The first thirteen weeks of pregnancy are known as the "First Trimester." Here is a rundown of the growth pattrens in your baby as well as the effects you will notice in yourself.
During the First Trimester your baby will have grown about 3 inches in length. All of his/her major organs will have developed.
The noticable sign or symptom that you are pregnant may be breast tenderness, and nausea or vomiting. You will have little, if any, weight gain. Your baby is still in the embryo stage. The organs are just starting to form.
The embryo now becomes a fetus. The arms, hands, and legs start to form. Other organs such as the liver and stomach, are developing. You may slowly start to gain weight, and may tire more easily. Your diet is very important, and you may already be taking prenatal vitamins.
By this time, your baby is about 3 inches long and weighs about an ounce. His or her arms and legs begin to move, but you still will not feel them. Sexual organs are developing now. Your clothes may begin to feel tight, as the uterus begins to grow out of the pelvis. There may be a weight gain of three to four pounds by now.