Effect of phototherapy in preterm infants on growth in the neonatal period.

A total of 120 preterm infants were randomly divided at 24 hr of age into three groups: Group I, controls; Group II, continuous phototherapy for 5 days; and Group III, intermittent phototherapy (12 hr on and 12 hr off) for 5 days. At the end of week 1 80% of the control group regained and surpassed their birth weight as opposed to 44 and 57.6% in the continuous and intermittent phototherapy groups, respectively. In weeks 2 and 3 both phototherapy groups had greater weight gain than the control group. Similar but less marked differences were observed in body lenth and head circumference in the three groups. Data suggest decreased growth during phototherapy with subsequent catch-up in growth during weeks 2 and 3. Differences were less marked between infants on intermittent (rather than continuous) phototherapy and controls. Increased metabolic demands and decreased intestinal absorption during phototherapy may be two of the factors responsible for the observed differences in growth in the three groups.