What you can expect

To use combination birth control pills:

• Consult your health care provider about a starting date. If you use the quick-start method, you can take the first pill in the pack immediately. If you use the Sunday start, you'll take your first pill on the first Sunday after your period starts.

  With either method, use a backup contraception method for the first seven days you take combination birth control pills. If you use the first-day start, you'll take your first pill on the first day of your next period. No backup method of contraception is needed.

• Pick a time to regularly take the pill. Following a routine might keep you from missing a pill and help you take the pill at the same time every day. For example, consider taking your pill when you brush your teeth in the morning.

• Follow your health care provider's instructions carefully. Birth control pills only work if you use them correctly, so make sure you understand the instructions. If you're using conventional combination birth control pills and want to have regular periods, you will take all of the pills in your pack — the active and the inactive ones — and start a new pack the day after you finish your current one.

  If you want to avoid monthly periods, ask your health care provider about how to take the pills and how many active pill packs you can take in a row.

• Be cautious with missed pills. If you miss an active pill, take it as soon as you remember — even if it means taking two active pills in the same day. Take the rest of the pack as usual, and use a backup method of contraception for seven days if you missed your pill by more than 12 hours.

  If you miss more than one active pill, take the last pill you missed right away. Take the rest of the pack as usual, and use a backup method of contraception for seven days. If you've had unprotected sex, consult your health care provider about emergency contraception.

• Don't take breaks between packs. Always have your next pack ready before you finish your current pack.

If you vomit within two hours after taking a combination birth control pill or have severe vomiting and diarrhea for two or more days, proceed as if you've missed a pill.