Priority of postpartum nursing dx

I am having trouble determining the correct primary NDX for my concept map. These are the two main acute issues.

My pt. urinary output was decreased (200 ml in output from bed time to the end of my shift). Her bladder was distended. She was administered Lasix. She had no pain when urinating, no lady partsl discomfort. Lochia was scant/rubra. I am confused as to which NDX would be appropriate, Urinary retention or Impaired urinary elimination. AEB output

Her temp was elevated (100.4) and she was started on antibiotics. I understand that she is at risk for infection due to prolonged rupture of membranes and prolonged labor (27hr) and csection (incision showed no signs of infection). She would not be discharged until temp was stable for 24 hr. I have risk for infection as NDX.

When considering primary NDX I would say that "risk for" should not be primary. Is this correct? I am having trouble with priority. Is there something that I am missing here or not understanding? I have researched trying to figure this out but at this point I am just confusing myself. Any input or clarification would be greatly appreciated.

Thank you.