Its also, in many ways, more a state rather than federal issue.
For OB's, the main problem is not the lack of a cap on awards, but the absurd statute of limitations they have to deal with. In most states, you have until either the day before or the day after your 18th birthday to file suit against the OB who delivered you. Compare that to other specialties, where the statue is usually 3 to 5 years. (for a foreign object, like a sponge left behind during surgery, its usually 10 years.)
And for all specialties, I would argue that the failure of MD's to police their own profession and get rid of the incompetents and bad apples is the prime reason malpractice insurance costs as much as it does.