Transcript chapter 4 prenatal ppt

PREGNANCY
and
CHILDBIRTH
The Developing Baby
(section1)
 Conception
 Sperm penetrate and fertilizes the ovum
 Pregnancy begins
 Called Conception
All about the Woman
Ovum
Approximately every 28 days an ovum
(egg) is released by one of woman’s
two ovaries
Ovulation – this occurs as part of the
woman’s menstrual cycle
Hormones are released and woman’s
body prepare the uterus in case ovum
becomes fertilized
If fertilization does not occur, the lining
that was formed in the uterus is shed
as the monthly menstrual period
 Uterus – The organ in the woman’s body in which new baby
develops during pregnancy
 It is pear shaped – about the size of your fist
 Strongest muscle and is able to expand during pregnancy
 When ovum released…travels through the Fallopian
Tube…this connects the ovary to the uterus
 This journey takes 2 - 3 days
 When ovum reaches the uterus it USUALLY disintegrates
and leaves the body with the menstrual flow
 If a sperm (male cell) reaches the Fallopian tube
and penetrates the ovum…conception occurs
 Ovum live about 12 – 24 hours
 Sperm is capable of fertilizing an ovum about 48 –
72 hours
 During a woman’s menstrual cycle…about three–
four days that intercourse can lead to conception
 If conception occurs as the baby is developing this
is called
 PRENATAL DEVELOPMENT
Stages of Pregnancy
 Germinal Stage
 First Stage
 Formation of Zygote (fertilized egg)
 Germinal Stage lasts about two weeks
 Key Steps of Pregnancy Occur
 Cell Division
 Zygote grows by cell division while still in the
fallopian tube
 Rapid growth for about four days
 Reaches the uterus
 Implantation
 Lining of uterus is thick enough for the zygote to
attach itself and continue to grow
 Zygote implants in the uterus
 Size of the head of a pin
Stages of Pregnancy
Embryonic Stage
Baby is now called an embryo
Third week through about the
eighth week of pregnancy
Rapid growth
Organs and body systems
 Cells divide into major systems:





heart
lungs
bones
Muscles
Systems continue to grow and are too immature to function on
their own
Neural tube – tube in the back of
the developing baby – will become
the brain and the spinal cord (Folic
Acid in daily diet)
About 27 days after conception the
neural tube closes and the brain
begins to take control of the body
systems
By sixth week, connections
between brain and spine allow
movements of embryo (mom
cannot feel movements and she
might not even know she is
pregnant!)
 At this time, brain is sensitive to damage from any
drugs or alcohol mom might take
 If any woman is engaging in activities in which she
might conceive…it is imperative that she avoid all
alcohol and drugs
A sac firms around the
embryo…this is the amniotic sac
It is filled with amniotic fluid
that cushions and protects the
developing baby
The sac is formed from layers of
cells in the uterus
The developing embryo is about
1 inch long
Placenta develops…tissue from
special layers of cells in uterus
Rich in blood vessels and is
attached to the walls of the
uterus
Mom’s bloodstream carries food
and oxygen to the placenta
Placenta absorbs oxygen and
nourishment from mom’s blood
and transports to the baby
through the umbilical cord
Umbilical cord connects the baby
to the placenta
Umbilical cord takes carbon
dioxide and other waste products
away from the baby and to the
placenta
Umbilical cord is rarely flexible
enough to loop around the baby’s
neck
Umbilical cord and placenta
provide everything the baby needs
until birth
Fetal Stage
Longest stage begins about 8th or
9th week continues till baby’s birth
Developing baby is now called a
“fetus”
Buds for 20 “baby teeth” appear
Vocal cords develop
Digestive system and kidneys
begin to function
By end of third month spontaneous
movements are possible
 During fourth or fifth month fetus can touch the walls
of the uterus when stretching or kicking…mom can
now feel these
 (Quickening)
 Development continues as fetus prepares to live
independently
 Major organs become ready to function without mom’s
help
 Fat deposits accumulate under the skin
 Fetus’ appearance becomes smoother and rounder
 Fetus store nutrients and builds immunity to diseases and
infections
 By seventh baby is developed enough that it could
live outside of the womb but needing a lot of medical
help
 Fetus can:
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
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Suck its thumb
Cough
Sneeze
Yawn
Hiccup
 Fetus continues to grow
 Amount of amniotic fluid increases as fetus grows
 Uterus expands
 During last few months of pregnancy fetus doesn’t
have a lot of room to stretch and takes on “fetal
position”
 Note page 108 and 109 in text book…fetal
development month by month
Preparing for Birth
 Length of pregnancy…
 40 weeks
 280 days from last menstrual cycle
 Toward end of 40 weeks baby’s weight shifts
downward called “Lightening”
 Baby’s head drops into birth canal
 Most babies are born with head down
 If seat down or feet down this is called Breech
Presentation
 Sometimes requires a Caesarian Birth
 Even though mom’s uterus and abdomen have
stretched to limits…they return to normal size
and shape about six weeks after delivery
Closer Look at Conception
 Heredity
 Passing on of characteristics
 Inherited characteristics
 Physical characteristics
 Predisposition of talents or abilities
 Medical conditions
 Chromosomes
 Tiny threadlike structures in nucleus of cell
 At conception every human baby receives 46
chromosome
 23 chromosomes from mom
 23 chromosomes from dad
 Genes
 Genes determine a human’s inherited
characteristics
 Each chromosome has thousands of genes
 Genome
 Blueprint for each person
 DNA
 Genes are made up of DNA
 Human’s 46 chromosomes make up that persons
DNA
 No one has identical DNA except identical twins
 Each person receives two genes for every inherited
characteristic one from mom and one from dad
 If the genes are the same, that person inherits that
characteristic
 If the genes are different the characteristic is
controlled by the stronger gene
 Dominant Genes
 The stronger gene
 Recessive Genes
 The weaker gene
 This gene is not expressed in the inherited
characteristic
 Heredity tells us how people in a family resemble each
other
 Heredity also explains why people in a family look
quite different
 Each sperm and egg contain a different combination of
genes
 Sex of a child is determined at conception
 Sex chromosomes come in two types X and Y
 Each ovum in woman’s ovaries carries an X
chromosome
 Each sperm in the man’s body carries either an X or a Y
chromosome
 XX combination is a girl
 XY combination is a boy
Multiple Births
 Multiple Births – Birth to more than one child at a time
 Twins the most common multiple birth
 Identical Twins
 Woman’s ovum is fertilized
 Cell division occurs
 Mass of cells split in half and two separate masses
are present
 Each mass of cells continues to divide and grow into
separate embryos
 One ovum
 One sperm
 Two babies
 Same sex
 Same DNA
 Very similar physical characteristics
 Fraternal Twins
 Two eggs are released at the same time
 Each fertilized by two different sperm
 Fraternal twins are siblings who happen to
be in mom’s womb at the same time
 May be the same sex or one of each
 3% of all births are twins (3 out of 100
births)
 23 out of 1000 births are fraternal twins
 Out of this 1000 births only about 4 will be
identical twins
 Birth of 3 or more babies is rare
 Rise in use of fertility treatments increases
chance of greater number of babies
Family Planning
Every time a couple has
intercourse, conception may
take place
Contraception helps to prevent
conception from occurring
Contraception methods do not
eliminate the risk of STD’s
Abstinence is the only
contraception method that will
100% prevent pregnancy
 Methods of Family Planning
Page 119
Infertility
 Infertility is the inability to become pregnant
 Affects both males and females
 Treatments
 Drugs
 Procedures
 Expensive
 Invasive
 Emotionally trying
Options for Infertile Couples
 Adoption
 Couple takes on all legal responsibilities of raising
and loving and nurturing the child
 Artificial Insemination
 Doctor injects sperm into woman’s uterus
 Timed with ovulation
 Can have sperm donor
 In Vitro Fertilization
 Doctor combines ovum and sperm
 If ovum becomes fertilized, doctor places zygote in
woman’s uterus
 If zygote attaches to uterine wall pregnancy takes
place
Options for Infertile Couples
 Ovum Transfer
 Similar to in vitro but ovum has been donated
 Surrogate Mother
 Substitute mother becomes pregnant fo have a
baby for another woman
 A lot of legal arrangement