Pregnancy tips: fetal development during the first trimester

What an awesome and amazing time pregnancy is for you and your partner—to have your own little miracle forming inside your very body. Unfortunately, you cannot watch your new child form. You are only left to wonder what changes are occurring in your unborn child’s new little body. It is amazing how much change occurs in your unborn child in just the first trimester of your pregnancy. What starts out as an egg implanting inside your womb, at the end of 12 weeks will be a fairly complete person with plenty of growing yet to do.

The average pregnancy lasts forty weeks and is broken up into three periods known as trimesters. A baby delivered any time after week 37 is considered full-term, whereas, anything before that is considered pre-term.

The first trimester is a period of rapid growth and development for an unborn baby. The miracle of pregnancy actually begins with the first day of your last period. Your body begins by building up tissue in the uterus to prepare for the implantation of a fertilized egg. Most women have a 28-day cycle and ovulate at around day 14 or 15. The development of a fetus can be broken down as follows.

1. Week two: When ovulation occurs the egg travels through the fallopian tubes and, if conditions are right, meets sperm. If sperm meets egg then 46 chromosomes combine to create a fertilized egg. These chromosomes will give the baby, now considered a zygote, all of its physical characteristics. It continues down the fallopian tube into the uterus.

2. Week three: The egg will find its way into the uterus where it will look for a good place to implant. It will literally burrow into the wall of the uterus and will develop a yolk sac. This yolk sac will produce all of the blood cells during these early weeks of life until the liver takes over. The backbone, nervous system, and spinal column are beginning to take form. The kidneys, intestines, and liver are also beginning to form.

3. Week Four: The embryo produces hormones in the mother’s body to stop her menstrual cycle.

4. Week five: By day 21 the embryo’s heart begins to beat. The spinal cord grows much quicker than the rest of its body at this stage. This is why when you see pictures of a baby at this stage it looks as though your baby has a tail. Don’t worry. The rest of the baby will catch up very quickly. The brain is also beginning to take form.

5. Week seven: Facial features are apparent. A mouth, nose, and tongue are prevalent. A retina and lens are present on the eyes. The muscular system is present, and although it will be several weeks before you can feel it, the embryo begins moving. The baby’s blood cells are now produced by the liver instead of the yolk sac.

6. Week eight: The unborn child, now called a fetus, is about a half-inch long. It is surrounded by the amniotic sac which is filled with fluid that serves to protect the fetus. The baby now has arms and legs and brain waves that can be measured.

7. Week ten: The fetus now has an almost completely developed heart. Teeth are forming in the gums.

8. Week twelve: Vocal cords are complete. The fetus can and does use them—silently. The brain is completely formed and the unborn child can feel sensations. He may suck his thumb. Eyelids are fully formed and cover his eyes to protect the optic nerve fibers until the seventh month of pregnancy.

Major development is occurring during these early months of pregnancy. This is hard work for both you and your baby. Look at this time in your life as an opportunity to pamper and take extra special care of yourself. You will be doing both you and your unborn child a real favor by helping him to get his life started out on a healthy foot.