When U.S. babies die during home births, the cause is most often labor and delivery complications, birth defects or infections, a recent study suggests.
Infant mortality in the U.S. is rare. The death rate for midwife-attended home births was the highest, though, with almost 13 fatalities for every 10,000 deliveries, the study found. That compares with roughly 6 deaths for every 10,000 hospital deliveries by a doctor and about 3.5 deaths for each midwife-attended hospital birth.
While this isn't the first study to find a higher infant mortality rate for home births than hospital deliveries, it offers fresh insight into the causes of these deaths, said lead study author Dr. Amos Grunebaum, director of obstetrics at New York Weill Cornell Medicine.
"This new study for the very first time shows the actual reasons why more babies die in planned home births," Grunebaum said by email. "The main reasons are brain damage, but also infections."
To assess factors that contribute to neonatal deaths in the U.S., researchers examined data on 15.9 million babies born from 2008 through 2012.
All of the infants included in the analysis were from singleton pregnancies, and they were all born at full term and at a normal newborn weight.
Overall, there were 9,297 neonatal deaths during the study, or a mortality rate of about 5.8 babies for every 10,000 deliveries, researchers report in the Journal of Perinatal Medicine.
Babies included in this mortality rate were born alive and died within 27 days of delivery.
Half of the deaths involved congenital abnormalities, or birth defects, the study found.
Among midwife-assisted home births, 39 percent of infant deaths were attributed to problems with labor and delivery. The next most common causes were birth defects, accounting for 30 percent, followed by infections at 12 percent.
The most frequent causes of labor and delivery issues that contributed to neonatal deaths at home were situations that caused brain damage such as oxygen deprivation to the brain or suffocation.
These happened in 2.3 of 10,000 births at home versus 0.21 per 10,000 in hospital midwife deliveries.
With hospital births, congenital defects were the leading cause of infant mortality, accounting for 51 percent of deaths with physician deliveries and 43 percent for midwives.
The findings suggest that women and babies can have a safe midwife delivery in the hospital, Grunebaum said. At home, though, midwives may not have the same level of training or properly screen women to ensure they are unlikely to require medical interventions available only in a hospital, he added.
One limitation of the study is that researchers lacked data on neonatal deaths for situations when women started delivery at home but transferred to a hospital due to complications, the authors note. Deaths in these situations were counted as hospital fatalities, which may have underestimated risks associated with home births, the researchers point out.
Researchers also didn't know why women might have chosen home versus hospital births, which might be influenced by underlying medical conditions that could contribute to the odds of neonatal mortality, the authors also note.
"It is hard to determine exactly why the differences occurred here since we have no idea about the specific risk status or course of labor of the patients," said Erin Wright, a certified nurse midwife at Johns Hopkins School of Nursing in Baltimore who wasn't involved in the study.
Planned home births can have good outcomes for mothers and babies when a well-trained midwife attends the delivery, Wright said by email. But some women, and certain medical conditions, make a hospital birth the safer alternative.
"Having open and honest communications about risk factors can ensure a safer birth," Wright added. "That said, many women choose a home birth because it ensures there will be fewer routine interventions, which have been shown to increase rates of poor outcomes for moms and babies."