Menstrual Delay After Emergency Contraceptive Use

Emergency contraceptive pills can cause a delay in menstruation?

Hello Doctor, my girlfriend took the emergency contraceptive pill (Ella) around January 15.
She got her period on the morning of January 18, with her last period starting on December 20.
We had unprotected intercourse without ejaculation around January 25, and again from February 14 to 17 without ejaculation.
Her average menstrual cycle is 30 days and is relatively regular, but as of February 21, there are still no signs of her period.
According to her cycle, she should have started on February 18, and I am very worried.
Additionally, my girlfriend has not experienced nausea or fatigue, but she does have some frequent urination and mild pain while urinating, which may be due to a urinary tract infection.
I would like to ask if the delay in her period this month could be due to taking the emergency contraceptive pill last month?

nan, 20~29 year old female. Ask Date: 2016/02/21

Dr. Tian Yiwen reply Obstetrics and Gynecology

Without proper contraception, there is a possibility of pregnancy.
Emergency contraceptive pills taken within 24 hours can have about an 80-90% effectiveness rate.
The effects of emergency contraceptive pills on menstruation can vary; some individuals may experience an earlier period, while others may have a delayed one.
If there is concern about the possibility of pregnancy, it is advisable to take a home pregnancy test about 2-3 weeks after the last sexual intercourse.
Symptoms such as urinary discomfort may indicate a urinary tract infection, and it is important to seek medical attention promptly, as delayed treatment can worsen the infection.

Additionally, for those who engage in regular sexual activity, it is recommended that women consider long-term use of oral contraceptives (which provide optimal contraception) along with the male partner using condoms (to prevent sexually transmitted infections).
This approach protects both partners.
Relying on methods such as tracking safe periods, withdrawal, or solely using condoms are not appropriate contraceptive measures.
Frequent use of emergency contraceptive pills can lead to menstrual irregularities and should only be considered in urgent situations; regular use is not advisable.
By practicing effective pre-coital contraception, there is no need to feel anxious after each sexual encounter.

Reply Date: 2016/02/21

More Info

When it comes to understanding menstrual delays after the use of emergency contraceptive pills (ECPs), such as the "愉婷錠" (commonly known as Plan B or similar), it is essential to consider several factors that can influence a woman's menstrual cycle.
Firstly, ECPs are designed to prevent pregnancy after unprotected intercourse or contraceptive failure. They work primarily by delaying ovulation, preventing fertilization, or inhibiting implantation of a fertilized egg. However, one of the common side effects of taking ECPs is a disruption in the menstrual cycle. This disruption can manifest as a delay in the onset of menstruation, irregular bleeding, or changes in menstrual flow.
In your girlfriend's case, she took the emergency contraceptive on January 15, and her menstrual period started on January 18. This suggests that the ECP was effective in preventing pregnancy from any intercourse that occurred shortly before its use. However, since her average menstrual cycle is about 30 days, she would typically expect her next period around February 18. The fact that she has not had her period by February 21 could be attributed to several factors:
1. Hormonal Disruption: The hormones in emergency contraceptive pills can cause temporary changes in the menstrual cycle. It is not uncommon for women to experience a delay in their next period after taking ECPs, sometimes by a week or more.

2. Stress and Anxiety: Emotional stress or anxiety about potential pregnancy can also affect the menstrual cycle. If your girlfriend is feeling anxious about the possibility of being pregnant, this could contribute to a delay.

3. Underlying Health Issues: Conditions such as polycystic ovary syndrome (PCOS), thyroid disorders, or other hormonal imbalances can also lead to irregularities in the menstrual cycle.
4. Urinary Tract Infection (UTI): You mentioned that your girlfriend is experiencing frequent urination and some discomfort while urinating, which could indicate a urinary tract infection. While a UTI does not directly cause a delay in menstruation, the discomfort and stress associated with it could potentially impact her cycle.

Given these factors, it is plausible that the delay in her menstrual period could be related to the use of the emergency contraceptive pill. However, it is also important to rule out pregnancy, especially since there were instances of unprotected intercourse after the ECP was taken. A home pregnancy test can provide reassurance; these tests are most accurate when taken after a missed period.

If the pregnancy test is negative and her period does not arrive within a week or so, it would be advisable for her to consult a healthcare provider. They can assess her symptoms, including the urinary discomfort, and determine if further investigation is needed.
In summary, while the delay in your girlfriend's menstrual cycle could be related to the use of the emergency contraceptive pill, it is essential to consider other factors such as stress, health issues, and the possibility of pregnancy. Monitoring her symptoms and seeking medical advice if the situation does not resolve will be the best course of action.

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