What is the size of my baby during the 2nd trimester of pregnancy?

Dr. Deborah Raines, MSN
Nursing Specialist

At 20 weeks, the fetus weighs about 10.5 ounces and is about 10 inches long: head to heel. The fetus is swallowing amniotic fluid and producing meconium which will remain in the intestine until birth. The fetus is beginning to extend and flex its arm and legs and moving around in the uterus.

During the second trimester of pregnancy, your child grows in size at an incredible pace.

  • By week 13, your baby is about 2 1/2 to 3 inches long, is growing longer and is gaining weight rapidly.
  • During week 15, your baby is between four and five inches in length (about the size of an apple).
  • During week 18, your baby is around six inches long and weighs between seven and eight ounces. For the first time during your pregnancy, your baby is likely to be larger than the placenta.
  • By week 20, the halfway point, your baby has grown to be about 6 to 8 inches long.
  • During week 23 of pregnancy, your child will be between one and two pounds in weight and developing very quickly.
  • During week 25 of pregnancy, your child is already weighing between a pound and a half and two pounds and is as much as 13 and a half inches long.
  • During week 27 of pregnancy, the length of your child is about three times the size that it was at 12 weeks. Your baby weighs almost 2 pounds and measures around 14 and half inches long. Because your child is growing so much, their movements may be more noticeable to you.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.