Childbirth is the leading cause of hospital admission in the U.S., accounting for approximately four million hospitalizations each year. As standard as this procedure is, the prices that each hospital charges are not.
In an effort to understand the huge difference in the cost of having a baby across the U.S., Xiao Xu, assistant professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine and colleagues parsed data on nearly 275,000 low-risk childbirths at 463 hospitals across the country. They found that the cost of maternity stays can vary from as little as $1,200 to as much as $12,000.
The cost of a vaginal delivery ranged from $1,183 to $11,819. For cesarian sections, rates were between $1,249 to $13,688.
The research is published in the journal Health Affairs.
"Childbirth care is very complex" Xu told CBS News. "It's unique in the sense that other conditions in healthcare usually take care of one patient, but childbirth takes care of two so many factors can influence quality and cost."
Estimated facility costs were higher at hospitals with low proportions of childbirths covered by Medicaid, low volumes of childbirths, longer stays, locations in rural areas and having non-federal government or nonprofit ownership.
Researchers also found an association between facilities with higher rates of maternal death and cesarean delivery and higher estimated costs, which runs contrary to the belief that spending more leads to improved outcomes and maintains quality of care.
"We don't know exactly why this is," Xu said. "It could be because hospitals that are doing more interventions need to use more resources or maybe a hospital is spending more because it is trying to improve the quality of care."
All of the factors that the study looked into -- cesarean delivery rate, maternal morbidity rate, length of stay, and general hospital characteristics (teaching status, location, size, and ownership) -- explained only 13 percent of the variation in costs among hospitals. Xu said that continued efforts are needed to identify other factors that could explain the remaining majority of variation in childbirth hospitalization costs.
"Things are not as simple as we hoped," Xu told CBS News. "There's a lot of variation in how hospitals do things, when to intervene, policies to discharge... and there's limited information on what happens during this process."
Xu said that in future studies, she hopes to look into the physician's side of cost and the overall cost for mother and baby among other things in an effort to help lower overall healthcare costs.
"Hospital practices might be an important contributor to the variation in costs, and there may be opportunities for cost reduction," Xu said in a press release. "These may include safely reducing cesarean deliveries, increasing the coordination of care, and emphasizing the value of care through new payment and delivery systems."