Hi, my fiance missed periods in this months and we are thinking that she got pergnant. Is there any pills that helps to get period or prevent pregnancy?

Start with a test. If you think you might be pregnant check then check a home pregnancy test. They are cheap, reliable and available at any pharmacy.
Yes, but first... Very often a missed period is not due to pregnancy so the first step is to take a home pregnancy test. If positive, it's too late to prevent pregnancy but prescription drugs ru-486 (miprefistone) + Misoprostol are 92% effective in inducing abortion if taken within 5 weeks of a missed period-but it's pricey.See http://www.Ru486facts.Org.