The Most Critical Period for Heart Failure Risk in Pregnant Women with Heart Conditions

Women with pre-existing heart conditions face an increased risk of heart failure during the second and third trimesters of pregnancy. As the pregnancy progresses and the fetus grows larger, the physical burden on the mother significantly increases. During this time, major physiological changes occur, including an increase in blood volume and circulation speed, which place additional strain on the cardiovascular system.

Physiological Changes That Impact Heart Function

One of the key factors contributing to this increased risk is the elevation of intra-abdominal pressure, which causes the diaphragm to shift upward. This movement compresses the heart and reduces thoracic capacity, limiting lung expansion. These changes are particularly noticeable in the later stages of pregnancy when the fetus is fully developed and the circulatory system is working at a higher capacity.

How Pre-Existing Heart Conditions Are Exacerbated

For women with existing structural or functional heart issues, the high-output and high-volume circulatory state of pregnancy can push a previously compensated heart into decompensation. This shift often leads to acute heart failure, especially if the heart was already operating near its functional limits before pregnancy.

Risks for Women Without Prior Heart Disease

Even women without a history of heart disease are not immune to cardiac complications during pregnancy. Some may develop peripartum cardiomyopathy, a condition that typically manifests in the late stages of pregnancy or shortly after delivery. This form of cardiomyopathy can significantly impair heart function and increase the likelihood of heart failure.

The Role of Immune and Inflammatory Responses

Research suggests that immune and inflammatory mechanisms may also play a role in the development of cardiac dysfunction during pregnancy. These biological responses can lead to a marked decline in heart performance, particularly during the second and third trimesters when the body undergoes intense hormonal and metabolic changes.