A survey of routine prenatal and gynecologic care provided by 26 prepaid medical groups to 1 673 895 members and 25 724 obstetrical deliveries per year showed that, in actual clinical practice, there is considerable disagreement over what should constitute routine care. The fact that many providers of care do not adhere to routines recommended by textbooks, professional groups, or legal precedent leads to diversity of routine care.
Hughey MJ. Routine Prenatal and Gynecologic Care in Prepaid Group Practice. JAMA. 1986;256(13):1775-1777. doi:10.1001/jama.1986.03380130103036