Effectiveness of Emergency Contraceptive Pills After Missed Doses

Taking emergency contraception?

Hello doctor, I have been taking the oral contraceptive pill for over six months.
My last menstrual period started on March 14, and the last time I took the pill was on the night of March 20 at 11:00 PM.
I took the first pill of this month on March 18, and I took the pills on the nights of March 18-20 at 11:00 PM.
However, I forgot to take the pills on March 21 and 22, and I didn't take them until the morning of March 23 at 9:30 AM, when I took two pills.
By the time I took the pills on March 23, it had been 58.5 hours since the last dose.
I would like to ask the doctor if the contraceptive effect is still effective under these circumstances.
Thank you.
🙏

Miss Lin, 20~29 year old female. Ask Date: 2023/03/23

Dr. Cao Guotao reply Obstetrics and Gynecology

Hello, it is generally ineffective, and it is recommended to add other contraceptive methods.
Wishing you good health.

Reply Date: 2023/03/23

More Info

When it comes to the effectiveness of emergency contraceptive pills (ECPs) after missed doses of regular birth control pills, there are several important factors to consider. In your case, you have been taking YAZ® (which contains drospirenone and ethinyl estradiol) for over six months and have experienced a missed dose situation.

First, it's crucial to understand how birth control pills work. Combined oral contraceptives like YAZ® are designed to prevent ovulation, thicken cervical mucus, and thin the uterine lining to prevent pregnancy. When taken consistently and correctly, they are highly effective, with a failure rate of less than 1% per year. However, missed doses can compromise their effectiveness.

In your situation, you missed doses on March 21 and 22, and then took two pills on March 23, which was 58.5 hours after your last scheduled dose. According to guidelines for combined oral contraceptives, if you miss one pill, you should take it as soon as you remember and continue taking the rest of the pills at your usual time. If you miss two pills in a row during the first two weeks of your cycle, you should take the last missed pill as soon as you remember, discard the other missed pills, and continue with your regular dosing schedule. However, if you miss two pills in the third week, you should follow the instructions for missed pills or consider using backup contraception.

Since you took two pills on March 23, you have taken steps to mitigate the missed doses. However, because you missed two consecutive pills, your contraceptive effectiveness may have been compromised during that time. The general recommendation is to use a backup method of contraception, such as condoms, for at least seven days after missing pills to ensure protection against unintended pregnancy.

Now, regarding the use of emergency contraceptive pills (ECPs) after missed doses, it is important to note that ECPs are most effective when taken as soon as possible after unprotected intercourse. They can be taken up to 72 hours after the event, but their efficacy decreases the longer you wait. In your case, if you had unprotected intercourse during the time you missed your pills, taking ECPs would be a prudent choice to reduce the risk of pregnancy.

In summary, while you have taken steps to catch up on your missed doses, the effectiveness of your regular birth control may have been compromised due to the missed pills. It is advisable to use backup contraception for at least a week following missed doses. If you had unprotected intercourse during this time, considering the use of emergency contraception would be a wise decision to ensure you are protected against unintended pregnancy. Always consult with your healthcare provider for personalized advice and guidance based on your specific situation.

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