Procedure

The 280 eligible neonates were identified as falling into 4 subgroups based on breastfeeding status (Figure 1):

Flow chart of included patients.

Group I (control group): Formula supplementation for 0 days (n = 164)

Group II: Formula supplementation for 1 consecutive day (n = 18)

Group III: Formula supplementation for 2 consecutive days (n = 32)

Group IV: Formula supplementation for 3 consecutive days (n = 66)

They were further broken down into categories based on percentage of BWL at each time point: >4.5% at 24 h, >7.5% at 48 h, and >8.0% at 72 h after birth. Neonates were supplemented with 10 ml/kg interventional formula per meal.

The following variables were collected: gender, gestational age, birth BW, BW 24 h after birth (first day), BW 48 h after birth (second day), BW 72 h after birth (third day), delivery methods (normal spontaneous delivery or cesarean section), feeding method (exclusive breastfeeding or breastfeeding combined with formula), BWL rate during the 3 days after birth, daily number of urinations, the daily weight change obtained from the neonatal inpatient record, and bilirubin levels at 72 h after birth. Serum microbilirubin was routinely checked in infants by heel stick for blood sampling using direct spectrophotometric methods at 3 and 7 days after birth. Bilirubin levels were measured using an APEL Model: BR-501 bilirubin meter. Neonates were weighed daily for at least 3, and up to 5, days after birth. Measurements were compared with the first day to identify rates of dehydration and BWL. Gestational age was not analyzed because most infants were born at 39–40 gestational weeks.