It really depends on the shot, for me I got my shot early in the morning maybe around 9 am and ended up having Aiden around 12 hours later, I had to wait an extra day to get the shot because I was in too much labor and I was contracting every minute so couldnt get induced until they slowed down! Sometimes it goes really quick though so it will most likely be within that day! but good luck I cant wait to see baby pictures!