Maternal Noninfectious Fever Enhances Cell Proliferation and Microglial Activation in the Neonatal Rat Dentate Gyrus

Combined spinal-epidural analgesia and epidural analgesia induced maternal fever with a similar timing during labor-A randomized controlled clinical trial

Background

Both epidural and combined spinal-epidural (EA and CSEA) analgesia can induce intrapartum maternal fever. CSEA has a more rapid onset and wider nerve block than EA. Therefore, CSEA might have a different profile of intrapartum maternal fever, including higher temperatures or earlier occurrence. This randomized clinical trial was to determine whether CSEA could cause maternal fever earlier than EA.

Methods

A randomized, double-blind, controlled clinical trial was performed on 233 nulliparous full-term pregnant women during vaginal delivery. The pregnant women were randomly allocated into the EA group (n = 113) and the CSEA group (n = 120). The fever latent period, from analgesia start to fever occurrence, was the primary endpoint in this study. The temperature was measured every 30 min using an eardrum thermometer during labor analgesia. The fever was defined as an eardrum temperature of ≥38 °C.

Results

No difference was found in the maternal fever rate between the EA and the CSEA groups (10/113 vs. 7/120, P = 0.356). There was no significant difference in the fever latent period between the two groups (4.75 ± 0.86 h vs. 3.79 ± 2.2 h, p = 0.305). The temperatures at all points had no differences between EA and CSEA.

Conclusion

CSEA had a similar latent fever period as EA. A further study is warranted to confirm the similar characteristic between CSEA and EA in the development of intrapartum maternal fever.

Clinical trial registration

www.chictr.org.cn, identifier ChiCTR2000038793.

Risk factors of maternal intrapartum fever and the effect of fever duration on neonatal morbidity in different temperature

AIM

To investigate the clinical risk factors of intrapartum fever and explore the relationship between fever duration and neonatal morbidity of different fever peak.

METHODS

A case-control study was conducted, and 714 pregnant women were divided into fever and nonfever group. Multivariable logistic regression model was estimated to evaluate the risk factors for maternal intrapartum fever. Receiver operating characteristic curve was adopted to explore the relationship between fever duration and fetal distress of different fever peak to find the cut-off point, then the neonatal outcomes of women with fever ≥38°C in two groups of different fever duration were compared.

RESULTS

Epidural analgesia (odds ratio [OR]: 6.89, p < 0.001), longer time of membrane rupture (OR: 1.06, p < 0.001) and longer time of first stage of labor (OR: 1.04, p = 0.03) were considered as independent risk factors for maternal fever. For women with temperature <38°C, fever duration was not associated with fetal distress, whereas the women with temperature ≥38°C, fever duration longer than 93.5 min was a good predictor of fetal distress (Area under curve (AUC) = 0.82, p < 0.05). Further analysis showed that infants of women with fever peak ≥38°C and fever duration longer than 90 min had a higher rate of 1 min Apgar score <7 (15.5% vs. 2.2%, p = 0.03), assisted ventilation (29.6% vs. 11.1%, p = 0.02), and admission to neonatal ward (87.3% vs. 60.0%, p = 0.001).

CONCLUSIONS

Epidural analgesia, longer time of membrane rupture, and longer time of first stage of labor were considered as independent risk factors for maternal intrapartum fever. For women with fever ≥38°C, controlling fever time less than 90 min might be helpful to reduce neonatal morbidity.

Fever during pregnancy as a risk factor for neurodevelopmental disorders: results from a systematic review and meta-analysis

BACKGROUND

Fever during pregnancy is a relatively common and most often trivial event. However, under specific conditions, it could affect significantly fetal brain development. Few studies, with inconsistent results, investigated whether fever, regardless the pathogen, could represent a risk factor for neurodevelopmental disorders (NDD) in the offspring. We aimed to explore further this question by performing a systematic review and meta-analysis.

METHODS

Peer-reviewed studies exploring the occurrence of NDD in offspring after a fetal exposure to maternal fever were included. We specifically considered the impact of fever severity and duration, taking into consideration some confounding variables such as the use of antipyretic during pregnancy, the trimester in which the fever arose, the maternal age or smoking at time of gestation. MEDLINE, EMBASE, PsycINFO, Cochrane and Web of Science were searched without language restriction. PRISMA recommendations were followed. Odds ratio (OR) were pooled using random-effects meta-analysis. Heterogeneity in effect size across studies was studied using random-effects meta-regression analysis. (PROSPERO CRD42020182801).

RESULTS

We finally considered ten studies gathering a total of 10,304 children with NDD. Among them, 1394 were exposed to fever during pregnancy. The selected studies were divided into 5 case-control studies and 5 cohort studies. Maternal exposure to fever during pregnancy increased the risk of NDD in offspring with an OR of 1.24 [95% CI: 1.12-1.38]. Secondary analysis revealed an increased risk for NDD when fever occurred during the first trimester of gestation [OR 1.13-95% CI: 1.02-1.26].

LIMITATIONS

We excluded studies that considered infections with no evidence of fever. Another potential limitation may be the possible heterogeneity between study designs (cohorts and case-control).

CONCLUSION

Additional evidence supported the association between fever during pregnancy and increased risk for NDD in offspring. Careful monitoring should be considered for children born from mothers with a febrile episode during pregnancy (specifically during the first trimester).

Regulation of microglia population dynamics throughout development, health, and disease

The dynamic expansions and contractions of the microglia population in the central nervous system (CNS) to achieve homeostasis are likely vital for their function. Microglia respond to injury or disease but also help guide neurodevelopment, modulate neural circuitry throughout life, and direct regeneration. Throughout these processes, microglia density changes, as does the volume of area that each microglia surveys. Given that microglia are responsible for sensing subtle alterations to their environment, a change in their density could affect their capacity to mobilize rapidly. In this review, we attempt to synthesize the current literature on the ligands and conditions that promote microglial proliferation across development, adulthood, and neurodegenerative conditions. Microglia display an impressive proliferative capacity during development and in neurodegenerative diseases that is almost completely absent at homeostasis. However, the appropriate function of microglia in each state is critically dependent on density fluctuations that are primarily induced by proliferation. Proliferation is a natural microglial response to insult and often serves neuroprotective functions. In contrast, inappropriate microglial proliferation, whether too much or too little, often precipitates undesirable consequences for nervous system health. Thus, fluctuations in the microglia population are tightly regulated to ensure these immune cells can execute their diverse functions.