A week by week pregnancy calendar is simply a record of all the changes a mum-to-be and her baby go through during the average 36-week period of pregnancy. It also greatly helps both the parents to plan for the delivery in advance.

Changes that occur to mothers are quite evident by the changes that occur in her body outwardly. However, changes that occur to the baby inside the mothers’ wombs are not consequently apparent.

This is where a week by week pregnancy calendar comes handy. To know what stage of development the unborn baby is in at any given week, the parents-to-be can look at a week by week pregnancy calendar. Following is a general rundown on what you will find on a week by week pregnancy calendar.

Week one to four:

The sperm fertilized the egg by forming a zygote, which is the basic form of life.

Week five to eight:

By the sixth week, unborn baby’s heart begins to beat. At this stage baby has developed his arms and by week eight, legs have begin to develop.

Week nine to twelve:

Expansion of the body of a mother-to-be starts during this period to accommodate the growing fetus with growing body parts. Subsiding nausea or morning illness is also usually suffered by mothers-to-be.

Week thirteen to sixteen:

Sex of your baby may be determined by your doctor through an ultrasound during the thirteenth to fourteenth week period. Heartbeat of the unborn baby can also be heard during this time. The baby’s bones start to harden and you may start to notice it when he or she moves around in your womb. At this stage, it is usually for babies to begin sucking their thumbs.

Week seventeen to twenty:

By this time your baby’s internal organs begin to develop in a rapid way. Soft fine hair known as lanugo covers up the fetus. This is the time when accurate gender of the baby can be known.

Week twenty one to twenty four:

By this time, your baby begins depositing fat on his/her body, which helps him/her dealing with changes in temperatures during and after arrival.

Week twenty four to twenty eight:

At this stage your baby is capable of hearing muffled outside sounds and sense light. Lack of space in the uterus slows down your baby’s movement at this stage.

Week twenty nine to thirty two:

Your baby’s head grows rapidly in proportion to the rest of his/her body. The brain and eyes are almost fully developed, only the lungs need development.

Week thirty three to thirty six:

By this stage, you baby begins to open and close his/her eyes. Fingernails of the baby start to grow long.

Week thirty seven to forty:

This is the stage in which your baby’s lungs begin to get ready for birth. During this stage, you can go into labor at anytime.