Ovitrelle is Human Chorionic Gonadotrophin which is HCG. This the hormone that pregnancy tests look for as it is the hormone produced in the first trimester of pregnancy. Because the injection is HCG then you will not be able to differentiate between injected HCG and hormonal. So I am afraid that yes, using Ovitrelle could give a false positive pregnancy test. Depending when the IVF occurred, you could ask you doctors to take a blood sample as once pregnancy occurs the HCG levels should rise markedly. But this may be a few weeks after implantation. Your doctors will also use ultrasound to confirm pregnancy too.
Does this help?