Pregnancy and Delivery

1
Pregnancy and Delivery
2
First Trimester

• Fertilization the sperm and egg join in the
  fallopian tube to form a unique human being.
  Forty-six chromosomes combine, which
  pre-determine all of a person's physical
  characteristics.

3
First Trimester

• The picture is a fertilized egg, only thirty
  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 and towards the uterus.

4
First Trimester

• 3 weeks - Once in the uterus, the developing
  embryo, called a blastocyst, searches for a nice
  place to implant, where it actually burrows
  beneath the surface of the uterus. The yolk sac,
  shown on the left, produces blood cells during
  the early weeks of life. The unborn child is only
  one-sixth of an inch long, but is rapidly
  developing. The backbone, spinal column, and
  nervous system are forming. The kidneys, liver,
  and intestines are taking shape.

5
First Trimester

• 4 weeks - The embryo produces hormones which stop
  the mother's menstrual cycle.
• 5 weeks - Embryo is the size of a raisin. By day
  twenty-one, the embryo's tiny heart has begun
  beating. The neural tube enlarges into three
  parts, soon to become a very complex brain. The
  placenta begins functioning. The spine and spinal
  cord grows faster than the rest of the body at
  this stage and give the appearance of a tail.
  This disappears as the child continues to grow.

6
(No Transcript)
7
First Trimester

• 7 weeks - Facial features are visible,
  including a mouth and tongue. The eyes have a
  retina and lens. The major muscle system is
  developed, and the unborn child practices moving.
  The child has its own blood type, distinct from
  the mother's. These blood cells are produced by
  the liver now instead of the yolk sac.

8
First Trimester

• 8 weeks - The unborn child, called a fetus at
  this stage, is about half an inch long. The tiny
  person is protected by the amnionic sac, filled
  with fluid. Inside, the child swims and moves
  gracefully. The arms and legs have lengthened,
  and fingers can be seen. The toes will develop in
  the next few days. Brain waves can be measured.

9
First Trimester

• 10 weeks - The heart is almost completely
  developed and very much resembles that of a
  newborn baby. An opening the atrium of the heart
  and the presence of a bypass valve divert much of
  the blood away from the lungs, as the child's
  blood is oxygenated through the placenta. Twenty
  tiny baby teeth are forming in the gums.

10
First Trimester

• 12 weeks - Vocal chords are complete, and the
  child can and does sometimes cry (silently). The
  brain is fully formed, and the child can feel
  pain. The fetus may even suck his thumb. The
  eyelids now cover the eyes, and will remain shut
  until the seventh month to protect the delicate
  optical nerve fibers.

11
(No Transcript)
12
Second Trimester

• 14 weeks - Muscles lengthen and become organized.
  The mother will soon start feeling the first
  flutters of the unborn child kicking and moving
  within.
• 15 weeks - The fetus has an adult's taste buds
  and may be able to savor the mother's meals.
• 16 weeks - Five and a half inches tall and only
  six ounces in weight, eyebrows, eyelashes and
  fine hair appear. The child can grasp with his
  hands, kick, or even somersault.

13
Second Trimester
20 weeks - The child can hear and recognize her
mother's voice. Though still small and fragile,
the baby is growing rapidly and could possibly
survive if born at this stage. Fingernails and
fingerprints appear. Sex organs are visible.
Using an ultrasound device, the doctor can tell
if the child is a girl or a boy. The one on the
right is a baby girl.
14
Second Trimester

• 20 weeks - The child can hear and recognize
  her mother's voice. Though still small and
  fragile, the baby is growing rapidly and could
  possibly survive if born at this stage.
  Fingernails and fingerprints appear. Sex organs
  are visible. Using an ultrasound device, the
  doctor can tell if the child is a girl or a boy.
  The one on the left is a baby girl.

15
Second Trimester
16
Third Trimester

• 24 weeks - Seen here at six months, the
  unborn child is covered with a fine, downy hair
  called lanugo. Its tender skin is protected by a
  waxy substance called vernix. Some of this
  substance may still be on the child's skin at
  birth at which time it will be quickly absorbed.
  The child practices breathing by inhaling
  amnionic fluid into developing lungs.

17
Third Trimester

• 30 weeks - For several months, the umbilical
  cord has been the baby's lifeline to the mother.
  Nourishment is transferred from the mother's
  blood, through the placenta, and into the
  umbilical cord to the fetus. If the mother
  ingests any toxic substances, such as drugs or
  alcohol, the baby receives these as well.

18
Third Trimester

• 32 weeks - The fetus sleeps 90-95 of the day,
  and sometimes experiences REM sleep, an
  indication of dreaming.

19
Third Trimester

• 40 weeks - The baby, now approximately seven
  and a half pounds, is ready for life outside its
  mother's womb. At birth the placenta will detach
  from the side of the uterus and the umbilical
  cord will cease working as the child takes his
  first breaths of air. The child's breathing will
  trigger changes in the structure of the heart and
  bypass arteries which will force all blood to now
  travel through the lungs.

20
Labor and Delivery

• For 9 months, the unborn child has been
  developing within the womb. Now the fetus is
  prepared to make an exit. Birth in human beings
  typically occurs 270 days after conception, near
  the end of a full 9 months. Shortly before birth
  (typically a few weeks for first births but
  sometimes only a few hours for later
  pregnancies), the fetus usually rotates into a
  head-downward position. This movement is referred
  to as lightening because it releases pressure on
  the mother's abdomen.
• For women giving birth for the first time, labor
  will usually last between 12 and 24 hours, with
  an average of 14 hours. However, for women who
  have given birth before, labor usually averages
  only 6 hours.

21
Labor and Delivery 1st

• Labor is commonly divided into three stages
  that typically overlap each other. During the
  first stage, which lasts, on the average, about
  13 hours for a woman having her first child,
  uterine contractions begin. It was discovered
  that the levels of a certain enzyme increase
  dramatically as labor starts. This enzyme chews
  up the collagen that holds together the fetal
  membrane, which in turn causes the amniotic sac
  to rupture (commonly referred to as the time when
  a woman's "water breaks.") The ensuing
  contractions associated with the rupture are
  usually spaced from 10 to 20 minutes apart.
  Initially the contractions are gentle, but they
  tend to become more powerful and sometimes
  uncomfortable.

22
Labor and Delivery 2nd

• The second stage of labor usually lasts about
  90 minutes. During this stage, the cervix opens
  sufficiently and the baby begins to move down the
  birth canal. At this point, if the mother has
  been well prepared, she may use her abdominal
  muscles to help push the baby along. This second
  stage of labor may often be shortened
  considerably by having the mother give birth in a
  vertical position, for example, by using a bed or
  room especially designed to include a birthing
  bar. When the mother is upright, gravity helps
  the baby move down the birth canal. Although the
  second stage of labor usually takes about 90
  minutes, the average time in an upright position
  is only 30 minutes. At the end of the second
  stage of labor, the baby is born.

23
Labor and Delivery 2nd

• During birth, the human fetus is forced
  through the birth canal under extreme pressure
  and is intermittently deprived of oxygen. During
  this time, the baby secretes the hormones
  adrenaline and noradrenaline at levels that are
  higher than they are likely to be at any other
  time throughout his or her life. Adrenaline helps
  open up the lungs, dry out the bronchi, and thus
  achieve the switch from a liquid to an air
  environment. Noradrenaline, which is especially
  prevalent, slows the heartbeat, enabling the
  fetus to withstand fairly lengthy oxygen
  deprivation.

24
(No Transcript)
25
Labor and Delivery 3rd

• Following the exit of the infant, the third
  stage of labor occurs, during which the placenta
  is expelled. The placenta and other expelled
  materials are called the afterbirth.

26
Cesarean section

• Babies delivered by Cesarean section, are
  brought out of the mother surgically and do not
  pass through the birth canal. Interestingly these
  infants often have respiratory problems. One
  reason for such problems might be that the infant
  has not benefited from the usual stress of birth!
  

27
(No Transcript)
28
Question Are all babies born in the head-first
position?

• About 97 percent of babies are born in the
  head-first position. The fetus's skull is soft
  and pliable, which helps the head to pass through
  the birth canal. However, 2.4 percent of babies
  are born rump first this is called a breech
  birth. During a breech birth, great care must be
  taken to avoid damage to the baby's head, which
  is the most difficult part of the infant's body
  to pass through the birth canal. An even rarer
  occurrence is the shoulder presentation. This
  occurs in only 1 birth out of 200. The shoulder
  presentation is extremely dangerous because the
  baby must be forced by the attendants into a
  breech position. This forcing can rupture the
  uterus, which may cause the death of the infant
  and severe hemorrhaging in the mother.

29
Anoxia
Another dangerous problem that can occur during
birth is anoxia. Anoxia can occur if the placenta
detaches prematurely if the umbilical cord is
pinched or tangled, if the infant's head is
injured to the point of hemorrhaging, or if the
mother has been too heavily sedated during labor.
If there is a problem during birth, the child may
be removed from the uterus by Cesarean section.
Approximately 23 of all births in the United
States are Cesarean sections. In this procedure,
the mother's abdomen is opened surgically and the
baby is removed without passing through the
vaginal canal. The surgical incision is then
closed as it would be after any other surgical
procedure.
30
1 Cesarean, 2 cesarean

• Whenever possible, obstetricians use special
  surgical incisions in the uterus so that a woman
  who has had one Cesarean section may later
  deliver babies vaginally. In addition, some
  obstetricians have recommended that Cesarean
  sections not be used routinely if breech birth or
  labor problems begin. They argue that breech
  births for low-weight babies, especially if the
  obstetrician is skilled, may present no
  difficulty and that abnormal labor of and by
  itself is not sufficient cause for a Cesarean
  section. When it is necessary, however, Cesarean
  section can be a lifesaver for both infant and
  mother.

31
(No Transcript)
32
Carnegie Stages

• Carnegie stages are a system used by
  embryologists to describe the apparent maturity
  of embryos. An embryo is assigned a Carnegie
  stage (numbered from 1 to 23) based on its
  external features. This staging system is not
  dependent on the chronological age nor the size
  of the embryo. The stages, are in a sense,
  arbitrary levels of maturity based on multiple
  physical features. Embryos that might have
  different ages or sizes can be assigned the same
  Carnegie stage based on their external appearance
  because of the natural variation which occurs
  between individuals.

33
versus Postovulatory age

• Postovulatory age is frequently used by
  clinicians to describe the maturity of an embryo.
  It refers to the length of time since the last
  ovulation before pregnancy. Postovulatory age is
  a good indication of embryonic age because the
  time of ovulation can be determined and
  fertilization must occur close to the time of
  ovulation. The terms "gestation", "pregnancy",
  and "conception" are usually avoided in
  describing embryonic age because fertilization is
  not universally accepted as the commencement of
  development (some consider implantation as the
  beginning of development)

34
Fetal Images Early Pregnancy

• Twin gestation sacs at 4 ½ weeks gestation

35
Brain vesicles

• 8 week fetus showing the brain vesicles

36
heart

• Four-chamber view of the fetal heart showing
  left ventricle (LV), right ventricle (RV), mitral
  valve (MV), tricuspid valve (TV), left atrium
  (LA), right atrium (RA), descending aorta (Ao),
  pulmonary vein (PV), the fetal spine(Sp) rib.

37

• Image of a 7 week twin pregnancy with two
  live embryos (arrowheads).

38
(No Transcript)
39
(No Transcript)
40
References

• The Multi-Dimensional Human Embryohttp//embryo.so
  ad.umich.edu/index.html
• Fetal Development http//www.w-cpc.org/fetal1.htm
  l

41
(No Transcript)
42

• The photograph is that of a 21-week-old unborn
  baby named Samuel Alexander Armas, who was being
  operated on by a surgeon named Joseph Bruner. The
  baby was diagnosed with spina bifida and would
  not survive if removed from his mother's womb.
  During the procedure, the doctor removes the
  uterus via C-section and makes a small incision
  to operate on the baby, then returns the uterus
  to the mother's womb after he completes the
  procedure.  As the doctor was completing the
  surgery, the little guy reached his tiny, but
  fully developed, hand through the incision and
  firmly grasped the surgeon's finger.

43

• Dr. Bruner was reported as saying that when
  his finger was grasped, it was the most emotional
  moment of his life, and that for an instant
  during the procedure, he was just frozen, totally
  immobile.  The photograph captures this amazing
  event with perfect clarity. The editors titled
  the photograph, "Hand of Hope." Samuel was born
  in perfect health, the operation 100 per cent
  successful. Now see the actual photo it is
  awesome... incredible.

44
(No Transcript)