The evaluation of cases with hypocalcemia in the Neonatal Intensive Care Unit of Zonguldak Bülent Ecevit University

Neonatal hypocalcemia is one of the most frequently encountered electrolyte disturbances during the newborn period. Although most cases are asymptomatic, when symptoms do occur, they are often nonspecific. Clinically, seizures are the most notable finding due to their potential severity. Nevertheless, even in the presence of seizures, the neurodevelopmental prognosis is generally favorable with timely and appropriate intervention. Therefore, early recognition and, when necessary, treatment of hypocalcemia is of critical importance in preventing potential complications and ensuring complete recovery without sequelae. In this study, the medical records of 2,667 neonates who were admitted to the Neonatal Intensive Care Unit of Zonguldak Bülent Ecevit University Faculty of Medicine between January 1, 2019, and December 31, 2023, were retrospectively reviewed. The frequency of hypocalcemia associated risk factors, laboratory findings, and treatment characteristics were evaluated. A total of 169 infants diagnosed with hypocalcemia comprised the patient group, while the remaining neonates formed the control group. Infants were categorized by gestational age and birth weight as <1800 g preterm, ≥1800 g preterm, and term. Since routine total parenteral nutrition (TPN) is provided in our unit to infants weighing <1800 g at birth, the preterm group was analyzed separately in greater detail. The aim was to identify demographic, clinical, and laboratory parameters associated with the development of hypocalcemia and to determine risk factors that could serve as a guide for early diagnosis. The overall incidence of hypocalcemia was 6.3%. Mean gestational age and birth weight were significantly higher in the hypocalcemic group. Most hypocalcemic infants were term (76.3%), and the incidence of hypocalcemia in this subgroup was 11%. Large-for-gestational-age (LGA) births and male sex were also significantly more frequent in the hypocalcemic group. Total parenteral nutrition support was shown to have a protective effect against hypocalcemia. Maternal age was higher in the hypocalcemic group; however, no significant difference was observed for advanced maternal age. Hyperphosphatemia, hypomagnesemia, hypoalbuminemia, elevated alkaline phosphatase (ALP), hypoglycemia, and both vitamin D insufficiency and deficiency were significantly more common among hypocalcemic infants. Regarding clinical diagnoses, transient tachypnea of the newborn (TTN), asphyxia, seizures, and pneumothorax were more frequent in the hypocalcemic group, whereas respiratory distress syndrome (RDS), sepsis, and indirect hyperbilirubinemia (IHB) were less common. Hypocalcemia predominantly presented in the late neonatal period (63.3%), resolved mostly with short-term (71.9%) and oral (62.7%) therapy, and post-treatment calcium levels returned to normal. Logistic regression analyses were conducted to identify potential risk factors for hypocalcemia. In multivariate analysis, preterm birth, male sex, history of asphyxia, seizures, and pneumothorax emerged as independent risk factors for hypocalcemia, while the presence of RDS, occurrence of sepsis, and TPN support were found to exert a protective effect. The findings indicate that the etiopathogenesis of neonatal hypocalcemia should be addressed from a multifactorial perspective. Although some unexpected results were observed, the study identified important parameters for early diagnosis and prevention strategies. These results may serve as a basis for future large-scale studies.