In a pregnant woman with ventricular septal defect, what is the most important predictor of pregnancy outcome?

The size of the defect is a critical predictor of pregnancy outcome in a woman with a ventricular septal defect (VSD). Large defects can lead to significant hemodynamic changes, causing increased blood flow to the lungs and consequent pulmonary hypertension. This can result in complications during pregnancy, including heart failure and adverse outcomes for both the mother and the fetus.

In cases of small VSDs, many women can have a successful pregnancy with minimal risk, as these defects may not significantly impact circulation or cardiac workload. Therefore, assessing the size of the defect provides essential insight into the potential risks the woman may face during her pregnancy and guides management strategies.

Other factors, such as the presence of additional congenital defects or maternal age, can influence outcomes but are not as directly related to the physiology of the heart during pregnancy as the size of the defect itself. A history of heart disease can indicate a higher risk, but the implications are more variable and depend significantly on the specific defect's characteristics. Thus, assessing the size of the VSD is key in determining the most appropriate care and intervention during the pregnancy.