Prenatal Development

Sonja ShirdelPSY-1170-C05

STAGES OF PRENATAL DEVLOPMENT

1. Conception (sperm and egg cell unite in fallopian tube)

2. Fertilized egg (zygote) moves toward uterus.

3. Cell division begins (24-36 hours after conception)

Zygote divides into two cells, then into four, eight, sixteen, etc.As cells multiply, they separate into two distinctive masses: Inner cells (will form embryo) & Outer cells (will eventually become placenta)

Cells develop into blastocyst, which is made up of 3 layers:

1. Ectoderm Will become skin and nervous system

2. Endoderm Will become digestive and respiratory systems

3. Mesoderm Will become muscle and skeletal systems

4. Implantation (blastocyst arrives at uterus, attaches to uterine wall.)

Germinal Stage (lasts 0-2 weeks after conception)

Caution:  This pregnancy phase is very vulnerable; deformities are produced most often during this time.

1. Blastocyst that implanted in the uterus continues to divide rapidly after implantation.

2.Differentiation (cells take on different functions; division between cells that form placenta and the baby)

3. 4th week: Head begins to form, followed by the eyes, nose, ears, and mouth. 4. Cardiovascular system forms.5. 5th week: Buds that will form the arms and legs appear.6. 8th week: Embryo has all basic organs and parts except sex organs

Embryonic Stage (starts 3-8 weeks after conception)

Fetal Stage (From week 8 until delivery)

All organs develop: Development of circulatory system Heart development Development of digestive system Tooth development Development of the endocrine system Development of integumentary system Development of lymphatic system Development of muscular system Development of nervous system Development of the urinary and reproductive system Development of the reproductive system Development of the gonads Development of respiratory system

Factors influencing growth rate

Poverty:  linked to poor prenatal care, because mothers lack in education that would prevent them from harming the fetus by drug use, bad diet…etc.

Mother’s age: Women between the ages of 16 and 35 have a healthier environment for a fetus than women under 16 or over 35.

Drug use: Any type of drug can damage the fetus. Alcohol use leads to FASD, mental retardation, other birth defects…etc. Smoking leads to low birth weight, stillbirth… etc.

Diseases: The placenta cannot always filter out pathogens. Babies can be born with venereal diseases transmitted by the mother.

Diet of mother: Inadequate nutrition leads to mental retardation, birth defects, poor health of the developing fetus, which can cause permanent damage…etc.

Mother’s mental health: Prenatal depression can lead to complications and slow fetal growth, as maternal cortisol plays a role in fetal development.

Environmental toxins/ Teratogens: Lead to birth defects, stillbirths, mental retardation…etc.