Prenatal Development

You probably will have a lot of questions about the development of your baby. When does the heart start beating? When will I start feeling my baby move? To answer these questions, take a closer look at the details of development.

Fetal Development is broken down into three trimesters. The first trimester lasts from week 1 through week 11. The second trimester lasts from week 12 through week 24. The third trimester lasts from week 25 through the end of your pregnancy, which is usually between weeks 38-40.

A lot of basic growth occurs during the first trimester of pregnancy. In fact, the first few weeks begin the basic development of brain, spinal cord, heart, and gastrointestinal tract. On day 22 the baby’s heart starts beating. The formation of the lungs, jaw, nose, and palate has begun and the brain is continuing to form into all of its complex parts. At 8 weeks gestation, everything that is present in an adult human is now present in the small baby. The bones are beginning to form and the muscles can contract. By the end of the first trimester, the fetus has grown to about 3 inches in length and weighs about an ounce.

In the second trimester the baby starts moving around a lot more, and usually by week 16 the mother can feel movement. Fingerprints have now developed on the tiny fingers of the baby. By 20 weeks gestation the eyebrows and eyelashes have grown in, and nails have begun to grow on the fingers and toes. The baby’s heartbeat can now be detected by a stethoscope. At the end of the second trimester the brain will be developing rapidly and the mother will begin to recognize her baby’s sleep and wake cycles. The baby could possibly live outside of the womb with medical help if delivered early and should weigh about 2 1⁄4 pounds and be about 14 inches long.

During the third trimester the baby starts filling out and storing body fat. Some breathing movements are occurring even though the lungs are not fully developed. By 32 weeks gestation the baby’s bones are fully developed but still soft and flexible. The baby’s head will start to descend into your pelvis to begin getting ready for birth. As the baby continues to grow, the mother may start to feel less movement. At 38 weeks the baby is now considered to be full term and can be born at any time. The baby’s organs are now fully developed and the lungs continue to develop until the day of delivery. At birth, a healthy size baby is typically 19- 21 inches long and about 6 3⁄4 to 10 lbs.

For more information about fetal development, you can go to American Pregnancy Association.

Source American Pregnancy Association

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141 S 11th St.,
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Phone: 740-439-4568
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