This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
Most frequent site of tubal ectopic pregnancy is 
Select and explain. 
A. Interstitial, B. Isthmic, C. Ampulla, D. Infundibulum
C: Ampulla
Answer: C: Ampulla 
Explanation: Nearly 95 percent of ectopic pregnancies are implanted in the various segments of the fallopian tube. The ampulla (70 percent) is the most frequent site, followed by isthmic (12 percent), fimbrial (11 percent), and interstitial tubal pregnancies (2 percent).The remaining 5 percent of non-tubal ectopic pregnancies implant in the ovary, peritoneal cavity, cervix, or prior cesarean scarReference: William's Obstetrics; 25th edition; Chapter 19; Ectopic pregnancy