PRE-NATAL DEVELOPMENT • Placenta

THE STAGES OF PRE-NATAL DEVELOPMENT • Umbilical cord

• Amnion/amniotic sac

1.) GERMINAL PERIOD (First 2 weeks after

conception)
FETAL PERIOD (2months-7 months after
A. Creation of Zygote conception)

B. Continued cell division -growth and development Continue dramatically

C. Attachment of the zygote to the uterine wall

3 Months

Differeritiation of cells already begins as inner - 3 inches long Wt. 1 ounce

(Blastocyts) and outer Trophoblasti layers of the
- Active, moves its arms and legs, opens and closes
organism are formed.
it's mouth, moves its head.

- parts of the face, upper and lower extremities

2.) EMBRYONIC PERIOD (2-8 weeks after can be distinguished.
conception)
- Genitals can now be Identified.
A. Cell differentiation intensifies

B. Life support systems for embryo develop

4 Months
C. Organs appear
- 6 inches long Wt. 4-7 ounces

-Growth spurt occurs in the body's lower parts

Zygote attached to the wall of the uterus
- Reflexes are stronger

- Mother feels the movement of the embryo

2 layers of cells are formed
-Downy hair (lanugo) covers body
- Inner layer Endoderm

-Outer layerEctoderm + Mesoderm

5 Months
Organogenesis - Process of organ Formation
- 12 inches long Wt. close to a pound
during the first 2months of pre-natal development
- Structure of the skin (Fingernails, toenails are
formed
Life Support System
- More active
- Heartbeat is audible with ordinary stethoscope Teratology is the field that investigates the causes
of congenital (birth) defects.
A teratogen is that which causes birth defects. It
comes from the Greek word “tera” which means
6 months
“monster”.
- 29 inches long Wt. 1 pound

- Eyes and eyelids are completely Formed

Below are cluster of hazards to pre-natal
- Fine layer of head covers the head development :

- Grasping reflex present 01. Prescription and Nonprescription drugs

- Irregular movements occur - Antibiotic, thalidomide, diet pills, aspirin, coffee,

cocaine.

02. Psychoactive drugs

7 months
- Nicotine, Caffeineand illegal drugs.
- 16 inches long Wt. 3 pounds
03. Environmental Hazard
- Cerebral cortex of brain develops
- Radiation and x-rays, environmental pollutant,
toxic waste, sauna or hot tubs
8 Months 04. Other Maternal Factors
- 17 inches long Wt. 5 pounds - Rubella, syphilis, genital herpes, AIDS, Nutrition,
high anxiety, stress, age
- Subcutaneous Fat is deposited for later use.
05. Parental Factors
- Responds to sounds
- Lead, radiation, pesticides and petrochemicals

9 months
1. PRESCRIPTION AND NON-PRESCRIPTION
- 21 inches long Wt. 7 pounds
DRUGS
- Organ Functions actively
• Antibiotic, thalidomide, diet pills, aspirin, coffee,
- Vernix is present over the entire body cocaine.

- position for birth

(1) Implications

TERATOLOGY AND HAZARDS TO PRE-NATAL Antibiotic – bones and tooth development,

DEVELOPMENT obesity, allergies, infections and other
Thalidomide – impairments such as limb
difference, sight loss, hearing loss, facial paralysis, (4) Implications
and impact to internal organs.
Cocaine – reduced birthweight, length and head Rubella – death and malformation; mental
circumference, impaired motor development and retardation, blindness, deafness, and heart
information processing, and poor attention skills. problems.
Syphilis – damages organs; eye and skin lesions.
Herpes – death and brain damage
Stress – premature birth, reduced birth weight,
2. PROACTIVE DRUGS ADHD, and schizophrenia.
Maternal malnutrition – inadequate growth in
• Nicotine, Caffeine and Illegal Drugs
the fetus, fewer brain cells, spina bifida – paralysis
(2) Implications and mental retardation.
Maternal Age – double mortality rate, rarely
Caffeinated coffee – preterm deliveries and lower down syndrome
birthweight.
Alcoholic drinks – fetal alcohol syndrome; facial
deformities and defective limbs, face and heart, 05. Paternal Factors
below average in intelligence and mental
retarded. - Lead, radiation, pesticides and petrochemicals,
Smoking - fetal and neonatal deaths, preterm age and others
births and lower birth weights.
(5) Implications
Heroin – smaller size, toxemia, premature
separation of placenta, retained placenta, Lead, radiation, pesticides and petrochemicals –
hemorrhage and breech deliveries. abnormalities in sperm, childhood cancer.
Older father – may cause certain defects, such as
premature births and developmental disorder.
3.) ENVIRONMENTAL HAZARD
HUMAN LIFE BEGINS AT CONCEPTION
- Radiation and x-rays, environmental pollutant,
The phrase "human life begins at conception"
toxic waste, sauna or hot tubs
means that life is considered to start at the
(3) Implications moment a sperm fertilizes an egg, creating a
zygote. This zygote contains a unique set of DNA,
Radiation– chromosomal abnormalities. distinct from both the mother and father, and has
X-ray – affects developing embryo and fetus. the potential to develop into a full human being.
Toxic wastes – affects mental development. (Keith L. Moore and T.V.N. Persaud, 2015)
Sauna or Hot tubs – fever to mother, birth defects
or even fetal death.

04. Other Maternal Factors

- Rubella, syphilis, genital herpes, AIDS, Nutrition,

high anxiety, stress, age