How the Baby Grows: Week by Week

A fetus is a developing human being with its own separate, distinct set of DNA that manages its own development. Nourishment is the only thing it will need to grow – from conception until the end of its natural life.

Week 1
  Last Menstrual Period
Week 2
  Conception
Week 3
  Baby attaches to the uterus
Week 4
  Nerves, brain and spinal cord begin to develop
Week 5
  Baby’s heart begins to beat
Week 6
  Eyes, arms, legs, lungs, and stomach begin to form
Week 7
   Hands and feet are forming
Week 8
   Upper lip, teeth, fingers and ears begin to form
Week 9
   Toes and genitals are forming
Week 10
   Baby has permanent fingerprints
Week 11
  Baby starts to produce urine
Week 12
  Fingernails are forming
Week 13
  Baby flexes and kicks
Week 14
  Hormones gear up
Week 15
  Skin begins to form
Week 16
  Facial expressions are possible
Week 17
  Fat accumulates
Week 18
  Baby begins to hear
Week 19
  Lanugo covers baby’s skin
Week 20
  The halfway point
Week 21
  Nourishment evolves
Week 22
  Taste buds develop
Week 23
  Lungs prepare for life outside the womb
Week 24
  Sense of balance develops
Week 25
  Exploration continues
Week 26
  Eyes remain closed
Week 27
  Second trimester ends
Week 28
  Baby’s eyes open
Week 29
  Movement is more forceful
Week 30
  Baby packs on pounds
Week 31
  Reproductive development continues
Week 32
  Downy hair falls off
Week 33
  Baby detects light
Week 34
  Protective coating gets thicker
Week 35
  Rapid growth continues
Week 36
  Baby can suck
Week 37
  Baby is full-term
Week 38
  Organ function continues to improve
Week 39
  Placenta provides antibodies
Week 40
  Your due date arrives

 

Videos: The Endowment for Human Development. (2011). Retrieved from https://www.ehd.org/get-free-videos.php
Facts: Mayo Clinic (2011). Fetal Development – The first trimester.  Retrieved from: https://www.mayoclinic.com/health/prenatal-care/PR00112