Fetal Development
Month by Month
On the table, answer the true or false
worksheet, Write BEFORE on the
side you answer.
Prenatal Development
• Prenatal development – the process by
which a baby grows inside the mother
– Begins @ conception and ends at birth
• 9 months 280 days/40 weeks
• Support system also forms
• One structure is the protective sac that
surrounds and encloses the developing
baby. The sac is filled with amniotic fluid
which cushions the baby from outside
pressures.
Prenatal Development
• Placenta – the tissue, shaped somewhat like a
pancake, is attached to the uterine wall and
contains a rich network of blood vessels.
– Acts as a filter between the mother’s and baby’s bodies
• Baby is connected to placenta by the umbilical
cord.
• Pregnancy – blood will flow from the mother’s
body through the placenta and umbilical cord,
carrying nutrients & oxygen to the baby
• Wastes from the baby – same process into mom’s
bloodstream for processing & disposal.
First Month
• Week 1: The first day of last
menstrual period
• Week 2: Lining of uterus is
thickening
• Week 3: Congratulations!!
Baby is conceived
– Within hours after sperm
meets eggs, the fertilized
cell (zygote) divides and
then continues to divide.
Within days, baby is a
microscopic ball of cells.
– Zygote stage – last about 2
weeks
First Month
• Week 4: Implantation
Time!!
• Ball of cells – great
divide – Baby &
placenta (baby’s life line)
• Baby is about the size
of a pin head. The
heart, which is no
larger than a poppy
seed, has begun
beating.
First Month (Mommy)
• Fewer than 30% implantation bleeding
• Breast changes
• Bloating
• Fatigue
• Frequent urination
• Nausea
• Increase sensitivity to
smell
• Mood swings
• Drooling
On a sheet of paper
• Mini poster of the first month of pregnancy
First Month
Two Months
• Week 5: baby – growing
fast
– Size – orange seed
– Heart taking shape
• Week 6:
– Crown (head) to rump
(bottom) measurements
– Jaws, cheeks & chin –
beginning to develop
– 80 beats per minute
Two Months
• Week 7:
– 10,000 times bigger than at
conception
– Size blueberry
– Brain – 250,000 cells per minute
generated
– Mouth, tongue forming
– Arm, legs buds – begging to sprout
segment
• Week 8:
– Baby (embryo) is about 1/2 inch
long (size of a grape) and has
distinct, slightly webbed fingers.
Face, eyes, ears, and limb have
developed. Veins are clearly
visible. The heart has divided into
right and left chambers.
– Looks more human
– Spontaneous movements – you
cannot feel
Two Months (Mommy)
• Fatigue, urination, nausea
(with/out vomiting), breast
changes (darkening of the
areolas)
• Darkening of areolas
• Excess saliva
• Constipation
• Heartburn
• Food aversions & cravings
• Slight whitish discharge
• Occasional
faintness/dizziness
• Emotional ups & downs
Two Months (Mommy)
• Progesterone & relaxin –
tend to relax muscle tissue
• Spidery purplish vines –
extra blood flow, pregnancy
hormone flow, genetics
Two Months
Prenatal Stages
• Zygote
– After sperm & ovum unites
– Lasts about two weeks
• Embryo
– Last about the time of implantation (week 4)
until week 8
– Muscle, bone, organs & other body parts of the
body form
– Almost all internal organs begin to form
Beginning at the
rd
3
month/Week 9
• Fetus
– Growth – process of growth and maturation
– Last about 7 months
Three Months
• Week 9:
– At the beginning baby (fetus) is about
1 inch long by the end, 3 inches!!!
Weighing in at 1 ounce
– Bones forming, elbows can now bend
– Muscles & tissues start to develop
– Covered by very thin skin (see
through)
• Week 10:
– 1 ½ in” long
– Bones forming, elbows can now
bend
– Buds of baby teeth are forming
under gums
– Eye lids begin to close to protect
developing eyes
Three Months
• Week 11/12 :
– Just over 2 in @, 2 ½ @ 12”
– 1/3 oz @ 11, ½ oz @ 12
– Body – straightening out
– Fingers & toes nails forming
– Gender is evident (though
cannot tell with ultrasound)
– More Human characteristics
– Most systems formed,
though immature
Three Months
• Week 13:
– 3 in”
– Size – peach
– Head – about half the size of
baby
Three Months (Mommy)
• Same as month two plus:
– Increased appetite (if morning
sickness is easing)
– Visible veins on abdomen, legs,
& else where as blood supply
pumps up
– Rounding of belly, clothes
feeling a little snugger
– Headaches – (thanks to
hormonal changes)
Questions????
• Why the constipation??
• Which baby weighs more at birth: boys or
girls?? Why?
• Does a baby’s heart rate give you a clue if
baby is a he or she???
• What is a miscarriage?
• Why does the chance for miscarriage
decrease considerably after the first
trimester?
Answers
• Constipation – high levels of progesterone – relaxes
muscles (advantage – added time for nutrients to be
absorbed into bloodstream)
– Fiber, exercise
• Research – shows that moms carrying boys tend to eat
more than moms expecting girls. (food for thought)
• Old wives tell – a heart rate above 140 – girl, below
140 – boy
• Spontaneous loss of the pregnancy after less than 20
weeks of fetal development
• Since your baby's most critical development has taken
place, your chance of miscarriage drops considerably
after three months into the pregnancy.
Miscarriage
• A spontaneous loss of the pregnancy after
less than 20 weeks of fetal development.
• It is not uncommon 
• According to research 15-20% known
pregnancies end in miscarriage
• Many end before woman knows she is even
pregnant
Miscarriages
• Myths – physical activity, minor falls and
stress are not believed to cause the loss of a
pregnancy
• Early in pregnancy – usually genetic
abnormality
• Couples should not blame self
• Many are able to have successful pregnancy
later
Miscarriages
• Identified Risk Factors
–
–
–
–
–
Age (woman – over age 35)
Previous miscarriage
Family history of miscarriage
Certain diseases or infections
Exposure to hazards during pregnancy (alcohol,
drugs, smoking, heavy caffeine use or certain
chemicals)
Stillbirth
• If the fetus dies after the 20th week.
• Occurs approximately one out of 200
pregnancies
• Death can occur during labor or delivery,
but more often occurs before labor
• Causes vary & sometimes no cause can be
found
Bell Work
•
•
•
•
What is an ectopic pregnancy?
What are birth defects?
What are some causes of birth defects?
Can birth defects be prevented?
Ectopic Pregnancy
• Sometimes a fertilized egg never reaches
the uterus, it plants outside the uterus
(usually in the fallopian tube)
• The embryo cannot survive without the
nourishment and protection of the uterus
• When the embryo grows, it may eventually
burst the fallopian tube – life threatening bleeding - mommy to be
Birth Defects
• An abnormality that is present at or before
birth and results in mental or physical
disability
• My be genetic factors, environmental
factors or a combination
• Often the cause in unknown
Birth Defects – Genetic Causes
• Errors in genes or chromosomes
– Missing, damaged or duplicated
• (Down Syndrome is caused by an extra chromosome
21)
Birth Defects – Environmental
Causes
• What a pregnant woman eats, drinks,
breathes in and exposed to – has the
potential to either help or harm developing
baby
–
–
–
–
–
Poor nutrition during pregnancy
Tobacco, alcohol, drugs
Exposure to X-rays
Certain illness (chicken pox, rubella)
Certain prescriptions & over the counter meds
Prevention and Treatment
• Good health can help prevent birth defects
– Proper medical care, take steps to avoid hazards
– Medical advances
• Correct defect before baby is born
– Surgery or other means
• Not curable - early diagnosis & intervention – can
help child reach full potential
Working Time Line
• You are to create a time line for the 1st
trimester of pregnancy.
nd
2
Trimester
14 Weeks – 27 Weeks
• Babies will start growing at different paces
Four Months
• 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. Size about 3
inches long.
• Facial feature
becomes clearer
Four Months
• Baby becomes
sensitive to touch
Four Months (Mommy)
• Previous, plus:
– Nasal congestion &
occasional
nosebleeds; ear
stuffiness
– Sensitive gums (may
bleed when you
brush
– Mild swelling of
ankles & feet (hands
& feet)
– Varicose veins of
legs and/or
hemorrhoids
4 months
Five Months
• A protective coating
called vernix
caseosa begins to
form on baby's skin
• End of the month –
baby weighs one
pound and is nearly
8 inches long
Five Months
• Hair, eyelashes &
eyebrows appear
• Teeth continue to
develop
• Organs are maturing
• Hands able to grip
• Baby more active
Five Months
Previous Plus:
– More energy!
– Fetal movements @
end
– Achiness in lower
abdomen & along
sides (stretching of
ligaments supporting
the uterus)
– Backache
– Leg cramps
– Skin color changes
– A protruding naval
Six Months
• Eyebrows and eyelids
are visible. The baby's
lungs are filled with
amniotic fluid, and
he/she has started
breathing motions. If the
mother talks or sings,
the baby can hear.
• Grows to about two
pounds
• Fat deposits begin to
appear beneath wrinkly
skin
Six Months (Mommy)
• Previous, plus:
– More definite fetal
activity
– Itchy abdomen
– Stretch marks
– Enlarged breast
– Continued
absentmindedness
6 Months
rd
3
Trimester
• 28-40 Weeks
• Getting enough Omega-3 is more important
than ever in the 3rd trimester when your
baby’s brain development is being fast
tracked.
• Time to think about signing up for child
birth classes.
Seven Months
• At the beginning of
the seventh month,
the baby weighs
about 2 ½ pounds
and is about 14-16
inches long.
Seven Months
• His body is wellformed. Fingernails
cover his fingertips
• Nervous, circulatory
& other systems
mature
• Periods of fetal
activities are followed
by periods of rest &
quiet.
Seven Months (Mommy)
• Previous, plus:
–
–
–
–
Stretch Marks
Shortness of breath
Difficulty sleeping
Scattered Braxton
Hicks
– Clumsiness
– Colostrum, leaking
from nipples
– Strange and vivid
dreams
Eight Months
• Baby is gaining about
half a pound per week,
and layers of fat are
piling on. He/she has
probably turned headdown in preparation for
birth.
• End of the month, baby
weighs in at 5 ½
pounds
Eight Months (Mommy)
• Previous, plus:
– Strong, regular fetal
activity
– Increasing vaginal
discharge
– Increasing Braxton Hicks
Contractions
Nine Months
• Baby is a hefty 6-9
pounds at the end of
the month and
measures between
19 and 20 inches.
• Fetal movement
decreases with less
room to move
• Increase fat under
the skin makes baby
looks less wrinkled
Nine Months
• Baby gains diseasefighting antibodies
from the mommy’s
blood
• Baby descends
lower into the pelvis,
ready for birth
(breath easier)
Nine Months (Mommy)
• Previous, plus:
– Changes in fetal
activity (more
squirming, less
kicking)
– Vaginal discharge
becomes heavier &
contains more mucus
– Extra fatigue or extra
energy (nesting
syndrome)
Nine Months
• Fewer than 5% of babies
are actually born on their
due date
• 50% are late (born after
due date)