Pregnancy can be one of the most fascinating and frightening events of a woman's life. As each week goes by, a remarkable little life grows inside of a woman. But, unless she's been pregnant before, a woman will not know what to expect. It's normal to wonder what's happening inside and how the baby is developing and growing. It can also be frightening when the baby begins to kick and move. Knowing what happens each week can help assuage some of that fear, transforming it into excitement for the little being that she's nourishing within her.
Weeks 1 through 6
Week 1: Conception of the embryo has not yet taken place because the woman's menstrual cycles has started. Week 2: The uterus of the woman begins to prepare for the embryo by developing the blood supply. Week 3: The embryo is created when the egg and sperm join together. This marks the beginning of pregnancy and it also means that the baby will begin to develop. Week 4: The fertilized egg attaches itself deep within the uterus. During this time, tissues are formed in the uterus because the egg will divide. The tissues serve both the mother and the baby. When this process occurs, the mother may begin to feel extremely tired and could experience breast tenderness. Week 5: The baby is made of nothing but a lot of tiny cells. The baby's form has not yet taken shape. In this week, the cells that form the spinal cord, nerves and brain begin to form. Some of the cells that the baby is currently made up of will eventually become the tissue, blood vessels, bones, heart and muscles. Some of the heart cells have already taken position so they can start to form. During this time, she may begin to feel nauseated, as well. Week 6: The embryo begins to grow just a bit and is now about an inch long. The embryo starts to develop ears and eyes. And though the heart only contains a few cells, blood is starting to pump into it. In addition, cells begin to develop into limbs. The nauseous feeling will intensify, coupled with vomiting. Miscarriages tend to occur during week six, as well.
Weeks 7 through 12
Week 7: The brain begins to develop, as do the nose, eyes, legs and arms. Some women gain weight during this week while others lose weight. Week 8: The baby's heartbeat begins. The first ultrasound can be performed during this week, as well. Hormone changes can cause rashes or acne to develop, but these problems are not permanent. Week 9: The fetus develops webbed hands and feet. In addition, cartilage and bone starts to form. Week 10: The embryo develops into the form of a baby. The heart, brain, limbs and face will all be almost completely formed. Week 11: The fetus grows rapidly and continues to develop the functions that have already begun. Week 12: The fetus has fully-developed limbs. The sex of the fetus can also be determined during this week because development of the sexual organs has started.
Weeks 13 through 19
Week 13: The fetus has developed a digestive system. Week 14: The fetus during this week will typically weigh just 2 ounces. It will also begin to move its legs and arms and you might start to feel the heartbeat. Week 15: The fetus develops a coat of hair all over its body. The coat is fine and will be shed before the baby is born. Week 16: The baby is getting active and movement can be felt more frequently. An amniocentesis will also be performed during week 16 to make sure that the baby is not suffering from any birth defects. Week 17: The baby is gaining weight and the circulatory system is developing further. Week 18: The baby's digestive system becomes active and its eyes open. Week 19: In order to make birthing easier and to protect the baby from the wet conditions in the mother's womb, the baby will be covered in a wax-like substance.
Weeks 20 through 25
Week 20: If the baby is a girl, her internal sex organs develop. Regardless of sex, the baby will also have a soft covering of hair on its head. This is also the time to enroll in child-birthing classes. Week 21: The baby's development slows during this week. However the mother has probably gained about 15 pounds. Week 22: Though the sex organs and brain are still developing, the baby's development is almost complete. Week 23: If a baby were born during this week, it would be able to survive. This is minimum number of weeks that the child needs to be in utero in order to survive, if born. The baby's activity also increases during this week. Week 24: The baby continues to grow at a rapid rate. Week 25: The baby is developing its spinal column and arteries and veins begin to form.
Week 26 through 31
Week 26: The baby's respiratory system has been developed fully. Your belly will also have grown tremendously and you may begin to have false contractions. Week 27: The baby's eyes, brain and lungs are still in developmental stages, but your baby will soon have all the bodily functions and organs that an average person has. Week 28: The baby becomes aware of the sounds outside and inside the womb. Talking to the baby at this stage will help it to recognize your voice. Week 29: The baby is able to taste, see, smell and hear. The baby is also gaining more weight. Week 30: The fine coat of hair that's covered the baby has been shed and the baby can blink. Week 31: The brain is developing quickly and the baby's body is almost fully developed.
Week 32 through 40
Week 32: The baby weighs about 3 1/2 pounds and everything is developed, including finger and toe nails. Week 33: The baby continues to gain weight and the baby's head will grow a bit more this week. Week 34: The toe and finger nails grow long. The baby is capable of shutting and opening its eyes. Week 35: Movement of the baby increases and so does the height and weight. Week 36: The baby continues to move and gain weight and is ready to be born. Week 37: The baby weighs about 7 pounds at this point but continues to grow and gain weight until it is born. Week 38: The baby will position itself for birth. This usually means that it will be in a head-first position. However, if the baby will be born breached, it will settle in this position. Week 39: The baby's movement has slowed because of its size. There is not much room in which to move at this point. Week 40: This is the final week of pregnancy. Labor will begin at any time.