TAF. Placental tissue, membranes and umbilical cords were examined microscopically to distinguish three groups: chorioamnionitis (n = 9), funisitis (n = 17) and controls (n = 16).

Results

The funisitis group had lower sRAGE concentrations than both other groups in cord blood serum (median: 0.52 ng/ml [25th-75th centile: 0.32-0.91]; control, 1.72 [1.02-2.69]; chorioamnionitis, 1.44 [0.92-1.63], p < 0.01) and TAF on day 1 (290 ng/ngSC [140-400]; control, 2750 [1470-28920]; chorioamnionitis, 2150 [1220-7140], p < 0.01). sRAGE in TAF remained lower in the funisitis than in the chorioamnionitis group on days 3 and 10, p < 0.01 respectively.

Conclusions

Decreased sRAGE in airways and circulation after funisitis may contribute to an imbalance between pro- and anti-inflammatory factors priming very premature infants for pulmonary injury and increasing the risk of adverse outcome.     

Is term newborn body composition being achieved postnatally in preterm infants?

Background

The American Academy of Pediatrics (AAP) recommends that preterm infants' growth duplicates fetal growth rates and that body composition replicates in utero body composition.

Aims

To compare the total body fat mass between preterm infants assessed at term corrected age and full-term newborns, and to investigate the effects of gestational age, gender, weight increase, being breast fed on total adiposity.

Study design

Prospective observational study.

Subjects

One hundred and ten preterm infants [mean (SD) gestational age: 29.9 (2.3) weeks; birth weight: 1118 (274) g], and 87 full term [mean (SD) 38.6 (1.21) weeks, 3203 (385) g], breastfed infants.

Outcome measures

Growth and body composition by means of a pediatric air displacement system were assessed at term corrected age in preterm infants and on day 3 of life in full term infants.

Results

Weight, length and head circumference were smaller in the preterm group as compared to the term group. Mean (SD) percentage of fat mass in preterm infants was significantly higher as compared to term infants [14.8 (4.4) vs 8.59 (3.71), P < 0.0001]. Fat mass was negatively correlated with gestational age (P < 0.001), and positively associated with weight increase (P < 0.05).

Conclusions

Our data suggest that body composition, in terms of fat mass, in preterm infants at term corrected age is different from that of full term newborns.     

Functional impairments at school age of preterm born children with late-onset sepsis

Background

Late-onset sepsis is a relatively common complication particularly of preterm birth that affects approximately a quarter of very low birth weight infants.

Aim

We aimed to determine the motor, cognitive, and behavioural outcome at school age of preterm children with late-onset sepsis compared to matched controls.

Study design and subjects

A prospective case-control study that included preterm infants (gestational age < 32 weeks and/or birth weight < 1500 g) admitted to our Neonatal Intensive Care Unit in 2000-2001 with a culture-proven late-onset sepsis, and controls matched for gestational age.

Outcome measures

At school age we assessed motor skills, intelligence, visual perception, visuomotor integration, verbal memory, attention, executive functioning, and behaviour.

Results

At 6-9 years, 21 of 32 children with late-onset sepsis (68%) had borderline or abnormal motor outcome with most problems in fine motor skills. Their total IQ was 89 compared to 98 in controls. In addition, verbal memory and attention were affected compared to controls (0.61 standard deviations (SD), 95% confidence interval (CI) 0.04-1.17, p = 0.033 and 0.94 SD, 95% CI 0.32-1.62, p = 0.011, respectively). Multiple episodes of sepsis and gram-negative sepsis were risk factors for worse cognitive outcome.

Conclusions

At school age, a majority of preterm children with late-onset sepsis had motor problems. Their IQ was considerably lower than matched controls, and memory and attention were specifically impaired. Outcome at school age of preterm children with late-onset sepsis was worse than previously thought.     

Increased expression of matrix metalloproteinase-9 and hepatocyte growth factor in the cerebrospinal fluid of infants with posthemorrhagic hydrocephalus

Background

In approximately 60% of infants with posthemorrhagic hydrocephalus (PHH), ventricular dilation resolves by unknown intrinsic mechanisms, without the need for a shunt operation. A pathological hallmark of PHH is extensive deposition of extracellular matrix (ECM) proteins in the subarachnoid space. Our previous study revealed that matrix metalloproteinase (MMP)-9, which degrades ECM proteins, may play an important role in the resolution of ventricular dilation. MMP-9 is known to be induced by hepatocyte growth factor (HGF) in various cell lines.

Aims

The aim of this study is to confirm our earlier finding that MMP-9 contributes to the resolution of PHH, and to investigate whether HGF also contributes to this process.

Study design

Cerebrospinal fluid (CSF) samples were collected from 13 infants who developed ventricular dilation after intraventricular hemorrhage (IVH). Of these infants, 9 exhibited resolution of ventricular dilation without shunt operation; however, 4 infants had to be treated with shunt operation. The CSF levels of MMP-9 and HGF were measured using an enzyme immunoassay.

Results

Significantly higher CSF levels of MMP-9 and HGF were detected in patients in whom the ventricular dilation resolved without shunt operation than in those with progressive ventricular dilation (MMP-9: median, 128 ng/ml; range, 47-900 ng/ml vs median, 50 ng/ml; range, 12-110 ng/ml; p < 0.05; HGF: median, 2.42 ng/ml; range, 0.81-7.04 ng/ml vs median, 1.42 ng/ml; range, 0.67-3.87 ng/ml; p < 0.05).

Conclusions

Our results indicate that MMP-9 and HGF may participate in the resolution of ventricular dilation following IVH.     

Infant head circumference growth is saltatory and coupled to length growth

Background

Rapid growth rates of head circumference and body size during infancy have been reported to predict developmental pathologies that emerge during childhood.

Aims

This study investigated whether growth in head circumference was concordant with growth in body length.

Subjects

Forty infants (16 males) were followed between the ages of 2 days and 21 months for durations ranging from 4 to 21 months (2616 measurements).

Study design

Longitudinal anthropometric measurements were assessed weekly (n = 12), semi-weekly (n = 24) and daily (n = 4) during home visits. Individual head circumference growth was investigated for the presence of saltatory patterns. Coincident analysis tested the null hypothesis that head growth was randomly coupled to length growth.

Results

Head circumference growth during infancy is saltatory (p < 0.05), characterized by median increments of 0.20 cm (95% confidence interval, 0.10-0.30 cm) in 24-h, separated by intervals of no growth ranging from 1 to 21 days. Daily assessments identified that head growth saltations were coupled to length growth saltations within a median time frame of 2 days (interquartile 0-4, range 1-8 days). Assessed at semi-weekly and weekly intervals, an average 82% (SD 0.13) of head growth saltations was non-randomly concordant with length growth (p ≤ 0.006).

Conclusions

Normal infant head circumference grows by intermittent, episodic saltations that are temporally coupled to growth in total body length by a process of integrated physiology that remains to be described.     

Hypothalamic-pituitary-adrenal (HPA) axis function in 3-month old infants with prenatal selective serotonin reuptake inhibitor (SSRI) antidepressant exposure

Background

Prenatal exposure to stress and selective serotonin reuptake inhibitors (SSRIs) alter hypothalamic-pituitary-adrenal (HPA) stress reactivity in offspring, however, the effects of combined exposure to HPA activity in human infants is unknown.

Objective

To examine HPA basal levels and stress responsiveness in 3-month olds with prenatal exposure to SSRIs.

Methods

Salivary cortisol levels in infants of SSRI treated mothers (n = 31, mean exposure 230.2 ± 72.2 days) were compared with non-SSRI exposed (n = 45) infants in response to a challenge (infant-controlled habituation task) and under basal conditions in the late afternoon/early evening. Mode of feeding, to account for possible postnatal drug exposure via breast milk, as well as measures of pre and postnatal maternal mood, were included as covariates.

Results

Lower post-stress cortisol levels were observed in non-SSRI exposed/non-breastfed infants compared with non-SSRI exposed infants who were breastfed at 3 months of age. Stress reactivity patterns among SSRI exposed infants did not differ with mode of feeding. The cortisol reactivity slope (CRS) was significantly lower among non-SSRI exposed non-breastfed infants compared with non-SSRI exposed breastfed infants. Early evening basal cortisol levels were lower in SSRI exposed infants than in non-SSRI exposed infants, controlling for maternal mood and mode of feeding. Postnatal SSRI exposure (infant SSRI drug levels) via breast milk was not associated with stress or basal cortisol levels. Total cortisol, reflected by the AUC measure, did not differ significantly between exposure groups.

Conclusions

Prenatal SSRI exposure altered HPA stress response patterns and reduced early evening basal cortisol levels. Stress challenge HPA response differences only became apparent when the moderating effect of method of feeding was accounted for. These findings suggest an early “programming” effect of antenatal maternal mood, prenatal SSRI exposure and postnatal maternal care giving on the HPA system.     

Comparison of salivary cortisol, heart rate, and oxygen saturation between early skin-to-skin contact with different initiation and duration times in healthy, full-term infants

Background

There are few studies that compare the physiological and biological efficacies between different early skin-to-skin contacts (SSC) post birth.

Aim

To investigate physiologically and biochemically how early SSC with different initiation and duration time influence the stress post birth for full-term infants.

Study design

Non-experimental study.

Subjects

Study I; Thirty-two infants who began SSC 5 min or less [birth SSC, mean initiation time (standard deviation): 1.6 (1.1) min] after birth and 36 infants who did so more than 5 min [very early SSC, 26.3 (5.0) min] in heart rate (HR) and oxygen saturation (SpO₂) analysis. Study II; Eighteen infants who underwent SSC for 60 min or less [mean initiation time: 7.5 (12.2) min] and 61 infants who did so for more than 60 min [15.3 (12.5) min] in salivary cortisol analysis.

Outcome measures

HR and SpO₂ measured for 30 min post birth. Salivary cortisol concentration measured at 1 min, 60 min, and 120 min post birth.

Results

Birth SSC group reached HR stability of 120-160 bpm significantly faster than very early SSC group by Kaplan-Meier analysis (P = 0.001 by log-rank test). As for SpO₂ stability of 92% and 96%, no significantly between-group difference was found. Salivary cortisol levels were significantly lower between 60 and 120 min after birth in SSC group, continuing for more than 60 min compared with SSC group for 60 min or less after adjustment for salivary cortisol level at 1 min besides the infant stress factors (P = 0.046).

Conclusions

Earlier SSC beginning within 5 min post birth and longer SSC continuing for more than 60 min within 120 min post birth are beneficial for stability of cardiopulmonary dynamics and the reduction of infant stress during the early period post birth.     

The influence of extrauterine life on the aEEG maturation in normal preterm infants

Objective

To study, the maturational changes of the amplitude-integrated electroencephalogram (aEEG) in preterm infants without neurological disorders and especially the influence of the duration of extrauterine life, over this process.

Methods

96 preterm infants, 25-34 weeks' gestational age (GA) at birth, clinically stable and without ultrasonographic evidence of neurological abnormalities, were studied. The aEEG recordings were obtained within 72 h of life and then weekly until discharge. Four aspects of each tracing (continuity, sleep-wake cycling, bandwidth, and lower border), were evaluated by visual analysis, applying pre-established criteria.

Results

We analysed 624 aEEG recordings at postmenstrual age (PMA) of 25-42 weeks. With advanced GA the aEEG becomes more continuous (p: 0.022), it displays definite sleep-wake cycles (p: 0.011), and its bandwidth acquires the mature pattern (p: 0.012). A positive significant interaction of GA and PMA in the evolution of aEEG was found regarding continuity (p: 0.002), sleep-wake cycling (p: 0.002), and bandwidth (p: 0.02).

Conclusion

The evolution of the aEEG tracing depends on both GA and PMA. The older the infants at birth the more mature the aEEG pattern. At the same PMA, preterm infants of lower GA display an advanced maturation of the aEEG comparing with others of higher GA.