To mention to a dear friend that her 4 yo DD has body odour?

[Ham69]

I have a lovely, sensitive 'school gate' friend who I have spent a lot of time with recently. She's a very caring mum but does worry and over analyse things on occasion.
I have her DD back on regular playdates as she is in the same nursery class as my dd and they're great friends. They play dressing up games a lot and I can't help but notice the strong body odour my friend's dd has under her armpits. It slightly concerns me as she is very sensitive and starts school with my dd in September and children could pick up on it and be cruel.
So, do I mention it? Or should I mind my own business? Or any suggestions what it could be?

No, don't say anything! What makes you think she doesn't already know and it's dealing with it? She might have chosen not to discuss it with you. This will do nothing but embarrass her and it's really not your business tbh.

Totally agree with fuzzy

Say something. A friend of mine noticed that her friend's DD had a lazy eye (really really chronic) but didn't say anything as she felt there was no way on earth that the friend or a paediatrician can't have noticed. 1 year later her friend told her that the girl's eyesight was now damaged beyond repair and she would have to wear corrective lenses for the rest of her life as it was too late for surgery. She kicks herself every time she sees the little girl as she could have said something and saved her sight. Too sad. The friend since told me (in a very gentle way) that she was concerned about my DS's hand flapping and I was glad she did although as it happens there was nothing to worry about.

Your friend may be completely unaware.