Hilary DuBrock, MD - phaware® interview 329

Jun 16, 2020

Dr. Hilary DuBrock is an Assistant Professor of Medicine with joint appointments in Pulmonary and Critical Care Medicine and Cardiovascular Medicine from Mayo Clinic in Rochester, MN.

In this episode, she discusses pregnancy and pulmonary hypertension. 

Dr. DuBrock’s clinical and research interests include pulmonary hypertension (PH) and pulmonary vascular complications of liver disease. The goal of Dr. DuBrock’s research is to improve the quality of life of patients with PH and to improve the management of critically ill patients with PH and right ventricular failure.  

My name is Hilary DuBrock and I am a pulmonary hypertension specialist at Mayo Clinic. I've been taking care of patients with pulmonary hypertension for the last three and a half years, and today, I'd like to talk to you about pregnancy and pulmonary hypertension.

Patients with pulmonary hypertension are generally advised to avoid pregnancy, but why? What happens in pregnancy that is so poorly tolerated in patients with pulmonary hypertension?

First of all, the amount of blood in the body that has to be pumped by the heart increases by almost 50% in pregnancy. In order to accommodate this increased volume and flow of blood, the stroke volume which is the amount of blood the heart pumps per heartbeat increases and the pulmonary blood vessels have to dilate.

In patients with pulmonary hypertension, however, their pulmonary blood vessels may not be able to dilate. This can lead to a dangerous situation called right heart failure. In right heart failure, the right side of the heart has difficulty pumping blood through the pulmonary blood vessels to the left side of the heart due to the increased resistance to flow in these constricted or narrowed pulmonary blood vessels.

Right heart failure is characterized by symptoms of shortness of breath, swelling in the legs, abdominal swelling or bloating and can lead to low blood pressure and even death.

In addition to these changes, pregnancy is also associated with an increased risk of blood clots which are also poorly tolerated in patients with pulmonary hypertension. Because of this increased stress on the heart during pregnancy, pregnancy can sometimes unmask a diagnosis of pulmonary hypertension.

These patients may have had minimal symptoms before pregnancy when the heart did not have to work as hard, but then do not have the reserve capacity to handle all of these changes that occurred during pregnancy.

Additionally, the levels of certain hormones such as estrogen and progesterone changes dramatically with pregnancy and these hormones may play a role in the process of developing pulmonary hypertension and may explain why some patients with pulmonary hypertension presented during or just after pregnancy.

This in particular is an area of active research in the field of pulmonary hypertension because the symptoms of pulmonary hypertension such as shortness of breath and leg swelling can be nonspecific and common in pregnancy in general, physicians caring for pregnant patients have to be aware of the signs and symptoms of pulmonary hypertension and right heart failure in order to make a timely diagnosis and basic screening tests such as echocardiogram and electrocardiogram and blood tests are useful and safe screening tests that can be performed during pregnancy.

So we recommend that patients with pulmonary hypertension avoid pregnancy to prevent heart failure or death, but despite this important recommendation, many patients don't even recall being counseled about the risks of pregnancy and are not educated about different options to avoid pregnancy.

So what are these options?

Given the risk of failure with any one method, we do generally recommend that patients use at least two methods. One method is just the barrier methods such as condoms, which usually are not sufficient. Other methods include permanent methods of sterilization - such as having your tubes tied or having a vasectomy in the male partner. Intrauterine devices or IUDs are also generally considered to be safe in pulmonary hypertension and can provide some long-term contraception as well.

Estrogen birth controls or injected, progesterone such as Depo-Provera are associated with an increased risk of blood clots, which can be dangerous in the setting of pulmonary hypertension so are typically avoided.

In general, all of these decisions regarding contraception and family planning in patients with pulmonary hypertension, however, need to be individualized with a discussion of the risks and benefits and to be mutually agreed upon by the patient, the pulmonary hypertension specialist and an expert in family planning.

So what happens if pulmonary hypertension patients do get pregnant?

Unfortunately, the risk of death is still quite high during pregnancy and just after pregnancy. Older studies estimated this risk to be approximately 30 to 56%. There have been more recent studies suggesting that outcomes have improved over the years with close monitoring, aggressive treatment of pulmonary hypertension, newer therapies, and multidisciplinary care particularly in patients with mild pulmonary hypertension, but pregnancy still remains high risk.

Because of this high risk, a therapeutic abortion should be offered to patients with pulmonary hypertension who become pregnant and this should be performed in the first trimester if possible.

If patients choose to continue pregnancy however, then they need very close monitoring and may need adjustments to their pH therapy. Guidelines recommend monthly visits during the first trimester and visits every one to two weeks during the second and third trimester with regular assessments of symptoms, exercise capacity, serial echocardiograms to look at the heart function and blood tests.

It's incredibly important that patients have an effective multidisciplinary care management team with input from the patient, the OB provider, the PH specialist and anesthesiologist. Right heart catheterization may be performed and pulmonary hypertension therapies may need to be adjusted.

In terms of pulmonary hypertension targeted therapies, certain medications such as riociguat and endothelin receptor antagonists including macitentan, ambrisentan and bosentan are considered category X, meaning they are contraindicated in pregnancy due to the risk of harm to the baby and need to be discontinued.

Inhaled or IV prostacyclin therapy and sildenafil are generally considered to be acceptable and are preferred medications to use in pregnant patients with pulmonary hypertension.

Warfarin or coumadin is also harmful and should be discontinued, but heparin medications can be used instead if blood thinners are indicated and should also be considered around the time of delivery to prevent blood clots.

In terms of modes of delivery, C-section is generally preferred to avoid the stress of labor and its effect on the heart and lungs. Epidural or epidural spinal anesthesia is also preferred to general anesthesia due to the risks of general anesthesia, as well in patients with pulmonary hypertension.

Unfortunately, the risk does not end at delivery and patients remain at a high risk of heart failure and death in the postpartum period, as the body accommodates the changes in hormones and fluid shifts.

The highest risk period during and after pregnancy are at 20 to 24 weeks of gestation at the time of delivery and then up to two months postpartum. So women needs to be closely monitored with frequent visits after delivery as well.

Patients should be educated regarding the signs and symptoms of heart failure as well as blood clots in the legs, in the lungs, so these conditions can be promptly identified and treated.

The concept of pregnancy and avoidance of pregnancy in young women with pulmonary hypertension can be very challenging and difficult. It is not an easy topic to discuss and that's probably why patients don't recall discussions about this and why providers may not bring it up at initial visits.

A young woman with pulmonary hypertension is often coping with the concept of having a disease associated with decreased survival and then also has to now deal with the issue of being told that they have to also avoid pregnancy and this could be quite difficult.

I think it's important that they're educated regarding the risks of pregnancy, but then also the other options available for family planning and that includes adoption, potentially surrogacy and other different types of family planning options.

There's a lot of things you have to think about in terms of the hormones that are required with egg harvesting, things like in vitro fertilization is not recommended due to the hormones that are administered with that.

So generally, the safest options are things like adopting children.

So I hope this was a helpful overview of pulmonary hypertension in pregnancy. If you're interested in pregnancy or family planning and have pulmonary hypertension, I'd really encourage you to reach out to your physician to discuss different options with both your pulmonary hypertension specialists and other providers in your care team, and to also reach out to other patients with pulmonary hypertension who can be a really great source of support and encouragement and advice.

I'm Dr. Hilary DuBrock, and I'm aware that I'm rare.

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