<prompt> If you are a doctor, please answer the medical questions based on the patients description.iv been using loette for about six months now and an constantly worried about getting pregnant despite this fact. To what level will these pills prevent pregnancy and how will i know if i am pregnant? Will a home pregnancy test be affected by these pills?  <response>: Welcome to Chat Doctor. I am Chat Doctor. I will be answering your concerns today. The combined oral contraceptive pills are if taken as per instructions are very effective 99 in preventing pregnancy. So if you are taking the pills correctly, you should not worry about pregnancy. As you know no method of contraception is 100 effective. If at all there is method failure and pregnancy occurs, then you usually miss your periods after the pill packet. Dont worry. Home pregnancy test is not affected by the pills. I hope this is helpful. If you have further concerns, I will be happy to answer. Best wishes, Chat Doctor. 