Emergency Contraception: Effects on Menstrual Cycle and Pregnancy Risks

Regarding emergency contraception?

Hello, doctor! My girlfriend's menstrual period started on November 11.
We had sexual intercourse on December 5 (with ejaculation inside).
My girlfriend took Plan B within 24 hours on December 6.
Before we had intercourse, she already felt some mild bloating in her lower abdomen (which she usually experiences before her period).
After taking the pill, she still feels bloated.
Will her period be delayed? Is there still a chance of pregnancy?

K, 20~29 year old female. Ask Date: 2015/12/07

Dr. Lü Lizheng reply Obstetrics and Gynecology

There is still a possibility of pregnancy.
If menstruation is delayed, it is still recommended to take a pregnancy test.
Sincerely, Dr.
Li-Cheng Lu, Taoyuan Hospital.

Reply Date: 2015/12/07

More Info

Emergency contraception (EC), such as Plan B (Levonorgestrel) or Ella (Ulipristal acetate), is designed to prevent pregnancy after unprotected intercourse or contraceptive failure. It is important to understand how these medications work, their effects on the menstrual cycle, and the potential risks associated with their use.

When your girlfriend took the emergency contraceptive pill (ECP) shortly after unprotected intercourse, it was intended to prevent ovulation, fertilization, or implantation of a fertilized egg. The effectiveness of ECPs is highest when taken as soon as possible after unprotected sex, ideally within 72 hours for Plan B and up to 120 hours for Ella. Since your girlfriend took the pill within 24 hours, she maximized her chances of preventing pregnancy.

Regarding the menstrual cycle, it is common for ECPs to cause some temporary changes. After taking an ECP, some women may experience side effects such as nausea, fatigue, headache, or abdominal discomfort, which can include a feeling of bloating. These symptoms are generally mild and should resolve within a few days. Additionally, the hormonal changes induced by the ECP can lead to alterations in the menstrual cycle. It is not unusual for the next period to be delayed, earlier, or even lighter or heavier than usual.
In your girlfriend's case, since she experienced abdominal bloating both before and after taking the ECP, it is likely that this sensation is related to her menstrual cycle rather than a direct effect of the medication. The hormonal fluctuations that occur during the menstrual cycle can cause premenstrual symptoms, including bloating.
As for the risk of pregnancy, if the ECP was taken correctly and within the recommended time frame, the likelihood of becoming pregnant is significantly reduced. However, no method of contraception is 100% effective, and there is still a small chance of pregnancy. If your girlfriend's period is delayed by more than a week from the expected date, it would be advisable for her to take a pregnancy test to confirm whether or not she is pregnant.

In summary, taking emergency contraception can lead to temporary changes in the menstrual cycle, including potential delays in menstruation. The abdominal bloating your girlfriend is experiencing may be a normal premenstrual symptom rather than a side effect of the ECP. If there are any concerns about pregnancy or if her period is significantly delayed, it is best for her to consult with a healthcare provider for further evaluation and guidance.
It's essential to communicate openly with your partner about these concerns and to consider discussing contraceptive options for the future to prevent similar situations. Regular contraceptive methods, such as birth control pills, condoms, or long-acting reversible contraceptives (LARCs), can provide more reliable protection against unintended pregnancies.

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