This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physiological Changes of Pregnancy, Subject name: Gynaecology & Obstetrics
Of the following changes which happen in the renal system in pregnancy, which is FALSE ? 
Select and explain. 
A. The renal calyces and ureters have significant dilatation, B. Pregnancy induced changes are responsible for an increased risk of upper urinary infection,, C. Increased Glomerular filteration rate, D. Kidneys become smaller compared to the pre- pregnant size
D: Kidneys become smaller compared to the pre- pregnant size
Answer: D: Kidneys become smaller compared to the pre- pregnant size 
Explanation: The kidneys become larger, its size increase by 1.5 cm. Dilatation of the renal calyces and ureters can be striking. This is due to progesterone-induced relaxation of the muscularis. An impoant consequence of these physiological changes is an increased risk of upper urinary infection. Pregnancy induced intrarenal vasodilatation--both afferent and efferent resistance decreases--leads to increased effective renal plasma flow and glomerular filtration. Hydroureter- right side>left as pregnant uterus is usually dextrorotated and it compresses right ureter on pelvic brim.