CHICAGO (Reuters) - Babies born just a few weeks early are six times more likely to die in their first week of life than full-term babies and three times more likely to die before their first birthday, U.S. researchers said on Monday.
“The extent of the difference is quite surprising,” said Joann Petrini, director of the March of Dimes Perinatal Data Center, whose study appears in the Journal of Pediatrics.
“Regardless of the cause, the death rate was higher for preterm babies. It suggests they are a more vulnerable group,” said Petrini, who collaborated on the study with the U.S. Centers for Disease Control and Prevention.
Late preterm infants are born at 34 to 36 weeks gestation, just shy of the 37-week mark that is considered full-term. They account for 71 percent of all premature births and 12.5 percent of all births in the United States.
Previous studies have shown that babies born from one to three weeks early have a greater risk of breathing and feeding problems, trouble maintaining their body temperature, greater rates of jaundice and problems with brain development.
“Many recent studies have documented that these babies have complications that their full-term counterparts don’t,” Petrini said in a telephone interview.
She said her study was the first to look at death rates in preterm infants nationwide. The researchers evaluated death certificates between 1995 and 2002 in preterm and full-term infants in all 50 states.
“Overall the causes of death ran the spectrum,” Petrini said.
The leading cause of death was birth defects, with preterm infants about four times more likely than full-term babies to die of congenital deformities.
But even excluding these, the rate of death was higher in preterm infants, Petrini said.
“The rates of mortality overall are relatively low, but there is still a difference,” she said.
Other causes of death included sepsis, complications of placenta and other material complications and sudden infant death syndrome.
Petrini said increases in multiple births have helped fuel a rise in late premature babies. “About half of all twins and 90 percent of triplets are preterm,” she said.
She said doctors should use this information when weighing whether to induce delivery or perform a C-section before the baby is full term.
“We know the rate of Caesarean sections and induction of labor is increasing. Thirty percent of all deliveries are C-sections,” she said.
“These are complicated decisions, but we want to make sure this data goes into the mix when making those decisions,” she said. “Even a few weeks can make a difference.”
Editing by Will Dunham and Mohammad Zargham