Know About Your Embryo

pahlajanis know about your embryo

It is very important to understand the basics of oocytes and embryos. When a couple opts for a IVF treatment, it is a necessity to understand and gain a basic knowledge about their embryos. In order to make your IVF journey exciting, we have described and elaborated the details of oocytes and embryos here.

What Is Oocyte ?

Oocyte is a female germ cell involved in reproduction, it is also known as ovum or egg cell. It occurs in the ovarian follicle, a specialized unit of the ovary, during the course of oogenesis in the cortex. One of the largest cell in the body.

Oocyte Grading Is Based On Five To Six Categories

(1) Corona radiata

  • 2-3 layers of cell attached to zona pellucida
  • Supply vital proteins to cell

(2) Zona pellucida

  • Outer protective layer, thick membrane
  • Exit for sometime post fertilization

(3) Vitelline membrane

  • The vitelline membrane is a structure surrounding the outer surface of the plasma membrane of an ovum.
  • Plasma membrane of egg cell

(4) Nucleus

  • Heart of the egg cell

(5) Cytoplasm

What Is Embryo?

An embryo (the early stage of development before birth) is an egg that has already been fertilized by a sperm cell to form a zygote.


The formation and development of an embryo is called embryogenesis. here the zygote undergoes repeated cell division through mitosis which help in the growth of an embryo.

2 PN ( PRO NUCLEI) A Normally Fertilised Egg Is Called A 2PN.Which Represented The Male And Female DNA .(18-19HRS POSTINSEMINATION/ICSI)

Day1 ( Two Cell Embryo) The First Cleavage Event, Which May Occurs At Approximately 30 Hrs After Fertilization And Results In A 2-Cell Embryo.

Day2 ( Four Cell Embryo ) It Is The Result Of A Second Cleavage Event Which May Occurs At Approximately 40hrs After Fertilization ,These Are Basically Individual Cells Which Are Called Blastomere .

Day3 ( 8 Cell Embryo) The Day 3 Of Human Embryonic Development Mainly Develops The Eight Cell Stage Which Actually Consists Of 6-12 Cell At 68 Hrs.

Day4( MORULA STAGE) When Cell Have Rapidly Mitotically Divided To Produce A Solid Mass Of Cell ( More Than 16 Cell ) With A Mulberry Appearance Is Called Morula Stage.

Day5 (Blastocyst) A Cavity Forms Within This Ball Of Cells And The Embryo Is Then Called Blastocyst.(106-108hrs Post insemination/ICSI)

Embryo Grading

Embryos are graded in an attempt to decide which has the strongest possibility of achieving a successful pregnancy.

(GRADE-1 Equal Size Of Blastomeres <5% Or No Fragmentation)

(GRADE-2  Equal Or Irregular Size Of Blastomeres And Upto 10% Fragmentation)

(GRADE-3 Unequal Size Of Blastomeres With 10-25% Fragmentation)

(GRADE-4 equal or unequal size of Blastomere & 50% Fragmentation Moderate to high)

Blastocyst Grading

Early Blastocyst – Blastocoel Less Than Half Of The Blastocyst ( 1AA)

Blastocyst–  Blastocoel Less Than Half Of The Blastocyst (2AA)

Full Blastocyst – Blastocoel Fills The Blastocyst (3AA)

Expanded Blastocyst- The Embryo Is Large And The Zona Is Thin (4AA)


  • Numerous & Tightly Packed Cells
  • Several & Loosely Packed Cells
  • Few Cell


  • Many Cells Organized In Epithelium
  • Several Cells Organized In Loose Epithelium
  • Few Cells

It is very important to get an idea about your embryos so that you get a clear picture of the scheme of things that you are going through during your Ivf treatment. Pahlajanis’ IVF always believe in providing patients the right information and deal with utmost transparency. Gaining a knowledge on grading of the embryos will ensure that you understand the quality of your embryos and also assess the chances of your successful IVF pregnancy. For such more information’s and knowledge you can always explore our website and get in touch with our team of experts who are always ready to solve all your queries and doubts.

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