Pregnancy is a stress on the body even for healthy people. When we have a serious disease, we tend to have even more questions. 

As long as you have an excellent HCM specialty team and take health precautions, pregnancy with HCM is usually safe. It is vital that you take your time planning your pregnancy based on your symptoms and situation. Be sure to talk to a genetic counselor, your cardiology team, and your prenatal care provider. You may need to take steps to get your HCM symptoms under control before you get pregnant. This will improve your chances of having a safe and healthy pregnancy.

According to the 2024 AHA/ACC Guidelines the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy (JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY VOL. 76, NO. 25, 2020), "Pregnancy in most women with HCM is well tolerated. Maternal mortality is very low, with only three sudden deaths reported in the literature, all in high-risk (and one undiagnosed) patients, over the past 17 years. Symptoms (dyspnea, chest pain, palpitations) and complications (HF and arrhythmias) occur in 25% of pregnant women with HCM, for whom most had symptoms preceding their pregnancy. There is no difference in outcomes reported for women with LVOTO compared with those without obstruction."

• 75% of pregnant HCM patients get through their pregnancies without symptoms or complications. 
• 25% have symptoms during pregnancy, such as shortness of breath, chest pain, or palpitations. Most had these issues before pregnancy.
• Outcomes were the same for those with left ventricular outflow tract obstruction (LVOTO) and those without.

Recommendations for HCM care before & during pregnancy

Your care team should include a cardiologist and a maternal-fetal medicine specialist who can carefully manage pregnant women with HCM. These doctors should communicate with each other about your case. We recommend receiving care at a Center of Excellence(COE) for HCM.

Prenatal genetic counseling is helpful in learning the risk of passing HCM to the baby. A genetic counselor can help you understand your reproductive options. These options include:

• Preimplantation genetic diagnosis using in vitro fertilization (IVF)
• Screening of the developing baby
• Prenatal testing
• Postnatal genetic testing 

Talk to your genetic counselor about each option's risks and benefits. This will help you make informed decisions around pregnancy.

Shared Decision Making

Parents should discuss pregnancy with HCM with an HCM specialist cardiologist. This process should help the family understand their risk for complications during pregnancy. 

Those who are very symptomatic should learn how to reduce their risk before getting pregnant. Depending on the situation, the options might include:

• Septal reduction therapy (surgical myectomy or alcohol septal ablation) to relieve outflow tract obstruction
• Advanced heart failure therapies for those with heart failure 
• ICD implantation for those who are at high risk of dangerous arrhythmias

Medical Management

If you need  beta-blockers, they are generally considered safe during pregnancy, but avoid atenolol - there is some evidence of potential risk to the baby.

• Pregnant women who take beta-blockers should be closely monitored. Beta-blockers can affect the baby's growth and cause low heart rate in the baby. 

You should avoid most  antiarrhythmic medications during pregnancy because of the potential for adverse effects on the baby, not to mention that many are not recommended for patients with HCM. 

If you have  atrial fibrillation (AF or AFIB): 

• Cardioversion during pregnancy can be done with minimal risk to the developing baby. It is the safest way to restore sinus rhythm in pregnancy. Anticoagulation (blood thinners) to decrease the risk of blood clots should be based on the trimester of pregnancy and the risk to the baby.
• Low molecular weight heparin and warfarin are the safest during pregnancy when a blood thinner is needed. Blood thinners prevent clots that can lead to stroke.

If you are using Camzyos (mavacamten), you should stop taking it before becoming pregnant. This medication is not approved during pregnancy. It has not been tested during human pregnancy, and the effects on the developing baby are unknown. Animal studies showed that this medication can be toxic to the developing baby. You may need to find out how you do off this medication so that you can take other actions to reduce your symptoms of obstruction before getting pregnant.

Echocardiogram

Most complications from HCM during pregnancy occur in the third trimester. It’s a good idea to have an echocardiogram in the second and third trimesters or if new heart symptoms arise. 

An echocardiogram can also diagnose HCM in a baby before birth. This specialized ultrasound is helpful when there is a family history of early-onset HCM or severe heart symptoms.

Delivery

In pregnant women with heart disease, including cardiomyopathies:

• Poor outcomes during delivery are low (3% to 4%). They are similar between vaginal delivery and cesarean section. 
• Bearing down to push the baby out is well tolerated. 
• Vaginal delivery is safest unless there are complications. Cesarean section should only happen when the mother or baby is in distress. Severe bleeding is more likely for women who have a cesarean section. Bleeding can lead to low blood volume, which makes HCM symptoms worse. After speaking with your cardiologist and your birth team, you should make a delivery plan by the end of the second trimester. 
• Epidural analgesia and general anesthesia (for cesarean section) are types of pain relief. They can make the delivery more comfortable for the patient. Both of these forms of pain relief are available to most pregnant patients with HCM. Healthcare providers must monitor the patient for low blood pressure when using medical pain relief. Other forms of pain relief may be available, based on your situation, under the advice of your care team.

Of course, every pregnancy is different, so be sure to discuss all these issues with your doctors.