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
The characteristic problem in females taking nor-ethisterone is 
Select and explain. 
A. Irregular bleeding, B. Thromboembolism, C. Hirsutism, D. Weight gain
A: Irregular bleeding
Answer: A: Irregular bleeding 
Explanation: Norethisterone acetate is commonly used as an injectable steroid - 'NET-EN'
It is a progesterone based contraceptive like DMPA and its side effect are similar to those of DMPA.
The most frequent side effect is irregular bleeding.
NET-EN is given in doses of 200 mg at 2 monthly intervals.

Extra Edge: Combined injectable contraceptive.