Your Baby's Development

Even though you may not feel that you're pregnant yet, you have a baby growing and developing inside of you!

Your baby was just conceived, but already is working overtime. The fertilized egg goes through a process of cell division. About 30 hours after fertilization, it divides into two cells, then four cells, then eight, and continues to divide as it moves from the fallopian tube to the uterus. By the time it gets to the uterus, this group of cells looks like a tiny ball and is called a morula.

Watch Your Baby GrowThe morula becomes hollow and fills with fluid — it is then known as a blastocyst. Near the end of this week, the blastocyst will attach itself to the endometrium, the lining of the uterus. This is called implantation. The implantation in the uterus creates an essential connection — the endometrium provides the developing embryo with nutrients and removes wastes. Over time, this implantation site will develop into the placenta.

Week 3

Your Body

Watch your belly grow!Getting enough of certain nutrients, such as folic acid, protein, calcium, and iron, is essential for your baby's development. A folic acid supplement is particularly important because folic acid helps prevent defects of the neural tube (the structure that gives rise to the brain and spinal cord), which forms very early in pregnancy.

Your intake of protein, which is used to create new tissue, should increase during pregnancy. Calcium aids the development of bones and teeth, so make sure you're getting a good dose of dairy products, leafy green vegetables, and legumes (beans, peas, lentils, etc.). Iron is essential during pregnancy as you support your baby's increasing blood volume. Good sources of iron include red meat, legumes, eggs, and leafy green vegetables.

PREGNANCY CALENDAR: A week-by-week guide
  • Trimester 1
  • Trimester 2
  • Trimester 3
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Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.