Your body will be going through many changes.
At your first prenatal visit, your doctor will help you to determine an expected delivery date (EDD). Your EDD is 40 weeks from the first day of your last menstrual period.
Your calculated due date is only an estimate however, as only a small percentage of women actually deliver on their predicted due date. Most babies are born somewhere between 38 and 42 weeks from the first day of their mother's last menstrual period. By the end of week 37, your baby is considered full term.
The first trimester is the stage of gestation from conception through 12 weeks. Hormonal changes during this time causes many symptoms for the mother including frequent nausea and vomiting, increased fatigue, food aversion and cravings, heightened sense of smell, tender and swollen breasts, dizziness, constipation and frequent urination.
During the second trimester, which is the period from week 13 to week 27, the initial pregnancy symptoms abate. The fetus continues to develop and grow and begins to show signs of movement. Your abdomen will begin to expand and new symptoms may appear including back pain, stretch marks, and swelling of the ankles.
The last phase of pregnancy is the third trimester which lasts from week 28 until the birth of the baby. During this period the fetus grows significantly. Many women find it difficult to breath or have frequent urination as the growing fetus puts more pressure on their organs. As the delivery time approaches, the baby will "drop" or move lower in the abdomen and turn around in preparation for birth.