Multi-phase pills (biphasic, triphasic, or quadraphasic) have two disadvantages, compared to monophasic pills:

- They can be trickier to take. The more phases in the cycle, the more complicated the instructions are about what to do if you miss a day. Those instructions vary by pill.
- Be careful not to start the next pack late. Except for Natazia, Kariva, and Mircette, all multi-phase pill cycles include seven hormone-free days. Starting the next pack late means more than a week without hormones, making pregnancy more likely. One of the most common ways women become pregnant on the pill is to start the next pack late.

Extended-Cycle, Continuous-Cycle Pills

Extended-cycle pills and continuous-cycle pills mean fewer periods, or even no periods. They include Introvate, Jolessa, Lybrel, LoSeasonique, Seasonale, and Seasonique.

Women may wonder if it’s safe and healthy to skip periods. When a woman isn’t taking oral contraceptives, a menstrual period is necessary after ovulation to shed the lining that’s built up in her uterus.

Any birth control pill, regardless of cycle length, stops ovulation, so the lining of the uterus does not thicken - and there is nothing to shed. So though you do have several planned days of bleeding on most pills, it’s not really a menstrual period.

“Women often refer to the bleeding as menstruation, but in the case of birth control pills, it’s withdrawal bleeding [from the hormone-free interval],” Kaunitz says. “So it’s OK for women using hormonal birth control to bleed less often.”

Longer cycles of pills simply cause this withdrawal less frequently, and many doctors encourage patients to try it.

“For a patient that wants to start birth control pills, I say, ‘And how about we miss periods, too?’ I think that’s appealing to more and more women,” Micks tells WebMD.

But there are some drawbacks:

- You may be more likely to experience breakthrough bleeding than with other types of pills.
- It may be harder to tell if you get pregnant, because you’re having fewer (or no) periods.
- Extended-cycle and continuous-cycle pills are not available in generic form. But doctors often instruct patients on how to adjust generic pills containing seven placebo pills for extended or continuous use. This will require a prescription for more than 12 packs per year.

Pill Safety

Each woman is different and may have different experiences with the various types of birth control pills. Some side effects may include:

- Light bleeding or “spotting” between periods. Spotting may be most common in pills with higher estrogen doses and cycles with higher numbers of active pills.
- Nausea
- Breast tenderness
- Weight gain

But unwanted side effects tend to go away in time, so gynecologists recommend patients stay with a pill for three to six months before quitting because of side effects.

Combination pills may not be right for you if you have:

- Risk factors for blood clots, stroke, or other cardiovascular conditions, such as women over 35 who smoke
- Had liver or breast cancer, although it has no impact on future risk for breast cancer
- Migraines with aura

Remember, although birth control pills make pelvic inflammatory disease less likely, they don’t protect against sexually transmitted infections.

Once you start the pill, be careful with other prescription and over-the-counter drugs. The following medications can interfere:

- Antibiotics
- Certain seizure medications
- Certain HIV medications
- St. John’s wort

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By Dawn Stacey M.Ed, LMHC