My period started on 25 oct and ended on 27 and from 30 oct I had unprotected sex so when is the right time to take pregnancy test.. exact date?

When you miss your next cycle.

With first morning urine after your cycle is two weeks late.

I will miss my next period on 25 nov... and if I am pregnant does eating pumpkin cause miscarriage?

No. Eating pumpkin will not cause a miscarriage. It is actually very healthy.