4m old peeing less

My 4m old has suddenly started pain less then usual before she’d have 6-7 wet diapers a day and suddenly it dropped to about 3-4 a day and they aren’t full diapers she’s eating the way she always has been her mouth isn’t dry or chapped lips she isn’t pale or anything she seems her regular self but she’s suddenly stopped peeing as much . I will be calling her dr office as soon as they open but did this happen to anyone else’s baby and what was the issue ?