Effects of antenatal magnesium sulfate and corticosteroid therapy on sleep states of preterm infants

Quiet Sleep Organization of Very Preterm Infants Is Correlated With Postnatal Maturation

Background: Sleep is an important determinant of brain development in preterm infants. Its temporal organization varies with gestational age (GA) and post-menstrual age (PMA) but little is known about how sleep develops in very preterm infants. The objective was to study the correlation between the temporal organization of quiet sleep (QS) and maturation in premature infants without severe complications during their neonatal hospitalization. Methods: Percentage of time spent in QS and average duration of time intervals (ADI) spent in QS were analyzed from a cohort of newborns with no severe complications included in the Digi-NewB prospective, multicentric, observational study in 2017-19. Three groups were analyzed according to GA: Group 1 (27-30 weeks), Group 2 (33-37 weeks), Group 3 (>39 weeks). Two 8-h video recordings were acquired in groups 1 and 2: after birth (T1) and before discharge from hospital (T2). The annotation of the QS phases was performed by analyzing video recordings together with heart rate and respiratory traces thanks to a dedicated software tool of visualization and annotation of multimodal long-time recordings, with a double expert reading. Results are expressed as median (interquartile range, IQR). Correlations were analyzed using a linear mixed model. Results: Five newborns were studied in each group (160 h of recording). Median time spent in QS increased from 13.0% [IQR: 13-20] to 28.8% [IQR: 27-30] and from 17.0% [IQR: 15-21] to 29.6% [IQR: 29.5-31.5] in Group 1 and 2, respectively. Median ADI increased from 54 [IQR: 53-54] to 288 s [IQR: 279-428] and from 90 [IQR: 84-96] to 258 s [IQR: 168-312] in Group 1 and 2. Both groups reach values similar to that of group 3, respectively 28.2% [IQR: 24.5-31.3] and 270 s [IQR: 210-402]. The correlation between PMA and time spent in QS or ADI were, respectively 0.73 (p < 10^-4) and 0.46 (p = 0.06). Multilinear analysis using temporal organization of QS gave an accurate estimate of PMA (r ² = 0.87, p < 0.001). Conclusion: The temporal organization of QS is correlated with PMA in newborns without severe complication. An automated standardized continuous behavioral quantification of QS could be interesting to monitor during the hospitalization stay in neonatal units.

Antenatal magnesium sulphate and adverse neonatal outcomes: A systematic review and meta-analysis

BACKGROUND

There is widespread, increasing use of magnesium sulphate in obstetric practice for pre-eclampsia, eclampsia, and preterm fetal neuroprotection; benefit for preventing preterm labour and birth (tocolysis) is unproven. We conducted a systematic review and meta-analysis to assess whether antenatal magnesium sulphate is associated with unintended adverse neonatal outcomes.

METHODS AND FINDINGS

CINAHL, Cochrane Library, LILACS, MEDLINE, Embase, TOXLINE, and Web of Science, were searched (inceptions to 3 September 2019). Randomised, quasi-randomised, and non-randomised trials, cohort and case-control studies, and case reports assessing antenatal magnesium sulphate for pre-eclampsia, eclampsia, fetal neuroprotection, or tocolysis, compared with placebo/no treatment or a different magnesium sulphate regimen, were included. The primary outcome was perinatal death. Secondary outcomes included pre-specified and non-pre-specified adverse neonatal outcomes. Two reviewers screened 5,890 articles, extracted data, and assessed risk of bias following Cochrane Handbook and RTI Item Bank guidance. For randomised trials, pooled risk ratios (RRs) or mean differences, with 95% confidence intervals (CIs), were calculated using fixed- or random-effects meta-analysis. Non-randomised data were tabulated and narratively summarised. We included 197 studies (40 randomised trials, 138 non-randomised studies, and 19 case reports), of mixed quality. The 40 trials (randomising 19,265 women and their babies) were conducted from 1987 to 2018 across high- (16 trials) and low/middle-income countries (23 trials) (1 mixed). Indications included pre-eclampsia/eclampsia (24 trials), fetal neuroprotection (7 trials), and tocolysis (9 trials); 18 trials compared magnesium sulphate with placebo/no treatment, and 22 compared different regimens. For perinatal death, no clear difference in randomised trials was observed between magnesium sulphate and placebo/no treatment (RR 1.01; 95% CI 0.92 to 1.10; 8 trials, 13,654 babies), nor between regimens. Eleven of 138 non-randomised studies reported on perinatal death. Only 1 cohort (127 babies; moderate to high risk of bias) observed an increased risk of perinatal death with >48 versus ≤48 grams magnesium sulphate exposure for tocolysis. No clear secondary adverse neonatal outcomes were observed in randomised trials, and a very limited number of possible adverse outcomes warranting further consideration were identified in non-randomised studies. Where non-randomised studies observed possible harms, often no or few confounders were controlled for (moderate to high risk of bias), samples were small (200 babies or fewer), and/or results were from subgroup analyses. Limitations include missing data for important outcomes across most studies, heterogeneity of included studies, and inclusion of published data only.

CONCLUSIONS

Our findings do not support clear associations between antenatal magnesium sulphate for beneficial indications and adverse neonatal outcomes. Further large, high-quality studies (prospective cohorts or individual participant data meta-analyses) assessing specific outcomes, or the impact of regimen, pregnancy, or birth characteristics on these outcomes, would further inform safety recommendations. PROSPERO: CRD42013004451.

The relationship between micronutrient status and sleep patterns: a systematic review

OBJECTIVE

To review articles on the relationship of dietary and circulating micronutrients with sleep patterns, and to identify issues surrounding implications for future research and public health practice.

DESIGN

A systematic review was conducted. PubMed, Embase and Scopus were searched through January 2016.

SETTING

Both experimental and observational studies were included. However, studies that focused on secondary sleep impairment due to comorbidities were excluded.

SUBJECTS

Individuals in different age groups, from infants to older adults.

RESULTS

A total of twenty-six articles were selected. In the articles reviewed, researchers generally supported a potential role of micronutrients, particularly Fe and Mg, in the development of sleep stages among infants and in reversing age-related alterations in sleep architecture in older adults. Micronutrient status has also been linked to sleep duration, with sleep duration positively associated with Fe, Zn and Mg levels, and negatively associated with Cu, K and vitamin B12 levels. The mechanisms underlying these relationships include the impact of micronutrients on excitatory/inhibitory neurotransmitters and the expression of circadian genes.

CONCLUSIONS

Although the number of studies on the relationship between micronutrient status and sleep remains low, evidence has emerged that suggests a link between dietary/circulating micronutrients and sleep. Future research is needed to investigate the dose-dependent as well as the longitudinal relationships between micronutrient levels and human sleep across populations, test the interactions among micronutrients on sleep outcomes, and ultimately examine the clinical relevance of micronutrients on sleep health.

Newborns' sleep-wake cycle development on amplitude integrated electroencephalography

BACKGROUND

To observe the development of neonatal sleep among healthy infants of different conceptional age (CA) by analyzing the amplitude-integrated electroencephalography (aEEG) of their sleep-wake cycles (SWC).

METHODS

Bedside aEEG monitoring was carried out for healthy newborns from 32 to 46 weeks CA between September 1, 2011 and August 30, 2012. For each aEEG tracing, mean duration of every complete SWC, number of SWC repetition within 12 hours, mean duration of each narrow and broadband of SWC, mean voltage of the upper edge and lower edge of SWC, mean bandwidth of SWC were counted and calculated. Analysis of the correlations between voltages or bandwidth of SWC and CA was performed to assess the developmental changes of central nervous system of newborns with different CA.

RESULTS

The SWC of different CA on aEEG showed clearly identifiable trend after 32 weeks of CA. The occurrence of SWC gradually increases from preterm to post-term infants; term infants had longer SWC duration. The voltage of upper edge of the broadband decreased at 39 weeks, while the lower edge voltage increases and the bandwidth of broadband declined along with the growing CA. The upper edge of the narrowband dropped while the lower edge rised gradually, especially in preterm stage. The width of the narrowband narrowed down while CA increased.

CONCLUSIONS

The SWC on aEEG of 32-46 weeks infants showed a continuous, dynamic and developmental progress. The appearance of SWC and the narrowing bandwidth of narrowband is the main indicator to identify the CA-dependent SWC from the preterm to the late preterm period. The lower edge of the broadband identifies the term to post-term period.

Diffuse white matter injury and neurologic outcomes of infants born very preterm in the 1990s

Neurocognitive outcomes of infants born very preterm (less than 32 weeks gestation) remain a major concern in perinatal practice. Very preterm birth rates have increased, with enhanced survival since 1990. As focal brain lesions become less common, diffuse injury to both gray and white matter is now the primary focus for improving neurologic outcomes in survivors. Recent evidence supports preoligodendrocytes as the principal cellular target of diffuse white matter injury due to their susceptibility to hypoxic-ischemic and inflammatory insults. An understanding of their development and vulnerability can inform acute nursing care of very preterm infants.