Thursday's Brain Bender

What two words, formed from different arrangements of the same eight letters, can be used to complete the sentences below?

The hospital informed all mothers-to-be that it was their ________ duty to attend ________ classes.

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Okay, as always answers to follow in the comments....

Update: Today's speedy smartypants is Oddybobo! (With whom I had the distinct pleasure of talking to yesterday....) Yay! Kudos though, to the creative answers offered... (I am lookin' at you T1G, Bob and Raging Mom...)