Postpartum complications

We have a Medicaid patient who is maternity only. She came into our office (urology specialty) with urinary retention with catheter placement which was a complication from the delivery. Since she has maternity only Medicaid, we can't bill her like normal. There are specific code sets to cover this. I know our office has encountered this before but not since I've been doing the coding. Can anyone help me out with this?