In short: Sex hormones influence the airways. In some women asthma worsens before a period or changes in pregnancy, and in rare cases tissue similar to the womb lining in the lung or its lining (pleura) causes pneumothorax (air in the chest cavity), bleeding or pain that return with the menstrual cycle. When the pattern is recognised, treatment can be tailored and pregnancy and follow-up planned.
Why look at the lungs through a woman’s body
Lung disease does not always behave the same way in women and men. Hormones such as oestrogen and progesterone influence the airways and inflammation, and the lungs also respond to the hormonal changes of different life stages: the menstrual cycle, pregnancy and the menopause. As a result, symptoms can change with the menstrual cycle and with pregnancy. To understand the picture it is important to ask about periods, pregnancies and hormonal medication as well, not only about the lungs.
Asthma around periods (catamenial asthma)
In some women with asthma, symptoms worsen in the days before a period and at its start, when oestrogen and progesterone levels fall. Reviews report that this happens in about 19% to 40% of women with asthma; the wide range is partly due to different definitions in different studies. The asthma is sometimes more severe, with a tendency to flare-ups.
How to recognise it: cough, wheeze, chest tightness and shortness of breath, and a greater need for the reliever inhaler, returning at the same time each month. Recording symptoms and reliever use over two to three cycles, and sometimes peak flow measurements, helps to show the pattern. It is also important to rule out other causes of worsening.
Treatment: the foundation is optimising regular treatment, checking inhaler technique and adjusting treatment for the sensitive days. Sometimes, together with the gynaecologist, stabilising hormonal treatment is considered. In studies, women taking the contraceptive pill had fewer symptoms, but the evidence is limited and this is not a general recommendation.
Endometriosis of the chest and lungs
Endometriosis is a condition in which tissue similar to the womb lining is found outside the womb, usually in the pelvis. It is estimated that about 10% of women of reproductive age have it. Rarely, the tissue is also found on the diaphragm, the pleura (the lining of the lung) and in the lung itself; this is called thoracic endometriosis syndrome. The tissue responds to the hormones of the cycle, so symptoms return with periods.
At our clinic we have clinical experience in diagnosing and following women with thoracic endometriosis, and when needed we work together with thoracic surgeons.
The most common presentations
Percentages are from a review of symptomatic women (Gherzi et al., among others). Another review reports that catamenial pneumothorax accounts for up to a third of spontaneous pneumothoraces in women of reproductive age.
Symptoms and the typical pattern
- Sharp chest pain that is worse on breathing, shoulder or neck pain, shortness of breath and cough
- Mild to moderate coughing of blood, sometimes in younger women
- Symptoms usually start between 24 hours before a period and 72 hours after it begins, but not always
- About 90% of cases are on the right side, and the average age at diagnosis is about 35
- Up to about 80% of women with thoracic endometriosis also have pelvic endometriosis, and may not know it
- Sometimes there are no symptoms at all, or they are attributed to something else
Diagnosis
Suspicion arises from the history: recurrent symptoms or pneumothorax, mostly on the right side, close to a period. A CT scan or chest X-ray mainly helps to rule out other diseases, and an MRI of the chest and abdomen is considered suitable for planning before surgery. The diagnostic and therapeutic procedure is minimally invasive surgery of the chest (VATS), which is sometimes best timed for the first days of a period.
Treatment and follow-up
Drug treatment is hormonal suppression of the cycle (for example GnRH analogues or progestins), and according to reviews it is recommended for at least 6 to 12 months, usually both before and after surgery. In recurrent or resistant cases surgery is performed: removal of the lesions, repair of defects in the diaphragm and pleurodesis (sticking the lung lining together). Recurrence is not rare (about 30% or more in reviews), so joint follow-up with a gynaecologist and a thoracic surgeon is important, and above all continuing hormonal treatment after surgery.
Breathing and asthma in pregnancy
Shortness of breath in pregnancy: when it is normal
Shortness of breath is common in pregnancy: about 60% to 70% of women who have no heart or lung disease experience it, sometimes from early in pregnancy. At first the main reason is progesterone.
Later in pregnancy mechanical changes join in: the growing womb pushes the diaphragm up (by up to about 4 cm at term) and the volume left in the lungs at the end of a breath out becomes smaller. Total lung capacity and FEV1 are usually preserved.
Normal breathlessness does not appear at rest, does not steadily worsen, and is not accompanied by wheeze, chest pain, coughing blood, swelling in one leg or a fast pulse. Such signs justify a work-up, because pregnancy also raises the risk of pulmonary embolism and of worsening asthma or other conditions.
Asthma in pregnancy
Asthma affects about 4% to 8% of pregnant women, and is one of the most common medical conditions in pregnancy. Its course is unpredictable. It is commonly said that about a third of women improve, a third worsen and a third are unchanged, but the evidence for this is weak and comes mostly from older studies. In a more recent study worsening was less common (about 19%). Severe asthma before pregnancy raises the risk of worsening, and the course tends to repeat in later pregnancies. So it is important to reassess it throughout pregnancy.
The most important point: uncontrolled asthma is linked to a higher risk of pre-eclampsia, premature birth and low birth weight, and is considered a greater risk to the baby than standard inhalers. So do not stop treatment on your own; continue it, and adjust it together with your doctor.
- Inhaled treatment: a regular controller inhaler and a reliever inhaler are the core of treatment, and are usually continued in pregnancy, tailored to each woman. The risk of uncontrolled asthma is greater than the risk of the treatment.
- In severe cases a higher dose or oral steroids are sometimes needed, because untreated severe asthma carries more risk.
- Biologic drugs: data in pregnancy are accumulating. The decision is individual and is made in advance, with the obstetric team.
- Monitoring: a monthly check of symptoms and lung function, a written action plan, and reducing triggers such as smoke. Women whose asthma is not controlled may also need additional ultrasound monitoring.
Before pregnancy: it is worth meeting us at the planning stage, to stabilise the asthma and adjust treatment. For other chronic lung conditions, see below: planning a pregnancy with chronic lung disease.
How we work
- A detailed history that includes the link to periods, pregnancies and hormonal medication
- Tests at the clinic: spirometry, FeNO and interpretation of cardiopulmonary exercise tests (CPET), as needed
- Cooperation with your treating gynaecologist, and with thoracic surgeons in cases of thoracic endometriosis
- An online consultation or second opinion is available, including for women who live far away or abroad: how online consultations work
Frequently asked questions
Asthma in pregnancy: should I stop my inhalers?
Not on your own. Uncontrolled asthma poses a greater risk to mother and baby than standard inhalers do. It is important to continue treatment and to seek medical advice.
How can I tell whether a pneumothorax (air in the chest) is related to my period?
Signs include recurrence, mostly on the right side, and appearing from 24 hours before a period starts to 72 hours after it begins. If it has happened to you more than once, tell your doctor and raise the possibility of thoracic endometriosis.
Is thoracic endometriosis common?
It is relatively rare, and the exact frequency is not known. It is not always diagnosed, partly because the symptoms are mistaken for other problems. That is why it is important to think of it when there is a recurring pattern around periods.
Does the contraceptive pill reduce asthma around periods?
In some studies women taking the pill had fewer symptoms, but the evidence is limited. The decision is individual and is made together with your gynaecologist.
Planning a pregnancy with chronic lung disease
Women with a chronic lung disease, such as pulmonary hypertension or interstitial lung disease (ILD), are advised to consult both their lung specialist and a specialist in high-risk pregnancy (maternal-fetal medicine) at the planning stage, before becoming pregnant. This makes it possible to assess how the lungs are doing, check that medication is suitable for pregnancy, and plan shared follow-up.
The risk in pregnancy depends on the disease, its severity and general health. In some diseases, above all pulmonary hypertension, pregnancy is considered high risk, and in some cases it is not recommended. The decision is made together with you, individually, after a full assessment.
Sources
- Thoracic endometriosis syndrome: a comprehensive review and multidisciplinary approach to management (J Clin Med 2024)
- Thoracic endometriosis: a clinical review and update of current and evolving diagnostic and therapeutic techniques (Curr Pulmonol Rep 2021)
- Perimenstrual asthma: from pathophysiology to treatment strategies (Multidiscip Respir Med 2016)
- Quick reference: managing asthma during pregnancy (NHLBI)
- Respiratory physiology and lung disease in pregnancy (Cleve Clin J Med)
- Course of asthma during pregnancy (Allergy Asthma Clin Immunol 2018)
Related topics
General information only; it does not replace a medical consultation. עברית