Can Taking Emergency Contraceptive After Intercourse Prevent Pregnancy?

If unprotected intercourse occurs during the fertile window and emergency contraception is taken one hour later, the likelihood of pregnancy is significantly reduced. However, if ovulation occurs a week later, there is still a possibility of pregnancy if sperm from the earlier intercourse is still viable. Sperm can live in the female reproductive tract for up to five days. Therefore, while the emergency contraceptive pill is effective, it is not 100% guaranteed to prevent pregnancy if ovulation occurs after the unprotected intercourse?

Hello doctor, I had unprotected intercourse with my girlfriend on August 16, and I realized afterward that her last menstrual period was at the beginning of August, which means it was during her fertile window.
I took emergency contraception (Ella) within an hour, and on August 18, I took another dose because I was still worried.
Today, August 24, my girlfriend said she just ovulated, and she is leaving the country on August 25.
Can we be certain she will not become pregnant, or do we still need to wait for her period to confirm? The day after the intercourse, we visited a gynecologist who advised that if her period does not arrive by August 30, we should schedule a follow-up appointment.
I have already purchased a pregnancy test to take with us abroad, and my girlfriend and I have decided that if her period does not come by August 30, we will book a flight back to Taiwan for a consultation.

Niming, 20~29 year old female. Ask Date: 2017/08/24

Dr. Huang Jianzhong reply Obstetrics and Gynecology

On August 16, I had unprotected intercourse with my girlfriend, and I realized afterward that her last menstrual period was at the beginning of August, which means she was in her fertile window.
I took emergency contraception (Ella) within an hour, and on August 18, I took another pill because I was still worried.
Today, on August 24, my girlfriend mentioned that she just ovulated, and since she is leaving for a trip abroad on August 25, I would like to know if we can be certain that she will not become pregnant, or if we still need to wait for her period to confirm? The day after intercourse, we visited a gynecologist who advised that if her period does not arrive by August 30, we need to return for a follow-up.
I have already purchased a pregnancy test to take with us abroad, and my girlfriend and I have decided that if her period does not arrive by August 30, we will book a flight back to Taiwan for a consultation.
Answer: If her period does not arrive by August 30, a pregnancy test should be taken, and then we can decide whether to book a flight back to Taiwan for a consultation.

Reply Date: 2017/08/24

More Info

Taking emergency contraceptive pills (ECPs), such as Plan B or similar medications, after unprotected intercourse can significantly reduce the risk of pregnancy, but it is not 100% guaranteed. The effectiveness of ECPs is highest when taken as soon as possible after intercourse, ideally within 72 hours, but some formulations can be effective up to 120 hours (5 days) after. In your case, since you took the emergency contraceptive within one hour of intercourse, you maximized your chances of preventing pregnancy.

However, it is important to note that ECPs work primarily by delaying or inhibiting ovulation. If ovulation has already occurred, the effectiveness of ECPs diminishes. You mentioned that your girlfriend indicated she was about to ovulate shortly after your intercourse. If she indeed ovulated before taking the ECP, there is still a possibility of pregnancy, although the chances are reduced due to the timely administration of the emergency contraceptive.

Regarding your specific questions:
1. Can taking emergency contraceptive after intercourse prevent pregnancy? Yes, taking ECPs can significantly reduce the risk of pregnancy if taken promptly after unprotected intercourse. However, if ovulation has already occurred, the effectiveness may be compromised.

2. When can you confirm if pregnancy has occurred? The most reliable way to confirm pregnancy is to wait for the expected menstrual period. If your girlfriend's period does not arrive by the expected date (in your case, by August 30), it would be advisable to take a home pregnancy test or consult a healthcare provider for further evaluation.

3. What should you do if the period does not arrive? If her period is late, taking a home pregnancy test is a good first step. If the test is positive or if there are any concerns, it is essential to seek medical advice promptly. Since you mentioned planning to return to Taiwan for a check-up if her period does not arrive, that is a prudent decision.

In addition to the above, it's important to consider the emotional and psychological aspects of this situation. The anxiety surrounding potential pregnancy can be stressful for both partners. Open communication with your girlfriend about your feelings and concerns is crucial. Additionally, if you find yourselves in similar situations in the future, discussing and planning for contraception ahead of time can help alleviate stress and prevent unintended pregnancies.

Lastly, while emergency contraceptives are a useful option, they should not be relied upon as a regular method of contraception. It is advisable to explore more consistent and reliable forms of birth control, such as hormonal contraceptives, intrauterine devices (IUDs), or barrier methods, to prevent unintended pregnancies in the future.

In summary, while taking emergency contraceptive pills can significantly reduce the risk of pregnancy after unprotected intercourse, it is not foolproof, especially if ovulation has already occurred. Monitoring for the expected menstrual period and using a home pregnancy test if the period is late are the best ways to confirm whether pregnancy has occurred.

Similar Q&A

Emergency Contraceptive Pills: Do They Prevent Pregnancy After Unprotected Sex?

Having unprotected intercourse during ovulation carries a higher risk of pregnancy, even if there was no ejaculation inside. Taking emergency contraception immediately after intercourse can significantly reduce the chance of pregnancy. If you also had unprotected intercourse the ...

Dr. Zhang Kunmin reply Obstetrics and Gynecology
Hello, the questioner: There is a possibility of pregnancy even if ejaculation has not occurred during intercourse, as pre-ejaculatory fluid may contain sperm. The effectiveness of emergency contraception is not 100%, with a failure rate of about 3%, but it is still considered a ...

Can You Get Pregnant After Unprotected Sex? Understanding Risks and Prevention

Having unprotected intercourse, even if ejaculation occurs outside, carries a risk of pregnancy due to pre-ejaculate fluid potentially containing sperm. Since you took emergency contraception (the morning-after pill) within 24 hours after intercourse, it significantly reduces the...

Dr. Lin Wenbin reply Obstetrics and Gynecology
Improper use of condoms, even with the use of emergency contraception, does not guarantee a 100% success rate. It's important to monitor your body; if you miss your period, you should consult a physician for an examination.

Can You Get Pregnant After Taking Emergency Contraceptive Pills?

Your girlfriend took the emergency contraceptive pill last Monday and then again on Friday evening. They had sexual intercourse on Sunday. The first two times, a condom was used, but there was some external friction before penetration. The third time, no condom was used, but ejac...

Dr. Cao Guotao reply Obstetrics and Gynecology
Hello, emergency contraceptive pills should be taken within 48 hours after unprotected intercourse. If you suspect pregnancy, it's best to wait until the likelihood is low and to use preventive measures beforehand. If your period is more than a week late, it is advisable to ...

Can You Get Pregnant After Taking Emergency Contraceptive Pills?

Hello, doctor: On January 1st, the condom accidentally broke during intercourse. I took the emergency contraceptive pill on January 2nd. Today, I acted impulsively and had intercourse again without a condom. Doctor, is there a chance I could become pregnant?

Dr. Tian Yiwen reply Obstetrics and Gynecology
Unprotected intercourse can lead to pregnancy. Emergency contraception is only effective for sexual activity that occurred before taking the medication and does not provide protection for sexual activity afterward. If sexual activity is frequent, it is recommended that women cons...