Barre workout - help me figure out caloric burn?

Hi all.
Before I start - I KNOW a HRM would probably be the BEST way to figure this out, but if there are any of you out there who do barre workouts, maybe you can offer input...
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I did my first barre workout yesterday. It was a 60 minute beginner class, meaning there were periods of instruction on form and terminology before each part. Most instruction lasted 1-2 minutes with a 10 or so minute cycle after each. I would say the entire workout lasted 45 minutes (she also did an AB workout at the end for 10 mins.) Oh, I am 5'10", 178, and 22 weeks pregnant.

ANYWAY, because the movement is so fluid and controlled, my FitBit pretty much thought I was DORMANT during this time and I can't figure out how to log SOME calories for the workout. My online research says 300-500 calories in a "typical" barre class, and the exercise log doesn't have an entry for "barre".

My question: If you are a barre person who wears a HRM, how many calories do you typically burn ? OR, if you use the exercise diary, is there a similar exercise that you substitute for the caloric burn of barre?

Thanks!