Fertilization – fusion of the egg with the sperm 

When the egg meets the sperm and a fusion occurs, it means fertilization has happened. It means you have conceived and you are on your way to becoming a mum to a unique, complex being some 9 months later.

Fertilization Facts

• It takes only one out of the millions of sperms released during ejaculation to fertilize the single matured egg

• When trying to conceive have intercourse every 48 hours during the fertile period

• Fertilization takes place about an hour after intercourse

• Millions of eggs die; millions of eggs leave the female body because of gravity. Only 2000 odd sperm succeed in the journey to the vagina

• The egg can survive for 12-24 hours in the fallopian tube

• The sperm can survive for 2-3 days inside the female body

• Ovulation is an essential precursor to conception. Regardless of the length of cycles ovulation occurs 14 days before a period is due

• The best position to achieve conception is the missionary position

• Lying on your back with a cushion tucked under your buttocks for about 20 minutes after intercourse increases the number of sperm in your body

Journey of the EGG

Once a mature egg has been released by the ovary or ovulation has taken place, the egg will move into the fallopian tube. At this time, your body makes the necessary preparations for a possible pregnancy. The uterus lining called the endometrium thickens all set for the fertilized egg to embed itself. Fertilization takes place in the fallopian tube. Contractions of the tube along with the tiny hairs called cilia help to move the egg towards the uterus. The egg survives for only 24 hours in the fallopian tube. If fertilization does not take place, the egg will be reabsorbed into the system, the endometrium will come away and bleeding will commence as another menstrual cycle begins.


Journey of the SPERM

The sperm swims very quickly from the vagina into the cervix after ejaculation. It will swim towards the waiting egg into the fallopian tube. Special chemicals emitted from the egg attract the sperm towards it. Of the many sperms racing toward the egg, only one sperm will succeed in penetrating the egg. New chemicals are released by the egg to seal it and hence prevent other sperm from breaking through. The sperm that managed to fuse with the egg sheds its tail and body. Chromosomes from the sperm join with those of the egg.



The egg is usually fertilized in the fallopian tubes. Once the fusion occurs, hormones prevent the endometrium from breaking down. (No periods for 9 months or so). The blastocyst burrows into the thick lining. Finger-like projections sprout to develop into the placenta from the outer layer of cells. The pregnancy is now established with the placenta forming a crucial link between the mother and the embryo. The moment the egg becomes fertilized, the sex of your baby is established. Each parent contributes one sex determining chromosome, an X or a Y. It is the man’s contribution which will determine the baby’s gender


After Fertilization

With the fusion of the sperm and egg complete, a new cell forms called the zygote. The sperm and the egg are only cells which contain 23 chromosomes each; all human cells have 46 chromosomes. The new cell now containing 46 chromosomes will travel down the fallopian tube slowly. During its travel it will divide into identical cells of 2 then 4 and 8 and so on. By day four, it will be a solid mass of cells and is called a morula. By the time the morula reaches the uterus it will be a hollow ball of 100 odd cells now called a blastocyst. The blastocyst takes about 6 days to reach the uterus and implant. Once it is embedded in the endometrium it will continue to grow and develop into an embryo. The implantation process can cause slight bleeding in some which can be mistaken for a very light period.


X or Y – The Sex Chromosomes

The sperm and egg cells each contain 23 chromosomes. Of the 46 chromosomes, the sex of a baby is determined by just 2, the X and the Y. The egg has the single X chromosome while the sperm have either the X or the Y chromosome. The sperm with the X chromosome when united with the egg will go on to produce a baby girl. The sperm carrying the Y chromosome will go on to make a boy baby after it fertilizes the egg. In a gist 2 X or XX make a girl. One X and one Y or XY will result in a boy child.

When you have more than one .. at one Go

About 1 in every 80 pregnancies results in twins. The rise is due to fertility treatments being administered and the age of the mother. Women becoming pregnant after 35 are more likely to have twins. About two thirds are fraternal or non-identical and the rest are identical twins. Triplets are also becoming common with fertility treatments although its incidence is not as high, only 1 in 6000 pregnancies. These multiple births of identical and fraternal babies occur in the same way as twins do.

When the Egg Fails to Implant

In some instances the fertilized egg fails to implant in the womb. This is caused by some abnormality in the egg which doesn’t allow it to survive. When this happens the woman isn’t usually aware that the fertilization has occurred. What usually follows is a slight delay in periods which is possibly heavier than the usual periods.


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