Key Stages of Pregnancy Development

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While every week of a pregnancy is important, specific changes and stages of pregnancy development usually occur during certain phases of pregnancy. Staying in touch with what you eat can help further your baby’s development, according to the United States federal government website Women’s Health.

Week 4

By week four, your baby’s brain, heart and spinal cord have begun to develop, according to Women’s Health. The beginnings of his arms and legs appear and he is likely about 1/25 of an inch long. You may experience symptoms such as upset stomach, vomiting, tiredness and swollen breasts during this phase of your pregnancy.

Week 8

At eight weeks, your baby’s heartbeat now has a regular rhythm, according to Women’s Health. Also, she looks more like a human than an embryo by the eighth week of pregnancy. His eyelids have also formed.

Week 12

At 12 weeks, your baby’s sex organs are truly forming and soon your doctor can tell you if you’re expecting a boy or a girl. Her eyelids will also close in order to protect her developing eyes. Also, his nerves and organs will begin to work together so he can easily complete basic motor tasks such as making a fist.

Week 20

By week 20, your baby can now hear and swallow; some expectant moms may choose to play soothing music during this phase of pregnancy. By now, she is likely about six inches long and weighs in around nine ounces, according to Women’s Health.

Week 24

You’re nearing the end of the second trimester at week 24; during this stage your baby’s taste buds form on his tongue. The lungs also start to form, but do not work just yet, according to Women’s Health. Hair also begins to grow on your child’s head.

Week 32

Week 32 means you’re getting closer to delivery; most moms deliver babies in the 40th week of pregnancy. Your baby’s lungs still haven’t fully developed, but she will mimic breathing at this phase. By now, your baby likely weighs about four pounds and is approximately 12 to 17 inches long.

Week 37

Week 37 marks the stage where your baby has fully developed, according to Women’s Health. By now, all organs and other bodily functions are functional. Soon your baby will likely turn into a “head down” position to prepare for birth; most babies are born in this position. At birth, your baby will likely weigh anywhere from six to nine pounds and be about 19 to 21 inches long.

Week 40

Week 40 typically marks the end stages of pregnancy development; most women give birth around the 40th week of pregnancy, according to Women’s Health. Consult a doctor if you don’t have birth by the end of week 40; he may need to induce labor so you can safely bring your new child into the outside world.


Women’s Health: Healthy Pregnancy: