One of the most expensive parts of having a baby may involve the birth itself, a new Michigan Medicine study suggests.

For some families, average out-of-pocket health care spending for maternity care – including the pregnancy, delivery and three months postpartum – jumped from $3,069 in 2008 to $4,569 in 2015, according to findings published in the January issue of Health Affairs.

And the Affordable Care Act (ACA), which required large, employer-based health plans (used by about 50% of women in the U.S.) to cover maternity care, hasn’t protected families from shouldering a big brunt of costs.

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The reason: while the ACA requires full coverage of preventive services, such as pap smears and mammograms, there are few restrictions on how plans impose co-pays, deductibles and cost-sharing for maternity care.

“We were surprised to learn that the vast majority of women paid for critical health services tied to having a baby,” says lead author Michelle Moniz, M.D.,M.Sc., an obstetrician gynecologist at Michigan Medicine’s Von Voigtlander Women’s Hospital and researcher with the U-M Institute of Healthcare Policy and Innovation.

“These are not small co-pays. The costs are staggering.”

The study included a national sample of 657,061 women enrolled in 84,178 employer-sponsored plans who had been hospitalized for childbirth from 2008 to 2015. Researchers analyzed costs for all health care services used before and after delivery that might influence pregnancy outcomes.

Ninety-eight percent of women were found to be paying some out-of-pocket costs.

Costs of childbirth

Childbirth is a leading reason for hospitalization among women of reproductive age. Not surprisingly, out-of-pocket costs for cesarean sections were higher, with mean total out-of-pocket spending rising from $3,364 in 2008 to $5,161 in 2015 for C-sections compared to an increase of $2,910 to $4,314 for vaginal births.