Lecture 3
Prenatal Influences on
Healthy Development
Objectives
Upon completion of this chapter, the student will
be able to:
1. State the goals of the Genome project
2. Trace the steps of human fertilization and
implantation.
3. Discuss the critical periods of fetal development.
4. Compare the similarities and differences in two
types of twins.
5. Discuss the importance of prenatal health and
nutrition to the health of the newborn and
life expectancy.
6. Discuss the emotional changes that occur
during transition to motherhood.
7. Discuss bonding and attachment between
parents and newborn.
8. Discuss the techniques of calming a newborn
infant.
9. List the types of toys and activities that foster
growth and development of the neonate.
The Genome Project:
Unlocking the Secrets of Inheritance
• Growth and development are influenced by biology
and by the environment .
• Research concerning the maternal-fetal origins of
adult disease contributed to the development of the
HUMAN GENOME PROJECT.
• The project officially started in 1990 and a draft
findings was published in 2001.
The Original Goals of the Project Involved the
Following:
• Identifying the more than 30,000 genes
contained in human DNA.
• Determining the sequence of the billions of
chemicals that are contained in DNA.
• Development tools for analysis of the findings.
• Addressing the ethical, legal, and social
implications (ELSI) involved.
• Transferring the technology for use by the public
in the private sector.
A Genome Is a complete set of DNA that is contained in
all human cells. The DNA in the genome is the genetic
code of a cell that carried on the chromosome
Chromosome Is a thread of protein and DNA contained
in the nucleus of every cell. Each Chromosome contains
genes, and there are approximately 30,000 genes in a
genome
• Genetic counseling is the communication between a
geneticist ( a specialist in inherited conditions) and
the parents to discuss the risk of their infant
inheriting gene that result in an abnormality.
• Gene therapy involves placing a therapeutic gene on
the back of a virus vector ( a virus vector is a virus
that has the ability to enter specific cell in the body).
Screening Procedures and Therapies
• In the past it has been possible to screen individual
patients for the existence of some specific genetic
problems without looking at DNA.
• DNA-based genetic tests can
-detect carriers,
-Identify susceptibility
-Enable diagnosis before symptoms occur.
The prenatal phase
Critical periods
•
Many of the critical periods during fetal growth occur during the first trimester of
pregnancy (first 3 months) when basic structures are developing .
•
Many of these factors can affect growth and development throughout fetal life such as
undernutrition.
Toxins
Teratogens (toxins)are harmful influences on
fetal growth. such as
-Fetal alcohol syndrome Recreational drug.
-Exposure during pregnancy.
-Maternal cigarette smoking
-Radiation exposure
Maternal adaptations during the prenatal phase:
• Attitudes are forming . If the pregnancy is planned
and wanted, attitudes will most likely be positive .
• If the pregnancy is unplanned or unwanted,
interventions and referrals may be necessary to help
the parents develop a positive attitude.
• The mother is motivated to psychologically prepare
for the arrival of the infant.
Fatal development
• Fertilization occurs when the sperm penetrates the
ovum as it enters the upper portion of the woman ,s
fallopian tube.
• The zygote is the cell formed by the union of the sperm
and ovum.
• After 2 weeks of growth and development the zygote is
called on embryo.
• From the 9 week of life to birth, the developing baby is
called fetus.
Embryonic and fetal development
age
Length and weight
development
Week 3
1.5-2.5 mm
Week 4
3.5-4mm
Cardiovascular : Single tubular heart
is formed.
Nervous: Neural tube forms; primitive
spinal cord and brain appear.
Cardiovascular: Heart pumps blood.
Gastrointestinal (Gl): Esophagus and
trachea separate; stomach forms.
Nervous: Neural tube closes; forebrain
forms.
Musculoskeletal: Upper and lower
limp buds appear.
Senses: Ears and eyes begin to form.
Embryonic and fetal development----cont’d
Age
Development
Length and weight
Musculoskeletal: Skull and jaw ossify;
11-13 mm
hands and elbows differentiate.
Senses: Auditory canal forms; eye is
obvious.
Cardiovascular : Heart has all four
chambers.
GL: Nasal cavity and upper lip form.
Embryonic and fetal development----cont’d
Age
Week 8
length and weight
30 mm
Crown-rump 6 g.
Development
-Embryo has distinct human
appearance.
-Purposeful movements occur
tail has disappeared.
-sex organs form.
-Beginnings of most external and
internal structures are formed.
-Enters fetal period.
-Genitalia and leg movements are
Week 17
150 mm
Crown-rump
260 g
visible on ultrasound and may be
felt by the mother.
-Bones are ossified.
-Eye movements occur.
-Fetus sucks and swallows amniotic
fluid.
-Ovaries contain ovum.
-No subcutaneous fat is present.
-Thin skin allows blood vessels of
scalp to be visible.
Embryonic and fetal development----cont’d
Age
Length and weight
Week 25
28 cm
(11.2 inches)
Crown – heel
780 g
(1lb 10 oz)
Development
-Wrinkled skin, lean body results
from lack of subcutaneous fat .
-Eyes are open.
-Fetus is nom viable.
-Mother feels stronger movement
(quickening).
-Fetus has schedule of sleeping and
moving.
-Vernix caseosa is present on skin.
-Lanugo covers body.
-Brown fat is formed.
-Lungs begin to secrete surfactant.
-Fingernails are present.
- Respiratory movements begin.
Embryonic and fetal development----cont’d
Age
Length and weight
Week 29
38 cm
(15 inches)
Crown-heel
1260 g
(2 lb 10 oz)
Week 36
48 cm
(19 inches)
Crown-heel
2500 g
(5 lb 12 oz)
Development
-Fetus assumes stable (cephalic)
position in utero .
-Central nervous system is functioning.
-Skin is less wrinkled because of the
presence of subcutaneous fat.
-Spleen stops forming blood cells, and
bone marrow starts to form blood cells.
-Increased surfactant is present in lungs.
-Subcutaneous fat is present.
-Skin is pink and smooth.
-Grasp reflex is present.
-Circumferences of head and abdomen
are equal .
-Surge of lung surfactant is produced.
• The third week after fertilization, the heart begins to
beat and the neural tube (the beginning portion of the
central nervous system) forms.
• For this reason, the mother must take prenatal vitamins
to ensure adequate intake of folic acid, which is essential
for normal neural tube development.
• Conditions such as spina bifida can occur if there is a
deficiency of folic acid when the neural tube is forming.
Twins:
• Twins or other multifetal births (e.g.,triplets, quadruplets,
and so on) can occur.
• A fraternal twin is also called a dizygotic twin and occurs
when two ova are released at ovulation and each ovum is
fertilized by a separate sperm. The twins may or may not be
of the same sex and are as alike as siblings.
• Monozygotic twins are called identical twins and occur
when one single fertilized ovum separates into two
separate embryos. These twins will be of the same sex and
will be genetically identical (look alike).
The birth process:
• Childbirth is a normal physiological process that affects
the health of the mother and fetus , labor and delivery are
often a family affair with fathers or significant-others
participating and grandmothers closely involved.
Attendance at preparation classes during pregnancy and
the cultural background of the parents usually dictate the
extent of the supportive role of the partner or
grandmother in the labor and delivery unit.
The Newborn Infant
•
As the infant is born and the umbilical cord it cut, many
physiological changes occur in the infants body to enable it to
adjust to life outside of the uterus.
• It is important for the nurse to promote bonding and attachment as soon as
possible after birth.
•
Bonding refers to a strong emotional tie between parents and
the newborn.
•
Bonding begging during pregnancy, but it is most important that
touch and visual interaction occur as soon as possible after birth.
•
The newborn should be placed in the mothers arms, and put to
breast if breastfeeding, as soon as possible after birth.
• Attachment refers to an affectionate tie that
occurs over time due to parent-infant
interaction.
• The en face (face to face)position facilitates
eye contact between infant and parent.
Parent-infant bonding should be the focus of
care during this first hour of life.
The transition to motherhood:
Rubin's psychological changes after birth:
Phase 1
“Taking in” the woman is passive , lets others care for her and
infant, and talks about the delivery experience.
The mother usually requests food and opportunity to sleep.
“Taking hold” the woman begins to initiate care of the infant
Phase 2
and assumes responsibility for self-care.
The woman is most receptive to teaching at this stage.
“Letting go” the parents recognize the reality of the new
Phase 3
lifestyle and responsibilities they face and accept the gender and
unique appearance of the new child.
Siblings:
•
The influence of the new child’s birth on siblings depends on their age and
developmental stage.
•
Toddlers may regress and angry.
•
Older children may enjoy helping with the new born, and adolescents may feel
embarrassed about their mother giving birth.
The Neonate : Developmental Tasks And Responses
•
Neonatal period: first 30 days of life .
•
Swaddling, cuddling, rocking and use of a pacifier calm the newborn infant.
•
Newborn reflexes help the neonate adjust to the environment and disappear as
voluntary motor abilities develop such as Moro reflex, tonic neck reflex and palmar
grasp reflex
Development of intelligence
• Intelligence is a very difficult to define during the neonatal period
because it includes so many aspects and different types of abilities.
• Intelligence involves ability to learn from experience and adapt to the
environment and it is challenges.
Play Activities And Neonatal Development
• Because hearing and vision are present in the newborn, an appropriate
toy would include a musical mobile that placed above the crib within
sight of the infant .
• The neonate is in the Piaget’s sensorimotor stage of cognitive growth.
•
infant can learn and repeat behavioral responses looking, listening, and
touching the environment help the infant master the task of this stage.
Thank you