Skip to main content

Your Developing Baby by Kim Phagen Hansel

Before you even know you're pregnant and take a pregnancy test to confirm it, your baby is already growing and developing. Here's a quick look at your baby's development and how its growth may be impacting your body:

Weeks 1-4

From the moment of fertilization, a baby begins to grow. In the first four weeks the embryo begins developing structures for the face and neck. The heart, blood vessels, lungs, stomach and liver begin to develop. During this timeframe, a home pregnancy would show positive.

Weeks 5-8

The baby is growing immensely now and already has eyelids and ears. The baby is about half an inch in size and the arms and legs are well-formed. The fingers and toes are developing. In the first trimester, pregnant women may begin to experience morning sickness that can cause nausea throughout the day. While the baby draws nutrients and really starts to develop during this timeframe, a woman's body also changes drastically to support the pregnancy.

Weeks 9-12

It's moving! During this timeframe the baby starts moving and has grown to two inches. Also, the sex organs of the baby are developing and the baby's heartbeat can be heard with a fetal Doppler. Pregnant women nearing the 12-week mark will most likely begin to feel less tired and have fewer morning sickness symptoms.

Weeks 13-16

The baby is growing like crazy and already measures between four and five inches and can weigh close to four ounces. The baby can now blink and the heart and blood vessels are fully developed. Now the baby also has fingers and toes with fingerprints. Pregnant women may begin to feel the baby move and may have more energy now that they've moved into the second trimester.

Weeks 17-20

Now weighing about 10 ounces, the baby is about six inches long. The baby is starting to do normal baby activities such as sucking a thumb, yawning, stretching and making faces. At this point, the pregnant woman should be able to feel the baby move. Typically ultrasounds are done around 20 weeks to check on the baby's development and parents can find out whether it is a girl or a boy.

Weeks 21-24

The baby is fully active now, weighing more than one pound. The baby may respond to sounds outside the womb and can experience hiccups, which the pregnant woman can feel as well.

Weeks 25-28

Growing rapidly, the baby is close to three pounds now and moves frequently. At this point there is a good chance the baby would survive if born prematurely. It's a good idea to know the warning signs of preterm labor. Registering for birthing classes during this timeframe are recommended to help prepare for aspects of childbirth, as well as taking care of your newborn post-delivery.

Weeks 29-32

The baby is almost fully developed and weighs about four pounds. From this point to delivery, the baby will gain up to half its birth weight. As a layer of fat develops under the baby's skin, the baby has fewer wrinkles. It's important to monitor the baby's movement and begin preparing for the baby's arrival. Women may notice a yellowish fluid leading from their breasts, which is colostrum that develops as the body prepares for producing milk. At this point, most women are seeing a physician every two weeks.

Weeks 33-40

It's baby time! As the baby completes the final stages of development, it will gain a lot of weight to be close to six pounds at the time of birth. The brain is quickly developing. The lungs are one of the last organs to fully develop. At 37 weeks, the baby is considered full term and will most likely be positioned head down.

Welcome to the World!

A woman's due date is calculated from the first day of her last period to 40 weeks later. Pregnancies typically last from 38-42 weeks. Every labor and delivery is different. Be sure to schedule regular doctor's visits during your pregnancy.

Memorial Hospital of Converse County has several doctors who specialize in prenatal care, as well as labor and delivery.