Switching birth control pills - Pregnancy risks?

Originally Published: July 23, 2004 - Last Updated / Reviewed On: April 14, 2006
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Dear Alice,

I love your site, Alice. It has helped me a lot. I found that no one has asked this on here from what I've seen so far. I was wondering about when you switch birth control pills. I was on Diane 35 and then I switched to Tricyclen, and I was wondering if it was safe to have sex without condoms before waiting for the second month because they are both birth control pills.

Dear Reader,

The level of pregnancy protection when switching to a new type of birth control pill can vary. One of the most important things you can do is call and/or ask your women's health care provider or gynecologist about the risks related to pregnancy when you are being given a new prescription. S/he can provide you with information specific to the brand(s) being prescribed.

In your specific case, the Ortho Tri-Cyclen web page states that when switching from another brand of birth control pills to Ortho Tri-Cyclen, "simply start your new pack of ORTHO TRI-CYCLEN pills the next day after you take your last 'inactive' pill of your previous brand of birth control pills. If you follow these instructions carefully, you should not have to use a back-up method of birth control."

In most cases, there are some general rules to remember when changing birth control pills. When switching from an estrogen and progestin combined oral contraceptive (COC) pill to a progestin-only pill (POP), a woman begins the active POPs the day after she takes her last active combination pill. She does not need to take the inactive COCs and she would not need to use back-up contraception.

When changing from POPs to COCs, some health care providers mention the "rule of seven." This means that if seven days have passed since a woman's last active birth control pill, she will need to use back-up contraception for the first seven days of her new pill's active cycle. Others advise to begin taking the first active COC on the day a woman gets her period. If she follows this recommendation, there is no need to finish the remaining inactive POPs and she would not need any back-up birth control.

When making a change to COCs from other hormonal birth control options, such as the contraceptive patch or ring, the World Health Organization (WHO) states that a woman may start COCs at any time without a back-up method, if she has used the other hormonal methods as directed. However, if a woman's previous method was injectable birth control, such as Depo Provera, she needs to begin using the COCs or POPs when the next shot is scheduled in order to be continually protected from pregnancy.

As the chances of getting pregnant while properly switching between different birth control pills appear small, it can't hurt to use a back-up method, such as a lubricated condom with extra lube. Back-up protection could be used creatively, adding variety and even fun while waiting for the new birth control pills to take effect.

Alice