You may have noticed that your baby is more active at some times than at others, often when you're trying to relax or sleep! This is likely to be because when you're busy or distracted, you're less aware of your baby moving because you're not paying much attention to him as at other times. The moment you stop and sit down to put your feet up or go to bed will be the time your baby starts to do his somersaults.
Remember that, like newborns, babies still in the uterus spend a lot of time sleeping, so there will be periods when you don't feel your baby being very active-it's fine for him not to be moving all the time. Every baby has a different cycle of waking and sleeping, and there are no rules as to when your baby should be kicking and when he should be still.
If you're familiar with your baby's pattern of movements and are concerned that you haven't felt him move, try lying down on your side and relaxing or playing music to see if your baby responds. If, however, you're concerned, then call your doctor. She may want you to come in to examine you and listen for the baby's heartbeat.
Some women count their baby's kicks using a chart, noting down when they feel the baby move. Kick charts are not often used now, unless recommended by a doctor because they are thought to cause unnecessary concern. Babies have an individual pattern of movements, and it is this, rather than the number of kicks, that's important.