This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
Which of following is a predisposing factor for developing ovarian hyperstimulation syndrome, during invitro fertilization procedure 
Select and explain. 
A. Transfer more than 2 embryos, B. High serum estradiol, C. Older maternal age, D. Prior polycystic ovaries
B: High serum estradiol
Answer: B: High serum estradiol 
Explanation: High serum oestrogen is a risk factor to develop OHSS.