Pregnancy Is a Physiological Stress Test for the Heart,” Say Cardiologists

Pregnancy is often described as a natural milestone in a woman’s life, but medically, it is one of the most demanding physiological phases the body undergoes, especially the heart. Doctors frequently describe pregnancy as a “physiological stress test” because of the dramatic cardiovascular changes it triggers over just nine months.

During pregnancy, a woman’s blood volume increases by nearly 40–50% to support the growing foetus. To handle this surge, the heart must pump significantly more blood each minute, while the heart rate rises by 10–20 beats per minute. Hormonal changes relax blood vessel walls, and the enlarging uterus alters blood flow dynamics, sometimes increasing pressure in the veins. For most healthy women, the heart adapts remarkably well. However, for those with pre-existing heart disease, kidney disorders, or chronic high blood pressure, this added workload can pose serious risks.
“Pregnancy does not cause heart disease, but it can significantly accelerate underlying cardiac problems,” explains Dr Sameer Bhate, Senior Consultant and Head of Cardiac Surgery at Amrita Hospitals, Faridabad. “I recently treated a woman from Ethiopia who had undergone bioprosthetic mitral valve replacement at the age of 24 due to a heart ailment. Over the next two decades, she went through four pregnancies. The repeated haemodynamic stress placed on her heart during each pregnancy accelerated the degeneration of her tissue valve, leading to premature valve failure. By the time she reached us, she was experiencing severe breathlessness and persistent chest pain and was unable to walk even short distances. She ultimately required a complex redo valve replacement surgery, which was successfully performed in Faridabad.

Protecting heart health during pregnancy starts with planning. Women with known heart or kidney conditions should seek pre-pregnancy counselling to understand their individual risks. Once pregnant, regular follow-ups with both an obstetrician and a cardiologist are essential. Tests such as ECGs and echocardiograms help track heart function over time. Medications should never be stopped or adjusted without medical advice, and delivery planning should be done at centres equipped to manage high-risk cardiac pregnancies.
With informed care, early monitoring, and multidisciplinary support, most women, even those with existing heart conditions, can navigate pregnancy safely. The key lies in recognising that maternal heart health is not secondary, but central, to a healthy pregnancy outcome.