All of this info was given to me by a group of women ObGyns and CNMs that have a practice together in my area and they are brilliant.
*First: Use a second method of birth control during your first month on the pill. Despite the fact that some manufacturers state that you are protected after seven days this does not mean you are protected fully and may still become pregnant. Keep a second method handy all the time and learn to use it well.
*Second: If you miss two pills in a row take both as soon as you remember and then 2 more the next day. You may experience spotting. Use another means of contraception until you finish that package of pills.
*Third: If you miss 3 or more pills in a row chances are high that your ovaries will produce an egg (you will ovulate) and that you may get pregnant. Start using a second method of contraception immediately. Start a new pack of pills the Sunday after you realized you missed 3 or more pills, even if you are menstruating. Use your second method of birth control both while you are off the pills and the first two weeks that you are on your new pack.
*Fourth: If you miss no pills and skip a period, you probably shouldn't worry too much. You may be pregnant. but it is very unlikely. You are fairly safe and can start a new package of pills at the regularly scheduled time.
*Fifth: If you have spotting for 2 or more cycles call your CNM or ObGyn. You may need a slightly stronger pill.
The Two Commandments of the Pill
Commandment 1: If you are on antibiotics use a back up contraception method for the remainder of the cycle.
Commandment 2: If you have become ill and have several days of diarrhea use a back up contraception method for the remainder of the cycle.