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How Your Baby Grows

To get a rough idea of when your baby is due visit Due Date Calculator (SOGC).
Your due date is a best guess – most babies are born within two weeks before or after your due date.

The FIRST trimester weeks 1 to 13
first trimester pregnancy visual
By the end of the first trimester:

  • the placenta, the cord and all of baby’s organs have formed and are working together.
  • baby’s heart is beating.
  • the spine and bones are taking shape.
  • baby is using muscles to move and kick, but you won’t feel movement yet.
  • the face is forming and includes ears, a nose and eyes which are closed.
  • the arms, legs, fingers and toes have appeared – fingerprints are present
  • the brain is growing quickly.
  • baby is 7 to 10 cm (3 to 4 inches) and weighs 28 grams (1 ounce).

The SECOND trimester weeks 13 to 28

second trimester pregnancy
By the end of the second trimester:

  • baby’s eyes can open, eyebrows and lashes appear.
  • the heartbeat can be heard by your health care provider.
  • the external genitals are well developed by the end of the 14th week – an ultrasound can show if you are having a boy or a girl.
  • you will be able to feel baby moving (16-20 weeks).
  • tooth buds develop inside the gums.
  • soft, fine hair is growing on the body.
  • a white coat (vernix) covers baby’s body to protect it.
  • baby’s senses develop – can hear your voice (18 weeks) and open eyes.
  • baby is about 36 cm long (14 inches) and weighs 1 kilogram (2 pounds).

The THIRD trimester weeks 29 to 40

third trimester pregnancy
By the end of the third trimester:

  • baby can suck on its thumb and swallow.
  • the skin becomes less wrinkled as baby gains weight more quickly.
  • baby won’t be doing somersaults but you should still feel frequent movement.
  • baby has periods of sleep and wakefulness.
  • baby can see and will turn to a bright light.
  • the lungs and brain mature.
  • baby has stored iron, other nutrients, and antibodies from mom.

video icon
Conception to Birth Visualized (fragment) TED Talk

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