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CONCEPTION AND IMPLANTATION
CONCEPTION AND IMPLANTATION
Dr P.L Sankhwar MS, FICOG, FICS
Associate Professor,
Department of Obst.& Gynae., KGMU, Lucknow.
Dr P.L Sankhwar MS, FICOG, FICS
Associate Professor,
Department of Obst.& Gynae., KGMU, Lucknow.
REPRODUCTIVE PHASE IN A WOMAN
- Cyclical change in the reproductive organs.
- Purpose:
1.To render an Oocyte available for fertilization
Ovarian cycle – Follicular phase- Ovulation- Luteal phase
2.Prepare uterus for implantation of the fertilized ova.
Menstrual cycle- Proliferative phase- Secretory phase- menses or conception.
GAMETOGENESIS GAMETOGENESIS
Oogenesis &
ovulation
Spermatogenesis &
spermiogenesis
Oogenesis - process involved in the development of a
mature ova.
Ovulation – Release of ova from the ovary is k/a ovulation.
Germ cells
Oogonia
Primary Oocyte
Arrested first meiotic division(up to puberty)
Maturation of Graafian follicle
Completion of lst meiotic division
Secondary Oocyte(23,x) Ist Polar Body(23,X)
Ovulation
Not fertilized
(Degenerates)
Fertilized
OOGENEIS
Completion of second meiotic division
Second polar body (23,X)
Female pronucleus(23,X)
Maximum Number of oogonia – 20 wks - 7 mill.
At birth 2 mill.
At puberty 4 Lakhs
Ovulation in whole life- 400 Ova
OOCYTE
• 130 Micron
• Largest cell of the body.
• Haploid no. of chromosomes.
OVULATION
• Definition
• What causes ovulation?
• Changes in G.follicle & formation of Corpus luteum
• Changes in oocyte and its maturation
Flat epith Cuboidal epith Multi layered Cavity appear mature ova ovulation
OVULATION
Hypothalamus pulsatile GnRH release FSH & LH (anterior
pituitary) (Ovary) G. Follicle
Estradiol
I. Proliferative changes in endometriumII. Inhibits FSH secretion. III. Stimulates LH secretion.
Secrete
Estrogen peaks 48 hrs prior ovulation.
LH surge – 24- 36 hrs prior ovulation. LH causes dominant follicle to rupture & form C. luteum
Secretes progesterone --- secretary changes in endometrium
--- Inhibit LH secretion.
If no conception – FSH & LH Decline & Hypothalamus gets positive feedback to secrete GnRH.
C. Luteum starts degenerating on 8th post ovulatory day.
- shrinks ----- C. albicans ----- C atreticum
FERTILISATIONFERTILISATION
DEVELOPMENT OF EMBRYO• Zygote formation
• Morula formation
• Blastocyst formation
IMPLANTATION (NIDATION)
• Imbedding
• Changes at implantation site
• Changes in endometrium
• Formation of Chorionic villi
IMBEDDING Microvilli appear on the surface of trophoectoderm which interdigitate
with decidual cells to form junctional complexes.
Uterine receptivity is induced by – progesterone - LIF - Prostaglandin - Cox- 2
Lysis of stromal cells by histolytic action of blastocyst cells –
it gets burried more & more deeper in the endometrium and
erode the blood vessels – Synticium becomes continuous
with the endothelium – Maternal blood collected into the
lacunae – Further embedding is stopped by maternal
immunological factor and entry point is sealed by fibrin clot.
CHANGES IN ENDOMETRIUM (DECIDUA )Structural and secretory activity in endometrium increased
(Decidual reaction).
Stromal Fibrous changed into epitheloid decidual cells.
Glands show marked tortuousity & dilatation.
Endometrium – Uppermost – Compact layer
Intermediate – Spongy layer (plane of cleavage during
parturition).
lower most – thin basal layer.
After implantation • Decidua basalis • Decidua capsularis • Decidua parietalis
PRODUCTS OF CONCEPTION
• Fetus
• Umbilical cord
• Placenta
• Fetal membranes ( chorion and amnion)
• Amniotic fluid (liquor amnii)
DEVELOPMENT OF PLACENTA
Primary villi Secondary villi Tertiary villi
13th days 16th days 21st days
DEVELOPMENT OF PLACENTA• Principally fetal origin- Chorionfrondosum with some
maternal component- Decidua basalis.
• Start developing in 6th week and completed by 12th week of fertilization.
• Till 16th week placenta grows in all direction but later on it grows circumferentially Dimension
4th month at term
Diameter 80-85 mm 200 mm
Thickness 18 -21mm 20 -25mm
ESTABLISHMENT OF FETOMATERNAL CIRCULATION
PLACENTA• At Term – oval or circular cake like measuring 6 to
8”, 1” thick at center and weighing about 1 pound.
• Two surfaces (maternal and fetal),10 to 15 cotyledens.
Placental barrier (thickness- .025mm)- constituting double layered chorionic epithelium by a layer of stroma and by the fetal capillary wall in first half of pregnancy.and which gets attenuated and now becomes .002mm having a layer of syncytium a mere film of stroma and fetal capillary endothelium.
Fetal surface
Maternal surface
• Respiration
• Food Absorption
• Excretion
FUNCTIONS
ABNORMAL PLACENTATION
• Placenta previa
• Placenta accreta
ABNORMAL PLACENTA
UMBILICAL CORDConnect body of fetus with the placenta
Its earliest appearance – as ventral stalk
When fully formed it contains –
1.Ventral stalk
2.Umbilical blood vessels (two arteries and one vein)
3.Allantois
4.Vitelline duct and the obliterated extra-embryonic coelom and Wharton’s Jelly (gelatinonus embryonic connective tissue)
At term, cord length varies from 5” to 60” average being 18” to 24”, vessels almost always twisted and attaches with the placenta somewhere between center in edge - Eccentric attachment 73%, Central - 18% battledore- 7% and velamentous in 1-2%.
LIQUOR AMNIIAppears within amnion gradually increases until a term it amounts to approx. 600 ml. (range 300 to 1200 ml).
Clear pale fluid, low specific gravity, hypotonic.
COMPOSITION -
Content mg/100mlProtein 100-500
Sugar 10-60
Chloride (NaCl) 560-660
Sodium 280-310
Non protein nitrogen 20-40
Suspended Matters like lanugo hair, epidermal scales, cells derived from the amniotic epithelium and vernix caseosa also present in it. Abnormal content- glucose , bilirubin, blood, meconium.
INDICATIONS FOR AMNIOCENTESIS
Diagnostic-
- Rh in compatibility
- To know fetal maturity
- chromosomal analysis
- enzyme analysis in metabolic disorders
- Estimate alfa-fetoprotein in suspected neural tube defect.
Theraputic –
- Hydramnious
- Intrauterine transfusion