Fertility clinic & wearing tampons

So I’m on cycle Day 2/my period. Going in tomorrow (Day 3) for cycle monitoring (month 4 at the clinic).

Anyway, my, nurse usually calls me to confirm my appointment but this time they sent an email. So of course I read the whole thing and in it they say, “If you are still on your period, we strongly suggest that you avoid using tampons.”

I know it’s probably a silly question and I can imagine why you wouldn’t want to use them after clearing everything out (HSG, sonohystogram etc.) - but does anyone use tampons while on your period when working with a clinic? Since being at the clinic for the last 4 months I’ve been wearing pads but figured I’d just ask to see and get your thoughts.