Hi Ashley. If I understand your question correctly, you are NOT asking whether balance training should be utilized for pregnant clients or even for your specific client. Instead I’m reading your question to ask whether, since you are already using balance training for your pregnant client, this type of training increases the intensity of the training. To that question, I’d say generally “yes.” To the extent that balance challenges are introduced to pretty much any exercise, that exercise’s intensity can (usually is) be increased.
I hope that this helps.