Follie size questions


Is it common for follies to decrease in size so close to O? Or is it possible that the nurse practioner that measured them on that day of my IUI didn’t measure them right? Here was the progression. Wdyt?

CD14 - 3 follies - 22.5, 17.5, and 14.

CD15. Follies were 24.5, 19, and 15. Trigger 9am.

CD16. Follies at 25.5, 16.5, 14.5. IUI on this day.

Is that weird that it seems like 2 of the follies shrunk? I thought the trigger was supposed to grow them.

Also, what size do they consider mature with a possibility of releasing an egg?