New parents often expect their baby to start sleeping through the night around the time they reach six months of age. But according to a new study led by Professor Marie-Hélène Pennestri, parents should view sleep consolidation as a process, instead of a milestone to be achieved at a specific age. Tracking 44 infants over a period of two weeks, she found that sleeping patterns vary greatly – not only for different babies, but also night to night for the same baby.