My doctor used a 40 bougie, as I heard he confirming as they rolled me in that they had this ready for me (I was 1 of 3 that morning). LOL Should have found out more information about this prior, my mistake as I know nothing. Glad I am on the large end as I am very tall not that I know how they determine size or if there is a huge difference between them. May ask on follow up just to know. =-)