You've just taken the morning-after pill and you're wondering what's going to happen to your period. Will it come earlier? Later? Will you bleed before your due date? These questions are normal, and you're not alone in asking them. The morning-after pill temporarily disrupts the menstrual cycle in about 60% of cases, but these changes are generally not serious and disappear by the next cycle.
According to clinical studies conducted by the WHO and published in medical journals, the effects on menstruation depend mainly on when you took the pill in your cycle. Taken before ovulation, it tends to shorten your cycle and make your period come earlier. Taken after ovulation, it generally has less impact. In any case, if your period is more than 7 days late, a pregnancy test is essential.
⚡ The direct answer
How the Morning After Pill Works
To understand why the morning-after pill affects your period, you first need to understand how it works. Contrary to popular belief, it's not an abortion pill. It does only one thing: block or delay ovulation with a high dose of hormones.
There are two main types of morning-after pills in France. Norlevo (levonorgestrel 1,5 mg), which works up to 72 hours after intercourse, and EllaOne (ulipristal acetate 30 mg), which is effective for up to 120 hours. Both work by disrupting the hormonal surge that normally triggers ovulation.
The menstrual cycle in brief
Follicular phase (days 1-14) : Estrogen increases, a mature follicle. Around day 14, a surge of LH (luteinizing hormone) triggers ovulation.
Ovulation (around day 14) : The egg is released. This is the fertile window.
Luteal phase (days 14-28) : The corpus luteum produces progesterone to prepare the uterus. If pregnancy does not occur, progesterone drops and menstruation occurs.
The morning-after pill delivers a massive dose of progestin that short-circuits this natural process. It prevents the LH surge, which blocks or delays ovulation. The result: no egg is released, and therefore no fertilization is possible. But this sudden hormonal intervention also disrupts the expected timing of your cycle, hence the disruptions in your period.
When Will Your Period Come After The Pill?
This is THE question everyone is asking. The answer isn't simple because it depends on when you took the pill in your cycle. A study published in Contraception in 2006 and involving 120 women observed the following patterns.
💡 General rule The earlier in the cycle (follicular phase) the pill is taken, the more it tends to shorten the cycle and bring on early periods. The later it is taken (luteal phase), the greater the risk of lateness.
Bleeding between periods (spotting)
About 15% of women who take the morning-after pill experience light bleeding in the days following the pill, even if it is not the time of their normal period. This is called spotting or breakthrough bleeding.
A Cameroonian study published in Contraception In 2006, a study followed 232 women after taking levonorgestrel. The results showed that 14,7% experienced breakthrough bleeding. This bleeding usually occurs between 2 and 7 days after taking the pill.
Spotting or real periods?
Sometimes difficult to distinguish. Here's how to tell the difference:
Spotting : Light bleeding, pinkish or brown in color, lasting 1 to 3 days maximum. Very light flow, light protection is sufficient.
Rules : Bright red bleeding, heavier flow, usual duration of your period (3 to 7 days). Requires normal protection.
If you experience spotting after the morning-after pill, it's not necessarily a sign that the pill worked or failed. It's simply hormonal withdrawal bleeding, due to the upheaval caused by the massive dose of progestin.
How long does the pill delay your period?
If the morning-after pill delays your period, it usually takes between 2 and 7 days. In rare cases, it can be as late as 10-14 days, especially if you took EllaOne (ulipristal) instead of Norlevo (levonorgestrel).
A 2001 British study published in Contraception observed that among women who took levonorgestrel around ovulation, 4 out of 12 had a significant delay in their period, ranging from 8 to 25 days (average 17 days). But beware: these extreme cases are the exception, not the rule.
"Normal" delay vs. worrying delay
Normal delay : Between 2 and 7 days. You can wait a few more days before panicking.
Worrying delay : More than 7 days. Take a urine pregnancy test. If it is negative but you still haven't had your period after 1 month, consult for a blood test.
The delay is explained by the fact that the pill has blocked or delayed ovulation. If ovulation is delayed by several days, the entire luteal phase that follows is also delayed, and therefore the period arrives later.
Heavier or Lighter Periods
Beyond timing, the morning-after pill can also change the appearance and intensity of your period. The Cameroonian study cited above found significant changes in the appearance of menstruation in approximately 20% of women.
These variations are explained by the impact of the progestin on the uterine lining (endometrium). Depending on when the pill was taken in the cycle, the endometrium will be more or less developed at the time of menstruation, which influences the volume of blood evacuated.
Comfortable Protection During Your Period
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No Period 1 Month Later: Should You Be Worried?
If you still haven't had your period a month after taking the morning-after pill, there are two possible scenarios: either the pill failed and you're pregnant, or your cycle is so disrupted that it's taking a long time to restart.
The morning-after pill is not 100% effective. Norlevo has an average effectiveness of 85% (95% if taken within 24 hours, 58% if taken between 48 and 72 hours). EllaOne has an overall effectiveness of around 85%. So yes, there is a risk of pregnancy even after taking the pill.
What to do if you miss your period after 1 month
Step 1 : Take a urine pregnancy test. Wait at least 3 weeks after risky intercourse for beta-hCG levels to be detectable.
Step 2 : If the test is positive, make an appointment with a doctor or midwife to confirm and discuss your options.
Step 3 : If the test is negative but you still don't have a period, consult a blood test (beta-hCG dosage), which is 100% reliable. Hormonal imbalance due to the pill is possible but rare.
Beware of poor-quality urine pregnancy tests. A 2023 survey by the French Directorate General for the Prevention of Fraud (DGCCRF) revealed that 4 out of 10 urine tests have sensitivity abnormalities. Choose reputable brands or request a blood test directly.
Differences Between Norlevo and EllaOne on Periods
The two morning-after pills available in France do not have exactly the same effects on the menstrual cycle. EllaOne (ulipristal acetate) tends to cause more side effects than Norlevo (levonorgestrel), particularly on menstruation.
The choice between Norlevo and EllaOne should not be based solely on the effects on menstruation, but more importantly on the time since unsafe intercourse. Norlevo is effective for up to 72 hours, EllaOne for up to 120 hours. If you are within 72 hours, Norlevo is generally preferable because it is better tolerated.
Other Side Effects to Expect
Beyond menstrual cycle disruptions, the morning-after pill can cause other temporary side effects. A meta-analysis published in 2020 in Clinical Drug Investigation identified the most common side effects.
Common side effects
nausea : 20-25% of women. Taking the pill after a meal limits this effect.
Headaches : 15-18% of cases. Generally mild and disappear within 24-48 hours.
Abdominal pain : Cramps similar to period pain, in about 20% of users.
Tiredness : Feeling of tiredness for 1-2 days.
Tender or painful breasts : 10-12% of women for a few days.
Dizziness : Less common, about 5% of cases.
These effects usually disappear within 24 to 48 hours. If nausea is severe, ginger tea may help. If you vomit within 3 hours of taking the pill, it may not have been absorbed: take another pill quickly.
Does the Morning After Pill Trigger Periods?
No, the morning-after pill does not directly trigger your period. That's not its purpose. Its sole role is to block or delay ovulation. However, by disrupting the natural hormonal cycle, it can indirectly accelerate or delay the onset of menstruation.
Some women mistakenly believe that bleeding after the pill means it worked. False. Hormone withdrawal bleeding (spotting) is not a reliable indicator. The only way to know if the pill worked is if your period arrives or if you have a negative pregnancy test.
💡 To remember Bleeding after the pill doesn't mean it worked. No bleeding doesn't mean it failed. Only your actual period or a pregnancy test will tell you the answer.
Can the Morning After Pill Delay Your Period?
Yes, this is one of the most common side effects of the morning-after pill. About 30 to 40% of women experience a delay in their period after taking hormonal emergency contraception. This delay is perfectly normal and is explained by the pill's mechanism of action.
The morning-after pill blocks or delays the LH (luteinizing hormone) surge that normally triggers ovulation. If you take it just before your expected ovulation, it will delay ovulation by several days or even a week. As a result, the rest of your cycle is delayed, and your period arrives later.
How many days does the pill delay my period?
The delay varies depending on several factors:
Short delay (2-3 days) : Common if you took the pill in the luteal phase (after ovulation) or very early in the follicular phase.
Average delay (4-7 days) : Most common. Occurs when the pill was taken just before or during the ovulation window.
Long delay (8-14 days or more) : Rare but possible. Seen in about 5% of women, especially with EllaOne.
A 2001 British study of women taking levonorgestrel during the peri-ovulatory period showed that 4 out of 12 women experienced a significant delay ranging from 8 to 25 days, with an average of 17 days. But be warned: these extreme cases remain the exception.
Late period after morning-after pill: should you be worried?
A delay of less than 7 days is considered normal and does not require any special action. Patience.
If the delay exceeds 7 days, take a urine pregnancy test to rule out possible failure of the emergency contraception.
If you still haven't had your period after 1 month, consult a doctor for a blood test (beta-hCG dosage) which is 100% reliable.
It's important to note that even if the pill delays your period this month, the next cycle usually returns to normal. Studies show that over 95% of women return to a regular cycle the month after taking the morning-after pill.
⏰ All Causes of Late Period (Not Just Pregnancy) →
Taking the pill during your period
You can take the morning-after pill during your period if you have had unsafe sex at that time. Although the risk of pregnancy is very low during menstruation (especially at the beginning of your period), it is never zero.
Sperm can survive in your uterus for up to 5 days. If you have intercourse at the end of your period (day 5-6) and ovulate early (day 10-11 of a short cycle), fertilization is still possible. The morning-after pill taken during your period will simply delay or block this early ovulation.
Effect on the cycle: Your current period may be slightly longer (1-2 days longer) or have a changed flow. The next cycle will probably be disrupted as well.
How many times can you take it?
Technically, you can take the morning-after pill multiple times in the same cycle if necessary. There are no absolute medical contraindications. But be careful: the more often you take it, the more disrupted your cycle will be.
A study published in 2022 in Contraception showed that women who take the morning-after pill more than twice a year have significantly more irregular cycles in the months that follow. It takes the body longer to return to its natural rhythm.
The morning-after pill is not regular contraception.
It's reserved for emergency situations, such as a broken condom, missing the pill, or unprotected sex. If you need to use it regularly, it's a sign that you need to find a contraceptive that's right for you. Talk to your doctor or midwife.
By the way, if you're on your period and prefer to avoid penetrative sex during this time, there are plenty of other ways to maintain intimacy and pleasure.
Frequently Asked Questions
Your Rules Play Hide and Seek
The morning-after pill temporarily disrupts your menstrual cycle in about 60% of cases. Your period may arrive earlier (if taken early in your cycle), later (if taken late in your cycle), or on your expected date with a changed flow. About 15% of women also experience spotting in the days that follow.
These changes are normal and temporary. They disappear in the next cycle in over 95% of cases. If your period is more than 7 days late, take a pregnancy test. If you still have nothing after 1 month, consult a blood test, which is 100% reliable.
Sources & Scientific References
This article is based on scientific studies published in peer-reviewed medical journals.
- Okewole IA, et al. (2006). Menstrual bleeding patterns following levonorgestrel emergency contraception. Contraception. DOI: 10.1016/j.contraception.2005.08.006
- Raymond EG, et al. (2006). Bleeding patterns after use of levonorgestrel emergency contraceptive pills. Contraception. DOI: 10.1016/j.contraception.2005.08.006
- Brache V, et al. (2008). Levonorgestrel administration in emergency contraception: bleeding pattern and pituitary-ovarian function. Contraception. DOI: 10.1016/j.contraception.2007.11.011
- Okewole IA, et al. (2007). Effect of single administration of levonorgestrel on the menstrual cycle. Contraception. DOI: 10.1016/j.contraception.2007.01.019
- Croxatto HB, et al. (2001). The effects of peri-ovulatory administration of levonorgestrel on the menstrual cycle. Contraception. DOI: 10.1016/s0010-7824(01)00186-5
- Festin MP, et al. (2022). Effect of levonorgestrel emergency contraception on implantation and fertility: A review. Contraception. DOI: 10.1016/j.contraception.2022.01.007
- Leelakanok N, et al. (2020). A Systematic Review and Meta-analysis of the Adverse Effects of Levonorgestrel Emergency Oral Contraceptive. Clinical Drug Investigation. DOI: 10.1007 / s40261-020-00901-x
Footnotes : DOI links provide direct access to original scientific publications.
Medical Warning: This article is for informational purposes only and is not a substitute for professional medical advice. If you have any questions or experience unusual symptoms, consult a doctor, midwife, or pharmacist.
