In Sleeping Through the Night, Mindell lists some things that predispose a child to sleep problems:
Firstborn children are more likely to have sleep problems. This may be because parents are less tolerant of their child's cries and/or because they have more time and energy to devote to them. Parents are probably more likely to not be as strict about sleep rules with firstborns too.
Boys are more likely to have sleep problems than
girls. It isn't exactly known why, but parents have been shown to be less consistent with boys which certainly may add to this.
COLIC OR EAR INFECTIONS
Children that have colic or ear infections when they are young often develop sleep habits--while parents are trying to deal with these problems--that can cause problems later on.
SAME BED OR ROOM
Children that sleep in the same bed or room as their parents are more likely to wake more frequently at night time.
Breastfed children are more likely to take longer to sleep through the night.
Milk intolerance can cause sleep problems, although this is not very common. Introducing solid foods to infants has been shown, study after study, to not help them sleep longer at night.
Any major change like new child care, a vacation, a developmental change or illness can cause sleep problems to start or return.
AWAKE OR ASLEEP?
Many studies have shown that infants who are put to bed awake sleep better than infants who are put to bed asleep. Easier said than done, huh?