We included all infants born at or after 34 weeks gestation who were admitted to the NICU for greater than 24 hours between January 1, 2020, and January 31, 2022. Exclusion criteria included: infants who died, transferred to another facility for higher care, infants with genetic defects or congenital anomalies such as cleft lip or cleft palate, neurological disorders such as encephalopathy, seizures or intracranial hemorrhage, and infants with heart failure.
Each infant’s characteristics including birth parameters were collected as well as APGAR scores, time on respiratory support (invasive and/or non-invasive), length of stay, need for a swallow study, requirement of gastrointestinal tube, and days to full feedings. Infant growth parameters were assessed using the Fenton growth chart. Appropriate for gestational age was documented if birth weight was between 10th and 90th centile, small for gestational age if less than 10th centile and large for gestational age if birth weight was more than 90th centile.
It is important to note that oral feedings are initiated in our NICU only after the infant is off noninvasive respiratory support or requiring ≤ 2 liters per minute of humidified high flow nasal cannula. Noninvasive ventilation includes nasal continuous positive airway pressure, nasal intermittent positive pressure ventilation, and noninvasive neurally adjusted ventilator assist. Any ventilation with an endotracheal tube is considered invasive ventilation. Endotracheal intubation for surfactant administration was not deemed as invasive ventilation.
The date oral feedings were first allowed was considered the first day of oral feeds and full volume oral feedings were defined by the ability of the infant to take 150 mL/kg of current body weight per day. If the infant was exclusively or predominantly breast fed, then the day of full volume oral feeds was determined by weight gain on two successive days. Prior to discharge, an infant should not have required any gavage feeds or gavage supplementation for a minimum of 24 hours. It was also important to verify the infant was gaining weight adequately before discharging home.
When categorizing maternal disease, pregestational diabetes was defined by type 1 or type 2 diabetes diagnosed before pregnancy. This determination was made by the obstetricians and obtained from maternal charts. Gestational diabetes was also determined by the obstetrician and the diagnosis was obtained from maternal charts. Pre-pregnancy body mass index (BMI) was gathered from mother’s first prenatal visit. Hemoglobin A 1 C (HBA1C) was obtained from maternal charts, if available, and is not routinely determined in mothers with gestational diabetes.
All data was collected on RedCap database hosted by University of Missouri. Univariate analysis was performed was performed using GraphPad Prism v10.0.1 (GraphPad Software, Inc., Boston, MA) Continuous variables were analyzed with the Mann Whitney U test and are presented as mean (S.D.) unless otherwise specified. Binomial variables were analyzed with the Chi-Square test and are presented as number (%). Propensity score matching and linear regression analysis were performed using SPSS version 28 (IBM SPSS Statistics, IBM Corporation, Armonk, NY). A p-value of < 0.05 was used to define statistical significance.
Using baby’s sex, gestational age at birth in completed weeks, and anthropometry as independent variables, a 1:1 Propensity Score Matched Dataset was generated. Exact matches were found for 226 babies of mothers with diabetes. Linear regression analysis was run on this matched set of 452 babies to find the variables significantly associated with time to full feeds. Factors clinically considered to be affecting the time to oral feeds were used as independent variables, namely, baby’s sex, gestational age, birth weight, anthropometry, maternal age at delivery and maternal diabetes.
The institutional review board at University of Missouri, Columbia approved this retrospective chart review study.