Sleep regressions. I see questions about them all the time. 
What are they?
A sleep regression is usually when there is a developmental milestone.
When do they happen?
The 4 month sleep regression can be a big one. It happens first and can come in hard. The brain changes and sleep is becoming a learned skill. 7 months can be Crawling, 11-13 months can be walking. Those are big ones. 2 years old is increased awareness and co-ordination frustration.
How long do they last?
They can last a few days, a couple weeks or up to 8 weeks if you get one regression on top of another.
What do you do?
Offer more support when your baby is having a developmentally related sleep regression. The brain is trying to process new information, muscles may be being used in new and taxing ways and it’s very exciting for the baby who wakes between sleep cycles and wants to practice the developing skill. Practice the emerging skill during the day and offer more support at night. More holding, pick ups and attention. The sooner the skill gets mastered, the sooner the sleep can come back.
I will be available for full consultation after January 4th. I’m still available for quick free initial evaluations and to book consultations and to answer questions. I love calls like that. www.GetQuietNights.com