Fertilization and Implantation Facts

If you would like to know about fertilization and implantation you should know that it is almost impossible to know for sure when you got pregnant.

This is why the doctors calculate the due date based on the time when you had your last menstrual period.

Fertilization and Implantation

Ovulation, implantation and fertilization

During each month in the ovaries there are eggs growing inside the follicles. Due to the hormones released by your body one of these follicles ruptures and it releases an egg. This is known as ovulation. In the majority of the cases ovulation occurs about two weeks before the following menstrual period.

Hormone rise

Before thinking about the egg that is fertilized we have to consider the rise of the hormone levels. After the follicle ruptures it becomes what is known as corpus luteum. In this state it releases a hormone that makes the endometrium thicken, preparing it for a possible pregnancy.

Journey to the fallopian tube

Prior to the fertilization of the egg, after it is released, it travels through the fallopian tube. It spends here about 24 hours, waiting to be fertilized. As it has been mentioned before, this normally happens about two weeks after your last menstrual period.

The egg’s fertilization

If one of the sperms manages to reach the egg and it burrows into it, we can say that the egg is fertilized and conception takes place. At this point the egg changes so that no other sperm will be able to fertilize it again. This is the moment when the gender of the baby is set.


For implantation after fertilization the egg spends about 3-4 days in the fallopian tubes. However after it is fertilized it starts dividing into other cells very fast. This cellular division goes on as it moves through the fallopian tube towards the uterus. There it gets attached to the lining of the uterus and this is known as implantation.

Around the time of fertilization or implantation some of the women notice some spotting for a day or two. Simultaneously the uterus’ lining gets thicker and the cervix closes up, being sealed by a mucus plug. This will stay in place until the time comes for the baby to be born.

During the first week after implantation or fertilization a hormone called hCG or human chorionic gonadotropin appears in the blood and in the urine. This is made by the cells that will become the placenta. This is the hormone that the pregnancy tests are based on.

You might have to wait for 3-4 weeks after conception and implantation to get a positive result on the test. It is interesting to know that in only three weeks the first nerve cells of the baby are already formed. This means that the little one develops faster than you may have thought.

A fertilized egg is a lot more than just the combination of an egg and a sperm; it is a small life that in nine months will become your bundle of joy.


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