Prenatal Developmentfrom conception
to birth.
How life begins.
New life begins with the union of a male sex cell (spermatozoon) and a female sex cell (ovum).
Development begins with conception. All of the other cells in your body developed from this
single cell. Each cells contains enduring messages from the
parents carried on the chromosomes. Each chromosome houses many genes. Within the genes is a substance known as DNA (deoxyribonucleic acid).
Periods of prenatal development
The prenatal period extends from conception to birth, usually encompassing nine months of
pregnancy. Development during the prenatal period is
remarkably rapid. It is divided into three stages: (1) the germinal stage, (2) the
embryonic stage, and (3) the fetal stage.
The Germinal Stage
The germinal stage is the first phase of prenatal development, encompassing the first two weeks after conception. This stage begins when a zygote is
created through fertilization. Within 36 hours, rapid cell division begins, and
the zygote becomes microscopic mass of multiplying cells. The first cell
division is called blastocyst. On the seventh day, the cell mass begins to implant itself in the uterine wall, this
process is called implantation.
The Embryonic Stage
The embryonic stage, lasts from two weeks until the end of the second month. Once the placental circulation is in place; nutrients, oxygen, vitamins, and water in the mother’s blood stream pass through the placenta and umbilical cord to the developing organism, which is called
embryo.The embryo forms into three germ layers
which give rise to different organs and tissues. The mesoderm forms the skeletal, muscle, skin, and lymphatic system. The endoderm forms the respiratory system, stomach, colon, liver, pancreas, urinary system thyroid and parathyroid . The
ectoderm forms the central and peripheral nervous system.
The Fetal Stage
The fetal stage of the fetus is the third stage of prenatal development, lasting from two months through birth. Early in this stage muscles and bones begin to
form. Fetus becomes capable of physical movements as skeletal structures harden.
Organs formed in the embryonic stage continue to grow and gradually begin to
function. Sex organs start to develop during the third month. Approximately the end of the sixth month, the fetus attains
viability.
Physical and
psychological hazards
Common Physical Hazards During the Prenatal Period
Embryonic Stage - Miscarriage - Developmental irregularities.
Fetal Stage- Miscarriages- Prematurity
- Complications of delivery
- Developmental irregularities.
Germinal Stage-• Starvation-•Lack of uterine preparation-•Implantation in the wrong place.
Psychological Hazard
Traditional beliefs about
prenatal development.
Maternal stress during the prenatal
period.
Unfavorable attitudes
toward the unborn child.
Genetic Problem
s
Down SyndromeAlso known as trisomy21, Down syndrome is the most common
genetic anomaly during prenatal development. Down syndrome is
caused by and extra copy of the 21 chromosome (meaning there are
three chromosomes instead of usual two) and impact approximately 1 out
of every 1000 infants. Typical features of down syndrome include
flattened facial features, heart defects, and mental retardation. The
risk of having a child with Down syndrome increases with maternal
age.
Inherited Diseases A number of illness can be inherited if one or both parents carries a gene
for the disease. Examples of inherited diseases include Sickle-cell
anemia, Cystic fibrosis, and Tay-Sachs disease. Genetic tests can often determine if a parent is a carrier of genes for a specific
disease.
Sex-Chromosomes Problems
A third type of genetic problems involves sex-chromosomes. These
include conditions such as Klinefelter’s syndrome (an extra X-chromosome) and turner syndrome
(a single X-chromosome).
Environmental
Problems
Maternal Drug Use The use of substances by the mother can have devastating consequences to the fetus.
Smoking is linked to low birth weight, which can result in a
weakened immune system, poor respiration, and neurological
impairment. Alcohol use can lead fetal alcohol syndrome, which is
linked to heart defects, body malformations, and mental
retardation. The use of illicit drugs such as cocaine and
methamphetamine is also linked to low birth weight and neurological
impairment.
Maternal DiseaseThere are a number of maternal
disease that can negatively impact the fetus, including herpes,
rubella, and AIDS. Herpes virus is one of the most common maternal diseases and can be transmitted in
the fetus, leading to deafness, brain swelling, or mental
retardation. Women with herpes virus are often encouraged to deliver via cesarean to avoid
transmission of the virus.
Maternal Nutrition The developing fetus needs a variety of essential nutrients .
Effects of severe malnutrition can be poor motor skills, apathy, and
irritability during infancy. It is important for pregnant women to have nutritionally balanced diets.
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[ The End ]
• Presented by: Aimee-Marie Lopez, Gian Franco Lintao, Mary Valerie Locsin, Maicel Elmae Lucena, and April Mae Lumanglas.
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