Your Baby’s Growth: Stages of Fetal Development

It can be amazing watching your baby grow and develop, but frustrating not to be able to see that development in the womb as well. There are many books that show pictures of the fetus at different stages that can help you determine what your baby looks like as it grows within you. At some point you will also have at least one ultrasound during your pregnancy, allowing you to see your baby up close and personal. For now, here is some basic information on how your baby grows and develops in the womb.

The progress of your pregnancy is broken down into either weeks or trimesters. A pregnancy is considered 40 weeks long, which doesn’t break down evenly into three trimesters, so this can be a bit confusing. Essentially, each twelve weeks equals a trimester, with the last month of pregnancy being a separate final stage.

The First Trimester

Most of the actual development of your baby occurs in the first trimester. Within the first month the eyes and heart is developed, and your baby begins to take on some rudimentary features. In the second month, all of the major organs begin to develop, including the digestive system, respiratory system, and nervous system. By the end of the first trimester, your baby has developed eyes, ears and kidneys almost fully. Your baby also has all of its limbs, and is starting to look like a miniature newborn. Your baby is still very tiny at around four inches long, and only weighs about an ounce.

The Second Trimester

Throughout the second trimester, your baby’s body is developing and solidifying. In the beginning of the fourth month, your baby’s skin is transparent, but by the end of the second trimester, your baby’s skin will be red and wrinkly. By the end of the fourth month, you should be able to tell the sex of the baby, and this is likely around the same time your doctor will schedule an ultrasound. You will also begin feeling movement in the fourth month, increasing throughout the second trimester. Your baby will become more defined, with nose fully formed, finger and toe nails, and even eyelids and eyelashes. Essentially, by the end of this stage your baby will be nearly fully developed, and be ready to grow. At the end of this trimester, your baby is about a half pound in weight, and is about the length of a banana.

The Third Trimester

Throughout the third trimester, your baby will continue to grow at an increased rate. The infant gains weight quickly, and will more than double in size in the next six weeks, to about three and a half pounds. Throughout this trimester, the baby’s organs become fully developed, and the baby prepares for birth. He will move down into the birth canal, putting pressure on your pelvis. Your baby will move more than ever before, and will now be able to fully hear and see. By the end of the third trimester, your baby is fully developed.
The final stage of pregnancy, or the last month, is actually just a time for the baby to ready itself for delivery. The baby continues to put on weight, and grow in size. The closer to 40 weeks you can be before delivery, the healthier and bigger your baby will be. However, an infant at 37 weeks is considered to be a term pregnancy.

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