Intraocular pressure in infants and its association with hormonal changes with vaginal birth versus cesarean section.

To investigate cord arterial blood sample and the relationship between birth stress and intraocular pressure in infants at 5 min after delivery. The IOP measurements were taken using Tonopen-Avia tonometer to 158 newborns (158 eyes) at 5th min after birth, in a university hospital. Cord blood was collected within 3 min after delivery. Intraocular pressure, gender, gestation period, mode of delivery, and birth weight of newborns were noted from medical records. Sixty-two babies were delivered by normal vaginal delivery (NVD) and 96 by cesarian section (C/S). Mean IOP of NVD and C/S groups were 19.56 ± 3.84 and 17.42 ± 3.50, respectively. There was significant difference of mean IOP between two groups. (p < 0.001) There were significant differences between two groups regarding APGAR score (p < 0.001) and cord blood adrenaline (p = 0.003), noradrenaline (p = 0.008), and cortisol (p < 0.001) levels. There was no difference between infant corneal thickness measurements (p = 0.698). In correlation analyses, there is a strong negative correlation between the labor type and postpartum measurements except corneal thickness. Correlation analyses of the 5th min intraocular pressure of the groups individually revealed significant correlation in the NVD group. The conclusion is that the intraocular pressure of newborn infants was higher in NVD delivery compare to C/S. Blood hormonal changes in different anesthesia types and physical stress was thought as the main reason of this result.