Pregnant women are regularly preoccupied with wondering exactly what their baby looks like at that moment. While you don't have a window to your womb, medical science has taught us a lot about development in pregnancy. By knowing what is going on with your baby, you can help feel assured in your pregnancy and its progression.
Fetal Development -- First Trimester
Your first trimester runs from week 1 through either week 12 or 13, depending on how your doctor counts. This first trimester is when your fetus forms as a zygote and then an embryo and some of the most critical development happens. According to MayoClinic.com, your baby's heart, lungs and neural tube all develop during these first weeks. Her head, neck, arms, legs and even fingers and toes form. By the end of the trimester, your baby can be about 2.5 inches long.
Fetal Development -- Second Trimester
In your second trimester, your baby takes on even more human-like qualities. Your baby's bones form, and he starts to make facial expressions. MayoClinic.com reports that you should be able to learn the sex of your baby during these exciting weeks should you choose. Your baby will grow hair and actual fingernails, and will be able to swallow. When your second trimester is finished at around 26 weeks, your baby may be around nine inches long, almost triple her first trimester size.
Fetal Development -- Third Trimester
Your third trimester is the home stretch for your baby. According to MayoClinic.com, your baby's eyes will open, and she will starting practicing her breathing. Your baby begins to rapidly gain weight in her preparation to be born, and she will learn to grasp with her hand. Your due date falls in week 40, the end of the third trimester.
Development Tests
As your baby develops, your doctor will likely ask if you want to take a variety of development tests to see how your baby is doing. In the first trimester, you will be asked about the triple screen; according to the American Pregnancy Association, this test can help determine if your baby has markers for conditions like Down Syndrome, Trisomy-18 and Trisomy-21. In the second trimester, the quad screen tests for similar conditions to the triple screen and is often recommended for women with certain health histories. In the third trimester, the American Pregnancy Association reports that you'll often have to take a glucose tolerance test, or GTT, to check for gestational diabetes. You'll also be tested for Group B Strep, as this bacteria can be harmful to your baby if it is present during birth.
Development Complications
If your baby has complications in his development, you will likely be referred to a specialist such as a perinatologist or doctor of maternal-fetal medicine. The March of Dimes lists these complications as anything from known genetic conditions such as sickle cell disease to things that can't be known ahead of time like cleft lip and cleft palate.
