Green poo... can it be caused by transition to formula?

[CatAnnoyance]

My baby is 16 weeks old and has been breastfed since birth, up until the last couple of weeks when I have started to drop breastfeeds and introduce formula as I go back to work soon. I wanted to do it gradually so I still breastfeed during the night, morning and evening, I have just replaced day time feeds with formula so far.

The last week or so though, I've noticed her poo is green. It started off with a greeny/browny tint, but has got progressively greener and today was just green. No doubt about it, it was green. Dark green.

I've googled it, as you do, but I'm finding conflicting advice. Does anyone know if this is something to worry about, or whether it could just be caused by the transition to formula?

She's still feeding well at the breast, as I did worry she wasn't getting enough hind milk (as suggested when I Googled), and she's gaining weight well following the 50th centile.

Has anyone had experience of this?

My LO (6weeks old) has been having green poos, she's exclusively breastfed but is on nystan for thrush. I asked the health visitor aboit it yesterday and she said green poo in isolation isn't anything to worry about, eg if she is still weeing and pooing good amounts, and is well in herself. I also Googled it and worried myself she wasn't getting enough, but HV weighed her and she's gained xx

Green poo was one of my DS dairy allergy symptoms. If it started when formula was introduced then I'd be wary of that. If you're combi feeding then the symptoms might not show as obviously. My son was combi-ff from a week old and he got diagnosed at 5 months, he got progressively worse each day until I tried to hand him to the gp and leave

My FF DS often had/has dark green poo. He's fine. I'd go to the dr if you're worried though (wouldn't be the first time I went with poo related concerns armed with photos of dirty nappies on my phone! )