Fetal growth restriction: From Polyvagal theory to developmental impairments?

Differential fetal growth rates mediated by sociodemographic factors in Yucatan, Mexico: an epidemiological study

BACKGROUND

Fetal growth restriction (FGR) may be related to ethnicity. Additionally, ethnic groups experience adverse socioeconomic circumstances that increase FGR risk. However, the dearth of evidence of the interaction between socioeconomic factors and FGR highlights the need for additional research.

OBJECTIVE

To analyze the association between socioeconomic factors and FGR in Maya and non-Maya populations in Yucatan, Mexico.

METHODS

A total of 21,320 singleton births in 2017 in Yucatan were analyzed. The student's t-test and the chi-square test were used to compare the means and proportions of maternal and perinatal variables between the FGR group and the birthweight appropriate for gestational age (AGA) group. Path analysis was performed to identify the direct and indirect effects of socioeconomic factors on FGR and mediators between predictors and FGR.

RESULTS

The prevalence of FGR at birth was 9.06%; this rate was higher in the Maya population (12.4, 95% CI 11.3-13.5), without differences between socioeconomic levels. Path analysis revealed sociostructural variables (ethnicity and poverty) are reliable predictors of FGR at birth mediated by maternal education (β = -.152, p < .001) and teenage pregnancy (β = .065, p = .037). The proposal path model had a good fit index CFI = .968, TLI = .920, RMSEA = .046.

CONCLUSION

The prevalence of FGR was higher among Maya women than non-Maya women The socioeconomic conditions associated with FGR at birth were ethnicity, poverty, maternal education, and teenage pregnancy. Maternal education and teenage pregnancy act as mediators between sociostructural variables and FGR at birth.

A Review on the Vagus Nerve and Autonomic Nervous System During Fetal Development: Searching for Critical Windows

The autonomic nervous system (ANS) is one of the main biological systems that regulates the body's physiology. Autonomic nervous system regulatory capacity begins before birth as the sympathetic and parasympathetic activity contributes significantly to the fetus' development. In particular, several studies have shown how vagus nerve is involved in many vital processes during fetal, perinatal, and postnatal life: from the regulation of inflammation through the anti-inflammatory cholinergic pathway, which may affect the functioning of each organ, to the production of hormones involved in bioenergetic metabolism. In addition, the vagus nerve has been recognized as the primary afferent pathway capable of transmitting information to the brain from every organ of the body. Therefore, this hypothesis paper aims to review the development of ANS during fetal and perinatal life, focusing particularly on the vagus nerve, to identify possible "critical windows" that could impact its maturation. These "critical windows" could help clinicians know when to monitor fetuses to effectively assess the developmental status of both ANS and specifically the vagus nerve. In addition, this paper will focus on which factors-i.e., fetal characteristics and behaviors, maternal lifestyle and pathologies, placental health and dysfunction, labor, incubator conditions, and drug exposure-may have an impact on the development of the vagus during the above-mentioned "critical window" and how. This analysis could help clinicians and stakeholders define precise guidelines for improving the management of fetuses and newborns, particularly to reduce the potential adverse environmental impacts on ANS development that may lead to persistent long-term consequences. Since the development of ANS and the vagus influence have been shown to be reflected in cardiac variability, this paper will rely in particular on studies using fetal heart rate variability (fHRV) to monitor the continued growth and health of both animal and human fetuses. In fact, fHRV is a non-invasive marker whose changes have been associated with ANS development, vagal modulation, systemic and neurological inflammatory reactions, and even fetal distress during labor.

Habituation Alteration in Infants with Periventricular Echogenicity as an Indicator of Neurocognitive Impairment

Habituation difficulties may suggest neurocognitive impairment. Periventricular echogenicity (PVE) potentially causes subtle damage that poses neuropsychological risk. Habituation was evaluated through heart rate and behavioral states in infants at 36-37 weeks of corrected age between control and PVE groups. PVE infants showed early alertness and abrupt changes in behavioral states. However, the comparison group could better regulate their states. Heart rate was significantly high and remained unchanged in the PVE group but decreased in the control group. Alterations during the habituation paradigm in PVE infants could be early indicators of neuropsychological risk impairment. Scope of early habituation assessment is discussed.