1. First, Second and Third Trimesters
Fetal Development
First, Second and Third Trimesters

2. Definition: Trimester
One of the three periods of approximately 3 months into which pregnancy is divided.
The first trimester includes the time from the first day of the last menstrual period to the end of 12 weeks. (conception – 12 weeks)
The second trimester, closer to 4 months in length than 3, extends from the twelfth to the twenty-eighth week of gestation. (12 – 28 week)
The third trimester begins at the twenty-eighth week and extends to the time of delivery. (28 – delivery)

3. 1st Month

4. 1st Month Milestones Arms and legs begin to form
The brain and spinal cord begin to form
The heart and lungs begin to develop.
The heart begins to beat near the end of this month

5. First Trimester
Week 2: Conception is the moment at which the sperm penetrates the ovum. Once fertilized it is called a zygote, until it reaches the uterus 3-4 days later.
Fact:
The zygote contains all of the genetic information (DNA) needed to become a baby.
Week 4: The embryo may float freely in the uterus for about 48 hours before implanting. Upon implantation, complex connections between the mother and embryo develop to form the placenta.

6. Month - 2

7. 2nd Month Milestones Eyelids form, but remain closed
The inner ear begins to develop
Bones appear
Ankles, wrists, fingers and toes form
The genitals begin to develop
By the end of month, all major body systems have begun to develop

8. First Trimester (cont.)
Week 6: The embryo is about 1/5 of an inch in length. A primitive heart is beating. Head, mouth, liver, and intestines begin to take shape.
7 weeks - Brain has the first detectable brain waves, muscles develop and get stronger

9. Month - 3

10. 3rd Month Milestones Twenty buds for future teeth appear
All internal parts are formed, but are not fully developed
Soft nails begin to form
The intestines begin to form
Skin is almost transparent
Hand are more developed thatn feet
Arms are longer than legs

11. First Trimester (cont.)
Week 10: The embryo is now about 1 inch in length. Facial features, limbs, hands feet fingers and toes become apparent. The nervous system is responsive and many of the internal organs begin to function.
The end of the 10th week of pregnancy marks the end of the "embryonic period" and the beginning of the "fetal period."
8 weeks - Eyes are well-developed, Fingers lengthen while distinct grooves (digital rays) form between the fingers

12. 12 Weeks
12 weeks - Fetus begins to move around, though the mother cannot yet sense these movements.

13. Month - 4

14. 4th Month Milestones Eyebrows, eyelashes, and fingernails form
Arms and legs flex
External sex organs are formed
The placenta is fully formed
The outer ear begins to develop
The fetus can swallow and hear
The neck is formed
Kidneys are functioning and begin to produce urine

15. Second Trimester
Week 14: The fetus is now 3 inches long and weighs almost an ounce. The muscles begin to develop and sex organs form. Eyelids, fingernails, and toenails also form. The child's spontaneous movements can be observed.

16. 14 Weeks
14 weeks - Fetus is more flexible with ability to move head, mouth, lips, arms, wrists, hands, legs, feet, and toes

17. Second Trimester (cont.)
Week 18: The fetus is now about 5 inches long. The child blinks, grasps, and moves her mouth. Hair grows on the head and body.
Fetus has phases of sleep and waking and may prefer a favorite sleep position, temporary hair called lanugo appears on the head.

18. Month - 5

19. 5th Month Milestones The sucking reflex develops
The fetus sleeps and wakes regularly
Nails grow to tips of fingers
The Gallbladder begins to produce bile, which is needed to digest nutrients
In Girls, the eggs have formed in ovaries
In Boys, the testicles begin to descend from the abdomen into the scrotum

20. Second Trimester (cont.)
20 weeks -  Fetus may suck on thumb. Extremely rapid brain growth; eyebrows and scalp hair become more visible and fetus blinks more often

21. Second Trimester (cont.)
Week 22: The fetus now weighs approximately 1/2 a pound and spans about 10 inches from head to toe. Sweat glands develop, and the external skin is no longer transparent

22. Month - 6

23. 6th Month Milestones Real hear begins to grow
The brain is rapidly developing
The eyes begin to open
Finger and toe prints can be seen
The lungs are fully formed, but not yet functioning

24. Third Trimester
24 weeks - Fetal brain waves begin to activate auditory and visual systems, both mouth and lips show more sensitivity. Eyes respond to light, while ears respond to sounds originating outside uterus.

25. Month -7

26. 7th Month Milestones
The eyes can open and close and sense changes in light
The fetus kicks and stretches
The fetus can make grasping motions and responds to sound

27. Third Trimester (cont.)
Week 26: The fetus can now inhale, exhale and even cry. Eyes have completely formed, and the tongue has developed taste buds. Under intensive medical care the fetus has over a 50% chance of surviving outside the womb.

28. Month - 8

29. 8th Month Milestones
Bones harden, but the skull remains soft and flexible for delivery
The different regions of the brain are forming
Taste buds develop and the fetus can taste sweet and sour
The fetus may now hiccup

30. Third Trimester
Week 30: The fetus is usually capable of living outside the womb and would be considered premature at birth.

31. Month - 9

32. 9th Month Milestones
The fetus usually turns into a head-down position for birth
The skin is less wrinkled
The lungs mature and are ready to function on their own
Sleeping pattern develop
The fetus will gain about ½ pound per week this month

33. Third Trimester Cont…
Week 40:This marks the end of the normal gestational period. The child is now ready to live outside of his mother's womb.

34. Fetal Development Vocabulary
Progesterone: hormone that changes the lining of the uterus and prevents the ovaries from releasing any more eggs
Fertilization: union of an ovum and sperm; also called conception
Estrogen: Any of a group of steroid hormones that promote the development and maintenance of female characteristics of the body
Zygote: a fertilized egg
Chromosome: a threadlike structure that carries genes; 23 male/23 female
Fetus: a developing human from usually two months after conception to birth

35. Vocabulary continued…
Umbilical Cord: is a robe-like structure that connects the embryo to the placenta; the area in which the mother’s blood caries nutrients and oxygen to the fetus
Afterbirth: the placenta and fetal membranes that are expelled after delivery
Gene: is a unit of hereditary material
Oxytocin: referred to as the “love” hormone
Progesterone: hormone that changes the lining of the uterus and prevents the ovaries from releasing any more eggs

36. Facts:
Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the U.S. are pregnant.
Only 25% of couples actively trying to conceive will experience pregnancy within the woman’s first cycle. However, 90% of couples will achieve pregnancy within the first 12 months of actively trying.
Approximately 10% of pregnancies will end in miscarriage. Many miscarriages often occur before a woman even knows she is pregnant.
Just under 500,000 babies are born each year in the U.S. to teenage mothers
The average size of a full-term baby in the U.S. is 8 pounds. This is an increase from an average size of 6 pounds 30 years ago.

37. Facts continued….
The largest baby ever born weighed in at over 23 pounds but died just 11 hours after his birth in The largest surviving baby was born in October 2009 in Sumatra, Indonesia and weighed an astounding 19.2 pounds at birth
Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the U.S. has risen nearly 46% since 1996
Fewer than 10% of babies are born on their exact due date, 50% are born within one week of the due date, and 90% are born within two weeks of the date