Early insulin treatments intended to improve health of premature babies failed to boost the survival rate for infants weighing 1,000 g or less, according to a European study published in The New England Journal of Medicine.

Newborns are considered premature when they are delivered prior to 37 weeks of gestation. Premature babies have a higher risk of respiratory problems, neurological diseases, and the risk of early childhood mortality is up to seven times higher for preemies than for babies born at full term with normal birth weight.

Kathryn Beardsall of the University of Cambridge in the United Kingdom and colleagues looked at 195 babies randomized to receive insulin and 194 babies who were given standard neonatal care for the first seven days of life. Those who were put on insulin from birth had a higher risk of death than those who received standard care. Specifically, for those who received insulin, the death risk increased by 12% after just 4 weeks, compared to babies that received standard care.

In a second study, Brenda H. Morris, M.D., of the University of Texas Medical School in Houston and colleagues looked at 1,974 infants with extremely low birth weight at 12 to 36 hours of age who were randomly assigned to undergo either aggressive phototherapy (990 babies) or conservative phototherapy (984). They found that the therapy reduced neurodevelopmental impairment in very low-birth-weight babies, but they were more likely to die if they were given aggressive treatments. For babies under 2 pounds, the risk of death was even higher.

“Aggressive phototherapy may be preferred for infants with birth weights of 751 to 1,000 g, because we found significant neurodevelopmental benefits in this subgroup and no evidence that the therapy increased the rate of death or other adverse outcomes at 18 to 22 months,” the authors write in the study published in the Oct. 30 issue of The New England Journal of Medicine.