I found with mine, they had their days and nights mixed up. Bath time, in my opinion, determines, the sleep cycle. I found that when I changed bath time from noon or afternoon to 7 p.m. every night, my babies went to sleep at 8-9 p.m. and slept mostly thru the night. My first went from 8 p.m. to 6 a.m. My second was a bit trickier. 9 pm to 3-4 p.m. depending.