My Exclusive Breast Milk Twins suddenly don't poop daily

Jaime • Had our boy/girl twins at 35 weeks on September 30th. They are healthy and perfect!!!
Hi ladies! My B/G twins are 9 weeks old and used to poop almost every time I changed them. Suddenly, they both go only every few days! Their stool seems the same (more of it when they finally go). Do you think they are constipated or could this be a normal change as they get older? Anyone else have this experience? Thank you!!!