This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET Jan 2020, Subject name: Gynaecology & Obstetrics
A woman with 18 weeks gestation presented to the OPD. On abdominal examination, the uterine size was 16 weeks. On USG, oligohydramnios was found, which of the following is suspected. 
Select and explain. 
A. Renal agenesis, B. Fetal anemia, C. Jaundice, D. Anencephaly
A: Renal agenesis
Answer: A: Renal agenesis 
Explanation: Oligohydramnios can be caused by - Renal agenesis Uteroplacental insufficiency: IUGR ACE inhibitors Premature rupture of membranes Amniocentesis (leak) Pre-ecclampsia Amnion nodosum NSAIDs Post term pregnancy Over estimated gestational age