Congrats Mrina!
Couldn't really find a def answer online, just that I'm not the only one who has ever passed a hard clot. Eewww. One site said it was an old clot. Idk. It's almost like sth encapsulated. It seemed more common after miscarriages, but with my so far way too short LP I doubt there was even a chance of a chemical. I have a checkup at my OBGYN at the end of the year an if I remember I'll ask and update.