Blue Shield and the nurse-midwives.
D054598:Blue Cross Blue Shield Insurance Plans / Q000191:economics*; D005260:Female; D006801:Humans; D007348:Insurance, Health / Q000331:legislation & jurisprudence*; D007349:Insurance, Health, Reimbursement / Q000331:legislation & jurisprudence*; D007357:Insurance, Physician Services / Q000191:economics*; D008880:Midwifery / Q000191:economics; D009721:Nurse Midwives; D010414:Pennsylvania; D011247:Pregnancy