While studies have found that infants born during hospital off-hours may have a heightened risk of death, the same may not be true of the tiniest preemies cared for at major medical centers, a new study suggests.
A number of studies have found that infants born during night or weekend shifts have a relatively higher risk of dying or suffering complications than those born on weekdays — though the absolute risks among full-term infants is still quite low, regardless of the day or time of day of delivery.
The new study, published in the journal Pediatrics, focused on more than 11,000 very-low-birthweight infants — those newborns most at risk of death or serious complications. All were cared for in neonatal intensive care units at one of 17 major university-affiliated medical centers in the U.S.
Overall, the researchers found no evidence that infants born at night or on the weekend had a heightened risk of death.
Nor were those born in July or August at higher risk — which is a potential issue at academic medical centers because that is the time of year when newly graduated doctors begin working.
In general, it is believed that staffing issues at least partly account for the higher rates of newborn death and complications that past studies have linked to nighttime and weekend deliveries. That is, fewer senior staff are on-site during off-hours, leaving more quick decisions to less-experienced staff.
But the current findings suggest that NICUs at academic medical centers in the U.S. do have adequate staffing round-the-clock, said lead researcher Dr. Edward F. Bell, of the University of Iowa in Iowa City.
"I think for parents this means that you can probably be confident that you will get the same level of care regardless of the timing of birth," Bell told Reuters Health.
He added, though, that while the findings can likely be extrapolated to U.S. academic medical centers in general, it is not clear if they would be applicable to smaller hospitals.
Nor do the findings contradict those of other studies that have found a connection between timing of birth and newborn complications, according to Bell — who noted that those studies have generally looked at newborns overall.
"We looked at a very specialized group of patients — those infants who are most vulnerable," Bell said. In NICUs, he explained, these tiny preemies get a "high level of care that has to be maintained round-the-clock."
The findings are based on 11,137 infants born between 2001 and 2005, all of whom weighed no more than 1,250 grams — or about 2 pounds, 12 ounces.
Overall, about 12 percent died within a week of birth, and 16 percent within the first month of life. The researchers found that infants born in the evening or overnight had no greater risk than those born between 8 a.m. and 5 p.m.
Similarly, the risk was no greater for infants born on the weekend compared with weekdays.
Nor was timing of birth tied to the risks of complications common among very premature infants, such as death of intestinal tissue and abnormal blood vessel development in the eyes that can lead to blindness.
The study was well-conducted, Dr. Gordon Smith, a professor at Cambridge University in the UK who was not involved in the research, told Reuters Health in an email.
He agreed, though, that the findings do not contradict other studies, given the differences in the questions the studies have asked.
Last week, Smith and his colleagues published a study in the British Medical Journal that found higher rates of death from oxygen deprivation during delivery among full-term infants born outside of the "normal working week" — that is, Monday to Friday between 9 a.m. and 5 p.m.
The absolute risks were quite low. Of more than 1 million singleton births in Scotland between 1985 and 2004, the researchers found 539 newborn deaths — a rate of 0.05 percent — with 273 deaths attributed to intrapartum anoxia.
Still, relative to infants born during the normal working day, those born during off-hours had a 70 percent greater chance of dying from intrapartum anoxia.
"Death of a baby due to anoxia in labor at term is seen as a measure of quality of intrapartum care," Smith explained.
He and his colleagues estimate that if the risk of intrapartum anoxia overnight and on weekends could be reduced to the level seen on weekdays, one-quarter of all newborn deaths from the complication could be prevented.
Bell agreed that even where the absolute risks of a complication are small for newborns, it is important to find out whether any changes in hospital organization or procedures can cut the risk.
The connection between off-hours hospital admissions and patients' outcomes is not limited to obstetrics.
Studies have found, for instance, that heart attack and stroke patients admitted overnight or on the weekend have a higher risk of dying than those admitted on weekdays. A similar pattern has been seen among adults admitted to the intensive care unit.