Need more information. Why was the u/s done?

Z31.83 may be your only choice here. In the outpatient setting you can't code a "probable" diagnosis as confirmed as you could if she was inpatient and there are no specific code for abnormally rising beta HCG levels. I think this might be a great question for you to submit to the AHA Coding Clinic. https://www.codingclinicadvisor.com/question-submissionI have the same thing. I am not, in anyway, an OB coder. Mine is slightly different tho. My dr says there is a "porbably corpus luteum right ovary. She is status post intrautrine insemination with abnormally rising beta HCG levels. No evidence of intrauterine pregnancy and no definite ultrasound evidence of ectopc pregnancy. Tailed pregnancy and/or ectopic pregnancy can not be excluded and close follow up is recomended. Any help would be appreciated. Thank you in advance.