The association of serum 25-hydroxyvitamin D levels with early neonatal morbidity and mortality in late preterm infants monitored in the neonatal intensive care unit

Objective: We aimed to determine the association of serum vitamin D levels with early neonatal mortality/morbidity in late-preterm (LP) infants (born between 34 0/7 and 36 6/7 weeks of gestational age) monitored in the neonatal intensive care unit (NICU). Patients and Methods: This retrospective study was conducted by reviewing live -born LP neonates from singleton pregnancies. The infants were monitored and treated in our hospital's NICU between June 2016 and June 2019. Results: Maternal age at delivery was higher among infants with adequate vitamin D levels than among those with deficient vitamin D levels (P=0.007). A weak positive correlation was found between maternal age at childbirth and neonates' vitamin D levels (r=0.296). The rate of low -birth -weight deliveries was greater in babies with sufficient vitamin D levels than in those with deficient levels. There was a weak negative association between the number of stools on the day that the infants' serum 25-hydroxyvitamin D (25-OHD) levels were taken and their vitamin D level (P=0.027, r=-0.244). Conclusions: A significant correlation was shown between serum 25-OHD levels and maternal age and low birth weight in LP neonates. Upon examining the influence of vitamin D levels on the number of defecations per day, no significant difference was detected; however, a weak negative association was identified between them.