Stages of Prenatal Development

Stages of Prenatal
Stages of Prenatal Development
Conception occurs when a sperm cell
penetrates and fertilizes an egg cell
Successful conception depends on
ovaries releasing one healthy egg cell
egg cell migrates most of the way down the
fallopian tube
One sperm must penetrate the ovum to form
a zygote
About 15 percent of couples are unable to
conceive or carry a pregnancy to term
after one year of unprotected intercourse.
Causes of male infertility involve the
quantity or strength of sperm produced.
Infertility (2)
Causes of female
infertility involve
abnormalities in the
Fallopian tubes or
uterus or a failure to
ovulate and release
mature eggs.
New technologies are
now available to help
overcome infertility
The Germinal Stage
(first two weeks)
1. The blastocyst is differentiated into three
layers: the ectoderm, the endoderm, and the
2. The blastocyst moves down the fallopian
tube into the uterus for implantation.
3. The embryonic stage begins with
implantation, and the fully implanted
blastocyst is referred to as the embryo.
Blastocyst at day six
Another blastocyst, day six
Embryonic Stage (3rd
through 8th weeks)
1. Growth in the embryonic and fetal stages
follows a cephalocaudal (head-to-tail) pattern
and a proximodistal (near-to-far) pattern.
2. The head, blood vessels, heart, and most
vital organs begin to develop before the arms,
legs, hands, and feet.
Early Embryonic Stage
Embryonic stage (slide 2)
• 3.
The placenta forms as an area
of the uterine wall through which
oxygen and nutrients reach the fetus.
• 4.
The umbilical cord connects
the embryo to the placenta and provides
nutrients and carries away waste
• 5.
The amniotic sac surrounds the
embryo and protects it.
Later embryonic stage
Fetal Stage (9th to birth)
1. The fetal stage is marked by the
development of the first bone cells. The
embryo is now called the fetus.
2. By the third month, the fetus is able to
move its head, legs, and feet. By the
fourth month, the mother may feel
quickening, or fetal movement.
3. The beginning of the seventh month is
considered the age of viability.
4. At the end of nine months, the fetus
weighs on average 7.5 pounds and is
almost 20 inches long.
Fetus at 12 weeks
Fetus at 18 weeks
The experience of
1. Physical complaints such as nausea are
2. Normal weight gain is about thirty
pounds and is dispersed in organs, baby,
and bodily fluid.
3. Changes in the woman's body bring
mixed feelings.
Prenatal influences on the
A. Key concepts
–1. Canalization is seen in prenatal
–2. Drugs
environmental influences can also
canalize development, usually in
negative ways.
–3. Risk factors can interfere with
canalized processes that lead to the
development of specific organs.
Maternal diet and nutrition
1. Poor nutrition leads to specific physical
deformities and increased risk for
prematurity and infant mortality; later
nutritional deprivation leads to a reduced
number of brain cells.
2. Pregnant women should eat between
two hundred and one thousand calories
more per day, adding mainly carbohydrates
and protein.
Prenatal health care (1 of
1. Adequate early prenatal health care is
critical to infant and maternal health.
2. There are racial differences in
adequacy of care.
3. Special programs have been
implemented in communities to help highrisk mothers.
Prenatal health care (2)
1. Prolonged anxiety just before or during
pregnancy increases the likelihood of medical
2. Emotional stress is related to spontaneous
abortion as well as to labor and birthing problems.
The birth episode
After about thirty-eight weeks in the
womb, the baby is considered "full term,"
or ready for birth. Fetal presentation
refers to the body part closest to the
mother's cervix. There are three types of
presentation: Cephalic (normal), breech,
and transverse.
Stages of labor
• 1.
During the last weeks of
pregnancy, it is common for the mother
to experience false labor, or BraxtonHicks contractions.
• 2.
The first stage of labor usually
begins with relatively mild contractions,
leading to stronger contractions and the
dilation of the cervix to accommodate
the baby's head (10 centimeters).
Stages of labor
3. Toward the end of the first stage,
which may take from eight to twentyfour hours, a period of transition
begins, and the baby's head begins to
move through the birth canal.
4. The second stage of labor is from
complete dilation of the cervix to birth, lasting
about one to one and one-half hours.
5. During the third stage of labor, which lasts
only a few minutes, the afterbirth (consisting
of the placenta and umbilical cord) is expelled
Childbirth settings and
Traditionally, childbirth was attended by a
midwife and was seen as a natural process.
With the advent of modern technology,
births increasingly took place in medical
settings. This resulted in decreased
mortality rates, but birth was now seen as a
medical event controlled by physicians.
Hospital births. Birthing rooms are
becoming more popular in hospitals.
Non-hospital settings
Freestanding birth centers are
non-hospital facilities that provide family
centered maternity care.
Birth centers have lower rates of
Caesarean sections.
Home births are another alternative
for pregnancies predetermined to be low
Prepared childbirth. Methods of
prepared childbirth help parents rehearse
the sensations of labor.
Programs emphasize educational,
physical, and emotional preparation
for the birth process and use of a
b. Women
birthing programs report favorable
c. Leboyer claimed a gentle birth
has benefits for the child.
Lamaze birth philosophy
Integral to the work of Lamaze International is a fundamental
philosophy of birth:
Birth is normal, natural, and healthy.
The experience of birth profoundly affects women and their
Women's inner wisdom guides them through birth.
Women's confidence and ability to give birth is either enhanced
or diminished by the care provider and place of birth.
Women have the right to give birth free from routine medical
Birth can safely take place in birth centers and homes.
Childbirth education empowers women to make informed
choices in health care, to assume responsibility for their
health, and to trust their inner wisdom.
Medicinal aids to birth
Despite good psychological preparation, the
mother may experience considerable pain, which
can be made bearable through pain-reducing
drugs such as narcotics or other sedatives.
a. The most common anesthetics are epidural
and spinal, which allow the mother to remain
awake and alert during birth.
b. A general or local anesthetic delays the
recovery of the mother as well as the bonding
between mother and child.
Pain in childbirth
Perceptions of pain during childbirth
a. It is difficult to determine how much
discomfort or distress a laboring woman is in
and how to respond appropriately.
b. There are cultural differences in the
perceptions of pain.
Problems during labor and
delivery (1 of 3)
1. Faulty power is the failure of the
uterus to contract strongly enough to make
labor progress to an actual delivery.
Induced labor can be stimulated by the
hormone oxytocin.
2. A
faulty passageway condition
occurs when the placenta develops so
close to the cervix that it blocks the
baby's passage down the birth canal
during labor. This condition is called
placenta previa.
Problems with Labor and
Delivery (2 of 3)
3. A faulty passenger condition occurs when
problems exist with the baby's position or size.
Usually babies enter the birth canal head first,
but occasionally one turns in the wrong
direction during contractions. Forceps
sometimes are used to remedy the situation.
4. In a Caesarean section, the mother receives
a general anesthetic and the baby is removed
surgically. Techniques for this surgery have
improved; however, a common criticism is that
too many Caesareans are performed.
Problems with Labor and
Delivery (3 of 3)
To deal with such problems, in most
hospitals, electronic fetal monitoring is
used to record uterine contractions and
the fetal heart rate.
Low-birth weight infants
Normal is around 7.5
Low-birth weight is
5.5 pounds or less
6 or 7 percent of all
births in U.S.
At risk for
neurological, and
health problems
Pre-term Babies
Formerly called
More than three
weeks before due
At risk for respiratory
distress syndrome
Extended oxygen
use=Retinopathy of
Negative Prenatal
Influences on the Child
Window of
opportunity concept-critical time of
Teratogen is any
substance or
influence that can
interfere with or
damage a child’s
Teratogenic Medicinal
Thalidomide is a sedative, also an antinausea drug--but deforms children.
Diethylstilbestrol (DES) was used to
prevent miscarriages but causes damage
to reproductive systems of offspring.
Other potentially harmful prescribed drugs
are accutane, streptomycin, and
Teratogenic non-medicinal
drugs (1 of 3)
Active ingredient is
tetrahydraconabaninol or THC
Is stored in fatty
tissues of body
Placenta is no barrier
Babies are born with
psych. if not physical
An opiate not totally
unlike morphine, but
more addictive
Severe withdrawal
Newborn babies of
heroin addicts vomit,
tremble, cry, and
have fever, disturbed
sleep, and abnormal
Fetal alcohol syndrome
CNS damage, heart
defects, small head,
distortion of joints,
and abnormal facial
Are evident in their
inability to pay
attention or maintain
Nicotine and carbon
monoxide interfere
with fetal oxygen
Smoking is associated
with low birth weight,
abortion, higher
infant mortality, and
poor postnatal
Maternal Diseases (1 of 2)
Rubella, or German measles. Disastrous
in first trimester.
Syphilis and gonorrhea. Blindness,
jaundice, anemia, pneumonia, skin rash,
early death. Silver nitrate in the eyes.
Genital herpes. (1) Disease of skin and
mucous membranes, or (2) blindness,
permanent brain damage, seizures, and
developmental delay.
Maternal diseases (2 of 2)
Cytomegalovirus (CMV). High risk for
infants; jaundice, microcephaly, deafness,
and eye problems.
Toxoplasmosis. Parasite from uncooked
meat and cat feces. Low birth weight,
enlarged liver and spleen, microcephaly,
anemia, and calcifications in the brain.
Pediatric AIDS.
Home Factors
Teenage Pregnancy
“Babies having
babies”--own growth
is not complete
Pelvic cradle not
Threat to education
Responsibility not yet
Maternal malnutrition
Domestic Violence
Seven to Eight
percent of pregnant
women are beaten by
partners; most more
than once
High rate of