You will often hear the stages of your pregnancy referred to as trimesters, which are three equal time periods of about 13 weeks each.
During your first trimester, you might experience frequent nausea, with or without vomiting, which is often called morning sickness. But you can rest assured that morning sickness usually improves by the end of the first trimester.
Other symptoms you might notice at this early stage are fatigue, breast tenderness, frequent urination, and heartburn.
By about the sixth to eighth week, you should have your first visit with your healthcare provider, at which time he or she will prescribe prenatal vitamins, ask about your medical history, and discuss with you the coming months of your pregnancy.
In most cases, you will be asked to return every 4 weeks for the first 7 months, then every 2 weeks until the last month, then every week.
As your doctor will remind you, during the first trimester it is very important that you focus on a healthy lifestyle, particularly in terms of your nutrition, exercise, and rest. You want to create the best environment for your rapidly developing baby, who over the course of these first 13 weeks will grow from the size of the head of a pin to about the size of a peach!
Excerpt from Your Pregnancy™ Week by Week, 7th Edition