What is the greatest risk for heart failure during pregnancy?

The greatest risk for heart failure during pregnancy is at the end of the second trimester, specifically between 28 to 32 weeks of gestation. This time frame is critical because it coincides with significant physiological changes in the cardiovascular system as the body adapts to support both the mother and growing fetus. By this stage, blood volume has increased significantly, and the heart must work harder to pump this extra volume through the circulatory system.

In women with pre-existing heart conditions or those who may develop pregnancy-related cardiovascular issues, this increased workload can lead to heart failure symptoms manifesting during this period. Additionally, at around this gestational age, there is also an increased risk of pregnant women presenting with additional stressors such as hypertension or gestational diabetes, which can further strain cardiac function.

While the risk of heart failure remains throughout pregnancy and can also occur during labor and the early postpartum period, the unique combination of increased circulatory demand and physiological changes peaking around the end of the second trimester makes this time particularly risky for the onset of heart failure in susceptible women.