Isn’t there a blood test that can be done? I remember my vet doing one when I imported a mare just to confirm she was still pregnant.
Yes there’s certainly a blood test back in Europe and presumably there is one available over here although I have a feeling it’s not 100% accurate??
The blood test was done here in the US. It was accurate for me —> positive.
It was quite a few years ago and I can’t remember what it measured.