Transcript Human Reproduction

Unit 2 – Reproduction
and Development
Unit Outcomes
Examine the principal features of the
human reproductive system
 Identify the male and female reproductive
structures and describe their functions
 Identify the risks that STIs present to
individuals and to human reproduction
 Explain how STIs can interfere with the
passage of eggs and sperm

Unit Outcomes
Research the effects of STIs
 Identify the main reproductive hormones
and describe how they interact
 Explain the role of sex hormones in the
development and regulation of primary
and secondary sex characteristics
 Analyze blood hormone data and
associated physiological events

Unit Outcomes
Research and assess the medical use of
reproductive hormones in humans
 Trace the processes and events that occur
during embryonic development
 Describe the significance of the primary germ
layers and identify the tissues and organs that
come from them
 Compare embryonic changes and
extraembryonic structures in humans and other
animals

Unit Outcomes
Trace the processes and key events that
occur during fetal development
 Describe and investigate the effect of
teratogens and other environmental
factors on the development of prenatal
body structures and systems
 Trace the processes of parturition and
lactation, and outline their control
mechanisms

Why is Reproduction Important
It produces variation within a species
 It provides a basis for natural selection
within a species

14.1 – The Male and Female
Reproductive Systems
Both male and female reproductive
systems include a pair of gonads (which
produce gametes)
 These gonads also produce sex hormones
 These hormones often control primary sex
characteristics and secondary sex
characteristics

The Male Reproductive System
Male & female reproductive organs do not
differ greatly until the 3rd month of fetal
development
 The purpose of this system is to produce
sperm and allow them to leave the body

The Male Reproductive System
Structures:

Scrotum:

Testes:

Epididymis:
holds the testes away from the body to keep them
cool. Sperm production only occurs at temperatures about 3
degrees below body temperature.
are the organs responsible for spermatogenesis. They
develop inside the abdominal cavity of a male fetus and descend
only about 2 months before birth. The testes hold seminiferous
tubule that produce sperm.
holds spermatozoa for about 2-4 days while they
mature

Vas deferens:
stores sperm, and conducts sperm during
ejaculation. When a male has a vasectomy, the vas deferens if cut
and tied off, to prevent conduction of sperm.

Seminal Vesicle:

Prostate Gland:

Cowper’s Gland:

Ejaculatory Duct:
produces a rich nutrient fluid (fructose)
that is an important component of semen.
produces a white, milky, alkaline fluid
component of semen. This fluid neutralizes the acidity of urethra
and the vagina, allowing sperm to survive.
(aka bulbourethral gland) produces a rich
alkaline mucous that becomes part of the seminal fluid. This also
neutralizes any acid sperm might be exposed to.
is responsible for the movement of
fluid from the seminal vesicle to the vas deferens.

Urethra:

Penis:

Prepuce (foreskin):
is responsible for conduction of urine and semen out
of the penis. During ejaculation, a sphincter muscle closes off the
bladder, preventing urine from exiting the urethra.
is the male organ for copulation. Beneath the skin, lies
the urethra surrounded by spongy protective tissue that expands to
form the glans penis.
is a loose sheath of skin covering
the glans penis of uncircumcised males. The foreskin produces an
oily secretion known as smegma.
Erectile Tissue
The erectile tissue of the penis (corpus
cavernosum) fills with blood when a man
is sexually excited (controlled by the
parasympathetic nervous system through
vasodilation)
 This causes the penis to swell and become
rigid

Erectile Dysfunction (ED)
Increased blood flow to the penis is
actually controlled by the parasympathetic
nerves
 They cause a relaxation of muscle tissue
that allows the arteries running into the
penis to dilate and carry more blood
 Therefore, if the parasympathetic nerve is
damaged, erections become difficult or
impossible to sustain

Other factors may also lead to erectile
dysfunction, including an imbalance in
hormones, particularly testosterone
 Stress can also lead to erectile dysfunction
 Viagra is a drug that relaxes the muscles
constricting the blood vessels running into
the penis (these muscles are similar to the
smooth muscle in the digestive system).
 Therefore, it is much easier for the blood
to enter the erectile tissues and cause an
erection.

Sperm
Sperm are very small
cells built for speed
 There is very little
cytoplasm in a sperm
cell, which increases
the cell’s mobility

http://img.tfd.com
A single sperm cell has a large number of
mitochondria
 It also has an acrosome, which contains
special enzymes that allow it to penetrate
the membrane of an egg cell

Spermatogenesis
Inside the testes are tiny tubes called
seminiferous tubules
 They are lined with spermatogonia
 These spermatogonia divide and form

spermatocytes

In about 9 to 10 weeks, the
spermatocytes develop into sperm cells
Sertoli cells
nourish the
developing
sperm
 When they
are ready,
sperm cells
move to the
epididymis to
complete
their
maturation

Spermatogenesis Animation
http://faculty.sunydutchess.edu
Seminal Fluid
Seminal fluid consists of contributions
from three different glands
 This fluid protects and nourishes the
sperm as it travels out of the man’s body
and into the woman’s reproductive tract

Seminal Vesicles

This gland produces one component of
seminal fluid:
– Fructose -
provides energy sperm need to swim
Prostate Gland
The prostate produces:
1. an alkaline buffer that neutralizes the
acidity of the vagina
2. Prostaglandins – stimulates contraction of
vaginal walls to help move sperm along
to uterus/oviduct

Cowper’s (bulbourethral) Gland

This gland produces mucus-rich fluids that
provide lubrication and buffer the acidity
in the vagina
Sperm Survival
Within the epididymis, the sperm can
survive for extended periods (some die
and are removed by the immune system)
 However, at body temperature sperm only
live for 24-72 hours
 Sperm can be stored indefinitely at -100oC
(which is how they are stored at sperm
banks)

The Female Reproductive System
The female reproductive system involves
more complicated cycles than the male
reproductive system
 Female hormone levels fluctuate
throughout their menstrual cycle (whereas
males maintain a relatively constant level
of testosterone)

The Female Reproductive System
http://www.uh.edu
Structures

Ovary -

Corpus Luteum –

Oviduct -

Fimbriae -
Produces ovum (eggs) – from approx.
400,000 follicles - and is the site of egg maturation
before ovulation. As well, is the site of corpus luteum
(important for pregnancy).
cells remaining after a follicle has
ruptured during ovulation, this scar-like tissue secretes
estrogen and progesterone for about 3 months if
fertilization and pregnancy occurs, or deteriorates after
about 14 days if fertilization does not occur.
aka the fallopian tube. Connects ovary to
uterus. Fertilization occurs here.
small fingerlike projections at the ends of
the oviducts that sweep to draw the egg
into the fallopian tube

Uterus
Organ where implantation of the zygote
(fertilized egg) occurs. Made up of 2 layers:
1. Myometrium – muscular lining of the uterus that
provides support for embryo and contracts during
labor.
2. Endometrium – glandular lining of the uterus that
provides nourishment to embryo (layer is shed
during menstruation)

Cervix

Vagina
Dense muscle band that plugs closed with mucous during
pregnancy and prevents material from getting into the
uterus. Separates the birth canal (vagina) from the uterus.
This keeps the fetus in the uterus and must dilate during
labor in order for the fetus to be born vaginally.
aka the birth canal. Site of many nerve endings and is very
acidic to protect the person from pathogens or microbes
that enter the vagina.
External Structures (Vulva)

Labia majora – large, fatty, hair covered folds
that protect the genitals

Labia minora – smaller folds of skin inside the
labia that are kept moist with special secretory
cells

Clitoris – small shaft of erectile tissue with a
large number of nerve endings (very sensitive)
Oogenesis and Ovulation





The ovary contains many small groups of cells
known as follicles
Within the follicle, an oocyte undergoes meiosis
and becomes an ovum and 3 polar bodies
The ovum created contains 23 chromosomes
and most of the cellular material from the oocyte
Granulosa Cell - nourish the developing ovum
and becomes the corpus luteum after ovulation.
When it is ready, the follicle ruptures the outer
ovary wall and releases the ovum
Oogenesis & Ovulation
http://faculty.sunydutchess.edu
Differences Between Sperm & Eggs
Sperm
Egg
Size
50 μm long (5 μm head, 5 μm
middle piece, 40 μm tail)
100 μm diameter
Energy
Reserves
Mitochondria
Fat before ejaculation, fructose in Fertilized eggs rely on the
seminal fluid after ejaculation
endometrium as an energy
source
Middle piece of sperm has 50 to
100 mitochondria
Cytoplasm contains about
140 000 mitochondria
Number
Produced
300 – 500 million per day
300 – 400 thousand follicles
are present at the start of
puberty – 1 egg is released
per month
Motility
High motility due to flagellum
No structures for propulsion
Other
Structures
Sperm has an acrosome which
contains enzymes that help the
sperm to enter the egg
Egg is covered by an outer
membrane which can only
be penetrated by a sperm of
the same species
14.2 – The Effect of Sexually
Transmitted Infections on the
Reproductive System
During sexual intercourse, body fluids are
exchanged
 The fluids can contain STIs (Sexually
Transmitted Infections) in the form of
bacteria or viruses

Viral vs. Bacterial STIs
Bacterial STIs
Viral STIs
Chlamydia
Gonorrhea
Syphilis
HIV
HPV
Hepatitis
Genital Herpes
HIV / AIDS
AIDS is caused by the
human
immunodeficiency virus
(HIV)
 This virus attacks and
destroys helper T cells

http://biology.kenyon.edu
HIV Replication Animation
Hepatitis B
Hepatitis viral infections
come in 3 subtypes: A, B
and C
 Hepatitis B is transmitted
in the same fashion as
HIV
 The hepatitis B virus
attacks the liver

http://www.torontoliver.ca
Hepatitis B
Symptoms of hepatitis B include flu-like
symptoms, jaundice, and liver failure
 Hepatitis viruses can cross the placenta and
infect the unborn child
 Occasionally, a person who is infected with the
hepatitis B virus may be asymptomatic, and can
therefore pass on the virus to others without
knowing it
 There are effective vaccines for both hepatitis A
and B

Genital Herpes
It is estimated
that 1 in 3
sexually active
Canadians has
genital herpes
 Herpes is caused
by either HSV 1 or
HSV 2 viruses
 The majority of
genital herpes
cases are caused
by HSV 2

Genital Herpes





Symptoms can vary from case to case
Symptoms may include tingling, itching, and
appearance of blisters
Blisters can then rupture and become painful
sores (these open sores increase the chance of
HIV infection)
Outbreaks may be accompanied with swollen
glands, aching joints, and fatigue
The herpes virus may infect babies during the
birthing process, possibly leading to blindness,
neurological disorders, or death
Genital Herpes
There is no cure for herpes
 Even if an infected person is not
symptomatic, they can still pass on the
virus during intercourse
 No vaccine is yet available for herpes

HPV (Human Papilloma Virus)
HPV is the name of a
group of viruses
 It is transmitted during
skin-to-skin contact
 Some people infected
with HPV develop
genital warts, while
other people can show
no symptoms at all

http://upload.wikimedia.org
Cervical Cancer




Cervical cancer is one of the primary
forms of cancer in women
Pap tests done by physicians collect cells
from the surface of the cervix
These cells are then checked for any
abnormal tissue growth
New evidence indicates that cervical
cancer may be caused by the Human
Papillomavirus (HPV)
Chlamydia
Chlamydia is the most
common bacterial STI
in Canada
 Infection rates are
twice as high in young
women than in young
men

Chlamydia
Symptoms are immediate and often
include discharge from the penis or
vagina, burning pain during urination, or
fever
 75% of infected people show no
symptoms
 In women, the infection may lead to pelvic
inflammatory disease (PID), which causes
scar tissue in the oviducts
 Chlamydia can be treated with antibiotics

Gonorrhea
Often found together with
chlamydia bacterial
infections
 The rate of infections is
higher in men than in
women
 Symptoms are similar to
those of chlamydia
 This can also cause PID and
serious eye infections for
babies born to mothers with
gonorrhea

http://www.faqs.org/health
Syphilis

Although much less
common than other
bacterial STIs, the
rate of syphilis
infection has
increased sharply
since 1997
http://www.wales.nhs.uk
Syphilis





Initially, infectious ulcerated sores appear
(known as chancres)
This is followed by a rash (often on palms of
hands, soles of feet), and then the bacteria
affects the cardiovascular and nervous system
Infected persons may become mentally ill, blind,
lame, or develop heart disease
If bacteria infect a developing embryo, birth
defects or stillbirth can result
Syphilis can be treated effectively with
antibiotics
Preventing STI Transmission

1.
2.
3.
4.
There are a number of ways to reduce
the chance of passing on STIs:
Abstinence
Long-term monogamous relationships
Condom use
Personal responsibility
14.3 – Hormonal Regulation of the
Reproductive System
Hormones play an important role in the
operation of the reproductive system
 The hormones involved in reproduction
are produced in the hypothalamus, the
pituitary, and the gonads

Male Reproductive Hormones

GnRH – gonadotropic releasing hormone,
released in hypothalamus; stimulates the
anterior pituitary to release LH and FSH
 LH – luteinizing hormone, stimulates the
interstitial cells of the testes to produce
testosterone
 FSH – follicle stimulating hormone, stimulates
production of sperm in the seminiferous tubules
 Testosterone – responsible for male secondary
sex characteristics (including hair growth,
muscle growth, deeper voice), required for
sperm production
Hormones (con’t)

Inhibin – hormone that inhibits GnRH, LH, and
FSH production (negative feedback)
 Interstitial Cells – surround the seminiferous
tubules, produce testosterone when stimulated
by LH
 Sertoli Cells – provide nutrients and support
for developing sperm
Feedback of Gonadotropins
Aging and the Male Reproductive
System
Most men experience a gradual decrease
in testosterone levels starting at about 40
years of age
 This is known as andropause
 As well, hormonal changes in males over
age 40 can also result in gradual growth
of the prostate gland
 Older males also have a higher chance of
prostate cancer as well

Female Reproductive Hormones
The pituitary and hypothalamus control
the production of estrogen and
progesterone
 FSH (Follicle-stimulating hormone) and LH
(luteinizing hormone) regulate the
production of estrogen and progesterone
 Estrogen is also responsible for female
secondary sex characteristics:

– Breast development
– Hair growth
Hormones

GnRH – (released from the hypothalamus)
stimulates the anterior pituitary to produce FSH
and LH
 LH – responsible for the development of the
corpus luteum, promotes secretion of
progesterone, surges of LH cause ovulation
 FSH – stimulates development of the follicle
and the production of estrogen
 Estrogen – secreted by the follicles in the
ovaries, causes maturation of the egg and
stimulates growth of the endometrium
 Progesterone – secreted by the corpus
luteum, causes the endometrium to become
secretory and inhibits both FSH and LH to
prevent ovulation
The Menstrual Cycle
This cycle is divided into 4 phases (28
days):
1. Flow Phase

– shedding of the endometrium (lasts ~ 5
days)
2. Follicular Phase
– development of follicles within the ovary.
During this phase, estrogen concentration in
the blood increases (thickens endometrium);
(lasts ~ 8 days)
3. Ovulation
– oocyte bursts from ovary (lasts ~ 1 day)
4. Luteal Phase
– follicle cells differentiate into the corpus
luteum following ovulation. Progesterone
(inhibits further ovulation, stimulates
endometrium, and prepares the uterus for the
embryo) and estrogen are secreted. Without
fertilization, secretions decrease and the
endometrium is then shed during the next
flow phase; (lasts ~ 14 days)
Birth Control Pills
Along with its effect of maintaining the
uterine lining, progesterone also prevents
further ovulations
 Women can prevent ovulation by ingesting
progesterone in a pill form, or through
implanted capsules containing similar
hormones
 The pill increases a woman’s progesterone
levels, preventing the release of an ovum

Aging and the Menstrual Cycle
Women have a limited number of
menstrual cycles due to their limited
number of follicles
 As the number of follicles decreases, the
amount of estrogen and progesterone in
the woman’s body decreases
 The woman’s menstrual cycles become
irregular and eventually stop completely

Menopause


1.
2.
3.
4.
5.
Menopause (the cessation of menstrual
cycles) often occurs around age 50
During menopause, a number of
different effects are experienced:
‘Hot flashes’
Variable changes in mood
Increasing cholesterol levels
Diminished bone mass
Increased risk of breast and uterine
cancer
Treatment for Menopause
Many women consider hormone
replacement therapy during or following
menopause
 However, there are some risks to the
hormone replacement therapy (increased
risk of blood clots, stroke, breast &
colorectal cancer, and dementia)

Endocrine Disruptors
A number of man-made chemicals can
interrupt the function of hormones
 If these disrupt the function of sex
hormones, then the reproductive cycles of
men and women can be effected as well
 As well, testosterone-blocking chemicals
can lead to feminization in males

15.1 – Fertilization and
Embryonic Development
150 to 300 million sperm cells travel
through the cervix upon ejaculation during
intercourse
 Ultimately, only a single sperm cell fuses
with the ovum

http://content.answers.com
Embryonic Development
The fertilized egg (the
zygote) undergoes a
number of cellular
divisions on its way to
the uterus
 By the time it reaches
the uterus, the single
fertilized egg has
become a cell mass
known as a blastocyst


The blastocyst then attaches to the
endometrium wall (this is known as
implantation)
Maintenance of the Endometrium
If the corpus luteum deteriorates, then the
endometrium will be shed
 High levels of estrogen and progesterone
must be maintained to prevent this from
happening
 However, the level of the pituitary
gonadotropin, LH, decreases as the
estrogen and progesterone levels increase

The outer layer of cells in the blastocyst
produces a hormone called HCG (Human
Chorionic Gonadotropin)
 HCG maintains the corpus luteum during
the first three months of pregnancy,
preventing the shedding of the
endometrium
 The functioning corpus luteum keeps
producing estrogen and progesterone
 Pregnancy tests identify HCG in the urine
of a woman

Once cells from the endometrium and
embryo form the placenta, HCG is no
longer produced
 Instead, the placenta itself produces
estrogen and progesterone which maintain
the endometrium until birth

Prenatal Development – The
Blastocyst
The outer layer of the blastocyst produces
two membranes - the chorion and the
amnion
 Within the blastocyst’s inner layers,
different germ layers form (gastrulation):

Germ Layers
Ectoderm – forms hair, nails, sweat
glands, nervous system, eyes, ears, teeth,
mouth lining
 Mesoderm – forms muscles, blood vessels
& blood, kidneys & reproductive
structures, connective tissue, cartilage &
bone
 Endoderm – forms liver, pancreas, thyroid,
bladder, lining of digestive system &
respiratory tract

The Germ
Layers
Neurulation and Organ Formation
Between weeks 3 and 8, the organs form
 The germ layers separate and form organs
 During the 3rd week, a band of mesoderm
cells forms along the back of the
embryonic disk
 These cells forms a rod-like notochord,
which will make up the skeleton
 The nervous system develops from the
ectoderm located above the notochord

Neurulation
Organ Formation
Neurulation marks the beginning of organ
formation. First, the heart begins to form
 This is followed by blood vessels, lungs,
kidneys, arms & legs, and structures of
the head
 The brain continues its development, and
the gonads begin to produce hormones
that develop external genetalia (about the
6th week)

Extra-Embryonic Membranes
The Allantois & Placenta
The placenta forms from cells from the
endometrium and the fetus
 The placenta has numerous blood vessels
 Chorionic villi ensure that the placenta’s
blood vessels come in close contact with
the blood vessels of the mother
 The blood vessels that are found in the
placenta come from the allantois, a third
membrane in the blastocyst (forms part of
the umbilical cord)

The Amnion and Yolk Sac
The amnion is a transparent sac that
contains the amniotic fluid
 This fluid acts to cushion the fetus and
prevents temperature fluctuations while
allowing freedom of movement
 The yolk sac does not provide nutrients,
but rather will become part of the
digestive system later

Uterine Structures
1.
2.
3.
4.
5.
Cervix
Umbilical Cord
Placenta
Oviduct
Amniotic Fluid
(Amniotic Sac)
15.2 – Fetal Development and Birth

1.
2.
3.

Fetal development is typically broken
into three (roughly equal) trimesters:
1st Trimester (Weeks 1 to 12)
2nd Trimester (Weeks 13 to 24)
3rd Trimester (Weeks 25 to 38)
The number of weeks is counted from
the last day of the mother’s last flow
cycle, not the time from fertilization
Fetal Development – First Trimester
By week 2, germ layers
form
 By the end of this
trimester, the heart,
brain, limb buds (with
fingers & toes) have all
developed
 Arms & legs move and
there is a sucking reflex
 By end of the trimester,
external reproductive
organs distinguish male
from female

http://www.babyart.org
Development of Male and Female
Sex Organs:
Sex of an individual - determined at conception.
 SRY gene - sex determining region of the Y

chromosome (aka testis determining factor (TDF)
gene)

Anti-Mullerian hormone - prevents development of
female sex organs (causes them to degenerate).

Dihydrotestosterone (DHT) - promotes
development of male sex organs.

Testosterone - stimulates development of the
epididymides, vas deferens, seminal vesicles, and
ejaculatory duct.
Second Trimester
Fetus moves enough to be noticed
 All organs have formed
 Eyelids and eyelashes form
 Cartilage has been replaced with bone
cells
 Soft hair covers the body

http://static.flickr.com
Third Trimester
Rapid growth of baby (from 680 g to
3400 g), particularly layers of fat
 Organ systems are already established,
but continue to develop

http://health.state.ga.us
Teratogens
Whatever the mother inhales or ingests
can end up in her circulating blood
 Many of these compounds can pass across
the placental system into the fetal blood
 A number of substances and conditions
can affect the normal development of the
embryo and fetus

Various Teratogens
1.
2.
3.
4.
Cigarette Smoke – constricts fetus’s blood
vessels, preventing the fetus from receiving
enough oxygen
Alcohol – affects the fetus’s brain, CNS, and
physical development
Prescription medications – antibiotics, acne
medications, anti-thyroid drugs, and anticancer drugs
Some nutrients – vitamin C in excess during
pregnancy can lead to scurvy after birth (the
drop in vitamin C supply after birth is
responsible for this)
Birth (Parturition)
At the end of the third trimester, the fetus
turns so that the front of the head faces
the backbone
 The fetus also drops into the birth canal

Stages of Labor
Labor – Latent Phase
Labor begins 38-40 weeks after
conception
 Initially, the cervix begins to thin and the
mucus plug that sealed the cervix falls out
(usually one or two days prior to birth)

Stage 1 (Active Phase)
The cervix begins to dilate due to muscle
contractions
 These contractions become more regular and
intense as labor progresses
 Sometimes the amniotic sac will break because
of uterine contractions, but often the attending
physician will break the sac with a long needle
 This stage usually ends when the cervix has
dilated to a diameter of 10 cm

Stage 2 (Birth or Parturition)
As the contractions continue, the fetus is
moved down the birth canal
 A hormone known as relaxin (which is
produced by the placenta prior to labor)
causes a loosening of the ligaments in the
pelvis
 Uterine contractions (along with active
pushing of the mother) push the baby out
of the birth canal

Stage 3 (Afterbirth)
Once the baby is
born, the umbilical
cord is clipped and
cut
 A number of
contractions expel
the placenta and
most of the
umbilical cord

http://en.wikipedia.org
Lactation
During pregnancy, high levels of
estrogen and progesterone
prepare the breasts for milk
production
 Each breast has about 20
glands that produce milk
 Prolactin, whose levels rise
dramatically after birth,
stimulates milk production in
these glands
http://www.breastguide.info

Feeding
Immediately after birth, the breast
produces colostrum
 It takes a few days for true breast milk to
be produced
 When a baby feeds, the suckling action
stimulates the nerve endings in the areola
of the breast

The stimulation of these nerve endings
causes the release of oxytocin, which
causes muscle contractions in both breast
and uterine tissue
 At the height of lactation, some women
can produce as much as 1.5 L of milk per
day (containing 50 g of fat and 100 g of
sugars)
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Medical Issues
1.
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Teratogens and the Fetus
A teratogen is any agent that can cause
a structural abnormality of the fetus
during pregnancy
Cigarette smoke, drugs, some
prescription medications and alcohol are
all teratogens
2.
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Fertility Treatments
A number of treatments may be used to
increase fertility
About 15% of Canadian couples cannot
conceive a child
Drugs may be used to increase the
number of eggs produced by the
woman’s ovaries
In vitro fertilization can be used to
increase the chance of a sperm cell
fertilizing an egg cell
In some cases, a man cannot produce
sperm
 TSE (testicular sperm extraction) may be
used
 In this case, seminiferous tubule tissue is
taken from the testicle and is cultured to
produce sperm, which can then be used in
in vitro fertilization or in ICSI (intracytoplasmic sperm injection)
 Artificial insemination can also be an
option

Ectopic Pregnancy
On rare occasions, a fertilized embryo embeds
itself in the wall of the fallopian tube (or other
structure) instead of in the uterine lining
 As the fetus develops, it may rupture some of
the blood vessels in the lining of the fallopian
tubes
 About half of the ectopic pregnancies
spontaneously abort, while the other half
require medical intervention to remove the
fetus
3.
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4.
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Problems During Labor
If the front of the baby’s head is facing
forward instead of the spine, labor can be very
painful and difficult for the mother
In some cases, a baby might also be
transverse (where the shoulders are turned 90
degrees to their normal position)
In the case of a transverse birth, the attending
physician can try to turn the baby with his or
her hands while the mother rests between
pushes
In rare instances, a breech birth occurs
 During a breech birth, the baby enters the
birth canal feet or buttocks first
 A breech baby who is delivered buttocks
first can be delivered normally, but an
episiotomy may be required
 If the baby arrives feet first, then a
Caesarian section birth must be performed
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