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