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GROWTH AND DEVELOPMENT OF PRENATAL PERIOD
SHINU K ANTONY
Ist YEAR MSc NURSING
GOVT COLLEGE OF NURSING
ALAPPUZHA
PERIODS IN PRENATAL DEVELOPMENT
• Ovular period or germinal period: This lasts for first 2 weeks following ovulation.
• Embryonic period: Begins at 3rd week following ovulation and extends upto 10 weeks of gestation
• Fetal period: Begins after 8th week following conception and ends in delivery
GAMETOGENESIS
Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes
FERTILIZATION
Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube
ZYGOTE
PLACENTATION
PRINCIPLES EVENTS
• Days 14-21 post conception: notochord develops, ectoderm thickens to form neural plate and neural folds.
• Days 21-28 post conception: neural folds fuses to form neural tube. Four primitive cardiac chambers. First heart beat on day 21.
• Weeks 4-6 post conception: optic vesicles appear, complete neural tube closure (D30). Limb buds appear. Formation of face.
• Weeks 8-12 post conception: external genetalia develop
PRINCIPLE EVENTS…………….
• Weeks 20: skin is covered with lanugo. Vernix caeosa is present.
• Weeks 28: testes descend to the internal inguinal ring
• Weeks 36: one testicle usually descends into the scrotum. Lanugo tends to disappear.
• Weeks 40: both the testicles descend into the scrotum. Nails project beyond the finger tips. Posterior fontanelle is closed.
FETAL PHYSIOLOGY
Nutrition: Three stages of fetal nutrition• Absorption• Histotrophic transfer• HematotrophicFetal blood:• Haematopoiesis first in yolk sac by 14th day.• 10th week the liver becomes the major site.Leucocyte: Leukocytes appear after 2 month of gestationUrinary system : • the end of first trimester- nephrons are active • near term the urine production rises to 650ml per
day.
skin :• At 16th week, lanugo• Sebaceous glands at 20th week and and the sweat
glands later.Gastrointestinal tract: • As early as 10-12week, the fetus swallows amniotic
fluid. • The meconium appears from 20th week.Respiratory system: • At 28th week, alveoli expand and are lined by cuboidal
epithelium. • At the end of 24th week lung surfactantFetal endocrinology: Growth hormone, ACTH, prolactin, TSH and gonadotropin hormones are produced by fetal pituitary as early as the 10th week.
FETAL CIRCULATION
PRENATAL CARE
Systemic supervision (examination and advice) of a women during pregnancy is called antenatal / prenatal care. It comprises of•Careful history taking and examination (general and obstetrics)
•Advice given to the pregnant women
AIMS • To screen the high risk cases• To prevent or detect and treat at the earliest any
complications• To ensure continued medical surveillance and
prophylaxis• To educate the about the physiology of pregnancy
and labour by demonstrations, charts and diagrams• To discuss with the couple the place, time, mode and
the delivery, provisionally and the care of new born• To motivate to the couple the need of family planning
and also appropriate advice to the couple seeking MTP
The objective is to ensure a normal pregnancy with delivery of a healthy baby from a healthy mother.
OBJECTIVE
PROCEDURES AT FIRST VISIT
HISTORY COLLECTIONPHYSICAL EXAMINATIONGeneral examinationObstetrical examinationinvestigations
PROCEDURE AT SUBSEQUENT VISITObjectiveTo assess fetal well being Lie, presentation, position and number of fetusAnemia, preeclampsia, amniotic fluid volume and fetal growthTo organize specialist antenatal clinics for patients with problem like cardiac disease and diabetics.To select time for USG, amniocentesis or CVS when indicated.
Antenatal assessment of fetal wellbeing
AIMS OF ANTENATAL FETAL MONITORING
• To ensure satisfactory growth and well being of the fetus throughout pregnancy
• To screen out the high risk factors that affect the growth of the fetus
INDICATIONS OF ANTEPARTUM FETAL MONITORING
• Pregnancy with obstetric complications• Pregnancy with medical complications• Others like advanced maternal age, previous still birth, birth of a baby with structural abnormality etc
• Routine antenatal testing
NONINVASIVE PRENATAL TESTS
•Fetal ultrasonography•Fetal echocardiogram•Computerized Tomography and MR imaging•MS-AFP and triple test•Fetal Nuchal Translucency
INVASIVE PRENATAL TEST
AminocentesisChorionic villus samplingCordocentesis or percutaneous umbilical blood sampling
Fetal tissue sampling
METHODS OF PRENATAL DIAGNOSIS
AMNIOCENTESIS CHORION VILLOUS SAMPLING
ULTRASONOGRAPHY
METHODS OF PRENATAL DIAGOSIS
PERCUTANEOUS UMBILICAL BLOOD
SAMPLINGFETOSCOPY
GENETIC TESTING
METHODS OF PRENATAL DIAGNOSIS
MATERNAL SERUM SAMPLE
PREIMPLANTATION DIAGNOSIS
DEFINITION OF GENETICS
The branch of biology that deals with heredity and variation.
BRANCHES OF GENETICS
CYTOGENETICSIT IS THE BRANCH OF GENETICS THAT CORRELATES
WITH THE STRUCTURE, NUMBER AND BEHAVIOR OF
CHROMOSOMES
BRANCHES OF GENETICS
MOLECULAR GENETICSIT IS THE BRANCH OF GENETICS WITH THE STRUCTURE
AND ACTIVITY OF GENETIC MATERIAL AT MOLECULAR LEVEL.
GENOMICS
It involves all of the genes in human genome together including their interaction with each other, with the environment and their influence on psychosocial and cultural factors.
PHENOTYPE A PERSONS OBSERVABLE CHARACTERISTICS OF HIS OR HER GENOTYPE
GENOTYPE A PERSONS UNIQUE GENETIC DISTRIBUTION
HISTORY OF GENETICS
FATHER OF GENETICSGREGOR MENDEL
Discovered fundamental law of genetics
In 1853 Mendel conducted his
experiments on garden peas (Pisum
sativum).
CHROMOSOMES
In human body 23 pairs of chromosomes are there. Out of these 22 are autosomes and one pair sex chromosomes
STRUCTURE OF DNA
Double helix structure
GENE :- Unit of heredity
CELL DIVISION
MITOSIS MEIOSIS
STAGES OF CELL DIVISION
Interphase Prophase
STAGES OF CELL CYCLE
Metaphase Anaphase
STAGES OF CELL CYCLE
Telophase
GENETIC TESTING
GENETIC TESTING Genetic testing refers to the analysis of a
person’s DNA, chromosomes, proteins or certain metabolites obtained from a sample of blood or other body tissue in order to detect changes that indicate the presence or absence of a genetic condition or a pre disposition to develop one.
[JOYCE M BLACK, 2010] Genetic screening is presumptive
identification of an unrecognized genetic predisposition for a future disease in individual or their progency for which preventive or disease course altering interventions exist.
PURPOSES OF GENETIC TESTING
To confirm a present condition.
To determine whether an
individual is a carrier of a genetic
condition.
To detect fetal abnormalities.
To predict diseases in
asymptomatic individual
INDICATIONSOne or more birth defects
A genetic disorder
A chromosome abnormality
Intellectual development disorder or developmental delay
Neuromuscular abnormalities
Unexplained metabolic problems
Congenital or familial hearing loss of blindness
Abnormal sexual development
Prenatal exposure to drugs or medications including alcohol
Cancer
APPROACHES
GENOTYPE
PHENOTYPE
TYPES OF GENETIC TESTING
NEW BORN SCREENING
PRENATAL DIAGNOSIS
TYPES OF GENETIC TESTING
DIAGNOSTIC TESTING
CARRIER TESTING
TYPES OF GENETIC TESTING
PREDICTIVE TESTING
PRE IMPLANTATION TESTING
TYPES OF GENETIC TESTING
FORENSIC TESTINGRESEARCH TESTING
TYPES OF GENETIC TESTING
PHARMACOGENOMICS GENETIC ANCESTRY TESTING
METHODS OF GENETIC TESTING
MOLECULAR GENETIC TESTS
CHROMOSOMAL GENETIC TESTS
BIOCHEMICAL GENETIC TESTS
MOLECULAR GENETIC TESTS
I. AMPLIFICATION POLYMERASE CHAIN REACTION CLONING DNA IN BACTERIA
II. SEPERATION AND DETECTION CELL CULTURES
III. DNA ISOLATION
CHROMOSOMAL GENETIC TESTS KARYOTYPING HIGH RESOLUTION BANDING SOMATIC CELL HYBRIDIZATION FLOW CYTOMETRY FLURESCENT INSITU
HYBRIDIZATION
BIOCHEMICAL GENETIC TESTS
Study of body's enzymes
ASSESSMENT OF FETAL WELLBEING IN LATE PREGNANCY
CLINICAL BIOCHEMICAL BIOPHYSICAL
Click icon to add pictureAssessment of fetal lung maturity
• Estimation of lecithin:sphingomyelin ratio• Shake’s test or bubbles test or Clement’s• Foam stability index• Thin layered chromatography• Measurement of saturated phosphatidyl
choline• Fluorescence polarization• Amniotic fluid optical density• Lamellar body count• Orange colored cells• Amniotic fluid turbidity
Click icon to add pictureASSESSMENT OF SEVERITY OF RH-ISOIMMUNIZATION
It is done by amniocentesis for estimation of bilirubinin the amniotic fluid by spectrometric analysis. The optical density difference at 450nm gives the prediction of the severity of fetal hemolysis
Click icon to add pictureBIOPHYSICAL PROFILEI.FETAL MOVEMENT COUNT1. Fetal movement count 10 formula2. Daily fetal movement count (DFMC)3. Doppler imaging
II.VASIII.NONSTRESS TESTiv.BIOPHYSICA L PROFILEv.MODIFIED BPP
BIOPHYSICAL
PROFILE
Observation
for 30 minutes
SCORING
(MANNING-1985)
Normal score =2
abnormal=0
parameters Minimal normal criteria score
Non stress test(NST)
Fetal breathing
movements
Gross body
movement
Fetal muscle tone
Amniotic fluid
Reactive pattern
One episode lasting >30sec
3discrete body or limb
movements
1 episode of extension (limb
or trunk) with return of
flexion
1 pocket measuring 2cm in
two perpendicular planes
2
2
2
2
2
BPP score Interpretation management
8-10
6
4
0-2
No fetal asphyxia
Chronic asphyxia
Chronic asphyxia
Certain asphyxia
Repeat testing at
weekly interval
If >36wk deliver
If >=36wk deliver, if
<32wk repeat testing
in 4-6hrs
Test for 120mts,
persistent score <=4
deliver regardless of
gestational age
Click icon to add pictureVI.FETAL CARDIOTOCOGRAPHY
VII.ULTRASONOGRAPHY
VIII.DOPPLER ULTRASONOGRAPHY
IX.CONTRACTION STREE TEST
CONGENITAL MALFORMATIONS
Maternal factor Fetal / infant risks
Adolescent age,
pregnancy that
occurs at the two
age extremes
<16yrs and
35yrs.
Advanced
maternal age
issues
Small maternal
size
Large maternal
size
Nutrition
Prenatal care
Support system
Socioeconomic system
Preeclampsia
IUGR
LBW
Chronic diseases that affect pregnancy
Increased incidence of chromosomal abnormalities
Pregnancy related conditions might occur eg. Diabetes,
preeclampsia,vaginal bleeding
Increased risk of congenital or chromosomal abnormalities
IUGR
Increased potential for hypoxia during labor and delivery
Increased risk for poor fetal nutrition
Chromosomal(6%)
Trisomy 21 (down’s syndrome)
Trisomy 18 (Edward’s syndrome
Trisomy 13 (Patau’s syndrome)
Single gene disorder(5%)
1. Autosomal 2. X-linked
Infections(2%)
Rubella CMV Varicella Parvo
virus Toxoplas
ma
Maternal illness (5%)
Diabetes epilepsy
Drugs & environment(1-2%)
warfarin lithium dilantin radiation alcohol hypoxia
Mutifactorial (20%)
neural tube defects
congenital heart defects
cleft palate & lip
CAUSES OF CONGENITAL DISORDERS
SINGLE GENE DISORDERS
Click icon to add pictureAutosomal dominant (70%)• achondroplasia• marfans syndrome • neurofibromatosis• recessive (20%)• cystic fibrosis • galactosemia• sickle cell anemiaX linked disorders (recessive- 5%, dominant- rare)• hemophilia• duchenne muscular dystrophy• color blindness • fragile X syndrome
PATTERNS OF INHERITANCE
I. AUTOSOMAL DOMINANT INHERITANCE
VERTICAL PATTERN OF INHERIANCE
MALES AND FEMALES ARE EQUALLY AFFECTED.
50% OF CHANCE OF INHERITNG NORMAL GENE AND 50% OF MUTATED GENE
PATTERNS OF INHERITANCE
II. AUTOSOMAL RECESSIVE INHERITANCE HORIZONTAL PATTERN OF
INHERITANCE.
RELATIVES OF SINGLE GENERATION TEND TO HAVE THE CONDITION.
WHEN CARRIERS HAVE CHILDREN TOGETHER,25% CHANCE OF INHERITING MUTATED GENE.
III. X LINKED DOMINANT INHERITANCE
The sons of a man with an X-
linked dominant disorder will not
be affected, but all of his daughters
will inherit the condition.
A woman with an X-linked
dominant disorder has a 50
percent chance of having an
affected daughter or son with each
pregnancy.
PATTERNS OF INHERITANCE
IV. X LINKED RECESSIVE INHERITANCE . The sons of a man will
not be affected, and his daughters will be carrier.
a woman has a 50 percent chance of having sons who are affected and a 50 percent chance of having daughters who carry one copy of the mutated gene.
PATTERNS OF INHERITANCE
V. Y LINKED INHERITANCEMale to male
transmission.Only males are
affected.
PATTERNS OF INHERITANCE
VI. MULTIFACTORIAL INHERITANCECaused by a
combination of genetic and environmental factors
GENETIC DISORDERS
CHROMOSOMAL ABNORMALITIES
(cytogenic disorders)Nondisjunction abnormalitiesDeletion abnormalitiesTranslocation abnormalitiesMosaicismisochromosomes
GENETIC DISORDERS
III. SEX CHOMOSOME ABNORMALITIES
TURNERS SYNDROME
KLINFELTERS SYNDROME
SINGLE GENE DISORDERS
•cystic Fibrosis•Tay Sach Disease•Sickle cell disease
Autosomal
recessive inheritan
ce
•Neurofibromatosis•Huntington's disease•Achondroplasia
Autosomal
dominant inheritan
ce
SINGLE GENE DISORDERS
•Vitamin D Resistant Rickets•Rette syndrome
X Linked Dominan
t Inheritan
ce
•Hemophilia•Color Blindness•Duchenne Muscular Dystrophy
X Linked Recessiv
e Inheritan
ce
SINGLE GENE DISORDERS
•Alzheimers Disease•Diabetes Mellitus•Cancer
Multifactori
al Inheritance
GENETIC DISORDERS
•Phenylketonuria•Maple Sugar Urine Disease•Homocystinuria
Inborn Errors
Of Metabolism
GENETIC COUNSELLING
GENETIC COUNSELLING
DEFINITIONGenetic counselling is the process in which patients or their relatives at the risk of genetic disorder are made aware of the consequences of the disorder, its transmission ant the ways by which this can be prevented or mitigated.
[GANGANE SD, 2008]
Genetic counselling is defined as a communication process which deals with the human problems associated with the occurrence or the risk of a genetic disorder in a family
[THE AMERICAN SOCIETY OF HUMAN GENETICS, 2008]
AIMS
To obtain a full history.
To establish an accurate diagnosis.
To draw the family tree.
To estimate the risk of a future pregnancy
being affected or carrying a disorder.
To give information on prognosis and
management.
To provide continued support and follow up.
To do genetic screening
Indications Advanced parental age
Previous child with or family history of
Congenital abnormality
Adult onset genetic disease (pre symptomatic
testing)
Consanguinity
Teratogen exposure (occupational abuse)
Repeated pregnancy loss or infertility
Pregnancy screening abnormality
Heterozygous screening based on ethnic risk
Follow up testing
TYPES OF GENETIC COUNSELLING
DIRECTIVE
NON DIRECTIVE
TYPES OF GENETIC COUNSELLING
RETROSPECTIVE
PROSPECTIVE
GENETIC COUNSELLING TEAM The family or referring physician
The geneticist
The nurse
The other members of helping professions.
INFORMATIONS CONVEYED The specific condition or conditions
Knowledge of the diagnosis of the particular condition
Natural history of the condition
Genetic aspect of the condition and recurrence risk
Prenatal diagnosis and prevention
Therapies and referral
Support groups
Follow up
Nondirective counseling
The magnitude of the risk of occurrence or recurrence
The impact of disease on the patient and the family
Modification of disease impact and/ or risk
Anticipated future development
LEGAL AND ETHICAL ISSUES
OF GENETIC COUNSELLING
ROLE OF NURSE N GENETIC COUNSELLNG
ASSESSMENT
IDENTIFICATION
PROVIDING EDUCATION,CARE AND SUPPORT
FOLLOW UP
PRENATAL DIAGNOSTIC
TECHNIQUE ACT(PNDT) 1994
CONGENITAL MALFORMATIONS IN NEWBORN AND THE SURGICAL EMERGENCIES
Imperforate anus Esophageal atresia Meconium ileus Exomphalos / omphalocele Congenital diaphragmatic hernia
(CDH) Duodenal atersis
Emerging Methods of Fetal Assessment
Fetal physiology assessment
Fetal magnetoencephalography
NEW TECHNOLOGIES
STEM CELL PRESERVATION AND IMPLANTATION
NEW TECHNOLOGIES
Diseases for applying gene therapy
Disease Defect Target cell
Severe combined Bone marrow cells or
immunodeficiency T-lymphocytes
Hemophilia Liver, muscle
Cystic fibrosis Lung Cells
Cancer Many cell types
Neurological diseases Parkinson’s/ Alzheimers Nerve Cells
Infectious diseases AIDS, hepatitis B White Blood Cells
BIBLIOGRAPHY Dedas. A.K screening And Diagnosis Of Fetal
Malformation: A Practical Guide. Newdelhi. B. I Publication.2004
Hiralal konar. D. C Dutta’s textbook of obstetrics. 7th ed. India. New central book agency private limted. 2009
Randhawa S. S. atext book of genetics. 3rd ed. India. Vikas & company medical publishers. 2010
Terrikyle & susan carman. Essentials of paediatric nursing. 2nd edition. Newdelhi. Wolters kluwer Lippincott Williams & wilkins. 2013
Anoop kumar tiwar. Human genome project: an overview. Hitkarini journal of modern nursing services (HJMNS). Jan-june 2012.volumeII. issue I. page numbers 22-23
World Health Organisation (WHO). Geneva. Woldheath organisatation;2011. Available from:http://www.whocc.org/