Chapter 4
Pregnancy and Childbirth
Slide show was developed by:
Richard C. Krejci, Ph.D.
Professor of Public Health
9.21.15
In this chapter, you will learn to:
LIST
Key anatomic structures related to
pregnancy
Needed health habits during pregnancy
Benefits of breastfeeding
Process of fertilization and implantation
Changes in the mother and baby
DESCRIBE during pregnancy
Three stages of childbirth
Major Topics in the Chapter
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Fertilization
Fetal Development
Sexual Interaction During Pregnancy
Childbirth Options
Cesarean Births
Premature Births
Postpartum Transition
Breast Feeding
Infertility Issues
Fertility Awareness (FAM)
FAM is also known as family planning, can combine each method to identify when a
woman is fertile. However, it must be remembered that the cycles for most women
are not consistently 28-day cycles.
Hormonal Influences on Prenatal
Development
• Becoming male or female
 Undifferentiated state
 Normal sexual differentiation
 Abnormal sexual differentiation
• Androgen
 Male determination hormone
Fertilization
After its release from the follicle, the ovum begins its week-long journey down the fallopian tube.
Fertilization generally occurs in the outermost third of the tube. Now fertilized, the ovum
progresses toward the uterus, where it embeds itself in the endometrium. A pregnancy is
established.
Fertilization
• The union of sperm and ovum
• Both must be mature and in the fallopian tube
• Maturation of Sperm
• Produced in seminiferous tubules in the testes
• Round cells are incapable of fertilization
• With hormonal influence these cells mature
• Spermatogenesis ~ 70 day maturation process
• Phase 1 – meiosis reduces the cells 46 chromosomes to 23
• Phase 2 – develop tadpole-like anatomy
Fertilization
• Maturation of Sperm
• Mature sperm move to epididymis, storage
• Ejaculation causes the sperm to move through the
genital ducts and mix with fluids from the seminal
vesicles and the prostate gland.
• Fluids nourish and protect the sperm
Fertilization
• Sperm Transport in the Female
• Once entering the vagina, sperm must enter the uterus through
the cervix, and then into one of the fallopian tubes for fertilization
• Cervix
• Normally has a thick mucus preventing penetration by sperm
and microorganisms
• Near ovulation the mucus becomes less dense and
organized into channels to help sperm travel through
Fertilization
• Sperm Transport in the Female
• Soon after ejaculation some sperm move through
the cervix into the uterus
• Most sperm are trapped in coagulated semen
within the vagina
• This coagulated semen liquefies later and sperm
move through cervix
• Healthy sperm are released into the uterus
continuously over the next 48 hours
Ovulation
• Preparation of Ova for Fertilization
• Description
• Several ova approach full maturation at each cycle
• Usually one (and sometimes more) completes the process of
maturation and is released
• Matures in a follicle, providing nutrients and hormones
• Special fluid is produced within the follicle cells
• As LH increases and peaks, cells around the follicle degrade
and the follicle ruptures, releasing the ovum and some cells
from the ovary
Ovulation
• Preparation of Ova for Fertilization
• Once freed from the ovary the ovum survives for 24
hours
• Pregnancy occurs if the ovum is fertilized in this 24
hour period
• If pregnancy does not occur the ovum degrades
• After ovulation the ruptured follicle turns into a
progesterone secreting structure (corpus luteum)
which prepares a woman's body for pregnancy
Ovulation
• Ovum Transport
• Ovum is captured and ushered into the fallopian
tube by currents from fimbriae, fingerlike folds that
sweep across the surface of the ovary
• Rhythmic motion and hair like projections inside
the tube promote ovum capture and movement
toward the uterus
Fertilization
• Sperm Penetration of the Ovum
• Description
• A few hundred sperm survive to enter the fallopian
tube
• Fluids in the cavity of the uterus prepare sperm for
penetrating the follicle cells surrounding the ovum
• About 20 reach the ovum and only 1 penetrates the
outer membrane
Fertilization
• Sperm Penetration of the Ovum
• Entry of other sperm blocked by:
1. Release of granules that surround the ovum
2. Changes in the electrical charge of the
membrane
3. Structural changes in the ovum’s membrane that
prevent the binding of additional sperm to the
ovum’s surface
Fertilization
• Sperm Penetration of the Ovum
• After entering the sperm loses its tail and its nucleus
enlarges becoming a male pronucleus
• Ovum’s nucleus enlarges to the female pronucleus
• Fertilized ovum called a zygote
• Each pronucleus has 23 chromosomes
• Chromosomes in each replicate
Fertilization
• Sperm Penetration of the Ovum
• 20 hours after fertilization
• Membranes in each pro-nucleus breaks down
• 92 Chromosomes (46 from each parent) meet in
the center of the zygote
• Zygote immediately divides into two attached cells
each with 46 chromosomes (23 from each parent)
Fertilization
• Sperm Penetration of the Ovum
• Replications continue to form a ball of cells, moving
toward the uterus by the cilia on the inner walls of the
fallopian tube
• Day 4 – zygote is a ball of 50-100 cells arranged as a
fluid-filled sphere or blastocyst
• Most of the cells are designed to form the placenta
• A few cells clustered at one pole of the blastocyst are the
first cells of the child’s body, the embryo
Fertilization
• Implantation
• Day 6
• Embryo is a large ball of several hundred cells
• Outer covering becomes sticky so it can attach to the lining
of the uterus
• Embryo burrows into the uterine lining by releasing
enzymes that break down uterine tissue
• Becomes in contact with the nutrient filled glans in the lining
of the uterus
• Chorionic villi – fingerlike projections from the embryo
burrow deeper into the uterus
Fertilization
• Implantation
• Chorionic villi – fingerlike projections from the
embryo burrow deeper into the uterus in order to
reach maternal blood vessels and break them
open to acquire nutrients from the mother’s blood
First Eight Weeks
(Embryonic Stage)
12 weeks
7 weeks
16 weeks
Fertilization
• Cessation of Menstruation
• After implantation the embryo produces Human Chorionic
Gonadotropin hormone (hGC)
• hGC is secreted into the maternal bloodstream
• Stimulates the mother’s ovaries to increase estrogen and
progesterone production
• Prevents another menstrual period
• Bring about beginning signs of pregnancy
• e.g. nausea, vomiting, enlarged and tender breasts, increased
urination and uterine enlargement
Fertilization
• Cessation of Menstruation
• Pregnancy tests use the detection of hCG as a sign
that a woman is pregnant
• At home tests are fairly accurate if taken after a
missed period
Fetal Development
• After implantation the placenta continues to enlarge
• Embryo begins organ development – called a fetus
• Almost all organs are formed by the 10th week
• During the rest of development, the fetal body grows
and the organs become functional
• Amnion – where development takes place, fluid-filled
membranous sac inside the uterus, amniotic fluid
protects the fetus
 By the 4th month, it can be sampled (amniocentesis) for
possible genetic abnormalities
Fetal Development
• Placenta
• Organ unique to pregnancy
• Develops from the chorionic villi
• Transports oxygen and nutrients from the mother to the fetus
and waste produces from the fetus to the mother
• Nutrients move from maternal blood into fetal blood within
the chorionic villi
• Maternal and fetus bloodstreams do not mix
• Blood flows from the fetus to and from the placenta through
the umbilical cord
Overview: Stages of
Development
Conception
Zygote
(outer third of Fallopian tube)
Blastocyst
(implants in uterus
3-4 days after fertilization)
Embryo
Fetus
(implanted in uterus for 2 months)
(human-like characteristics beyond
2 months)
Fetal Development
• Placenta
• Maternal and fetus bloodstreams do not mix
• Blood flows from the fetus to and from the
placenta through the umbilical cord
• Functions include:
• Transfer gases and nutrients
• Excretes waste
• Transport heat
• Produces various proteins and hormones
• Brings maternal and fetal blood close together but are
completely separate
Pregnancy
• Ectopic Pregnancy
• when implantation occurs outside of the
uterus
• 0ccur most often in the fallopian tube
Pregnancy
• Duration of Pregnancy
• 266 days required for full development
• Usually 280 days or 40 weeks
• Discrepancy from when the beginning of pregnancy is
marked
• First day of the last menstrual period
• Day of fertilization
• Typical range is 260-315 days
Pregnancy
• Duration of Pregnancy
• Changes that occur in the mother:
1. Increase in blood plasma – 50%
2. Increased heart rate – 10%
3. Greater output of blood – 20-30%
4. Red blood cells increase
5. Deeper and faster breathing
6. Uterus grows from ~7-8 cm
and 60-100 grams to 30 cm
and 1000 grams
Pregnancy
• Health Habits During Pregnancy
• Good nutrition and health is essential to the growing
child’s lifelong health and well-being
• Nutrition, prenatal care, exercise, avoiding smoking
and alcohol and other drugs, and accepting
emotional changes are all important to pregnancy
Pregnancy
• Nutrition During Pregnancy
• All fetal nutrients come from the mother
• Many need to supplement with iron and folic acid
• 25-30lb weight gain is appropriate during pregnancy
• 7lb –fetus
• 2lb – uterus
• 1lb – placenta
• 1lb – amnion and amniotic fluid
• 4-8lb – blood and fluid increase
• 4lb – maternal body fat increase
Typical Weight Gain (~27 pounds)
Pregnancy
• Good Prenatal Care
• Increases the likelihood of successful pregnancy and
healthy child
• Can detect and lessen the consequences of diseases
specific to pregnancy
• Reduces the risk of birth defects
• Educates and reduces anxiety (new parents)
• Reduces maternal mortality rate
– 8/100,000 births
• Is usually 12 visits
Pregnancy
• Physical Activity and Exercise
• Exercise is beneficial during pregnancy
• Wide variety of acceptable activities, lots depends on the
mother’s desires for exercise
• Benefits: maintain posture, strengthens bones and
abdominal muscles, improves breathing, reduces
backaches, reduces constipation, bloating and swelling,
better sleep and relaxation.
Pregnancy
• (No!) Smoking During
Pregnancy
• Reduces the amount of oxygen available
to the fetus
• 4000+ chemicals in tobacco smoke, 43
are carcinogens
• Increases risk of birth defects, abnormal
heart and brain, cleft lip and palate,
retarded fetal growth, spontaneous
abortion, death of fetus, small infant at
birth
Pregnancy
• (No!) Alcohol During Pregnancy
• Alcohol consumed passes to the fetus to the same
level that is in the mother
• Remains in the fetal blood stream much longer than
in the mother’s
• Greater risk for birth defects and fetal alcohol
effects (FAE) and fetal alcohol syndrome (FAS)
• No amount of alcohol is safe for pregnancy
Pregnancy
• Sexual Interaction During Pregnancy
• There is generally less sexual interaction during and just
after pregnancy
• Due to comfort level, nausea, or fatigue
• Postpartum depression and infant care can diminish sexual
desire for the woman
• Sex is safe during pregnancy unless there is a physical
problem which would be worsened by sex
• A couple may need to alter positions so both parties are
comfortable and pleasured during sex
• It is advised that a couple refrain from sex for
approximately 6 weeks postpartum
Childbirth
• Can be a time of great joy, relief and surprise
• Lightening – fetus becomes positioned for birth
• Happens a few weeks before birth
• Fetus descends in the uterus
• Head-down position (95%)
Birth Positions
Childbirth
• Labor – forceful expulsion of the fetus from the
uterus along with amniotic fluid, and the placenta
• Rhythmic contractions of the uterus
• Begins with minute long contractions at 20-30 min
intervals
• Regular contractions become more intense, frequent,
and of longer duration
• Voluntary contractions of the abdominal muscles help
expel the uterine contents
Childbirth
• Braxton-Hicks Contractions – irregular and short
uterine contractions
• Occur during the second half of pregnancy
• Stages of Childbirth
1. First – Dilation of the cervix (effacement)
2. Second – Delivery of the fetus
3. Third – Delivery of the placenta and fetal membranes
The Stages of Childbirth
Childbirth
• Stages of Childbirth
• First – Dilation of the cervix (effacement)
• Lasts 8-12 hours
• Ends when the cervix is fully dilated at 10cm
• May be initiated by “breaking the bag of waters”
(amniotic fluid) and “bloody show” (mucous plug)
• Can be induced by a variety of interventions
Childbirth
• Stages of Childbirth
• Second – Delivery of the fetus
• Lasts 30 min - 2 hours
• Involuntary contractions continue and the mother
can push to help birth the baby
• Episiotomy – an incision in the perineum which
can be performed to enlarge the opening for the
baby
Childbirth
• Stages of Childbirth
• Third – Delivery of the placenta and fetal membranes
• Lasts 15 - 30 min
• Uterine contractions dislodge the placenta and
remnants of the fetal membranes from the wall of the
uterus and expel them from the vagina
• Contractions continue over then next 2-3 hours which
helps constrict uterine arteries, and return the uterus to
its pre-pregnant size
• Breastfeeding also stimulates uterine contractions to
return uterus to its pre-pregnant size
Childbirth
• Relief of Discomfort and Pain
• Variety of options
• Hypnosis, warm water bath, walking, massage, deep breathing,
meditation, sterile-water injections, pain-relieving medication
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Birthing Options
• Lamaze
• LeBoyer
• Hypnobirthing
• Underwater
• Fitness Ball
• Social ad psychological support help
lessen pain and discomfort
• A positive outlook before the birth begins
helps a woman have less discomfort
Cesarean Births
• Surgical birth of the fetus through the woman’s abdomen
• Caused by large baby, improper fetal position (Breech),
slow fetal heart rate or fetal distress, active genital herpes
and prior cesarean birth
• Less safe than an uncomplicated vaginal delivery
• 28% of births in the US
• View
Breech Positions
Premature Births
• 12% of babies are born before 37 weeks
• High risk of disabilities
• Those born at 22-25 weeks are extremely underdeveloped
and vulnerable
• 80% show severe cognitive deficiencies and neurological problems
• Causes
• Mother’s age, infertility treatments, maternal illness and infection
• 50% of those who show signs of
premature labor deliver early
Postpartum Transition
• Lasts several weeks after childbirth
• Physiological changes of pregnancy slowly reverse
• Vagina and surrounding structures recuperate
• Uterine tissue is discharged
• Estrogen and progesterone levels drop extremely low
• Psychological transition
• “Baby blues” is common
• 13% - clinical depression
Postpartum Transition
• Sudden Infant Death Syndrome (SIDS)
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Sudden death of an infant less than 1 year old
2300 every year in the US
Cause is unknown, no abnormalities evident
Infants must sleep on their backs
Postpartum Transition
• Breast Feeding
• Preparation starts early in pregnancy
• Colostrum – produced by the breasts midway
through pregnancy, precursor to milk
• This is what nourishes the newborn in the first few
days after birth
• High in antibodies which protect against
infection
• As the newborn nurses, colostrum is
replaced by milk
Postpartum Transition
• Breast Feeding
• Milk has specific proteins, antibodies, lactose, fat and
water
• Production controlled by prolactin
• Infants have a sucking reflex
• Sucking causes nerve impulses to be transmitted to the
mothers brain
• Triggers the release of oxytocin
• Oxytocin circulates through the bloodstream to the
breasts, causing the muscle cells that line the milk ducts
to contract and eject milk from the nipple
Postpartum Transition
• Breast Feeding
• Milk production continues as long as the baby continues
to nurse and the breasts are regularly drained of milk
• Without continued stimulation milk production stops
• Poor nutrition, stress, fatigue, and lack of social support
can also cause milk production to cease.
• As long as the mother continues to nurse, she is highly
unlikely to become pregnant due to the hormones that
support milk production
Postpartum Transition
• Breast Feeding Advantages
1. Economical
2. Transfers immunity from the mother to the infant
3. Promotes infant digestive system development
4. Tend to have fewer allergies, less diarrhea, fewer dental
problems and less colic
5. Breast milk is nutritionally balanced for the infant and its
stage of life
6. May increase attachment between mother and baby
Postpartum Transition
• Breast Feeding Advantages
• Hormones involved in the production and release of
milk also cause uterine contractions, helping the
uterus return to normal size
• Gives the mother a reason to sit down and rest
• Bottle feeding can be very good too
• Disadvantages
• Time
• Discomfort
• Awkward for some
• Job/school interference
Infertility
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~7% of American couples
Unable to get pregnant after trying for 1 year
40% due to male biology
40-50% due to female factors
10% no known cause
With help ½ are able to have children
Sterility – permanent infertility
Infertility
• Causes
• Ill health, smoking, alcohol, marijuana and other drug
use, radiation or toxic chemical exposure, malnutrition,
anxiety, stress, fatigue
• Age – fertility declines with age
• Hormonal problems – underproduction of GnRF, FSH,
LH, testosterone, estrogen or progesterone
• Anatomical abnormalities, scarring, growths
• Insemination and sperm transport
• Infertility treatments increase the likelihood of multiple
births
Fertility
• Enhancing Fertility Options
• Assisted reproductive technologies (ART)
• Ova and sperm are combined outside of the body and
then placed into a woman’s body
• In Vitro Fertilization (IVF) – woman is given hormones to
induce the release of several ova, which are removed and
combined with sperm , several of the resulting embryos
are placed into the uterus of the donor woman or
surrogate
• Successful 50% of the time
• 1/3 – 1 child, 1/3 – twins, 1/3 triplets
Fertility
• Enhancing Fertility Options
• Assisted reproductive technologies
• Gamete Intrafallopian Transfer (GIFT) – ova and
sperm are placed in each of the fallopian tubes where
fertilization can take place
• Zygote Intrafallopian Transfer (ZIFT) – fertilization of
ova and sperm occur in a laboratory and the fertilized
egg is placed in a fallopian tube
ART Methods
• In Vitro Fertilization (IVF)
• Gamete Intra-fallopian
Transfer (GIFT)
• Zygote Intra-fallopian Transfer
(ZIFT)
• Donor egg IVF
• Intracellular Sperm Injection
(ICSI)
– Many methods result in having
multiple babies!
What is the difference between each
of these methods?
Pre-Pregnancy Planning
Pre-pregnancy planning should encompass all of the following:
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Non-drug use
Nutritional planning
Exercise
Time lapse of one menstrual
cycle between contraceptive
use and conception
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Folic acid supplements
Quit smoking
Avoid alcohol beverages
Avoid OTC drugs
Avoid megadoses of nutritional
supplements
Chapter Review
• Sperm are transferred from male to female during sexual
intercourse.
• In adult females, ova (eggs) are produced in ovaries and are
transported to fallopian tubes to be fertilized.
• Pregnancy is established when a fertilized ovum implants in
the uterus.
• Fetal development requires 266 days.
• Childbirth is a three-phase process.
• Breast feeding has numerous benefits for both baby and
mother
• Infertility can sometimes be overcome through use of new
medical technologies
The End
Slide show was developed by:
Richard C. Krejci, Ph.D.
Professor of Public Health
All Rights Reserved