Understanding Pregnancy Week By Week

For understanding pregnancy week by week, you usually go through 40 weeks of pregnancy. These 40 weeks are divided into three pregnancy trimesters - from Week 1 to 14, from Week 15 to 26, and Week 27 to 40. This is a look at what goes through your body during pregnancy.

First Trimester

In the first two weeks, you actually are not pregnant, but it is the time when your egg is being fertilized by the sperm. During Week 3, your body is still unaware that it is pregnant and the implantation of the fertilized cell begins. The following week you realize that you are pregnant, and in between Week 4 and 5, you experience morning sickness. 

During Week 5 of pregnancy week by week, the cells develop into three layers - Endoderm, Mesoderm, and the Ectoderm. This week is the start of forming of the embryo's head, and the baby's cell. Your baby's heart starts to beat at the beginning of Week 6, and the eyes, liver, gall bladder, stomach and intestines, lungs and pancreas begin to form by mid-week. Week 7 is when there is development of the eye lenses, tongue, legs and arms, and the jaws, and your baby doubles in size. During Week 8, the four chambers of the heart start to develop, along with teeth buds within the gums, the windpipe, bronchi, voice box, and the cerebellum. Week 9 is when your body determines whether you are having a boy or a girl. Week 10 is when the embryo is now a baby, albeit on a small scale.

In the next four weeks of pregnancy week by week, your morning sickness begins to subside, the structure of the brain is completed, baby begins to open and close its mouth and the vocal chords are formed. During Week14, your areolas may begin to darken and become large, and the baby practices breathing, sucking, and swallowing.

Second Trimester

In the second trimester of monitoring of your pregnancy week by week, your baby's head begins to rest on its neck, instead of shoulders, by Week 15, and it begins to turn its head and feet. The toenails begin to grow the following week, muscles become stronger, and the head and neck grow straighter. Your baby starts blinking, sucking, and swallowing during Week 17, along with development of all existing body structures. By mid-Week 18, the eyes and ears will be in the right position, and the pads of fingertips and toes will develop. Fingerprints start to develop during this week.

If it is a baby girl, egg cells will be developing in her ovaries by Week 19 of pregnancy week by week. The following week, the scalp hair and eyebrows begin to form, and the baby will start to wake and sleep as babies do. By the end of Week 21, your baby's heartbeat can be heard through a stethoscope. The following week, the testes will move from the pelvis to the scrotum, if it is a boy. During Week 23, the body gets into proportion, and the bones in the middle ear begin to harden. By Week 24, your baby's heartbeat can be heard by placing an ear on your stomach. Nostrils start to open, lungs start to develop blood vessels during Week 25, and the following week the nostrils are fully open, and brain wave activity starts.

Third Trimester

Lungs grow rapidly, and you should feel your baby kicking during Week 27 of pregnancy week by week monitoring. The next week, the eyelids open and the lungs can breathe air. A premature baby born now has chances of surviving. During Week 29, the senses of sound, taste and smell are developing, and the baby can move its eyes. During the next two weeks, the baby is still growing, and ensure your intake of proper nutrients, along with folic acid, vitamins, and calcium is still continuing. By Week 32, the baby can sense all the five senses.

In the next three weeks, your baby begins to suck its fingers, starts to develop its own immune system, and in case of boys, the testes would have fully descended. Your baby could turn in a head down position. Due to continuous deposit of fat, during Week 36 elbows and knees will start to form dimples. You should be alert for any signs of labor as you enter Week 37, as your baby could be born two week before or after the due date.

Week 40 is the final week of pregnancy week by week, and you should be ready for your newborn any time!