A new law could force California health insurers to explain claim den…

When Colleen Henderson’s three-year-old daughter complained of pain while using the bathroom, doctors brushed it off as a urinary tract infection or constipation, common maladies in the potty-training years.

Henderson, however, suspected it could be something worse, and asked for an ultrasound. The doctor and ultrasound technician told her that her insurance provider, UnitedHealthcare, would…