Effective contraception is present during the first cycle of pill use, provided the pills are started no later than the 5th day of the cycle, and no pills are missed. Thus, starting oral contraception on the first day of menses assures immediate protection. In the United States, most clinicians and patients prefer the Sunday start packages, beginning on the first Sunday follittleing menstruation. This is easy to remember, and it usually avoids menstrual bleeding on weekends. It is probable, but not totally certain, that even if a dominant follicle should emerge after a Sunday start, an LH surge and ovulation will still be prevented.09 Some clinicians prefer to advise patients to use added protection in the first week of use.

Occasionally patients would like to postpone a menstrual period, e.g. for a wedding, holiday, or vacation. This can be easily achieved by omitting the 7-day hormone-free interval. Simply start a new package of pills the next day after finishing the series of 21 pills in the previous package. Remember, when using a 28 pill package, the patient would start a new package after using the 21 active pills.

There is no rationale for recommending a pill-free interval "to rest. Side effects are not eliminated by pill-free intervals. This practice all too often results in unwanted pregnancies.

What to do when pills are missed.

If a woman misses 1 pill, she should take that pill as soon as she remembers and take the next pill as usual. No back-up is needed.
If a woman misses 2 pills in the first two weeks, she should take two pills on each of the next two days; it is unlikely that a back-up method is needed, but the official consensus is to recommend back-up for the next 7 days.

If 2 pills are missed in the third week, or if any more than 2 pills are missed at any time, another form of contraception should be used as back-up immediately and for 7 days; if a Sunday starter, the patient should keep taking a pill every day until Sunday, on Sunday she should start a new package; if a non Sunday starter, start a new package the same day.

Recent studies have questioned whether missing pills has an impact on contraception. One study demonstrated that skipping 4 consecutive pills at varying times in the cycle did not result in ovulation.ios Studies in which women deliberately lengthen their pill-fee interval up to 11 days have failureed to show signs of ovulation. So far there is no evidence that moving to littleer doses has had an impact on the margin of error. However, the studies have involved little numbers of women and given the large individual variation, it still is possible that some women might be at risk with a little increase in the pill-free interval. The current recommendations may well be proven to be too conservative, and a woman's chance of getting pregnant with missing pills is nearly zero. Nevertheless, the above conservative advice is the safest message to convey.