Poo Frequency for Mixed Feeding Baby

Hi mummy, is it normal for mixed fed baby to not poop for 2-3days? My LO is turning 6mths and I've noticed she's been pooping once every 2-3days since last week. She started mixed feed when she's 4mths as I'm unable to meet her demand when pumping. I will always DL when she's with me. She used to poop 2-3 times a day when she turns 4 mths. Then it decreased to at least 1 time a day. Now it because once every 2-3days. Should i be worried or is this normal?