Postpartum Palpitations: When a Fast Heartbeat Needs a Heart Check
When to call 1669
Call 1669 for chest tightness or pressure, pain traveling to the back, neck, or arm, severe breathlessness that makes speaking a sentence hard, fainting, or palpitations that do not settle together with lightheadedness. Do not drive there. The CDC HEAR HER page, 15 May 2024, says to get care immediately for these warning signs during pregnancy or within one year after delivery, and to say if you were pregnant or gave birth within the last year.
Direct answer
Palpitations after birth can come from poor sleep, stress, caffeine, anemia, or a thyroid change. The year after delivery still changes the context, because a rhythm problem, a lung clot, and uncommon peripartum cardiomyopathy can look similar. Recurrent symptoms need a check. Emergency symptoms need 1669.
Why can the heart race after birth?
The NHS, last reviewed 17 March 2026, says palpitations are a heartbeat that feels racing, irregular, pounding, or fluttering. They are common and not usually serious. Common causes include strenuous exercise, lack of sleep, stress and anxiety, medicines, alcohol, caffeine, nicotine, and recreational drugs. Some people notice them in pregnancy. Conditions that can cause them include iron-deficiency anemia, an overactive thyroid, an arrhythmia, and other heart problems such as valve disease.
After birth, poor sleep, pain, low fluid, caffeine, and medicines can sit beside problems that need a test. This page does not treat hormones as a finished explanation. The pages on short sleep and palpitations and coffee and palpitations are different questions, because they do not start from the postpartum window.
The NHS says to see a clinician if palpitations keep returning, happen more often, last longer than a few minutes, a heart condition is already known, or heart problems run in the family. Call emergency care if palpitations do not go away, or if they come with chest pain, shortness of breath, or feeling faint. In Thailand that number is 1669.
Can postpartum thyroiditis cause palpitations?
It can in one phase, and the phase needs a blood test. The American Thyroid Association says postpartum thyroiditis can raise thyroid hormone in the blood first and lower it later. Not everyone has both phases. About one third have both, and the other groups have only the high phase or only the low phase.
The high-hormone phase often starts 1 to 4 months after delivery and lasts about 1 to 3 months. The page lists anxiety, insomnia, palpitations, fatigue, weight loss, and irritability. It says these symptoms are often attributed to life with a new baby, so the phase is overlooked. The low-hormone phase often starts 4 to 8 months after delivery, may last up to 9 to 12 months, and can include fatigue, weight gain, constipation, dry skin, low mood, and poor exercise tolerance.
The association says this occurs in about 5 to 10 of every 100 women in the United States. That is a population figure on that page, not a personal chance. Diagnosis comes from tests, not from palpitations alone. The page on early thyroid symptoms is a different question, because it is not limited to the months after birth.
Treatment depends on the phase and the symptoms. In the high-hormone phase of this condition the gland is not overproducing, so antithyroid medicines are not used. A clinician may use a beta blocker to ease palpitations or tremor, then reduce it as the phase fades. Some people in the low phase receive thyroid hormone if symptoms are clear. Starting a medicine belongs to the clinician, and breastfeeding status belongs in the history.
What is peripartum cardiomyopathy?
It is an uncommon form of heart failure, not the label for every postpartum palpitation. The American Heart Association, last reviewed 28 May 2024, says it happens toward the end of pregnancy or in the months after delivery when no other cause of heart failure is found, in someone without a prior heart-disease diagnosis. It is most often diagnosed in the last month of pregnancy and the weeks after delivery, and can occur up to five months postpartum.
The chambers enlarge and the muscle weakens, so less blood leaves the heart with each beat. The page’s diagnostic criteria are heart failure in the last month or within months after delivery, left-ventricular ejection fraction less than 45, usually on an echocardiogram, and no other cause. It states a usual ejection fraction of 50 to 70. Those figures are criteria after imaging. They are not numbers to calculate at home, and they do not mean every palpitation needs an echocardiogram.
Listed symptoms include breathlessness with light activity and when lying flat, fatigue, swollen ankles or feet, cough, chest congestion, more urination at night, chest pain or tightness, a racing or skipping heartbeat, and lightheadedness or near-fainting. The page says heart-failure symptoms can mimic pregnancy, so new breathlessness especially at rest, swelling after delivery, or a sudden onset in pregnancy should lead to prompt evaluation.
Listed risk context includes maternal age of 35 or older, high blood pressure including preeclampsia, a multiple pregnancy, and a statement that it is reported more often in people who identify as Black, while it is not understood how race plays a role. The cause is unclear, and most people who develop it have no family history of cardiomyopathy. This page does not apply those factors to a social-media post.
Which pattern should be checked again?
These are details to tell a clinician, not a diagnosis. Spells that return or come more often, spells that last longer, a fast heartbeat at rest, a feeling that the rhythm is irregular, a shorter walking distance, dizziness or near-fainting, chest discomfort, breathlessness, swelling, or symptoms that keep growing.
The NHS uses return, increasing frequency, or lasting longer than a few minutes as reasons to see a clinician. The CDC uses a fast, pounding, irregular, or skipped heartbeat together with dizziness, fainting, disorientation, or trouble catching the breath while talking as a reason for immediate care. The two sources do not draw one line for every spell. Symptoms in the first box of this page mean calling 1669.
How long after birth does the warning window last?
At least three frames exist, and they should not be folded into one number.
The first is the CDC urgent maternal warning list, used during pregnancy and up to one year after delivery. Chest pain or a fast-beating heart is on that list, and the page says to tell the clinician if you were pregnant within the last year.
The second is peripartum cardiomyopathy on the American Heart Association page. It is most often the last month of pregnancy and the weeks after delivery, and it can occur up to five months postpartum. Five months does not replace the one-year warning list, and the one-year list does not mean every person has a weak heart muscle through month twelve.
The third sits on the same CDC page but carries its own clock. Severe swelling, redness, or pain of a leg or arm, usually one side, is written as anytime in pregnancy or up to 6 weeks after birth. That is not the full year.
Does one normal ECG rule out an arrhythmia?
Not always. The NHS ECG page says a resting ECG records for a few minutes while you lie still. A spell that comes and goes may be absent from that strip. The same page describes a portable recorder, usually worn for 24 to 48 hours and sometimes up to 7 days. The type depends on the symptoms, and the clinician explains which one will be used.
This page does not say to demand a recorder. The page on palpitations with arm pain and a normal ECG is a different question, because it does not start from the months after birth.
Which tests might be used?
There is no single panel for everyone. When a clinician sees a reason, sources opened here mention pulse and blood pressure, an ECG, a blood count for anemia or infection, thyroid function, electrolytes, kidney and liver tests, and the history of how long ago the birth was.
The American Heart Association says evaluation for peripartum cardiomyopathy looks for fluid in the lungs, a rapid rate, and an echocardiogram when weak pumping is suspected. BNP or NT-proBNP may be added when the team sees a reason. Those tests are not a bundle that every palpitation requires. A portable ECG is for spells that come and go, as the NHS describes. A lung-clot evaluation is for the symptom pattern, not for palpitations alone.
Which pattern can be a clot in the lung?
The NHS pulmonary embolism page lists sudden difficulty breathing, chest pain that is worse when breathing in, coughing up blood, and sometimes pain and swelling in a leg, usually the calf, or in an arm. The same page says to call emergency care for sudden breathing difficulty, pain in the chest or upper back, a heart beating very fast, or someone passing out. In Thailand that is 1669.
The CDC separates swelling, redness, or pain in a leg or arm, usually one side, as a warning sign during pregnancy or up to 6 weeks after birth. That pattern needs a prompt assessment. It does not mean every palpitation is a clot.
Prepare the questions before the visit
The list below organizes what to ask. It does not decide that the heart muscle is weak, and it does not order a test.
10 questions to ask when palpitations follow pregnancy or birth
- Do these spells sound more like an arrhythmia or like a fast but regular sinus rhythm?
- What did the ECG show?
- If the ECG was normal and the spells come and go, is a portable recorder needed?
- Is a blood count needed to look for anemia?
- Is a thyroid test needed, including postpartum thyroiditis?
- Is there a reason for an echocardiogram to look at pumping?
- Is there a reason to consider peripartum cardiomyopathy?
- Is there a reason to assess for a pulmonary embolism?
- Could a medicine, caffeine, a supplement, or a weight-loss product be a trigger?
- Which symptoms should bring me back before the visit, and which mean calling 1669?
What should be written down for the visit?
- Date and time of the spell
- Approximate heart rate if it was counted, and whether it felt regular or skipped
- How long it lasted
- Whether it started at rest or with effort
- Chest discomfort, breathlessness, lightheadedness, fainting, or swelling
- How many hours of sleep came before it
- Caffeine, medicines, and supplements, including weight-loss products
- How many weeks or months since birth, and whether breastfeeding is under way, because medicine choice can depend on that
Causes that are common, and problems that should not be missed
| Possible path | Clue from a source opened here | How a clinician looks |
|---|---|---|
| Poor sleep, stress, caffeine | The NHS lists these among common causes of palpitations | Ask about triggers first. Breathlessness, chest pain, or fainting does not stop at this explanation |
| Anemia | The NHS names iron-deficiency anemia as a cause of palpitations | A blood count when there is a reason, not with every spell |
| Postpartum thyroid change | Palpitations with anxiety or poor sleep can occur 1 to 4 months after birth | Thyroid blood tests. Symptoms alone are not enough |
| An arrhythmia | Skipped beats, or spells that a resting ECG can miss | An ECG, and a portable recorder if the clinician sees a need |
| Peripartum cardiomyopathy | Breathlessness at rest or lying flat, swelling, fatigue. Uncommon | Examination and an echocardiogram when weak pumping is suspected, not for every palpitation |
| A clot in the lung | Sudden breathlessness, pain on breathing in, coughing blood, one-sided leg swelling | Urgent assessment, not watchful waiting at home |
Spells to log, and spells that should be checked soon
| Log and discuss if no other warning sign is present | Do not close the question with “this is just after birth” |
|---|---|
| A short spell after caffeine or a short night, which settles, without breathlessness or chest pain | Spells that return, come more often, last longer than a few minutes, or start at rest |
| One spell that ended, with usual daily activity afterward | A shorter walking distance, swelling, breathlessness when lying flat, or lightheadedness |
| Worry, while full sentences are still easy and there is no chest pain | Chest pain, severe breathlessness, fainting, or sudden trouble speaking: call 1669 |
The table does not name a disease from one column.
How the author separates the layers
Asst. Prof. Dr. Norawit Raatpiboon keeps three layers apart so “after birth” does not close the evaluation, and so palpitations do not become heart failure by default.
The first layer is the triggers the NHS describes as common: short sleep, stress, caffeine, medicines, and anemia. That layer is possible. It is not the answer when breathlessness, chest pain, or fainting is present.
The second layer is time, and the sources do not share one number. The CDC uses one year for urgent maternal warning signs. The American Heart Association uses up to five months for uncommon peripartum cardiomyopathy. The CDC uses 6 weeks for one-sided leg or arm swelling, redness, or pain. Folding those numbers together both misses cases and overstates risk.
The third layer is testing matched to the question. A short ECG can miss a spell that comes and goes. Thyroid blood tests confirm a postpartum phase. An echocardiogram is for suspected weak pumping, not a standard bundle for every palpitation. The page on menopause or heart disease is a different life stage.
Common questions
Are palpitations after birth usually harmless?
The NHS says palpitations are common and not usually serious. Frequent causes include lack of sleep, stress, medicines, and caffeine. See a clinician if they keep returning, last longer than a few minutes, or there is a family history of heart problems. From pregnancy through one year after delivery, the CDC says to tell the clinician about that history, because chest pain or a fast heartbeat is a warning sign in this window.
What can make the heart race after birth?
Several paths exist. The NHS lists lack of sleep, stress, caffeine, medicines, iron-deficiency anemia, an overactive thyroid, and an arrhythmia. The American Thyroid Association describes a high-hormone phase after birth that can cause palpitations. The American Heart Association describes uncommon peripartum cardiomyopathy. Symptoms alone do not name the cause.
Can postpartum thyroiditis cause palpitations?
Yes, in the phase when thyroid hormone in the blood is high. The American Thyroid Association says that phase often starts 1 to 4 months after delivery and can include palpitations, anxiety, poor sleep, fatigue, weight loss, or irritability. Those symptoms resemble the strain of a new baby, so the phase needs a blood test. Symptoms alone do not confirm it.
What is peripartum cardiomyopathy?
It is an uncommon form of heart failure late in pregnancy or in the months after delivery, when no other cause is found. The American Heart Association says it is most often diagnosed in the last month of pregnancy and the weeks after delivery, and can occur up to five months postpartum. Symptoms include breathlessness, especially when lying flat, fatigue, swelling, chest pain or tightness, racing or skipped beats, and lightheadedness or near-fainting. Palpitations after birth do not mean every person has this condition.
Does every postpartum palpitation need an ECG?
The NHS says a clinician may use an ECG to look at the heart’s electrical signals. That does not mean every person needs every type of recording. The choice depends on the symptoms and belongs to the clinician.
What if one ECG is normal but the spells return?
A resting ECG on the NHS page records only a few minutes. A spell that comes and goes may be absent from that strip. The NHS describes a portable ECG usually worn for 24 to 48 hours, sometimes up to 7 days, when the clinician decides a longer recording is needed. It is not a test to order for yourself.
Can breathlessness after birth be the heart?
It can, and it is not the only answer. The CDC lists trouble breathing, including needing pillows to lie flat, as a warning sign from pregnancy through one year after delivery. The American Heart Association says new breathlessness, especially at rest, or swelling after delivery should be evaluated promptly, because heart-failure symptoms can resemble ordinary pregnancy symptoms.
How many months after birth does the warning window last?
The windows are different. The CDC urgent maternal warning signs apply during pregnancy and up to one year after delivery. Peripartum cardiomyopathy, in the American Heart Association description, is most often in the last month and the weeks after birth and can occur up to five months. The CDC leg or arm swelling, redness, or pain item is written as during pregnancy or up to 6 weeks after birth. Those three numbers are not the same.
Can caffeine cause palpitations after birth?
The NHS lists caffeine among common causes of palpitations. That does not mean every spell comes from a drink. If breathlessness, chest pain, or lightheadedness is also present, do not stop at the drink as the explanation.
Which symptoms mean calling 1669?
Call 1669 for chest pain or pressure, severe breathlessness, fainting, palpitations that do not settle, or a very fast heartbeat together with those symptoms. In Thailand the number is 1669. The CDC says to get care immediately for warning signs during pregnancy and up to one year after delivery, and to say if you were pregnant within the last year.
Sources opened for this page
Limits of this page
This page is general information. It does not diagnose from a described spell, it does not say that every postpartum palpitation is peripartum cardiomyopathy, and it does not say that everyone needs an echocardiogram or should start a medicine. If a symptom in the first box is present, call 1669 before reading the visit list.