WASHINGTON — Where a woman delivers her baby can make a major difference to her own health – a quality gap that remains largely hidden from mothers-to-be.

A new study comparing hospitals nationwide finds that women who delivered at low-performing facilities suffered more than twice the rate of major complications for vaginal births. For cesarean section deliveries, the disparity was even greater: nearly a fivefold difference, according to the study in Monday’s issue of Health Affairs.

But try to figure out which hospital in your area provides better care and odds are you’ll be frustrated. There’s no comprehensive database that women and their families can rely on to find the best hospitals ahead of time.

That appears to be changing. Spurred in part by the new research, medical groups such as the American Congress of Obstetricians and Gynecologists are working on a consumer-friendly database that will tap clinical information from electronic medical records. That effort could take another three to five years.

Monday’s study comes amid a national effort to improve medical quality, and hopefully reduce costs, by using data to compare care providers. Those lagging usually try to improve. Research-based approaches have been used successfully in other industries.