Trish good on you for sticking up for her. I had my first antenatal class with DH last Tues night (next one tonight) and I can honestly say that after hanging around BB and reading everything i can, I knew alot more about certain things than the mw! Also I have noticed dealing with different mw's each time I go in for a check up, they all know different things or have differing opinions on certain subjects and may not know anything on other subjects (no one has been able to tell me much about manually turning a breech baby for example). Fortuantely I havent come across any with attitude like this one though and the hospitail I am going with is very big on letting things run its natural course and letting the woman choose how she would like to things to go etc..
I would be livid dealing with someone like this mw you & your SIL went to, I guess there are types in every profession that are always 'right' about everything hey.