If you are seeing Dr S I know he is reluctant to begin clexane from a bfp. He also told me to commence after "fetal hearbeat has been seen" at 6ish weeks.

I too have done a lot of study on this - the risks outweigh the benefits imo of beginning the clexane at a bfp. My obs was also of the opinion that it should be commenced from bfp. Some even commence it during the luteal phase.

The placenta begins to form at conception - or at least the framework for it does. It can be argued that this is good enough reason. That was my reasoning anyway.

I would plead and beg cry and put on a tanty. This is your body, your baby, your call.