Coughing Up Blood When Pregnant: Causes & What to Do

Coughing up blood during pregnancy is uncommon but demands prompt medical attention, because the range of possible causes spans from minor airway irritation to life-threatening conditions like pulmonary embolism. In most reported cases, the bleeding is mild and a specific cause can be identified, though a small number of pregnant patients experience massive, dangerous hemorrhage that requires emergency intervention. The challenge for both patients and clinicians is that many normal pregnancy symptoms, such as breathlessness and a faster heart rate, overlap with the warning signs of serious lung disease, which can delay diagnosis.

Why Pregnancy Changes the Picture

Pregnancy transforms the respiratory and circulatory systems in ways that make both the occurrence and diagnosis of hemoptysis more complicated. Blood volume increases substantially, the heart works harder, and the blood itself becomes more prone to clotting. These shifts are protective in one sense: they prepare the body for the blood loss of delivery. But they also raise the odds of clot formation in the lungs and increase blood flow through the bronchial vessels, which can make existing lung conditions bleed more easily.

Symptoms that would immediately raise red flags in a non-pregnant person can blend into the background during pregnancy. Shortness of breath, a resting heart rate that is faster than usual, and swollen legs are all common in healthy pregnancies. That overlap is a recognized problem. A review in CHEST noted that pulmonary embolism diagnosis during pregnancy is particularly challenging because symptoms like breathlessness, rapid heart rate, and leg swelling are often present due to normal physiological changes, contributing to delayed recognition and investigation.¹ The upshot is that coughing up even a small amount of blood during pregnancy should not be brushed off as trivial, because the same physiological changes that make harmless symptoms feel dramatic can also mask genuinely dangerous ones.

Pulmonary Embolism as a Leading Concern

When a pregnant person coughs up blood, the first serious diagnosis clinicians tend to rule out is pulmonary embolism, a blood clot that has traveled to the lungs. Pregnancy is a well-established hypercoagulable state, meaning the blood clots more easily than usual. That heightened clotting tendency, combined with reduced mobility late in pregnancy and compression of pelvic veins by the growing uterus, makes PE one of the leading causes of maternal mortality worldwide.¹

Hemoptysis from PE can range from faint blood-streaking in sputum to heavier bleeding when a portion of lung tissue dies from lack of blood supply, known as a pulmonary infarct. A case report described a first-time pregnant woman at 38 weeks who presented with repeated unexplained bouts of coughing up blood, which turned out to be caused by a pulmonary infarct from a blood clot.² That case was managed successfully, but it illustrates why clinicians treat hemoptysis during pregnancy as a PE-until-proven-otherwise situation in many settings.

Infections That Can Cause Bleeding

Lung infections are another common cause of coughing up blood during pregnancy, and they cover a wide range of severity. Garden-variety bronchitis or pneumonia can inflame the airway lining enough to cause blood-tinged mucus, and these cases usually resolve with appropriate antibiotics and supportive care. But in some parts of the world, tuberculosis remains a significant cause of hemoptysis in pregnant patients and can be far more dangerous.

One case report described a pregnant healthcare worker who developed massive hemoptysis and a completely collapsed lung due to active pulmonary tuberculosis, yet both mother and baby survived with treatment.³ Another case involved a woman at 25 weeks of pregnancy with a history of lupus and past TB who suddenly coughed up a large volume of blood. Investigations revealed both invasive fungal lung infection and a TB co-infection, and she required antifungal and anti-tuberculosis treatment simultaneously.⁴ These cases are extreme, but they highlight that pregnancy can tip the balance in favor of serious infections, particularly in people whose immune systems are already compromised.

Heart Disease and Vascular Problems

A less obvious cause of hemoptysis during pregnancy is undiagnosed heart disease, particularly problems with the heart’s valves. When a narrowed mitral valve restricts blood flow out of the lungs, pressure builds up in the pulmonary blood vessels. The extra blood volume of pregnancy can push that pressure past a tipping point, causing blood to leak into the airways.

In one striking case, a 43-year-old pregnant woman with no prior medical complaints presented with massive hemoptysis that turned out to be the first sign of severe rheumatic mitral valve stenosis. She had never known she had the condition. She was treated with a catheter-based valve procedure and survived.⁵ Rheumatic heart disease has become less common in high-income countries, but it remains prevalent in many parts of the world. For someone who grew up in a region where rheumatic fever is common, pregnancy can unmask a heart condition that was previously silent.

Autoimmune and Inflammatory Conditions

Systemic autoimmune diseases can flare during pregnancy and, in rare cases, cause bleeding into the lungs. Lupus is the best-documented example. The disease can inflame blood vessels in the lungs (pulmonary vasculitis), leading to a condition called diffuse alveolar hemorrhage, where blood fills the tiny air sacs. One reported case involved a pregnant patient whose lupus presented for the first time during pregnancy with vasculitis and multiple organ dysfunction, including confirmed lung hemorrhage on bronchoscopy. She was treated with steroids, cyclophosphamide, and plasma exchange and improved.⁶

Another group of autoimmune conditions, the ANCA-associated vasculitides, can also cause hemoptysis during pregnancy. A systematic review found cases where patients with granulomatosis with polyangiitis (formerly called Wegener’s) developed serious lung bleeding that required transfusions and aggressive immunosuppressive treatment.⁷ These conditions are rare, but when they do appear, they tend to be severe and require a specialist team working together.

Less Common Causes Worth Knowing About

Not every case of hemoptysis in pregnancy fits neatly into the categories above. A case report in the Journal of Medical Case Reports described a pregnant woman whose hemoptysis was initially assumed to be from a pulmonary embolism but turned out to be caused by a rare type of lung cancer. The authors noted that when hemoptysis occurs in pregnancy, it is frequently assumed to be from PE, but as in the non-pregnant population, it can be caused by a range of other conditions and can signal serious underlying disease.⁸ Lung tumors in young pregnant women are rare enough that they are almost never the first diagnosis considered, but this case is a reminder that anchoring too quickly on PE can delay finding the real cause.

There is also a poorly understood category of idiopathic hemoptysis in pregnancy, where no identifiable cause is found despite thorough investigation. A study from a French respiratory intensive care unit described three pregnant women admitted between 16 and 20 weeks of gestation for massive hemoptysis with no clear explanation, and proposed that pregnancy-related vascular changes might create a distinct entity of hemoptysis unique to pregnancy itself.⁹ In severe pre-eclampsia and eclampsia, the systemic vascular damage can lead to pulmonary edema, which occasionally produces blood-tinged frothy sputum, though this is more of an overflow problem than true bleeding from the airway.

How Doctors Investigate Safely

One of the biggest anxieties for pregnant patients is whether diagnostic tests will be safe for the baby. Imaging is often essential to figure out why someone is coughing up blood, and the two most relevant tests for ruling out PE are CT pulmonary angiography (a specialized chest CT scan) and lung perfusion scintigraphy (a nuclear medicine scan). Both involve some radiation exposure to the fetus, but the doses are far below thresholds considered harmful.

A comprehensive review found that the fetal radiation dose from a chest CT ranges from about 0.01 to 0.03 milligray early in pregnancy and 0.06 to 0.1 milligray in late pregnancy, while a perfusion lung scan delivers roughly 0.1 to 0.8 milligray depending on the stage of pregnancy.¹⁰ To put that in perspective, radiation-related risks to a developing baby become a concern only at doses many times higher than either test delivers. The real danger is not the scan. It is failing to diagnose a PE because of reluctance to image.

When the cause of bleeding is unclear or when direct airway intervention is needed, bronchoscopy, which involves passing a thin camera through the airway, may be performed. Flexible bronchoscopy has been used in the majority of reported pregnancy cases, though the literature is limited mostly to case reports.¹¹ The procedure carries procedural risks, and the sedation drugs used must be chosen carefully because pregnancy changes how the body handles medications. Still, when a patient is actively bleeding and the source needs to be identified or controlled, the benefits of bronchoscopy typically outweigh the risks.

Treatment Approaches

Treatment depends entirely on the cause and the severity of the bleeding. For mild hemoptysis caused by bronchitis or minor airway irritation, the approach may be as simple as treating the underlying infection, staying hydrated, and monitoring. For PE, anticoagulation therapy with heparin-based drugs (which do not cross the placenta) is the standard treatment during pregnancy.

When bleeding is heavy, medications that help the blood clot can be used to slow things down while the underlying cause is addressed. Tranexamic acid, a drug that stabilizes clots, has shown promise in managing bleeding during pregnancy and appears to be safe based on available evidence, though researchers have called for larger, better-designed trials to fully confirm its safety profile.¹²

For life-threatening, massive hemoptysis that does not respond to medication, more aggressive interventions enter the picture. Bronchial artery embolization, a procedure where interventional radiologists thread a catheter into the arteries feeding the bleeding site and block them, has been performed successfully during pregnancy. In extreme cases, clinical teams have combined emergency cesarean delivery with bronchial artery embolization and even extracorporeal membrane oxygenation (ECMO), a machine that takes over the work of the lungs temporarily. One such case involved an emergency multidisciplinary effort where a cesarean section was performed first to deliver the baby, followed by ECMO support and embolization to stop the mother’s bleeding.¹³ These heroic interventions are rare, but the fact that they exist reflects the seriousness with which massive hemoptysis in pregnancy is treated.

When You Should Go to the Emergency Room

Any amount of blood coughed up during pregnancy warrants at least a phone call to your obstetric provider. But certain scenarios call for immediate emergency care:

• Volume: More than a teaspoon or two of bright red blood, or blood that keeps coming rather than appearing once and stopping.
• Breathing difficulty: If you feel short of breath beyond what is normal for your stage of pregnancy, especially if the breathlessness came on suddenly.
• Chest pain: Sharp or stabbing chest pain, particularly pain that worsens with breathing, is a classic sign of PE.
• Leg swelling or pain: Sudden, one-sided calf swelling or pain alongside hemoptysis raises the likelihood of a blood clot.
• Fever and cough: Hemoptysis with fever, chills, and a productive cough suggests a serious lung infection that may need intravenous antibiotics.
• Lightheadedness or fainting: Signs that you may be losing enough blood to affect your circulation.

A small streak of blood in mucus during a cold or after a particularly harsh cough, with no other symptoms, is often minor. But the threshold for seeking evaluation should be lower during pregnancy than at any other time, because the diagnostic overlap between normal pregnancy symptoms and serious disease makes self-assessment unreliable.

The Multidisciplinary Approach

One theme that runs through almost every published case of significant hemoptysis in pregnancy is that managing it requires more than one specialist. Obstetricians, pulmonologists, interventional radiologists, anesthesiologists, and neonatologists often need to collaborate, sometimes on a very compressed timeline. The decisions are intertwined: whether to deliver the baby early, whether imaging or procedures can be done with the baby still in the uterus, how to sedate the mother without harming the fetus, and how to time interventions so that both patients have the best chance.

A review of massive hemoptysis cases during pregnancy found that flexible bronchoscopy was used in about 70% of the reported patients, with rigid bronchoscopy and bronchial artery embolization used in more severe cases.¹⁴ The coordination required for these interventions is one reason why pregnant patients with significant hemoptysis are often transferred to tertiary medical centers with maternal-fetal medicine and interventional pulmonology capabilities.

The Emotional and Psychological Aftermath

An aspect that gets far less attention in the medical literature is what happens to the mental health of someone who goes through a frightening medical event during pregnancy. Coughing up blood is alarming under any circumstances. During pregnancy, the fear is compounded by concern for the baby, uncertainty about the diagnosis, and the feeling of losing control over what is supposed to be a healthy, normal process.

Research on women who survived life-threatening illness during pregnancy or childbirth has found that these experiences often leave lasting psychological marks, including anxiety, panic attacks, and post-traumatic stress disorder.¹⁵ A study exploring the narratives of women who nearly died during pregnancy identified a complex set of acute stress-related reactions tied both to the physical crisis itself and to the experience of care they received.¹⁶

Even if the bleeding turns out to have a benign cause, the anxiety it triggers can linger, especially if the evaluation process involves frightening-sounding tests or an ICU stay. If you have experienced hemoptysis during pregnancy and find yourself struggling with fear, intrusive memories, or difficulty bonding with your baby afterward, those reactions are well-documented and treatable. Bringing them up with your provider, even weeks or months later, is worth doing.

How Pseudohemoptysis Can Confuse Things

Not everything that looks like coughing up blood actually is. Blood that originates in the nose or throat and drips down the back of the airway can trigger coughing and produce what looks like hemoptysis but is really posterior nosebleed or bleeding gums. Pregnancy increases blood flow to the nasal mucous membranes, making nosebleeds far more common. Severe acid reflux, which worsens as the uterus grows, can also cause bleeding from the esophagus that gets confused with blood from the lungs.

Distinguishing true hemoptysis from these look-alikes matters because the workup and the urgency differ. Blood from the lungs is usually bright red, frothy (mixed with air), and brought up with a cough. Blood from the stomach tends to be darker, sometimes resembling coffee grounds, and is usually vomited rather than coughed. Blood from the nose or gums is often noticed first in the mouth and may worsen when lying flat. Your doctor may ask you to describe the color, consistency, and circumstances to help sort this out before ordering imaging or invasive tests.