Learn about how your baby grows during pregnancy
How Long is a Pregnancy?
How long is pregnancy?
Pregnancy typically lasts about 40 weeks, or 9 to 10 months. This time is divided into three parts called trimesters.
Stages of Growth Month-by-Month
First Trimester (Weeks 1-12):
Month 1 (Weeks 1-4): Early development starts. By the end of week 4, the embryo is the size of a poppy seed.
Month 2 (Weeks 5-8): The embryo’s heart starts beating, and tiny buds for arms and legs appear. By the end of this month, the embryo is about the size of a black bean.
Month 3 (Weeks 9-12): The embryo becomes a fetus, and major organs and features form. By the end of this month, the fetus is the size of a plum.
Second Trimester (Weeks 13-28):
Month 4 (Weeks 13-16): The fetus starts making movements, and you might begin to show. The fetus is about the size of an avocado by the end of this month.
Month 5 (Weeks 17-20): You might feel your baby move for the first time. The fetus is about 10 inches long and weighs 1 pound by the end of this month.
Month 6 (Weeks 21-24): The fetus can hear sounds and may start responding to them. By the end of this month, it is about 12 inches long.
Third Trimester (Weeks 29-40):
Month 7 (Weeks 25-28): The fetus gains more fat and muscle. By the end of this month, it’s about 15 inches long.
Month 8 (Weeks 29-32): The brain develops rapidly, and the fetus is preparing for birth. It’s about 17 to 18 inches long by the end of this month.
Month 9 (Weeks 33-36): The fetus’s lungs mature, and it continues to gain weight. By the end of this month, it’s about 19 inches long.
Month 10 (Weeks 37-40): The baby is ready for birth! It’s around 20 inches long and weighs about 7 to 9 pounds.