This document provides information about conception and implantation. It discusses the reproductive phases in women including the ovarian and menstrual cycles. It describes gametogenesis and oogenesis, noting that the maximum number of oogonia a woman is born with is around 2 million. The document then discusses ovulation, fertilization, embryo development, implantation, and the products of conception including the fetus, placenta and fetal membranes. It provides details on placental development and establishment of the fetomaternal circulation. The functions and abnormalities of the placenta and umbilical cord are summarized. The document concludes with information about the liquor amnii and its indications for amniocentesis.

1. CONCEPTION AND
IMPLANTATION
Dr P.L Sankhwar
MS, FICOG, FICS
Associate Professor,
Department of Obst.& Gynae.,
KGMU, Lucknow.

2. 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.

3. 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.

4. 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)

5. 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.

6. 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

7. OVULATION
Hypothalamus  pulsatile GnRH release  FSH & LH (anterior
pituitary)  (Ovary) G. Follicle
Estradiol
I. Proliferative changes in endometrium
II. 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

8. FERTILISATION

9. DEVELOPMENT OF EMBRYO
• Zygote formation
• Morula formation
• Blastocyst formation

10. IMPLANTATION (NIDATION)
• Imbedding
• Changes at implantation site
• Changes in endometrium
• Formation of Chorionic villi

11. 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.

12. 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

13. PRODUCTS OF CONCEPTION
• Fetus
• Umbilical cord
• Placenta
• Fetal membranes ( chorion and amnion)
• Amniotic fluid (liquor amnii)

14. DEVELOPMENT OF PLACENTA
Primary villi Secondary villi Tertiary villi
13th
days 16th
days 21st
days

15. 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

16. ESTABLISHMENT OF
FETOMATERNAL CIRCULATION

17. 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

18. • Respiration
• Food Absorption
• Excretion
FUNCTIONS
ABNORMAL PLACENTATION
• Placenta previa
• Placenta accreta

19. ABNORMAL PLACENTA

20. UMBILICAL CORD
Connect 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%.

21. LIQUOR AMNII
Appears 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/100ml
Protein 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.

22. 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