Why does the utrogestan vaginal suppositories state on side effects it can cause blood clots, stroke, heart attack etc? the dr told me it was a natural progesterone and i'd be safe using it. now i'm terrified. how likely is this to happen?

If there is any risk at all, no matter how small, regulatory agencies require medication packaging to include such warnings. There's probably no higher than one chance in a million you'll have such a complication. Follow your doctor's advice without worry!

The main ingredient of utrogestran is progesterone which may cause the noted side effects but not common. However, you should be aware of any side effect when using a medication but you should not be terrified. The benefits are outweighing the risks for the indication and that is why this medication is approved for use. Good luck.