Later on in pregnancy, usually the third trimester, women complain about insomnia. This can be due to the increased size of the fetus and uterus making the woman too uncomfortable to sleep.
Most people say that the reason why you cannot sleep during pregnancy is that your body is preparing you for when the baby is actually born. When the baby is born you will be up a lot with him/her so you have to get used to your sleep patterns changing.
