Comparison of Umbilical Cord Serum Vitamin D Levels between Infants with Transient Tachypnea of the Newborn and those without Respiratory Distress

Background: Transient tachypnea of the newborn (TTN) is one of the most frequent causes of respiratory distress in neonates. A relationship has been shown between vitamin D deficiency and respiratory disorders in neonates. This research was carried out to evaluate the serum level of vitamin D in TTN newborns and their mothers compared to the control group. Methods: This case-control research was conducted during 2016-2019 in a general hospital affiliated with Mashhad University of Medical Sciences, Iran. Thirty-four infants with TTN and 82 neonates in the control group as well as their mothers were investigated. The levels of umbilical cord serum vitamin D in infants with TTN and also their mothers were compared to the control group. Results: The mean levels of serum vitamin D in infants with TTN and their mothers were 8.11 4.32 and 12.6 +/- 10.12 ng/mL, respectively (P < 0.001), whereas they were 19.21 +/- 12.71 and 25.96 +/- 16.6 ng/mL in the newborns of the control group and their mothers, respectively (P < 0.001). The mean differences (95% CI) of neonatal and maternal vitamin D level between the two groups were 11.10 (7.92-14.28) and 13.36 (7.90-18.08), respectively. In the TTN group, 100% of the infants had vitamin D levels less than 30 ng/mL (79.4% had severe, 17.6% had moderate and 2.9% showed mild deficiency). However, vitamin D levels lower than 30 ng/mL were observed in 76.4% of the neonates in the control group (28.8% had severe, 31.1% showed moderate and 16.3% had a mild deficiency) (P< 0.001). Conclusion: The serum vitamin D levels of infants with TTN and their mothers were significantly lower than the control group. Therefore, TTN in infants may be reduced through the treatment of vitamin D deficiency in mothers.