Morning-After Pill Side Effects: Know How Long Do They Last

The morning-after pill can reduce the chance of pregnancy after unprotected sex or contraceptive failure.

Some women experience temporary symptoms after taking it, while others notice no side effects at all.

Nausea, headache, tiredness, dizziness, abdominal discomfort, breast tenderness and changes in vaginal bleeding can occur.

Most reported side effects are mild and settle without specific treatment.

However, the exact duration varies from person to person.

It is also important to separate short-term medication side effects from menstrual changes.

A headache may settle quickly, while the timing or appearance of the next period can remain different for part of the following cycle.

How Long Do Morning-After Pill Side Effects Last?

There is no single number of hours or days that applies to everyone who takes the morning-after pill.

Short-term symptoms such as nausea, headache, dizziness, fatigue and abdominal discomfort generally improve on their own.

Menstrual changes can last longer because they involve the timing and pattern of the menstrual cycle rather than simply a short-lived physical symptom.

The two commonly used oral emergency contraceptive options are levonorgestrel and ulipristal acetate.

Both are generally well tolerated.

The World Health Organization describes nausea, vomiting, slight irregular vaginal bleeding and fatigue as possible side effects and notes that they are usually mild and resolve without further medication (World Health Organization, 2021).

What Side Effects Can the Morning-After Pill Cause?

Not everyone develops symptoms after taking emergency contraception.

When symptoms do occur, they are usually temporary.

The experience can also differ depending on the type of emergency contraceptive used.

Nausea and Vomiting

Nausea can occur after taking the morning-after pill.

It may appear during the first several hours and then gradually settle.

Some women do not experience nausea at all.

Vomiting is more important if it happens soon after taking the tablet because the medicine may not have been completely absorbed.

Current CDC guidance recommends taking another dose as soon as possible if vomiting occurs within 3 hours of taking an emergency contraceptive pill (Centers for Disease Control and Prevention, 2024).

Headache

Headache is another reported side effect.

It may occur during the first day or two and generally improves without specific treatment.

A mild headache that is gradually settling is different from a severe or unusual headache.

The latter should not automatically be attributed to emergency contraception.

Abdominal or Pelvic Discomfort

Some women experience mild abdominal discomfort or cramping.

This can feel similar to menstrual cramps and may settle as the immediate effects of the medication pass.

Severe, persistent or worsening abdominal or pelvic pain requires medical assessment, particularly if pregnancy is possible.

Tiredness or Fatigue

Feeling tired after taking the morning-after pill is possible.

For some women, fatigue is brief.

Others may notice reduced energy for longer.

Stress, poor sleep and anxiety surrounding an episode of unprotected sex can also contribute to tiredness, so not every symptom experienced afterward is necessarily caused by the medication.

Dizziness

Dizziness can occur after emergency contraception.

If you feel dizzy, sit or lie down until you feel steadier and avoid activities where losing your balance could be dangerous.

Persistent dizziness, fainting or significant weakness should be assessed medically rather than assumed to be a normal medication effect.

Breast Tenderness

Some women notice breast tenderness or sensitivity after emergency contraception.

This symptom can overlap with normal hormonal changes during the menstrual cycle.

Therefore, breast tenderness cannot be used to determine whether the emergency contraceptive worked or whether pregnancy has occurred.

Spotting or Irregular Bleeding

The morning-after pill can temporarily alter vaginal bleeding.

Some women may notice spotting between periods, while others may find that their next period arrives earlier or later than expected.

Research on levonorgestrel emergency contraception has found temporary changes in menstrual cycle length, period length and menstrual appearance, with most of these changes disappearing in the following cycle (Gainer et al., 2006).

How Long Do Side Effects Usually Last?

The duration depends on the type of symptom.

Short-term symptoms such as nausea, headache, dizziness or tiredness generally settle relatively quickly.

However, it would be inaccurate to say that every side effect must disappear within exactly 24 or 48 hours.

Clinical evidence shows that adverse effects associated with levonorgestrel emergency contraception are generally mild and not serious, but individual experiences vary (Leelakanok & Methaneethorn et al., 2020).

Side Effects During the First 24 Hours

The first day is when symptoms such as nausea, headache, dizziness or tiredness may be most noticeable.

Some women experience symptoms only briefly, while others may continue to feel mildly unwell for a little longer.

If symptoms are mild and gradually improving, monitoring them is usually reasonable.

Side Effects During the First Few Days

Some symptoms can continue for several days.

The overall trend is more useful than focusing on an exact number of hours.

Symptoms that are gradually improving are generally less concerning than symptoms that become progressively worse.

If a symptom is severe, persistent or interfering significantly with normal activities, medical advice is appropriate.

What About Changes to Your Period?

Menstrual changes can last longer than short-term symptoms.

Your next period may come earlier or later than expected, and the amount or appearance of bleeding may be different.

The timing of these changes can depend partly on when emergency contraception was taken during the menstrual cycle.

Studies of levonorgestrel emergency contraception have found that the effect on the timing and duration of the next menstrual period varies according to when in the cycle the medication was taken. (Raymond et al., 2006).

Does Levonorgestrel Cause Side Effects for Longer?

Levonorgestrel is generally well tolerated.

Possible symptoms include nausea, headache, dizziness, fatigue, abdominal discomfort and changes to the next menstrual period.

The duration is not identical for every woman.

A short-lived headache or episode of nausea should not be expected to follow exactly the same timeline as a change in menstrual bleeding.

If symptoms are worsening rather than improving, they should be assessed instead of assuming that they are simply taking longer to disappear.

Does Ulipristal Acetate Cause Side Effects for Longer?

Ulipristal acetate is another oral emergency contraceptive option.

Clinical research has reported headache, nausea and abdominal pain among the more frequent adverse events.

In a large study of ulipristal acetate used 48 to 120 hours after intercourse, adverse events were mainly mild or moderate (Fine et al., 2010).

Ulipristal can also affect the timing of the next menstrual period.

Therefore, a later period does not necessarily mean that the medication is continuing to cause physical side effects for the entire time. It may instead reflect a temporary change in the menstrual cycle.

Can Side Effects Last Until Your Next Period?

Some women may continue to notice changes in their menstrual cycle after the initial physical symptoms have disappeared.

For example, nausea may settle within a short period, but the next period could still arrive earlier or later than usual.

This distinction is important because a menstrual change does not necessarily mean that the medication is still producing the same short-term effects in the body.

If the next period is significantly delayed, pregnancy should be considered rather than assuming the delay is simply another side effect.

What If Your Side Effects Are Getting Worse?

The direction of your symptoms matters.

Mild nausea that gradually improves is different from vomiting that becomes persistent.

Mild cramps that settle are different from severe or worsening pelvic pain.

Seek medical advice if symptoms become severe, continue without improvement, or are accompanied by fainting, significant weakness, severe abdominal or pelvic pain, or unusually heavy bleeding.

Can Morning-After Pill Side Effects Affect Exercise?

Most women do not need to stop normal physical activity simply because they have taken emergency contraception.

However, if you feel dizzy, weak, nauseated or generally unwell, reducing strenuous exercise until you feel better is sensible.

There is no routine physiotherapy or exercise restriction required simply because you have taken the morning-after pill.

Your symptoms should guide your activity level. If you feel normal, ordinary physical activity can generally continue.

If you feel unwell, rest and recovery are more appropriate than pushing through a workout.

Can Physiotherapy Help With Morning-After Pill Side Effects?

Physiotherapy does not treat the hormonal or medication-related effects of emergency contraception.

A physiotherapist cannot make nausea, headache, dizziness or menstrual changes disappear faster, and physiotherapy is not required simply because you have taken the morning-after pill.

The physiotherapy role becomes relevant only when there is a separate musculoskeletal or pelvic-floor problem.

For example, if pelvic pain continues after appropriate medical assessment and a musculoskeletal contribution is identified, pelvic-health physiotherapy may help address issues such as pelvic-floor muscle overactivity, movement-related pain, breathing strategies or other musculoskeletal contributors.

Evidence supports pelvic-floor physiotherapy as one possible component of management for selected chronic pelvic pain conditions, but this evidence should not be interpreted as showing that physiotherapy treats emergency contraception side effects themselves (Bittelbrunn et al., 2023).

Do You Need Pelvic-Floor Exercises After Taking the Morning-After Pill?

No.

Taking emergency contraception does not create a routine need for Kegel exercises or other pelvic-floor strengthening exercises.

Pelvic-floor exercises should be prescribed according to an individual’s symptoms and assessment.

They do not make emergency contraception leave the body faster, prevent medication-related side effects, or restore the menstrual cycle.

If pelvic discomfort continues, the first step is to determine why it is happening before choosing exercises.

Lesser-Known Fact: Side Effects Do Not Tell You Whether the Pill Worked

One of the most useful things to remember is that side effects are not a test of emergency contraception effectiveness.

Some women experience nausea, headache, cramping or spotting, while others experience no noticeable symptoms.

Having side effects does not prove that the medication worked, and having no side effects does not mean that it failed.

If pregnancy is possible, symptoms alone cannot reliably answer that question.

A pregnancy test is more useful when the next period is significantly delayed or when otherwise indicated.

When Should You See a Doctor?

Most morning-after pill side effects are temporary, but certain symptoms should not simply be attributed to the medication.

Seek medical advice if you experience:

• Severe or worsening abdominal or pelvic pain
• Very heavy or persistent vaginal bleeding
• Fainting or severe dizziness
• Significant weakness
• Persistent vomiting or inability to keep fluids down
• Symptoms that are severe or continue without improvement
• A positive pregnancy test accompanied by significant pain or bleeding

A pregnancy test is also appropriate if your period is significantly delayed or if you have concerns about pregnancy after taking emergency contraception.

Conclusion

Morning-after pill side effects are usually temporary, but there is no universal timeline that applies to every woman.

Nausea, headache, dizziness, tiredness and mild abdominal discomfort may settle within a short period, while changes to the next menstrual period can continue later into the cycle.

The most important thing is to look at the overall pattern.

Mild symptoms that gradually improve are different from symptoms that become severe, persistent or progressively worse.

From a physiotherapy perspective, taking emergency contraception does not create a need for pelvic-floor exercises or physiotherapy.

Physiotherapy becomes relevant only when a separate pelvic-floor or musculoskeletal problem is present, particularly persistent pelvic pain after appropriate medical causes have been assessed.

If you develop severe pain, heavy bleeding, fainting, significant weakness, persistent vomiting or other concerning symptoms, seek appropriate medical care rather than assuming the symptoms are simply a side effect of the morning-after pill.

Stay tuned with us for more health related topics.

Follow us on LinkedIn and Instagram for more.