Diagnosis??

I am a nursing student working in a clinic (offering primary health care), and I was just wondering about the following case...

28 year old female came into the clinic with main complaint of lower right-sided abdominal pain. Her last normal menstrual period was 20/5/2011, and she said she is late with her period this month. I saw the patient yesterday (29 June 2011). Also, the patient said she started bleeding on the day she came to the clinic, but a urine test confirmed pregnancy. Urine was bloody as well. So, the registered nurse I was working with, went to the patient and explained all the findings and she decided that the patient need to be transferred to a hospital. On the transfer form the nurse wrote the diagnosis as a "query threatened abortion". Can it be this, and why? Is it associated with one-sided LAP, because I know EP manifests as one-sided pain. Or can it be Ectopic pregnancy this early?

Please help.. what do you need to assess to tell what it is? I know the patient is going to be assesses at the hospital, so she is not in my care anymore, but I woud like to know what the diagnosis might be?

I hope this makes sense!