There are a lot of causes for insomnia (http://www.nhlbi.nih.gov/health/dci/Diseases/inso/inso_whatis.html). In fact any number of changes to your lifestyle, drugs, medical conditions or stress can cause insomnia problems. Certainly pregnancy involves a great deal of sudden changes happening within your body. These changes can upset the delicate balance that is needed to regulate your sleep cycles. So it is very possible that pregnancy, at any stage, could certainly lead to an outbreak of insomnia. Talk to your doctor if the insomnia does not go away after a short period of time.