Hereditary angioedema and pregnancy

Last updated Jan. 13, 2025, by Lindsey Shapiro, PhD
Fact-checked by Joana Carvalho, PhD

Having a safe pregnancy and delivery is entirely possible for patients with hereditary angioedema (HAE), a genetic condition characterized by swelling attacks in the deep layers of the skin and mucus membranes. Still, managing HAE and pregnancy simultaneously may take some extra considerations.

While every pregnancy is different, some patients will experience an increase in the frequency and/or severity of their HAE attacks during pregnancy, and not all HAE medications will be safe to use during this period. It’s also important to be prepared for a potential attack during labor and delivery, though these are generally rare.

HAE patients who are pregnant or planning to become pregnant should always work with their doctors to develop an individualized management plan for dealing with angioedema during pregnancy that minimizes any risks to both mother and child.

How pregnancy affects HAE

With appropriate care and planning, most women with HAE can have a safe and uncomplicated pregnancy and birthing experience. Still, pregnancy may cause changes to a woman’s angioedema symptoms that are important to be prepared for.

While both men and women can have HAE, women have been found to experience more frequent and severe swelling attacks. This is believed to be, at least in part, related to higher exposure to estrogen, a female sex hormone.

As estrogen levels surge during pregnancy, pregnant women often report an increase in HAE attack frequency or severity — though evidence about which trimester is associated with increased attack rates remains conflicting. Studies have also indicated that attacks with abdominal symptoms are the most common presentation of HAE during pregnancy, which may be related to stress from fetal movements and enlargement of the uterus.

As every pregnancy is different, it’s possible for some women to find that their HAE symptoms remain unchanged or become less severe. Moreover, symptom severity during one pregnancy does not necessarily predict what will happen during a future pregnancy. The risk factors that predict HAE attacks during pregnancy are not currently well established.

Breastfeeding may also affect the frequency or severity of a woman’s angioedema attacks, and this has been linked to increased levels of the hormone prolactin during lactation.

Care during pregnancy and beyond

While women with HAE can have a safe pregnancy and delivery, adjustments to care and thoughtful planning at each stage may be needed to help ensure the best possible outcome.

Pregnancy

When planning for pregnancy, women should discuss starting long-term prophylactic treatment with their healthcare providers, especially if they experience frequent or severe attacks, or if their swelling episodes are often triggered by mood changes or stress. Clinicians will assess whether existing regimens need to be stopped or changed — or if new ones should be started — to best fit a person’s individual needs and preferences during pregnancy.

During pregnancy, regular check-ins with healthcare providers are essential to ensure treatments remain effective and side effects are properly managed. Doctors can also prescribe safe on-demand treatments for patients to promptly manage any attacks that may occur.

While women with HAE should let their doctors know anytime they feel any swelling symptoms, it’s important to note that not all swelling experienced during pregnancy is a sign of an angioedema attack or a cause for concern. For example, it’s quite common for pregnant people with and without HAE to gradually experience swelling in their legs and feet, which can be uncomfortable but is usually not harmful.

Swelling can also be a sign of preeclampsia, a serious condition marked by high blood pressure and organ damage that can happen during pregnancy. Sudden facial swelling, as well as swelling in the hands, are common signs of preeclampsia.

Labor and delivery

Having HAE does not increase a woman’s risk of premature delivery, miscarriage, or cesarean delivery (also known as a C-section), and most patients have an uncomplicated vaginal delivery.

Still, it is important for women with HAE to talk with their healthcare providers ahead of time about measures that may be needed to ensure their HAE remains well controlled through the birthing process.

HAE swelling attacks during delivery are rare, but can happen. Depending on a woman’s particular case, a doctor may recommend administering a dose of prophylactic treatment, especially if a C-section or other surgical procedure is required. On-demand treatment should also be available in the delivery room for emergency use in case of an attack.

After giving birth, a small percentage of women may experience an HAE swelling attack. For this reason, it’s recommended that women are closely monitored for 72 hours (or three days) after delivery.

Breastfeeding and postpartum period

In the weeks following delivery, some women may experience more frequent attacks, especially affecting the vulva. Facial swelling postpartum or swelling affecting other body areas can also occur at any time, just like before pregnancy.

In general, it is safe for women with HAE to breastfeed, and they are even encouraged to do so. But because there may be an increased risk of HAE attacks during this period, maintaining a stable prophylactic treatment regimen and having access to on-demand therapies is recommended.

Women should talk with their doctors ahead of time about what medications may be needed and ensure they have them at hand during this period. They should also discuss their long-term treatment plans for after the postpartum period.

Treatment of HAE during pregnancy and breastfeeding

It is generally recommended that pregnant people with HAE with recurrent attacks or a high-risk pregnancy remain on a stable prophylactic treatment regimen to keep the disease under control. However, not all available HAE medications are considered safe for a developing fetus.

Women should reach out to their doctors if they are pregnant or are planning to become pregnant to discuss which prophylactic therapies could work best in their particular situation, based on the benefits and risks of each available regimen. It’s important not to start or stop any medications without discussing it with a healthcare provider first, as this could compromise the health of the mother or child.

Approved treatments

According to recent guidelines, it’s recommended that human C1 inhibitor (C1-INH) products be used as a first-line option for preventing and treating HAE attacks in pregnant and breastfeeding patients. Both plasma-derived or lab-made products may be used, but preference is given to blood-derived products.

These medications should also be used to prevent attacks during any procedures or surgeries done during pregnancy, and should be available at the hospital during labor and delivery.

Examples of C1 inhibitor products include:

• Berinert
• Cinryze
• Haegarda
• Ruconest.

Virally inactivated fresh frozen plasma products also can be safely used in pregnant women when C1-INH products are not available.

Potential treatment risks

It’s not well established whether antifibrinolytics such as tranexamic acid, which are sometimes used off-label to prevent and treat HAE attacks, can be safely and effectively used in pregnant people, and current guidelines suggest avoiding them if possible.

However, this may be considered as a prophylactic treatment option if there are not any suitable alternatives. Tranexamic acid can pass into breast milk and shouldn’t be used during breastfeeding.

Attenuated androgens, such as danazol, are not considered safe during pregnancy due to their ability to cross the placenta and affect fetal development. They are also contraindicated during lactation because they can pass into breast milk.

There are less available data about the use of newer HAE therapies during pregnancy, so current guidelines generally do not recommend their use until more data become available.

When considering any HAE medication for a pregnant or breastfeeding woman, doctors will carefully weigh the potential benefits of the treatment for controlling the disease against the potential risks to the fetus or infant.

Will my baby also have HAE?

HAE is a genetic condition that can be caused by mutations in the genes SERPING1, F12, and several others. For this reason, it can be inherited from a parent.

Humans have two copies of most genes — one from their mother and one from their father. HAE is inherited in an autosomal dominant manner, meaning that one faulty copy of a gene is sufficient to cause the disease. If a person has HAE, there is a 50% chance that any of their biological children will inherit it.

In most cases, HAE can be diagnosed in a child by measuring the levels and activity of C1-INH, a protein that’s either missing or dysfunctional in the most common types of HAE. While it’s important to reach an HAE diagnosis as soon as possible, it is generally recommended that babies do not receive this blood test for HAE until after their first birthday, when test results are most accurate. C1-INH levels are often decreased during the first year of life, and this could lead to inaccurate test results.

Genetic screening is another possible test for HAE that can be performed when C1-INH lab results are not conclusive, and this can be done at any age. A genetic counselor can help families go through their family planning options when considering pregnancy. They can also counsel families about the best time to run HAE testing in a child.

Angioedema News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.