Fetal Development

  • Day 1=1 cell. Hair and eye color are set.

    Day 1

    Once a sperm fertilizes an egg, a BRAND NEW, unique and WHOLE ORGANISM is created with her own DNA. The chromosomes from the parents help determine the new human being’s sex, eye color, skin and hair color, balding, even earlobe attachment. After fertilization nothing new is added or needed to the human except oxygen, nutrition and time.[1]
  • The heart begins to beat.

    1st Month
    1-4 Weeks

    The first cell divides in two and cell division continues as it travels down the fallopian tube to the uterus. Foundations of the brain, spinal cord and nervous system are already established and by day 21 the heart begins to beat in a regular fashion.[2] Muscles are forming and arms, legs, eyes and ears begin to show.
  • Brain waves can be detected.

    2nd Month
    5-8 Weeks

    By six weeks, brain waves can be detected.[3] The jaw forms, including teeth and taste buds.[4] She swallows amniotic fluid and hiccups.[5] Fingers and toes are developing and at seven weeks the chest and abdomen are fully formed.[6] Swimming in the amniotic fluid, she now looks like a miniature human infant.[7, 8]

  • Unique fingerprints are beginning to form.

    3rd Month
    9-12 Weeks

    Unique fingerprints are beginning to form.9 The baby now sleeps, awakens and exercises her muscles. The baby is very active. The gender can be visually determined and family resemblances may appear.[10] By the end of the month all the organs and systems of her body are functioning.[11]



  • Baby’s ears are functioning.

    4th Month
    13-16 Weeks

    By the end of the fourth month, the baby is 8–10 inches in length and weighs about one-half pound. Her ears are functioning and she hears her mother’s heartbeat as well as external noises like music.[12] Lifesaving surgery has been performed on babies at this age.


  • Baby may jump in reaction to sound and suck her thumb.

    5th Month
    17-20 Weeks

    If a sound is especially loud, the baby may jump in reaction to it. Thumb-sucking has been observed during the fifth month.[13]

  • Oil & sweat glands function.

    6th Month
    21-24 Weeks

    Oil and sweat glands are functioning. She grows rapidly in size and strength while her lungs become more developed.[14]

  • The baby can now recognize her mom's voice.

    7th Month
    25-28 Weeks

    The baby can now recognize her mother’s voice. She exercises by stretching and kicking. She uses the senses of hearing, touch & taste. She can even look around with open eyes.[15]

  • The skin begins to thicken.

    8th Month
    29-32 Weeks

    The baby swallows a gallon of amniotic fluid per day and often hiccups.[16] The baby’s kicks are stronger and mom may be able to feel an elbow or heel against her abdomen.[17]

  • 1/2 pound is gained per week, the baby is getting ready for birth.

    9th Month
    33-36 Weeks

    Up to birth, the baby gains half a pound per week. Her head bones are flexible for the trip through the birth canal.[18] 41 of the 45 cell divisions that occur before adulthood have taken place.

1. “The Drama of Fetal Development”, American Baby. Jan. 1989. p. 45. Print. | 2. Moore and Persaud, The Developing Human-Clinically Oriented Embryology. 2nd ed. W.B. Saunders Company 1973 p. 310. Print. | 3. Hamlin, H. “Life or Death by EEG,” JAMA. Oct. 12, 1964, p. 113 Print. | 4. Britt, Robert Roy. “Lasting Impression: How Fingerprints Are Created.” LiveScience, Purch, 2 Nov. 2004,| 5. Flanagan, Geraldine Lux, Beginning Life DK Publishing , 1996 Limited p. 68. | 6. Health & Wellness Resource Center, “Normal Growth of a Baby During Pregnancy.” Clinical Reference Systems Annual. 2001. p.1391. | 7. Gordon, Debra MD. “Pregnancy.” The Gale Encyclopedia of Medicine. 2nd ed., pp. 2694-2695. | 8. Ibid. | 9. Ibid. | 10. Ibid.

Image credits: Day 1 by David Marchal | Months 1-2 by Steven O’Connor M.D. | Month 3 © The Center for Bio Ethical Reform | Months 4-6 © Life Issues Institute | Months 7-8 Unborn.com Sound Wave Images.