I would like to inquire about birth control pills and ovulation issues?
My last menstrual period started on February 25th, and my cycles are usually very regular, ranging from 32 to 33 days.
I estimated my ovulation date to be March 12th.
I had sexual intercourse on March 18th, but there was no ejaculation inside.
The next day, I immediately purchased emergency contraception (Plan B) and took it (within 24 hours).
I would like to know if I could become pregnant under these circumstances.
Xiao, 20~29 year old female. Ask Date: 2023/03/24
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.
Additionally, the effectiveness of emergency contraception is not 100%, with a failure rate of about 3%.
It is recommended to check for pregnancy if your period is more than a week late.
Thank you! Wishing you peace and health.
Dr.
Chang
Reply Date: 2023/03/24
More Info
When it comes to understanding the effectiveness of emergency contraceptive pills (ECPs) like Plan B (known as Anliting in your case), it's important to consider several factors regarding your menstrual cycle, ovulation, and the timing of the sexual encounter.
Based on the information you provided, your menstrual cycle is typically 32-33 days long, with your last period starting on February 25. This would suggest that your expected ovulation date was around March 12. Since sperm can live inside the female reproductive tract for up to five days, if you had unprotected intercourse on March 18, it would be outside your fertile window, assuming you ovulated around March 12. Therefore, the likelihood of pregnancy from that encounter is relatively low.
You mentioned taking the emergency contraceptive pill within 24 hours after the sexual encounter. ECPs are most effective when taken as soon as possible after unprotected intercourse. They work primarily by delaying or inhibiting ovulation, which means if ovulation has already occurred, the pill may not prevent pregnancy. However, since your ovulation was expected to occur earlier in the cycle, the timing of your intercourse and the subsequent use of the ECP should significantly reduce the risk of pregnancy.
It's also worth noting that ECPs can cause some changes in your menstrual cycle. You might experience a delay in your next period, or it could come earlier than expected. If your next period is more than a week late, it would be advisable to take a pregnancy test to confirm whether or not you are pregnant.
In summary, given your regular menstrual cycle, the timing of your ovulation, and the prompt use of emergency contraception, the chances of becoming pregnant from the encounter on March 18 are quite low. However, if you have any concerns or experience unusual symptoms, it’s always best to consult with a healthcare provider for personalized advice and further evaluation.
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