How Does Conception Works?

When we were children, we learn from our parents about the miracle of life. Now that we are adults we know that in fact the miracle of life is known as conception.

How Does Conception Works

To become a mother, it`s necessary to know everything there is to know about conception and fertility. The correct planning of a pregnancy will contribute to the conception a healthy child, reason for which is recommended to inform yourself regarding everything about pre-conception and fertility in women and men.

What Is Conception?

Conception is a process of remarkable complexity. The man must produce a sperm, and the woman an egg, which must meet at the right time and place.

Conception represents a series of processes which result in the beginning of pregnancy development in the woman`s body. Conception doesn`t only include the sexual intercourse between a man and a woman, but also other complex processes which pass unnoticed for a woman.

If you want to give yourself the best chance to conceive, it`s essential to understand how women`s and men`s reproductive organs work, what`s happening and how. – Visit us here!

As it will be mentioned below, a pregnancy starts to develop a few days or even a few weeks after the intercourse.

How Does Conception Works?

The process of conception consists in 3 main stages:


Approximately once a month, one of the woman`s ovaries releases a female germ cell (the egg). This process is known as ovulation. The egg has very small sizes, it doesn`t move and reminds of a decreased chicken egg.

After being released during ovulation, the egg is caught by the fallopian tube and starts to move through it due to the undulating movements of the microscopic villi which cover the interior lining of the fallopian tube.

If the intercourse took place a few days (or sometimes hours) before ovulation and male sperm entered in the woman`s vagina, the male mobile cells from the vagina penetrates rapidly the uterine cavity, and then the fallopian tubes where meet the egg.

Sperm tries to fertilize the egg after meeting it. From hundreds of millions of sperm released during sexual intercourse (coitus or copulation), only one single sperm can fertilize the tiny egg. Immediately after this, the sperm shell becomes impermeable for the others.

If the egg isn`t fertilized, it dies after 24 hours after being released.

After fertilization, the male and female gamete genes join together to form a complete set of genetic information needed to develop the future baby.

The fertilized egg (the zygote) starts to divide rapidly (develop), but it`s still not able to result in a pregnancy because it doesn`t have a strong bond with the woman`s body, and thus, it doesn`t have resources for development. To start a pregnancy, the zygote continues to move slowly through the fallopian tubes towards the uterus where after a few days it will attach to the uterus.

Due to the fact that sperm can survive in the female genital tract for 5 – 7 days, fertilization can even happen after a week from intercourse when ovulation occurs. Therefore, the sexual intercourse itself shouldn`t be considered the moment when the conception took place.

During the stage of fertilization, the process of conception can be disturbed by the absence of the egg (for example, due to some gynecological diseases which violate ovulation) or the absence (or non-viability) of sperm.

The Penetration of the Fertilized Egg in the Uterine Cavity

The movement of the fertilized egg through the fallopian tube lasts, averagely, around 5 – 7 days. During this time, it divides several times and transforms into a vesicle (the embryo) made from several small cells that in the future will form the body of the baby and the membrane which will surround him in the uterus.

Even during this stage, which means after almost a week (in some cases, 2 weeks) after the intercourse, pregnancy doesn`t yet exists. The embryo, which moves through the fallopian tube, doesn`t yet have a strong connection with the mother`s organism and, lots of times, dies before reaching the uterus.

At this stage, the process of conception may be disturbed by the tubal obstruction that occurs due to STDs (chlamydia, gonorrhea, trichomoniasis) or other reasons (adhesions, inflammation).

In some cases, the embryo may start fixing before reaching the uterus (for example, in the fallopian tubes). If this occurs, it may occur an ectopic pregnancy.

The Fertilization Egg to the Uterine Lining

If it reaches the uterus (1 – 2 weeks after the sexual intercourse), the embryo releases special substances which help in dissolving a small part of the uterine mucosa and “sink” into it. This process is known as attachment or implantation.

If the embryo cannot attach, it dies.

During the implantation of the embryo (on average, 8 – 10 days before the next menstruation), at some women there`s a mild vaginal bleeding that occurs (implantation bleeding), which disappears rapidly – a few hours or days.

After implantation, the embryo starts to develop rapidly, and its shell starts to produce hCG. A successful implantation finalizes the process of conception. After implantation, we can recognize that the pregnancy is installed.

After sexual intercourse and fertilization, and until the final implantation of the embryo in the uterine cavity, it may pass around 2 weeks. – Click for more!

During the implantation period, the process of conception may be disturbed by several diseases (endometriosis, myoma), which make the implantation of the embryo impossible.

Therefore, the conception of a baby involves several major events:

  1. The fertilization of the female reproductive cell by the male reproductive cell.
  2. The division of the fertilized egg (the zygote) and its movement through the fallopian tubes to the uterus.
  3. The attachment of the developing zygote (the embryo) to the uterine lining,

The process of conception may be disturbed during any of these stages.

The violation of conception manifests through infertility, meaning the inability of a couple to conceive a baby.

What Happens in the Days after Ovulation?

The luteinizing hormone will force the egg to come out of the follicle where maturation generally occurs. After the ovulation process ends, the egg will move down the uterine tube on its way towards the uterus. Corpus luteum will be left over in the uterine tube. It will signal an increase of progesterone that will lead to a thickening of the walls of the uterus. Corpus luteum remains present in the uterine tube for up to 2 weeks after the ovulation process ends. If it`s not stimulated by hCG, the levels of estrogen and progesterone fall back to their normal limits.

What Is the Percentage of Fertilized Eggs that Implant?

Once the embryo turns into a blastocyst, around 5 to 6 days after the fertilization process ends, it comes out of its zone pellucid and starts the implantation process inside the uterus. – Read this!

In nature, around 50% of all eggs that are fertilized are lost before a woman`s missed period. In the IVF process, an embryo might start to develop but not turn into a blastocyst, which is the first stage where the cells that will become the fetus are separated from the other ones that turn into the placenta. The blastocyst might implant without growing, or it might grow but its development process may stop during the 2 week time until the pregnancy can be detected. The embryo`s health and the receptivity of the uterus are essential for the implantation process.

How Do You Know if You Ovulate Late?

The ovulation process occurs 12 to 24 hours after luteinizing hormone surge, when the follicle breaks open through the ovary`s wall. If sperm will be there waiting, or if there`ll be a sexual contact now, you may get pregnant.

For almost 90% of women, the menstrual cycle may vary between 23 and 35 days, and the ovulation process occurs in the cycle`s middle. There are also other factors, like stress, which may lead to a late ovulation, until as late of the 3rd or 4th week. Still, the way health care providers will generally calculate due dates is by simply assuming that ovulation occurs on the 14th day of a 28-day cycle.  This is also the major reason for which due dates aren`t always that accurate.

Not all women have a 28-day menstrual cycle, nor ovulate on the 14th day. A healthy cycle should be around 26 – 32 days in length.

Image courtesy of AnswersinGenesis.org

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