Why is my 7-month-old waking up at night when he's usually a great sleeper?

My easy-going 7-month-old son has always been a very good sleeper. Lately he hasn't been sleeping through the night and is easily aggravated. I've heard that the developmental milestones at any given age can carry over into a child's sleep and wake him. Is this true and will his disposition change, too?

Sleep patterns change throughout childhood. It's not unusual for babies to go through sleep disturbances while they learn new tricks such as rolling over, pulling up or walking. Once they master the feat, their sleep returns to normal. Separation anxiety is another red flag. If your son is afraid or tearful when you leave during the daytime, he may need you to stay by his side for reassurance at night to go back to sleep. A physical growth spurt can also cause both breast- and bottle-fed babies to wake up for additional night-time feeds for a short time. Another point to consider is whether your infant has self-soothing techniques - thumbsucking, a dummy or a cuddly object - to get himself to sleep. If you've been putting him to bed completely asleep, he may not have a clue as to how to do it on his own. Make sure that when you put him in his cot he's still awake so that he learns to settle without you. Finally, wait a few minutes before going to your baby when he wakes up. Give him time to change positions and comfort himself. If he works himself into a state and you're sure he's dry, fed, warm and healthy, then try this tried-and-tested technique: turn the baby monitor around to let him hear you and feel reassured by your presence. Just remember, this too will pass. One benefit you have is that your son is capable of sleeping through the night.