Hello and welcome to HCM.
Thank you for your query.
It is just a measure for risk prevention, and also to avoid contamination. As you will be entering a sterile operating theater, all foreign objects can cause a contamination and thus result in an infection. This cannot cause an abortion
in itself, it can lead to contamination.
This is the only reason why an individual taken into the OT is taken in a sterile robe, and is asked to remove everything he/she is wearing. The surgeons will have to decide what has to be done in your case, they will either have to take special care and precautions to decontaminate these piercings of yours, or take them out before starting the procedure.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you.