my baby is 4 months old and still waking every 2-3 hours every night to nurse. when will she likely start sleeping through the night? anything I should do to encourage this? she is on full breastmilk - direct latch evenings/nights and bottle fed in the day when I'm at work.

Ensure she is latching well and suckle well to receive enough milk from the first side of breast and offer 2nd side after burping her to satisfy the appetite well to space the frequency of feeds. Infants sleep goes in cycles of about 90 to 110mins, or shorter in younger babies. Brief arousals normally occur at the end of each sleep cycle, hence it can occur about 4 to 6 times a night. Babies who are unable to self sooth, may wake up and cry and require parents to carry, pat, rock or feed them before they can fall back to sleep. So try to encourage self soothing in your child.