This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Illness Complicating Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'The commonest pathogen responsible for acute pyelonephritis in pregnancy is: \nSelect and explain. \nA. Escherichia coli, B. Klebsiella pneumoniae, C. Proteus mirabilis, D. Pseudomonas aeruginosa', 'role': 'user'}, {'content': 'Answer: A \nExplanation: E. coli is the common bacteria responsible for acute pyelonephritis in pregnancy It also causes asymptomatic bacteriuria. Urinary tract infection in pregnancy is a risk factor for threatened aboion, chorioamnionitis, preterm labor, IUGR.', 'role': 'assistant'}]