Baby Developing inside you

Fetal Development


Baby developing inside you
over the weeks and months
baby inside




 

Weeks, Months and Trimesters Guides

 
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Week Twenty One: Nourishment evolves

  
You are 21 weeks pregnant. (fetal age 19 weeks)
  • Length is now measured crown to heel.
  • The fetus has grown to 10.5 inches (27 cm) - 12.7 ounces (360 grams).
  • It is now gaining weight steadily, with fat being added to the body.
  • Bone marrow has started making blood cells.
  • Their small intestine is starting to absorb sugars.
21 weeks
Your baby's bone marrow has started making blood cells, a job done by the liver and spleen until this point. The placenta has provided nearly all of your baby's nourishment, now your baby will begin to absorb small amounts of sugar from swallowed amniotic fluid.

Based on the size of baby's head, which is about 2 inches (5cm), the date of birth can be determined to within one week. The fetus is steadily gaining fat and has grown a whitish coat of a slick, fatty substance to protect skin in amniotic fluid and to ease delivery.

In girls, the vagina is formed and the ovaries already contain over six million eggs which will be reduced to about 400 by the time of puberty. For boys, the testes begin to descend from the abdomen this week. (Boys don't produce sperm until puberty).

The baby can hear and recognize the mother's voice, and may respond to some types of music.

<<< Week 20  |  Month 5  |  Month 6  |  Week 22 >>>


  

Week By Week Pregnancy Calendar

 
First Trimester
Week 1   Week 2   Week 3   Week 4   Week 5   Week 6   Week 7  
Week 8   Week 9   Week 10   Week 11   Week 12   Week 13
Second Trimester
Week 14   Week 15   Week 16   Week 17   Week 18   Week 19   Week 20  
Week 21   Week 22   Week 23   Week 24   Week 25   Week 26
Third Trimester
Week 27   Week 28   Week 29   Week 30   Week 31   Week 32   Week 33  
Week 34   Week 35   Week 36   Week 37   Week 38   Week 39   Week 40
 
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