Features of hormonal status in late preterm infants in early neonatal period

• Anastasiya V. Kubyshkina
• Iya I. Logvinona

Abstract

The assessment of the hormonal status in the early neonatal period is a difficult task, since the level of hormones is subject to significant fluctuations depending on the gestational and postnatal age of the newborn, the type of delivery and anesthesia allowance in the mother, birth weight and many other factors. To date, data on the early hormonal response in premature newborns are few and often contradictory. The lack of unambiguous data on the early hormonal response in late preterm infants, on the one hand, and the rapid growth of this group of children, on the other, dictates the need for further research on the hormonal response to birth stress in late preterm infants.

Aim. To determine the features of the hormonal response in the early neonatal period in newborns with a gestation age of 34-36 weeks.

Material and methods. A prospective cohort study was conducted. The study included newborns with a gestation age of 34-36 weeks, born in the maternity Voronezh City Clinical Emergency Hospital No. 10 in the period from 06.2020 to 01.2021. A comprehensive assessment of the course of the period of early adaptation was carried out, the hormonal status of newborns was determined. The level of the following hormones was studied: TSH, T₃, T₄, cortisol. Blood sampling for the study was carried out immediately after birth from the umbilical cord vein and on the 4th day of life from the subcutaneous veins of the head in the morning hours before feeding.

Results. When analyzing the early hormonal response, we were unable to identify the influence of gender and gestational age on the levels of the studied hormones. When conducting a correlation analysis of the relationship between hormonal adaptation and anthropometric indicators, a statistically significant relationship (r_xy=-0.293) between umbilical cord blood T₃ and birth weight was revealed, while the relationship between other indicators of physical development and hormonal adaptation did not reach the levels of statistical significance. In the group of children born by caesarean section, the level of T₄ of umbilical cord blood was higher compared to children born through the natural birth canal. In the group of children where the indications for delivery were from the fetus, there was a lower level of cortisol on the first day and T₃ on the fourth day of life. We were not able to identify a statistically significant effect on the hormonal response in late preterm infants of pregnancy pathology, as well as the therapy carried out in pregnant women, including antenatal prevention with steroids. The relationship between the hormonal adaptation of late preterm infants and the volume of necessary intensive care was determined. Conclusion: The early hormonal response in late preterm infants is significantly influenced by the state of the mother-placenta-fetus system immediately before delivery, the type of delivery. There are close links between changes in the hormonal status and the volume of therapy. The question remains open as to how long the changes in hormonal status are lasting and how they affect the subsequent development of late prematurity.

Keywords:late prematurity, early adaptation, hormonal status, thyrostat, cortisol

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