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
Causes of breech presentation are:a) Hydrocephalusb) Oligohydramniosc) Pelvic contracture d) Placenta praevia 
Select and explain. 
A. acd, B. ad, C. bc, D. bde
A: acd
Answer: A: acd 
Explanation: At 28 weeks of pregnancy, approximately 20% of women have breech presentation. The fetus undergoes spontaneous version usually between 30th and 34th week. This corrects the breech position such that, at term only 3% of pregnant women have breech presentation.
Any maternal or fetal condition, which prevents this spontaneous version will result in a persistent breech presentation.