How soon Should you know if your pregnant with an IUD?

Patient: My girlfriend and I had sex in eary dec 2014. She has an Iud. She claims to have had a miscarriage on jan 24 2015 with no previouse indication of pregnancy. Is this possible?

Symptoms: Bleeding and discharge

Doctor: Hi,Thanks for the query.I understand your concern.Usually getting pregnancy while having IUCD is uncommon.But rarely pregnancy can occur due to failure of contraception.Detecting the serum beta hcg levels may help in finding out the possible miscarriage.Take care.