1. Courtesy of: Peggy Pannell RN, MSN
FETAL DEVELOPMENT
Courtesy of:
Peggy Pannell RN, MSN

2. Learning Outcome:
2c) Students will be able to identify and describe all stages of typical fetal development
From ovulation to birth
From Conception to Birth

3. Selected Vocabulary: Blastocyst Conception Embryo Fertilization Fetus
HCG
Implantation
Gestational age
Vernix
Zygote
Placenta
Quickening
Umbilical Cord

4. FERTILIZATION
Begins with 46 pair of chromosomes, splits off to 23 then combine for a unique new 46 pair.

5. Stages and Time Frames Blastocyst Germinal Stage Embryo
Embryonic Stage
Fetus
Fetal Stage
Ovum
Before fertilization
Blastocyst
0-2 weeks
Embryo
2-8 weeks
Fetus
8-40 weeks

6. IMPLANTATION First weeks of human development:
Blastocyst - early development of the embryo from ovulation through implantation in humans. (Days 5-9). Embeds in endometrium.
Implantation occurs after the fertilized egg gets to the uterus and attaches to the lining of the uterus, or endometrium. The cells keep dividing.

7. GESTATIONAL AGE Since Fertilization LNMP Days 280 Weeks 40
Gestational age (duration of pregnancy) equals time since LNMP (LNMP=Last Normal Menstrual Period)
Since Fertilization LNMP
Days
Weeks 40
Calendar Months 9
Lunar Months 10

8. TRIMESTERS Trimester 1st = weeks 1-13 2nd = weeks 14 - 26
3rd = weeks 27 and on
(38-40 WEEKS)

9. STAGES OF DEVELOPMENT

10. 1 Month Baby Center Video: Weeks 1-9
First Trimester At the end of four weeks:
Baby is 1/4 inch in length
Heart, digestive system, backbone and spinal cord begin to form
Placenta (sometimes called "afterbirth") begins to develop
The single fertilized egg is now 10,000 times larger than size at conception

11. Month 2 First Trimester At the end of 8 weeks:
Baby is 1-1/8 inches long
Heart is functioning
Eyes, nose, lips, tongue, ears and teeth are forming
Penis begins to appear in boys
Baby is moving, although the mother can not yet feel movement

12. Month 3 Baby Center Video: Weeks 10-14
First Trimester At the end of 12 weeks:
Baby is 2 1/2 to 3 inches long
Weight is about 1/2 to 1 ounce
Baby develops recognizable form. Nails start to develop and earlobes are formed
Arms, hands, fingers, legs, feet and toes are fully formed
Eyes are almost fully developed
Baby has developed most of his/her organs and tissues
Baby's heart rate can be heard at 10 weeks with a special instrument called a Doppler

13. Month 4 Baby Center Video: Weeks 15-20
Second Trimester At the end of 4 months:
Baby is 6 1/2 to 7 inches long
Weight is about 6 to 7 ounces
Baby is developing reflexes, such as sucking and swallowing and may begin sucking his/her thumb
Tooth buds are developing
Sweat glands are forming on palms and soles
Fingers and toes are well defined
Sex is identifiable
Skin is bright pink, transparent and covered with soft, downy hair
Although recognizably human in appearance, the baby would not be able to survive outside the mother's body

14. Month 5 Baby Center Video: Weeks 21-27
Second Trimester At the end of 5 months:
Baby is 8 to 10 inches long
Weight is about 1 pound
Hair begins to grow on baby's head
Soft woolly hair called lanugo will cover its body. Some may remain until a week after birth, when it is shed.
Mother begins to feel fetal movement
Internal organs are maturing
Eyebrows, eyelids and eyelashes appear

15. Month 6 Second Trimester At the end of 6 months:
Baby is 11 to 14 inches long
Weight is about 1 3/4 to 2 pounds
Eyelids begin to part and eyes open sometimes for short periods of time
Skin is covered with protective coating called vernix
Baby is able to hiccup

16. Month 7 Baby Center Video: Weeks 28-37
Third Trimester At the end of 7 months:
Baby is 14 to 16 inches long
Weight is about 2 1/2 to 3 1/2 pounds
Taste buds have developed
Fat layers are forming
Organs are maturing
Skin is still wrinkled and red
If born at this time, baby will be considered a premature baby and require special care

17. Month 8 Third Trimester At the end of 8 months:
Baby is 16 1/2 to 18 inches long
Weight is about 4 to 6 pounds
Overall growth is rapid this month
Tremendous brain growth occurs at this time
Most body organs are now developed with the exception of the lungs
Movements or "kicks" are strong enough to be visible from the outside
Kidneys are mature
Skin is less wrinkled
Fingernails now extend beyond fingertips

18. Month 9 Third Trimester At the end of 9 months:
Baby is 19 to 20 inches long
Weight is about 7 to 7 1/2 pounds
The lungs are mature
Baby is now fully developed and can survive outside the mother's body
Skin is pink and smooth
Baby settles down lower in the abdomen in preparation for birth and may seem less active

19. AMNIOTIC FLUID Protects Fetus Controls Temperature
Supports Symmetrical Growth
Prevents Adherence to amnion
Allows Movement
Source of oral fluid
Acts as a excretion-collection repository
Clear, yellowish fluid surrounding the developing fetus.
Average amount 1000 ml.

20. UMBILICAL CORD Connecting link between fetus and placenta.
Transports oxygen and nutrients to fetus from the placenta and returns waste products from the fetus to the placenta.
Contains: 2 arteries and 1 vein supported by mucoid material (wharton’s jelly) to prevent kinking and knotting.
Contains NO pain receptors.

21. PLACENTA

22. PLACENTA MOM Baby Baby mom
Schematic drawing of placenta: how it supplies oxygen and nutrition to embryo and removes waste products. Deoxygenated blood leaves fetus through the umbilical arteries and enters placenta, where it is oxygenated. Oxygenated blood leaves placenta through the umbilical vein, which enters the fetus via the umbilical cord
mom
MOM
Baby
Baby

23. PLACENTA Produces protein hormones:
Human chorionic gonadotrophin (HCG) days past conception, is basis for pregnancy test
Progesterone
Estrogen
Human Placental Lactogen

24. PLACENTA
Sieve/filter – allows smaller particles through and holds back larger molecules. Passage of materials in either direction is effected by:
Diffusion: gases, water, electrolytes
Facilitated transfer: glucose, amino acids, minerals.
Pinocytosis: movement of minute particles

25. PLACENTA
Mother transmits immunoglobulin G (IgG) to fetus providing limited passive immunity.
Leakage: caused by membrane defect: may allow maternal and fetal blood mixing.

26. VIABILITY
Capability of fetus to survive outside uterus at the earliest gestational age weeks
Survival depends on:
Maturity of fetal central nervous system
Maturity of lungs

27. NEUROLOGICAL SYSTEM Formed during the 3rd week
Respiratory effort 18 1/2 WKS
Swallowing /2 WKS
Fetal movement felt WKS
(Quickening)
Sucking WKS

28. IMMUNE SYSTEM
Passive immunity - FROM MOM
Active immunity - FROM FETUS

29. What Now?
Using your notes for support, work with a partner to fill out the activity handout entitled “When’s That”? Be prepared to discuss your answers with the class. 