Pregnancy is a transformative journey that not only nurtures a new life but also places unique demands on a woman’s body, particularly her heart. Dr. Harvard Lin, Consultant Obstetrician, Gynaecologist, and Urogynaecologist at the Asian Obstetrics & Gynaecology Centre (AOGC), shares critical insights into the intersection of pregnancy and heart health.
How Pregnancy Strains the Heart
“Pregnancy significantly increases the workload on a woman’s heart and circulatory system due to several physiological changes,” explains Dr. Lin. These changes include:
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Increased Blood Volume: Rises by 30% to 50%, peaking between 28 to 34 weeks.
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Elevated Cardiac Output: Increases by 30% to 50% due to a higher stroke volume and heart rate.
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Reduced Systemic Vascular Resistance: Hormonal changes cause vasodilation, lowering blood pressure initially.
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Aortocaval Compression: The uterus compresses the inferior vena cava, causing dizziness.
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Hypercoagulable State: Increased clotting factors raise the risk of venous thromboembolism.
Monitoring Body Changes During Pregnancy
To manage physiological changes during pregnancy and support foetal development, Dr. Lin recommends having:
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Regular prenatal checkups: To monitor vital signs and detect early signs of complications.
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Blood and urine tests: Check for anaemia, infections, gestational diabetes, and kidney function.
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Ultrasound scans: Monitor foetal growth and well-being, including amniotic fluid levels.
- Doppler studies: Assess blood flow in the umbilical cord, uterus, and foetal organs, and also to assess foetal well-being in high-risk pregnancies.
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Cardiac monitoring (if necessary): Especially for those with known heart conditions.
Lifestyle Adjustments You Should Make During Pregnancy
In order to prevent complications and support the healthy development of your baby, it’s important to make lifestyle adjustments, such as:
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Eating a balanced diet and taking prenatal vitamins with folic acid, iron, and DHA.
- Avoiding high-mercury fish, unpasteurized dairy, and undercooked meat.
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Engaging in moderate physical activity such as walking, swimming, prenatal yoga for 30 minutes most days unless advised otherwise.
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Getting adequate sleep and rest, approximately 7–9 hours. Sleep on the left side to improve blood flow to the baby.
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Avoiding harmful substances like tobacco and alcohol. If drinking coffee, limit intake to <200 mg/day (about one 12-oz coffee).
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Managing stress by practising relaxation techniques like meditation, deep breathing, or gentle stretching.
- Staying hydrated by drinking at least 8–10 glasses of water a day to support circulation and amniotic fluid levels.
When Do Most Cardiovascular Issues Arise?
Most cardiovascular complications manifest during the third trimester or postpartum. Signs that may be flagged by the healthcare provider during a physical exam include an enlarged heart (cardiomegaly), a heart murmur, high blood pressure, protein in the urine, as well as swollen veins in the neck.
But as a mother, be mindful of chest pain, prolonged palpitations, blurred vision, fainting, and excessive swelling, as they are also warning signs for heart issues. “These symptoms may appear harmless but could signal a heart problem if the symptoms begin after week 20 of pregnancy, prevent the mother from doing normal daily tasks, shortness of breath even while resting or wake the mum up in the middle of the night.” Dr. Lin said.
Heart Disease Complications During Pregnancy and Delivery
Becoming a mother is more than taking care of the baby growing inside you; you should also take care of yourself, which also means learning about heart complications that might occur during your pregnancy and ways to prevent them.
During Pregnancy
Pregnancy naturally puts more stress on the cardiovascular system, which can worsen existing heart conditions or trigger new ones. Key complications include:
- Heart Failure: The heart may struggle to pump blood effectively due to increased blood volume (up to 50% more). This is more common in women with congenital heart disease, valvular disease, or cardiomyopathy.
- Arrhythmias: These are irregular heartbeats (too fast, too slow, or uneven), which can be benign or potentially serious if caused by underlying heart problems.
- Hypertensive disorders of pregnancy: These include preeclampsia, gestational hypertension, or eclampsia, which can raise the risk of heart complications and may lead to stroke, heart failure, or placental problems.
- Peripartum cardiomyopathy: This is a rare but serious condition where the heart weakens and enlarges in the last month of pregnancy or up to five months postpartum, causing shortness of breath, swelling, and fatigue.
- Pulmonary oedema: This is when fluid builds up in the lungs due to heart dysfunction, leading to breathing difficulties.
- Blood clots and thromboembolism: These can occur because pregnancy increases clotting risk; heart issues and immobility can make clots more likely to travel to the lungs (pulmonary embolism), brain (stroke), or heart.
During Delivery
- Acute heart failure can occur, as labour and the immediate postpartum period are highly stressful on the heart. Sudden shifts in fluid volume can overload the heart.
- Arrhythmias can occur, as physical and emotional stress during delivery may trigger abnormal
rhythms.
- Cardiac arrests may happen, however, this is rare but serious, can result from unrecognised heart
disease, embolism, or severe bleeding.
- Bleeding risks are also possible, as anticoagulant use (blood thinners) for heart disease management may increase the risk of bleeding during delivery.
Ways to Prevent Heart Complications During Pregnancy
“Many of these complications and risks associated with heart disease during pregnancy and delivery can be managed with proper care, if anticipated early enough.” Here are some ways to prevent or manage the risks:
- Preconception counselling: Women with known heart conditions should see a cardiologist and maternal-foetal medicine specialist prior to conceiving.
- Regular monitoring: Frequent checkups, echocardiograms, blood pressure monitoring, and lab work help track heart health throughout pregnancy.
- Multidisciplinary care: Management by a team: OB-GYN, cardiologist, anaesthesiologist, neonatologist, and nurses familiar with high-risk pregnancies.
- Medication adjustments: Some heart medications may need to be stopped or substituted during pregnancy due to potential harm to the foetus.
- Lifestyle modifications: Maintain a healthy diet, control weight gain, avoid smoking/alcohol, and stay active as advised by a doctor.
Safe Interventions for Mother’s with Heart Conditions During Delivery
“During the delivery stage, specific interventions may be necessary to ensure the safety of both the mother and baby, especially if the mother has a heart condition or is considered high-risk.” Dr. Lin said. The type of intervention will depend on many factors and be based on the woman’s risk profile for heart disease. Here are some factors to consider:
Table 1: Summary of efficacy and safety of each method of intervention
Mode of Delivery: Vaginal vs. Caesarean Section
- In most cases, vaginal delivery is recommended due to its lower risk of blood loss, infection, and clot formation. Assisted methods like vacuum or forceps may be utilised to reduce the duration of labour and alleviate cardiovascular strain. When closely monitored, vaginal birth is generally safe, especially with the use of epidural anaesthesia to manage pain and minimize cardiovascular stress.
- Caesarean section, while generally safe, is typically reserved for cases involving high cardiac risk, such as decompensation, arrhythmias, or medical emergencies. This method carries higher risks, including bleeding, thromboembolism, and prolonged recovery time.
Anaesthesia Management
Epidural anaesthesia is often preferred because it helps control blood pressure surges and alleviates heart strain, making it especially beneficial for patients with conditions like hypertension or cardiomyopathy. General anaesthesia is used selectively in emergencies and requires expert handling due to its potential cardiovascular risks.
Invasive Monitoring (for high-risk cases)
In high-risk pregnancies, advanced monitoring methods like arterial lines, central venous pressure monitoring, or pulmonary artery catheters allow continuous tracking of heart performance and blood pressure. These are critical tools for guiding timely interventions and are safe in the hands of skilled professionals.
Medication Adjustments During Labour
Specific medications may be adjusted to ensure maternal stability. Diuretics manage fluid overload, beta-blockers control heart rate, and anticoagulants—commonly paused before delivery—help reduce bleeding risks.
Emergency Interventions
In critical situations, interventions such as defibrillation or cardioversion for severe arrhythmias, Advanced Cardiac Life Support (ACLS) during cardiac arrest, and immediate caesarean delivery in response to acute cardiac events or foetal distress may be necessary.
Preparing for Another Pregnancy After Complications
“Women who have experienced complications in previous pregnancies should take extra precautions,” advises Dr. Lin. Steps include:
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Preconception check-up. Consult an OB-GYN or maternal-foetal medicine specialist to review any past pregnancy complications, such as preeclampsia, miscarriage, or gestational diabetes, and evaluate your overall health and family medical history.
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Managing health conditions. Ensure that any chronic conditions like diabetes, hypertension, thyroid dysfunction, or autoimmune diseases are well-controlled before trying to conceive. Address weight-related concerns to maintain a healthy BMI.
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Starting prenatal vitamins early. Start taking folic acid supplements (between 400 to 800 mcg daily) at least three months before trying to conceive. If you’ve had past pregnancy complications, consult your doctor about potentially higher doses.
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Maintaining a healthy diet and weight. Focus on whole foods—fresh fruits, vegetables, whole grains, and lean protein—and maintain proper hydration. Balanced nutrition supports a healthy weight and reduces pregnancy-related risks.
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Avoiding harmful substances. Stop using tobacco, alcohol, and recreational drugs. Always check with your doctor about the safety of any prescription medications or herbal remedies.
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Regular physical activity. Participate in doctor-approved exercises like walking, swimming, or prenatal yoga to build stamina and support cardiovascular health.
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Allowing time to heal between pregnancies. Ideally, give your body at least 18 months to heal after a full-term birth before becoming pregnant again—unless your healthcare provider advises differently.
Maternal Heart Health as Part of Pre-Conception Counselling
“Maternal heart health should be part of pre-conception counselling for all women—not just those with pre-existing conditions. Pregnancy can reveal silent cardiac issues and potentially escalate risks.” Dr. Lin advises.
Cardiovascular disease is a leading cause of pregnancy-related deaths worldwide, often impacting women previously unaware of any heart conditions. The cardiovascular stress of pregnancy can expose hidden issues such as high blood pressure, arrhythmias, or congenital abnormalities.
Integrating heart health into pre-conception planning helps prevent adverse outcomes and enhances both maternal and foetal well-being. It’s also an opportunity to assess lifestyle factors like nutrition, exercise habits, and substance use, and to educate women on recognising symptoms of heart problems during pregnancy.
Even those considered low-risk can develop severe heart-related complications like gestational hypertension, preeclampsia, or peripartum cardiomyopathy—each linked to elevated cardiovascular risks later in life.
Caregynaecologist’s Role in Postpartum Cardiovascular Follow-up Care
Gynaecologists have a crucial responsibility in the postpartum period to ensure cardiovascular issues are not overlooked. As Dr. Lin points out, “The postpartum period is a critical window where undiagnosed or poorly managed heart conditions can still pose significant risks.”
This involves identifying high-risk women based on medical and pregnancy history, performing relevant screenings such as monitoring blood pressure, heart rate, and other cardiovascular indicators, and working closely with cardiologists or other specialists to ensure a continuum of care. Gynaecologists are also key in educating new mothers on the importance of long-term heart health and promoting lifestyle changes that support recovery and reduce future cardiovascular risks.
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Conducting cardiovascular screenings.
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Coordinating with cardiologists.
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Educating patients on long-term heart health.
About Dr. Harvard Lin
Dr. Harvard Lin is a Consultant Obstetrician, Gynaecologist, and Urogynaecologist at the Asian Obstetrics & Gynaecology Centre (AOGC) in Singapore. With dual accreditation in both general obstetrics and urogynaecology, Dr. Lin combines clinical excellence with compassionate care to support women through all stages of life. He is a Fellow of the Royal College of Obstetricians and Gynaecologists (UK) and the Academy of Medicine, Singapore, with a strong commitment to high-risk pregnancy care, pelvic floor disorders, and minimally invasive surgery.
