Lower added risk
- Many repaired or simple heart problems
- Mild valve disease
- Well-controlled rhythm problems
- Often mWHO class I or II
Names & Terms You Will Hear
Plain-language meanings for the terms your care team may use.
| Term | Meaning |
|---|---|
| Pregnancy with heart disease | Being pregnant when you already have a heart or blood-vessel problem, known or newly found. |
| Cardio-obstetrics care | A team approach where a heart doctor and a pregnancy doctor plan your care together. |
| Preconception counseling | A visit before you get pregnant to check your heart and make a safe plan. |
| High-risk pregnancy (heart) | A pregnancy that needs extra care because the heart must work harder than usual. |
| mWHO risk class | A doctor's score from I to IV that rates how risky pregnancy is for your heart. I is lowest risk, IV is highest. |
| Maternal-fetal medicine (MFM) | A pregnancy doctor with extra training to care for a high-risk pregnancy. |
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
Call 911 now if a pregnant or recently delivered woman cannot breathe, faints, has chest pain, or has no pulse. Start Hands-Only CPR: push hard and fast in the center of the chest, about twice per second (the beat of the song "Stayin' Alive"). Call your team right away for a bad headache, vision changes, or sudden swelling (possible preeclampsia), or trouble breathing while lying flat (possible heart failure).What Is Pregnancy and Heart Disease?
- Pregnancy makes the heart work much harder. Blood volume goes up by about 40 to 50 percent. The heart beats faster and pumps more with each beat. A healthy heart adjusts. A weak heart can struggle.
- If you have a heart condition, pregnancy can be safe, but it needs a plan. The best time to start is before you are pregnant, at a preconception visit.
- A heart team guides you: your heart doctor, your pregnancy doctor (OB), and often a high-risk pregnancy doctor (MFM). Together they form your cardio-obstetrics team.
- Doctors rate your risk with the modified WHO (mWHO) classes, from I (low) to IV (so high that pregnancy is not advised). The ladder below shows what each class means.
- Some heart medicines are not safe for the baby and must be stopped or switched before pregnancy. The medicine chart in this guide shows which ones.
- The risk is not over at delivery. The first weeks after birth bring big fluid shifts and carry extra heart risk, so monitoring continues after the baby comes.
mWHO Class I — Lowest Added Risk
- What it means: pregnancy adds little extra heart risk. About a 3 to 5 percent chance of a heart problem.
- Examples: a small, repaired hole in the heart; mild pulmonary valve narrowing; a few extra heartbeats.
- Care: routine pregnancy care with one or two heart checkups. Most do very well.
- Bottom line: a safe pregnancy is expected with normal monitoring.
mWHO Class II — Small Added Risk
- What it means: a small rise in heart risk, about 6 to 10 percent.
- Examples: an unrepaired small hole in the heart; a repaired tetralogy of Fallot; many rhythm problems; some women with thick heart muscle (HCM).
- Care: see your cardiologist each trimester. Watch for symptoms.
- Read more: see our HCM guide if you have a thick heart muscle.
mWHO Class III — High Risk
- What it means: a high risk of a heart problem, about 19 to 27 percent. Pregnancy needs expert care.
- Examples: a mechanical heart valve; a moderately weak pump; some adult congenital heart disease.
- Care: frequent visits at a center with cardio-obstetrics experts. A detailed delivery plan is made early.
- Read more: if you have a mechanical valve, see our living with a prosthetic valve guide for the blood-thinner balance.
mWHO Class IV — Pregnancy Not Advised
- What it means: the risk is very high, about 40 to 100 percent chance of a serious heart event. Pregnancy is usually advised against.
- Examples: pulmonary hypertension; a very weak pump (ejection fraction under 30 percent); past peripartum cardiomyopathy that did not recover; severe valve narrowing; severe aortic widening.
- Care: if already pregnant, care happens at an expert center with intense monitoring and a frank talk about risks.
- Read more: see our pulmonary hypertension guide and peripartum cardiomyopathy guide.
Why It Matters
- Heart disease is now a top cause of serious illness and death in pregnancy in the United States. Knowing your risk and acting early saves lives.
- Planning before pregnancy lets your team treat problems first, stop unsafe medicines, and set a birth plan. Surprises are riskier than plans.
- Some conditions are very high risk. Pulmonary hypertension (high pressure in the lung arteries) is one of the most dangerous, and pregnancy is usually advised against.
- Medicines matter early. ACE inhibitors, ARBs, ARNI, statins, and warfarin can harm a baby, most of all in the first 3 months when organs form. Many women do not know this until they ask.
- Warning signs can look like normal pregnancy. Swelling, breathlessness, and tiredness are common, but they can also be signs of heart failure or preeclampsia. This guide helps you tell them apart.
- Good care lowers risk a lot. With the right team, plan, and checkups, most women with heart disease have healthy babies and stay safe.
The look-alike trap: swelling, tiredness, and feeling winded are common in normal pregnancy. But breathing trouble when lying flat, waking at night gasping, a pounding heartbeat, or sudden weight gain are different. If that is you, ask for a heart check.
Risk Factors
Knowing your personal risks helps your care team take extra precautions.
| Risk Factor | Why It Increases Risk |
|---|---|
| Prior peripartum cardiomyopathy | Heart failure in a past pregnancy can return, especially if the pump has not fully recovered. See our peripartum cardiomyopathy guide. |
| Mechanical heart valve | Needs blood thinners during pregnancy, and the choice of thinner is a careful balance for mother and baby. |
| Pulmonary hypertension | High pressure in the lung arteries. This is one of the highest-risk conditions, and pregnancy is usually advised against. |
| Aortic disease (Marfan, dilated aorta) | Pregnancy hormones and extra blood flow can stretch a weak aorta and raise the risk of a tear. |
| Congenital heart disease | A heart problem you were born with. Many women do well, but the type and any past surgery change the risk. |
| Coronary artery disease | Narrowed heart arteries can cause chest pain or a heart attack under the strain of pregnancy. |
| Cardiomyopathy (weak or thick heart muscle) | A weak pump or a thick muscle (HCM) can struggle with the extra workload of pregnancy. |
| Heart rhythm problems (arrhythmias) | Pregnancy can set off or worsen a fast or uneven heartbeat. Some rhythm medicines must be changed. |
| High blood pressure or past preeclampsia | Raises the chance of preeclampsia again and of heart strain in pregnancy. |
Conditions That Raise Pregnancy Risk — and Where to Read More
High risk — expert care
- Mechanical heart valve
- Weak heart muscle (cardiomyopathy)
- Aortic disease (Marfan, dilated aorta)
- Often mWHO class III
Very high — pregnancy not advised
- Pulmonary hypertension
- Very weak pump (EF under 30%)
- Past peripartum cardiomyopathy that did not recover
- mWHO class IV
Treatment Options
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
- Start with a preconception visit if you can. Your team checks your heart with an echocardiogram (a heart ultrasound) and other tests, rates your mWHO risk, and makes a plan.
- Switch unsafe medicines before you try to get pregnant. ACE inhibitors, ARBs, ARNI, statins, spironolactone, and SGLT2 pills are stopped, and safer ones are started.
- For high blood pressure in pregnancy, labetalol, nifedipine, and methyldopa are common safe choices. The medicine chart below shows the safe swaps.
- If you take warfarin for a mechanical valve, your plan is made just for you. Warfarin is often switched to heparin or low-molecular-weight heparin (LMWH), most of all in the first 3 months, to protect the baby.
- Through pregnancy you get extra checkups, blood pressure checks, and sometimes repeat heart scans. You will be seen more often than in a routine pregnancy.
- Labor and delivery are planned ahead with the heart team. Many women with heart disease can deliver vaginally. A cesarean is chosen for certain heart or pregnancy reasons.
- An epidural often helps because it eases the heart's workload during labor. Your team plans pain control, fluids, and monitoring ahead of time.
- After birth, monitoring goes on. The first days bring big fluid shifts, and some problems (like heart failure) can show up or get worse in the weeks after delivery.
Heart Medicines in Pregnancy — Stop, Switch, or Continue
| Medicine | In pregnancy | Why / safer option |
|---|---|---|
| ACE inhibitor, ARB, ARNI | Stop | Can harm the baby's kidneys; switch before conceiving |
| Statin (cholesterol) | Stop | Not needed for the baby; pause until after breastfeeding |
| Warfarin (first trimester) | Switch | Can cause birth defects early; often heparin or LMWH instead |
| Spironolactone, SGLT2 pill | Stop | Not enough safety data; switch before conceiving |
| Beta-blocker (labetalol, metoprolol) | Usually OK | Used for blood pressure and rhythm; team picks the dose |
| Methyldopa, nifedipine, hydralazine | Usually OK | Common safe choices for high blood pressure |
| Water pill (furosemide) | Usually OK | Used carefully for fluid overload |
| Low-dose aspirin, heparin / LMWH | Usually OK | Aspirin may lower preeclampsia risk; heparin for clots/valves |
Planning Labor and Delivery With Your Heart Team
- Make the plan early: by the third trimester your heart team and OB write a clear delivery plan, including where to deliver and who is in the room.
- Vaginal birth is often best for the heart: many women with heart disease can deliver vaginally, which is usually easier on the heart than surgery.
- An epidural can help: good pain control lowers the heart's workload during labor. Your team plans it ahead.
- A cesarean when needed: chosen for certain heart conditions (like a severely widened aorta) or for usual pregnancy reasons, not by default.
- Blood pressure matters: if you have high blood pressure or preeclampsia, the team manages it closely. See our high blood pressure guide.
- After delivery: monitoring continues for days to weeks, because fluid shifts and heart strain can peak after birth.
Comfort Measures at Home (No Medication Needed)
These simple steps support healing and ease symptoms. Use them alongside any medication your doctor prescribes.
- Keep every appointment, even when you feel well. Many heart changes in pregnancy have no symptoms until they are advanced.
- Take folic acid before and in early pregnancy as your team advises. It supports the baby and is part of good preconception care.
- Stay active as your team allows. Gentle, regular activity helps your heart, but ask what is safe for your condition.
- Watch salt and weight gain if you have heart failure or high blood pressure. Sudden swelling or weight gain can be a warning sign.
- Do not smoke, and avoid alcohol. Both harm the heart and the baby.
- Plan reliable birth control between pregnancies. Spacing pregnancies and timing them around your heart health is part of staying safe.
- Bring a medicine list to every visit. Confirm each medicine is safe before you keep taking it in pregnancy.
Risks, Benefits, and Alternatives
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
Every choice has trade-offs. Use this table to start the shared decision conversation with your care team.
| Option | Risks | Benefits | Alternatives |
|---|---|---|---|
| Preconception counseling and risk scoring | Takes time and may deliver hard news (some women learn pregnancy is too risky). | Finds and fixes problems early, swaps unsafe medicines, and builds a delivery plan before you conceive. | Skipping it (not advised). Waiting until you are already pregnant gives fewer safe options. |
| Switching unsafe heart medicines before pregnancy | The new medicine may control your condition a little less well, so it needs monitoring. | Protects the baby from medicines that can cause harm or birth defects, especially in the first trimester. | Staying on the unsafe medicine (not advised in pregnancy). Stopping all medicines (risky for your heart). |
| Blood thinners for a mechanical valve in pregnancy | All options carry some risk: warfarin can harm the baby; heparin and LMWH need close monitoring and may protect the valve a bit less. | Prevents dangerous clots on the valve, which can be deadly for mother and baby. | No blood thinner (not safe with a mechanical valve). The exact plan is individualized by your team. |
| Planned hospital delivery with the heart team | May mean delivering at a larger center, away from home, with more monitoring. | Brings heart and pregnancy experts together for the riskiest hours, with a plan for pain control and emergencies. | Routine local delivery without a heart plan (riskier for higher mWHO classes). |
| Advising against pregnancy in very high-risk conditions | A painful recommendation that affects life plans and may need counseling and support. | Avoids a 40 to 100 percent chance of a serious heart event in class IV conditions like pulmonary hypertension. | Proceeding with very close monitoring at an expert center, or other paths to parenthood. See our pulmonary hypertension guide. |
Common Misconceptions
| Myth | Reality |
|---|---|
| If I feel fine, my heart is fine for pregnancy. | Many serious heart problems cause no symptoms until they are advanced. A normal feeling does not equal a low risk. Get checked before and during pregnancy. |
| I can keep taking my usual heart medicines while pregnant. | Several common heart medicines, including ACE inhibitors, ARBs, ARNI, statins, and warfarin, can harm a baby. Some must be stopped or switched before you conceive. Always confirm each one with your team. |
| Pregnancy is safe for everyone as long as doctors watch closely. | For most heart conditions, good care makes pregnancy safe. But a few, like pulmonary hypertension, are so risky that pregnancy is advised against, even with the best care. |
| Once I deliver the baby, the heart risk is over. | The first days and weeks after birth bring large fluid shifts and carry real heart risk. Heart failure and other problems can appear or worsen after delivery. Monitoring continues postpartum. |
| Swelling and breathlessness are just normal pregnancy. | Mild swelling and breathlessness are common. But trouble breathing while lying flat, waking up gasping, a severe headache, vision changes, or sudden swelling can signal heart failure or preeclampsia. Get checked. |
| A cesarean is always safer for a heart patient. | Many women with heart disease can safely deliver vaginally, which is often easier on the heart. A cesarean is chosen for specific heart or pregnancy reasons, not by default. |
| Having a heart condition means I cannot become a parent. | Most women with heart disease can have a safe pregnancy with planning. For the highest-risk conditions, your team can discuss safer timing or other paths to parenthood. |
Possible Complications
Knowing what can go wrong helps you spot problems early. Most complications are uncommon, especially with treatment.
| Where / What | What Can Happen |
|---|---|
| Heart failure | The extra blood volume can be too much for a weak or stiff heart. This causes fluid in the lungs, breathlessness, and swelling. It can start during pregnancy or in the weeks after birth. |
| Preeclampsia (dangerous high blood pressure) | A pregnancy problem with high blood pressure and signs of organ strain. It can lead to seizures, stroke, and heart failure. Warning signs are a bad headache, vision changes, upper-belly pain, or sudden swelling. |
| Dangerous heart rhythms (arrhythmia) | Pregnancy can set off a fast or uneven heartbeat. Most are not harmful, but some cause fainting or strain the heart and need care. |
| Aortic tear (dissection) | In women with a weak or widened aorta, such as Marfan syndrome, the extra strain can cause the aorta to tear. This is a life-threatening emergency. |
| Blood clots (thromboembolism) | Pregnancy raises clot risk, and some heart conditions raise it more. A clot can travel to the lungs or brain. Leg pain and swelling, or sudden breathlessness, are warning signs. |
| Valve or device problems | A clot can form on a mechanical valve if blood thinners are not balanced well. Other valve problems can worsen under the extra workload of pregnancy. |
| Risk in the baby | Some heart medicines and very high-risk conditions raise the chance of preterm birth, low birth weight, or birth defects. Your team weighs this when planning care. |
Points to Know
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
If you remember nothing else, remember these key points.
- Pregnancy makes the heart work much harder. If you have heart disease, plan ahead with a heart team.
- A preconception visit is the safest start. It lets your team check your heart, score your risk, and swap unsafe medicines before you conceive.
- Stop or switch unsafe medicines: ACE inhibitors, ARBs, ARNI, statins, and warfarin (first trimester) can harm a baby. Confirm every medicine.
- Pulmonary hypertension is one of the highest-risk conditions; pregnancy is usually advised against.
- Know the warning signs: severe headache, vision changes, trouble breathing while lying flat, fainting, or sudden swelling. These can mean preeclampsia or heart failure.
- Labor and delivery are planned with your team. Many women can deliver vaginally; an epidural often helps the heart.
- Risk continues after birth. The first weeks postpartum need close watching.
- Use reliable birth control to time and space pregnancies around your heart health.
When to Call Us — and When to Call 911
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
If you are not sure, call. We would rather hear from you twice than miss a real problem.
- Trouble breathing at rest, gasping for air, or coughing up pink frothy spit — call 911.
- Fainting, chest pain or pressure, or a racing heartbeat that will not settle — call 911.
- Sudden severe headache, vision changes (blurring or spots), or upper-belly pain — call your team now; these can be preeclampsia.
- Sudden, severe swelling of the face or hands, or a fast weight gain over a few days — call your team today.
- Sudden, tearing chest or back pain — call 911; this can be an aortic tear in women with aortic disease.
- Shortness of breath when lying flat, or waking at night needing to sit up to breathe — call your team today.
- Pain, redness, or swelling in one calf — call your team today; this can be a clot.
- Less baby movement than usual, or any bleeding — call your OB right away.
Office: (727) 943-5200
Trusted Resources
Independent, evidence-based pages we recommend for deeper reading.
- American Heart Association — Pregnancy and Maternal Health — Patient-friendly overview of heart health before, during, and after pregnancy.
- Cleveland Clinic — Heart Disease and Pregnancy — Plain-language guide to planning and managing pregnancy with a heart condition.
- ACOG — Pregnancy and Heart Conditions — Obstetric FAQ on heart conditions, labor and delivery, and warning signs.
- CDC Hear Her — Urgent Maternal Warning Signs — The warning signs every pregnant and postpartum woman should know and act on.
- AHA Hands-Only CPR — How to do Hands-Only CPR if someone collapses — push hard and fast in the center of the chest.
Sources Used to Build This Guide
- AHA — Pregnancy and Heart Disease [patient-education] — Patient-facing overview of cardiovascular risks in pregnancy and care planning
- Cleveland Clinic — Heart Disease and Pregnancy [patient-education] — Preconception planning and pregnancy cardiac care in plain language
- Mayo Clinic — Heart Conditions and Pregnancy [patient-education] — Plain-language framing for pregnancy with existing heart disease
- ESC Guidelines — CV Disease During Pregnancy (2018) [guideline] — Source of the modified WHO (mWHO) risk classes and medicine-safety framework
- AHA Scientific Statement — Cardiovascular Care in Pregnancy (Circulation 2020) [guideline] — Cardio-obstetrics team model, preeclampsia risk, and postpartum monitoring
- CARPREG II Risk Score (JACC 2018, Silversides et al.) [research] — Validated predictors of maternal cardiac events used in risk counseling
- ACOG — Pregnancy and Heart Conditions (Patient FAQ) [patient-education] — Obstetric perspective on labor, delivery, and warning signs
- MedlinePlus — High-Risk Pregnancy [patient-education] — Plain-language reference for high-risk pregnancy monitoring
- CDC — Hear Her Campaign: Urgent Maternal Warning Signs [patient-education] — Source for the urgent maternal warning signs in the when-to-call section
- Preeclampsia Foundation — Signs and Symptoms [patient-education] — Patient-facing detail on preeclampsia warning signs
