Download March 02, 2010

March 02, 2010
March 02, 2010
*Every 28 days, an ovum, which is an egg cell, is released by one
of the woman’s two ovaries. This occurs as part of the woman’s
menstrual cycle, which is called ovulation.
*At the same time the body prepares the uterus for fertilization,
so it releases specific hormones. The uterus is the organ in the
body where the baby develops in the event that the ovum is
fertilized.
*During ovulation the inner lining of the uterus grows and
thickens. If the ovum is not fertilized, the lining breaks down and
passes out the body.
*When the ovum is released from the body it moves through the
Fallopian tubes, which connects the ovary to the uterus. This
movement usually takes 2-3 days. When the ovum reaches the
uterus, it usually disintegrates and leaves the body with its
menstrual flow.
*In the event that the sperm or male cell reaches the Fallopian
tubes, it may penetrate and fertilize the ovum. This process is
called conception.
*An ovum usually lives between 12-24 hours, while a sperm can
try to fertilize for 48-72 hours.
The sex of the child is determined.
March 02, 2010
PRENATAL DEVELOPMENT IS
CATEGORIZED INTO 3 STAGES
(or trimesters)
Stage I
THE GERMINAL STAGE
Prenatal development is the baby’s development
during a pregnancy.
*Formation of the zygote, which is the fertilized
egg- this lasts 2 weeks and includes 2 key
steps
1.
Cell division- The zygote in the Fallopian
tubes grow and the single cell splits
into two cells, then into 4, then to 8,
and so on
2.
Implantation- lining of uterus thickens
enough to provide a place for the
zygote to attach itself and grow-after
2 weeks the zygote is the size of a
pinhead.
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II. THE EMBRYONIC STAGE
From now through the 8 th week of pregnancy the baby is
called the embryo.
*Embryo grows rapidly
*During this stage the baby is called a fetus.
1.
20 buds for baby teeth appear.
2.
Vocal cords develop.
3.
Digestive system and kidneys begin to function
4.
Movements are now possible (at end of 3
5.
Fetus gains weight rapidly, uterus expands, and woman’s
rd month)
abdomen begins to grow more
6.
Fat deposits begin to develop which will help maintain body
heat after delivery.
7.
Fetus takes on smooth skin
8.
Stores nutrients and builds up immune system.
9.
Fetus can: sneeze, kick, yawn, cough, hiccup, and cry.
10.
Baby grows so much it cannot stretch out, so it positions
itself into the fetal position.
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By the end of the first
month, the embryo is
about 1/10 of an inch
long. The heart, which
is no larger than a
poppy seed, has
begun beating.
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The embryo is about 1
inch long and has
distinct, slightly
webbed fingers. Veins
are clearly visible. The
heart has divided into
right and left
chambers.
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By now the fetus is 2 1/2 to 3
inches long and is fully
formed. He has begun
swallowing and kicking. All
organs and muscles have
formed and are beginning
to function.
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*Longest stage and begins around the 8 or 9
th week and
continues on to birth.
*During this stage the baby is called a fetus.
1.
20 buds for baby teeth appear.
2.
Vocal cords develop.
3.
Digestive system and kidneys begin to function
4.
Movements are now possible (at end of 3
rd
month)
5.
Fetus gains weight rapidly, uterus expands, and
woman’s abdomen begins to grow more
6.
Fat deposits begin to develop which will help
maintain body heat after delivery.
7.
Fetus takes on smooth skin
8.
Stores nutrients and builds up immune system.
9.
Fetus can: sneeze, kick, yawn, cough, hiccup, and
cry.
10. Baby grows so much it cannot stretch out, so it
positions itself into the fetal position.
March 02, 2010
Your baby is covered
with a layer of thick,
downy hair called
lanugo. His heartbeat
can be heard clearly.
This is when you may
feel your baby's first
kick.
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A protective coating called
vernix begins to form on
baby's skin. By the end of
this month, your baby will
be nearly 8 inches long
and weigh almost a
pound.
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Eyebrows and eyelids
are visible. Your
baby's lungs are filled
with amniotic fluid,
and he has started
breathing motions. If
you talk or sing, he
can hear you.
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By the end of the
seventh month, your
baby weighs about 3
1/2 pounds and is
about 12 inches long.
His body is wellformed. Fingernails
cover his fingertips
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Your baby is gaining
about half a pound
per week, and layers
of fat are piling on. He
has probably turned
head-down in
preparation for birth.
He weighs between 4
and 6 pounds.
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Your baby is a hefty 6 to
9 pounds and
measures between 19
and 22 inches. As he
becomes more
crowded, you may feel
him move around
less.
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A regular pregnancy lasts about 40 weeks or 280 days.
*Physical Changes in mother:
*Toward end of pregnancy
baby’s weight shifts downward which is called lightening.
The baby drops into the birth canal at this time.
*Mother’s skin is stretched to capacity.
*6 weeks after birth, mother returns to normal.
*If baby’s head is downward, it makes birth much easier.
*If baby is in an upright position, chances are high that the
baby may have to be surgically removed which is called a
cesarean section (c-section)
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*At the moment of conception, every baby receives 46
chromosomes, which are tiny threadlike structures in the
nucleus of every cell. These chromosomes come in 23 pairs. The
father’s sperm and the mother’s ovum each contribute.
*Each chromosome has thousands of genes, which are units that
determine a human’s inherited characteristics.
*The complete blueprint for the creation of a person is called a
genome.
*Genes are made up of a complex molecule called DNA. A
person’s 46 chromosomes form that person’s unique DNA. No two
people expect identical twins have identical DNA.
For every inherited characteristic, the person receives two copies
of a gene- one from the mom and one from the dad. When
genes are the same (both blue eyes) the child will automatically
inherit that gene.
*Dominant genes are stronger genes.
*Recessive genes are weaker genes
*Sex chromosomes come in 2 types (X and Y)
*Female always carries an X.
*Males carry either an X or Y.
*If the sperm fertilizes the egg that is an X chromosome, the
baby receives XX from the parents, making the child a
female.
*If the sperm fertilizes the egg with a Y chromosome, it makes
the child an XY, which is a boy.
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Multiple Births- when the mother gives birth to
more than one child.
*The number of children that a woman will give
birth to is determined at conception.
*There are two types of multiple births.
1. Identical- always the same sex, children
look the same and born at around the
same time.
2. Fraternal- can be opposite sexes- children
do not look alike and are still born around
the same time.
Identical Twins:
When a sperm fertilizes the ovum, the cell begins to divide right
away. As the cells continue to divide, the mass of cells may split in
half, creating two separate masses. Each cell mass continues to grow
on its own.
Fraternal Twins:
Form when 2 eggs are released form the ovaries at the same time
and are fertilized by two different sperm. Because of the different
eggs and sperm, fraternal twins may not look very much alike.
3 in 100 of all birth are twins.
The chances of having identical twins are less than having fraternal.
Out of 1,000 births, 23 will be fraternal twins
3 or more babies:
Much more rare, however a rise in treatment to have children can increase
the chance in frequency of multiple births.
**The more children a woman carries the harder it is for all of the babies to
survive.
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*Anytime a couple has sexual
intercourse, conception may take
place.
There are many methods to prevent
conception, which are called
contraception.
Contraceptives
ABSTINENCE- 100%
BIRTHCONTROL PILLS- 95-98%
CERVICAL CAP-60-91%
Small cervical cap that must be in place 8 hours before
intercourse
CONDOM- 86-97%
Males or females can wear them-help reduce the spread of
STDs
DIAPHRAM-80-94%
HORMONAL IMPLANTS-99%
Capsules placed under skin in arm
HORMONAL INJECTIONS-99%
Given by physician monthly or once every 3 months- can cause
irregular bleeding
HORMONAL PATCH-99%
Patch worn on skin for 3 weeks each month-similar to pills
IUD-99%
Inserted into woman- may cause discomfort
NATURAL FAMILY PLANNING- RHYTHUM –53-80%
SPERMICIDE- 72%
Foams, creams, gels- should still be used with a condom
VAGINAL IMPLANT-95-99%
Ring worn internally for 3 weeks each month.
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-The inability to become pregnant
OPTIONS FOR INFERTILITY1.
Adoption
2. Artificial Insemination-doctor
injects sperm into woman’s uterusprocedure takes time
3. In vitro fertilization- doctors
combine a mature ovum from the
woman with sperm from her
husband. If the ovum becomes
fertilized, the doctor places the
new zygote in the woman’s uterusif the zygote attaches itself to the
woman’s uterus, she becomes
pregnant.
4. Ovum transfer- same as in vitro
except the ovum comes from
another woman (procedure is for
women who lack working ovaries,
poor ovum quality, or genetic
disorders).
5. Surrogate mother- woman who
becomes pregnant to have a baby
for another woman- requires legal
arrangements for all people involved
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4-3 Prenatal Problems
*If a baby dies prior to the 20 th week, it is called a miscarriage.
*If a baby dies after the 20
th
week, it is called a stillbirth.
*Unfortunately miscarries are very common- 15-20% of pregnancies
end this way.
* Stillbirth occurs in 2% of all pregnancies, because of problems
with the placenta, abnormal chromosome problems, poor growth,
and infections
Birth Defects
*
Babies that survive pregnancy, but are born with serious problems
that threaten their health or their life.
*Approx. 150,000 babies around the world are born with birth
defects each year.
*CAN CAUSE:
*Abnormalities of body structure
*Blindness
*Deafness
*Mental retardation
Causes of Birth Defects
*Mother’s nutrition during pregnancy
*Any diseases or infections mother had during pregnancy
*Harmful substances mother consumes such as illegal drugs, alcohol,
and OTC medicine
*Exposure to hazards such as certain chemicals, radiation, x-rays
HEREDITY
*Every person has about 20,000-25,000 genes that not only
determine things such as eye color, and hair color, but also the
direct growth and development of every system in the baby.
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Heredity
*
Every person has about 20,000-25,000 genes that not
only determine things such as eye
Color, and hair color, but also the direct growth and
development of every system in the baby.
*Children normally get 5-6 imperfect recessive genes
passed on to them that may have no effect on the
development of the baby.
*However sometimes the parents pass on the same
recessive gene to the baby.
* Sometimes a child inherits a bad gene that is
dominant- it is only necessary that one parent have
this gene to be passed on to the child.
Chromosomal Errors
*Several birth defects are caused by errors in
the chromosomes.
* An error may occur when an egg or a sperm
is developing, causing a baby to have too few
or too many chromosomes.
* The most common chromosomal disorder is
Down syndrome. 1 in 800-1,000 babies are
born with it. This happens because the when
the child is developing there is an extra pair
of chromosome #21. Instead of carrying 2
copies of #21, the child has 3 copies.
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PREVENTION AND DIOGNOSIS OF BIRTH DEFECTS
Genetic Counseling- people seek counseling to assess their risk of having
a child with a birth defect that is caused by a defect in their genes
Reasons:
*If they have already had a child with a genetic birth defect and do
not want to risk having another child with a defect.
*If there is a gene that runs in the family and the family is not sure
when it will pop up again
Prenatal Tests
1. Alpha-fetoprotein (AFP) - a blood test is performed on mother who is
15-20 weeks pregnant. AFP is a protein in the mother’s blood that is
produced in the liver and can indicate possible birth defects
2. Ultrasound- uses waves to make a video image of an unborn baby. It
can help the doctor monitor the development of the baby, pinpoint the
baby’s age, and detect certain birth
Amniocentesis - process of drawing a sample of the amniotic fluid
surrounding the unborn baby. This is used most often to detect Down’s
syndrome or after questionable results from an AFP test, especially if
the mother is over age 35.
Chronic villi sampling- uses a sample of the tissue from the membrane that
encases the fetus to check for certain birth defects. Samples of the
tissue are snipped or suctioned off for testing- can be performed quite
earl in the pregnancy.
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4-4 Avoiding Dangers to Baby
ALCOHOL- is a drug that many people forget about. If the mother drinks, the alcohol is
absorbed into the baby through the placenta- even a small amount can still harm the baby.
*Fetal Alcohol Syndrome-is an incurable condition found in some children of mothers who
consume alcohol during pregnancy.
**1 in 5 babies born with FAS never see their first birthday.
OTHER DRUGS*Medicines including prescription and OTC drugs
*Caffeine-low birth weight (less than 5.8 lbs.
*Nicotine- low birth weight, premature
*Inhalants*Cocaine- SIDS (sudden infant death syndrome) that is the sudden death of a baby under one
year old for no reason.
*Ecstasy- heart disease, physical abnormalities
Avoiding Dangers
The first 3 months of pregnancy are most crucial b/c that is when the baby’s body systems
are developing.
OTHER THINGS TO AVOID:
*X-rays-abnormalities
*Paint-check with doctor before exposure
*Pesticides used to exterminate bugs
*Lead in water and paint
*Carbon monoxide
*Mercury- found in fish
*Solvents, paint thinners,
Other Risks to Fetus
*Chicken Pox
*Toxoplasmosis-infection caused by a parasite
*STDs
*AIDS
*The following diseases can be passed from the mother to the baby:
1. Syphilis
2. Gonorrhea
3. Hepatitis B
4. Herpes
5. AIDS
6. Chlamydia