This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Illness Complicating Pregnancy, Subject name: Gynaecology & Obstetrics
Which of the following is not a contraindication to pregnancy? 
Select and explain. 
A. Severe pulmonary hypeension, B. Severe obstructive valvular lesions, C. Large secundum atrial septal defect with left to right shunt, D. Marfan syndrome with dilated aoa
C: Large secundum atrial septal defect with left to right shunt
Answer: C: Large secundum atrial septal defect with left to right shunt 
Explanation: Large secundum atrial septal defect with left to right shunt Pregnancy is associated with many haemodynamic changes. There is increase in hea rate and cardiac output and decrease in peripheral resistance. Total blood volume is increased. Stenotic lesions and severe cyanotic lesions have a higher complication rate during pregnancy. Regurgitant lesions and left to right shunts (without pulmonary hypeension) are better tolerated.