The day you hear your baby's heartbeat for the first time is undoubtedly one of the most euphoric moments in a woman's life. It is at that point that you begin to imagine what your baby will look like and want to know everything you can about your growing fetus. According to Stuart Campbell, M.D., author of "Watch Me Grow: A Unique, 3-Dimensional Week-By-Week Look at Your Baby's Behavior and Development in the Womb," we now have the opportunity to enter into the fetal world via advancements in ultrasound technology called 3-D scanning, which enhances the journey for the parents-to-be and sheds light on 40 weeks of the mysterious miracle of life in the womb.
First Eight Weeks
A zygote is formed from the moment of conception when a sperm fertilizes the egg. During the next few days after conception, the zygote makes the journey through the fallopian tubes to the uterus. Once in the uterus, the zygote implants in the uterine wall and the transformation begins.
By week three, your baby has developed from an empty ball of cells into a disc-shaped embryo complete with head and tail. Week four is when a primitive heart is formed and begins to beat.
During weeks four through six, the nervous system, spinal column and brain begin to take shape. In weeks seven and eight your baby is busy growing fingers, feet--complete with little notches for toes--teeth forming underneath the gums, and ears, eyes and nose.
Month Three
During the last few weeks of the first trimester, your baby has officially become a fetus and rapid growth begins to take place. Dr. Campbell describes how the baby begins to freely move as if enjoying the fluid-filled sac, knowing that the space will soon be cramped. Your baby's vocal chords are now beginning to form and the liver and pancreas are now functioning organs.
If you begin to refer to your fetus as "the precious little peanut," that is just about right. Your baby is about 2.13 inches long, weighing in at about .49 ounces. The hands may be in boxer position in front of the face or held close to the mouth, and he can now bend his knees and press his foot on the wall of your uterus.
Second Trimester
During the second trimester, weeks 13 through 24, your baby develops the ability to perform complex coordinated activities. You may want to start practicing your mommy voice because your baby can now hear noises. By week 17, the fetus is beginning to have more of a normal "human" appearance. Eyes, while still closed, are now looking forward and the baby's skeleton is turning from cartilage to bone. By week 21, your little one's tongue is fully formed. If you are having a girl, your daughter's vagina and womb are formed and she already has 6 million eggs. You baby is now almost 11 inches long.
During the last weeks of the second trimester, your baby can start to recognize your voice as well as the father's. The retinas are now formed, the eyelids become a little more open and he or she can distinguish between light and dark. If for some reason you were to go into labor now, your baby could survive outside of the womb with the help of a pediatric team.
Third Trimester
The following are some of the milestones that occur during the last few weeks of pregnancy: week 25--thumb sucking, week 27--blinking, week 30--grasping, week 32--yawning, week 34--grimacing and, finally, the most welcomed display during week 35--smiling.
During the early weeks of your final trimester, your baby's head is more in proportion with his body. He is now much more sensitive to changes in light and sound as well as taste and smell.
At week 37, your baby is officially full term and on the average weighs about 6 1/2 pounds. During week 38, you may notice that your baby hiccups frequently. This is because amniotic fluid can get into the windpipe. In addition, he or she may have a full head of hair by now, up to an inch long in some cases. At 40 weeks, your baby is fully developed and ready to face the outside world.
References
- Pregnancy.org: Fetal Development
- "Watch Me Grow: A Unique, 3-Dimensional Look Week-by-Week Look at Your Baby's Behavior and Development in the Womb"; Stuart Campbell, M.D.; 2004
