|
You may have heard conflicting information about fetal development. What some people call a “child” or “baby,” others refer to as a “product of conception” or a “mass of tissue.” Who is right?
You are perfectly capable of deciding for yourself once you know the facts.
Beware of anyone who withholds information from you about your pregnancy. If you’ve had an ultrasound which shows how far along you are, you should be permitted to see it. You may also ask questions about the development of your fetus.
You are faced with an important choice — one that should not be taken lightly. In order to make a wise, informed decision, you need to know the facts.
The information and photos below explain and show how a baby develops in the first nine months of his/her life.
If you have any questions about pre-born development, please call us and we can send you more information.
FIRST TRIMESTER
 Week 2 - Fertilization occurs.
The sperm and egg have joined in the fallopian tube to form a unique human being.
Forty-six chromosomes provide the unique blueprint for the embryo’s physical characteristics.
 This photo shows a fertilized egg only 36 hours after conception. Magnified here, it is no larger than the head of a pin.
Still rapidly dividing, the developing embryo, called a zygote at this stage, floats down from the fallopian tube toward the uterus.
Week 3 - At this point, the developing embryo is looking for a spot to implant in the uterus.
Early formation of the central nervous system, backbone, and spinal column has begun. The gastrointestinal system has also begun to develop with the kidneys, liver, and intestines forming. The heart has begun to form.
Week 4 - Hormones produced by the embryo stop the mother’s menstrual cycle.
Week 5 - The embryo’s tiny heart begins to beat by day 21. The brain has developed into 5 areas and some cranial nerves are visible.
Arm and leg buds are visible and the formation of the eyes, lips, and nose has begun. The spinal cord grows faster than the rest of the body giving a tail-like appearance which disappears as the embryo continues to grow.
The placenta begins to provide nourishment for the embryo.
 Week 6 - This remarkable photo of a tiny fetus in its unruptured amniotic sac was taken after surgery for an ectopic pregnancy (1972).
This picture shows the development of a baby at only 6 weeks after conception.
Photograph by University of Minnesota Medical Photographer,
Robert Wolfe
 Week 7 - Major organs have all begun to form.
The embryo has developed its own blood type, unique from the mother’s.
Hair follicles and nipples form and knees and elbows are visible.
Facial features are also observable. The eyes have a retina and lens. The major muscle system is developed and the embryo is able to move.
Week 8 - The embryo is reactive to its environment inside the amniotic sac where it swims and moves.
 Hands and feet can be seen.
At the end of week 8, the embryonic period is over and the fetal stage begins.
 Weeks 9-12 - The heart is almost completely developed and the heart rate can be heard on a Doppler machine in the doctor’s office.
Most major organs and tissues have developed and red blood cells are now produced in the liver.
The face is well-formed and the eyes are almost fully developed. The eyelids will close and not reopen until the 28th week.
Arms, hands, fingers, legs, feet, and toes are fully-formed. Nails and earlobes start to form and tooth buds develop in the gums. The fetus can make a fist with its fingers. Testosterone (male sex hormone) is produced by the testes in the male fetus.
SECOND TRIMESTER
 Weeks 13-16 - The brain is fully-developed and the fetus can suck, swallow, and make irregular breathing sounds.
 The fetus can feel pain.
(New England Journal of Medicine)
Fetal skin is almost transparent. Muscle tissue is lengthening and bones are becoming harder. Liver and organs produce appropriate fluids.
Eyebrows and eyelashes appear and the fetus makes active movements including kicks and even somersaults.
  Weeks 20 - “Quickening,” when the mother can feel the fetus moving, usually occurs around this time.
 Finger and toenails appear.
Lanugo, a fine hair, now covers the entire body. The fetus can hear and recognize the mother’s voice.
Sex organs are visible on ultrasound devices.
THIRD TRIMESTER
Week 24 - A protective waxy substance called vernix covers the skin. By birth, most of the vernix will be gone, but any that is left is quickly absorbed.
The fetus has a hand and startle reflex. Footprints and fingerprints are forming.
The fetus practices breathing by inhaling amniotic fluid into its developing lungs.
 Weeks 25-28 - Rapid brain development occurs during this period and the nervous system is able to control some bodily functions.
The fetus’ eyelids now open and close.
At 25 weeks, there is a 60% chance of survival if born. The fetus is considered legally viable at 28 weeks and there is a 90% chance of survival if born at this point.
Weeks 29-32 - There is a rapid increase in the amount of body fat the fetus has.
 Rhythmic breathing occurs, but the lungs are not yet mature.
The fetus sleeps 90 to 95% of the day.
At this point, the survival rate is above 95% if the baby is born.
 Weeks 38-40 - The fetus is considered full-term. Lanugo is gone except on upper arms and shoulders. Hair on the baby’s head is now coarser and thicker. The lungs are mature.
The average weight of the baby at this point is seven and a half pounds. At birth, the placenta detaches from the uterus and the umbilical cord will be cut as the baby takes his first breaths of air. Breathing will trigger changes in the heart and bypass arteries, forcing all blood to now travel through the lungs.
Pictures used on this page were taken, with permission, from the Westside Pregnancy Resource Center website. For more resources and information, visit www.wprc.org.
For more information about pre-born development, please contact PSS.
|
