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HUMAN FETAL PERIOD –

ASSESSMENT OF FETAL

DEFECTS

BY: DR TATHEER ZAHRA

ASSISTANT PROFESSOR ANATOMY

FETAL PERIODA final phase of prenatal life includes the 3rd to 10th

lunar months (period of fetus).

In it differentiation continues and organs become

competent to assume their specialized functions.

FETAL PERIODEarly fetal period

- 8-16 weeks

Middle fetal period

- 17-30 weeks

Late fetal period

- 31-38 weeks

THIRD MONTH (9-12 wks)

HEAD:

Disproportionately large

Makes up nearly half of the fetus' size

EYES:

Directed forward

Close and will not reopen until about the 28th week

EARS:

Rise to eye level

9 wks56 days 11 wks

PREUMBLICAL HERNIATION: Reduced

FACE: Is well formed

LIMBS: Are long and thin

OSSIFICATION CENTER:

NAILS: Begin forming

GENITALS: Appear well differentiated

RBC’S: Are produced in the liver

FIST: The baby can make a fist with its fingers

TOOTH BUDS: Appear

URINE: Start forming

FOURTH MONTH (13-16 wks)

FACE:

Broad

Human appearance

EYES:

Directed forward

Eyelids fused

UMBLICAL CORD:

Attaches higher on abdominal wall

13 wks

FETAL SKIN: Is almost transparent

LANUGO: Develops on the head

MECONIUM: Is made in the intestinal tract

LIVER AND PANCREAS: Produce fluid

secretions

ACTIVE MOVEMENTS: Begins

SUCKING MOTIONS: Are made with the

mouth

FIFTH MONTH (17-20 wks)

Downy hairs (LANUGO)

Head hairs

Fetal movements (QUICKENING)

Mother may feel a FLUTTERING in the lower

abdomen

Baby can HEAR

VERNIX CASEOSA

EYEBROWS AND LASHES: Appear

NAILS: Appear on fingers and toes

FETAL HEARTBEAT: Can be heard with a

stethoscope

BROWN FAT

SEX ORGANS

SIXTH MONTH (21-24 wks)

EYEBROWS & EYELASHES : Well defined

SKIN: Wrinkled, pink to red, more translucent

BODY: Lean but better proportioned

FOOTPRINTS AND FINGERPRINTS: Forming

BONE MARROW:

AIR SACS:

SURFACTANT:

FAT:

SEVENTH MONTH (25-28 wks)

FETUS LOOKS: Like dried up old person

SKIN: Red, Wrinkled, Covered with vernix caseosa

EYELIDS: Reopen

TOE NAILS:

CNS: Developed to control some body functions

RESPIRATORY SYSTEM: Immature

EIGHT MONTH (29-32 wks)

SUBCUTANEOUS FAT:

Depositing

Rapid ↑ in the amount of body fat (8%)

TESTIS: Begin to invade the scrotum

INFANTS OF THIS AGE, BORN

PREMATURELY: May survive with proper care

RHYTHMIC BREATHING MOVEMENTS: Occur, but lungs are not fully mature

BONES: Are fully developed, but still soft and

pliable

STORAGE: Baby's body begins storing iron,

calcium, and phosphorus

PUPILLARY LIGHT REFLEX

NINTH MONTH (33-36 wks)

SKIN:

Dull redness of the skin fades

Wrinkles smooth out

Lanugo begins to disappear

BODY AND LIMBS:

Become rounded

Body fat increases

Fingernails reach the end of the fingertips

FULL TERM

BODY: Plump

LIMBS: Upper limbs are slightly longer than lower

limbs

UMBLICAL CORD: At the centre of the abdomen

SKIN: Lost lanugo hair coat, but still smeared with

vernix caseosa

AVERAGE WEIGHT: 7 pounds

AVERAGE HEIGHT: 20 inches

TESTIS: Usually in the scrotum

HEAD & ABDOMINAL CIRCUMFERENCE

NAILS: Projects beyond the fingers & the tips of toes

BREAST BUDS: Small breast buds are present on

both sexes

THORAX: Prominent

HEAD HAIR: Is now coarse and thicker

WHITE FAT: Approximately 16% of body weight

GROWTH IN LENGTH & WEIGHT

DURING FETAL PERIOD

Age (weeks) CRL (cm) Weight (g)

9 -12 5 - 8 10 - 45

13 - 16 9 - 14 60 - 200

17 - 20 15 - 19 250 - 450

21 - 24 20 - 23 500 - 820

25 - 28 24 - 27 900 - 1300

29 - 32 28 - 30 1400 - 2100

33 - 36 31 - 34 2200 - 2900

37 - 38 35 - 36 3000 - 3400

WEIGHT OF THE FETUS

BI-PARIETAL DIAMETER &

CIRCUMFERENCE

FEMUR & FOOT LENGTH

DEVELOPMENTAL HORIZONS

DURING FETAL LIFE

EVENTS AGE (weeks)

Taste buds appear 7

Swallowing 10

Respiratory movements 14 – 16

Sucking movements 24

Some sounds can be heard 24 – 26

Eyes sensitive to light 28

VISION

Birth

1month

3 month

6 month

To

32

wk

s

Less than 1/10th of an

inch long

Less than 1 inch long

About 16.5–18 inches long, weighs 4 to 5 pounds

19 inches long, weighs 6 pounds

About 5.5 inches long,

weighs about 4 ounces

About 10-12 inches long,

weighs 1/2 to 1 pound

About 11-14 inches long, weighs 1 to 1.5 pounds

About 14-17 inches long, weighs 2.5

to 3 pounds

About 3 inches long,

weighs about 1 ounce

Third trimester

begins

Second trimester begins

First trimester

begins

The Three Trimesters of Prenatal

Development

FACTORS INFLUENCING FETAL

GROWTH

MULTIPLE PREGNANCIES

SMOKING

ALCOHOL & ILLICIT DRUGS

UTEROPLACENTAL & FETOPLACENTAL

BLOOD FLOW

GENETIC FACTORS

PROCEDURES FOR ASSESSING

FETAL STATUS

Ultrasonography

Diagnostic

amniocentesis

α-fetoprotein assay

Spectrophotometric

studies

Chorionic villus

sampling

Sex chromatin

patterns

Cell cultures &

chromosomal

analysis

Fetal transfusion

Fetoscopy

Percutaneous

umblical cord blood

sampling

CT scan & MRI

Fetal monitoring

ULTRASONOGRAPHY

AMNIOCENTESIS

CVS

SEX CHROMATIN PATTERN

NORMAL

MALE

NORMAL

FEMALE

FEMALE WITH

XXX TRISOMY

NORMAL

MALE

CHROMOSOMAL ANALYSIS

MRI

α-FETOPROTEIN ASSAY

I/U FETAL TRANSFUSIONS

P/C CORD BLOOD SAMPLING

FETOSCOPY

FETAL MONITORING

DOPPLER

EXTERNAL ELECTRONIC FETAL MONITERING

INTERNAL FETAL MONITERING

FETAL URETEROSTOMIES

Fetus at 21 weeks undergoing bilateral ureterostomies, the

establishment of openings of the ureter into the bladder

FETUS PAPYRACEOUS

MACERATED FETUS

STONE/CALCIFIED FETUS

STONE FETUS CALCIFIED FETUS

REFERENCES:

GRAY’S ANATOMY, 40th Edition

The Developing Human, Clinically Oriented

Embryology by KEITH L. MOORE, Latest

Edition

LANGMAN’S Embryology, Latest Edition, By

T. W. SADLER