Process of Fertility

Good morning everybody. I am Dr Vandana Hegde. I am practising reproductive medicine, the department of Hegde fertility centre for the last 10 years. Today I would be speaking about the various aspects of fertility. So I will start from the basics to know what happens exactly and what are the problems that arise.

So here is a normal menstrual cycle of the female. There are certain things you need to know. What happens is during the onset of the periods, when the menstrual cycle starts, the eggs start maturing. Now, this egg grows in a wall filled substance which is called Follicle. So normally when the egg starts maturing, it reaches the complete maturity level on the 14th day of the cycle, an average of 12-16 days. As the egg starts maturing, the follicle size increases. Now when the maximum diameter of an egg is reached, the follicle burst and egg comes out. This process is called Ovulation.

If this ovulation happens on the correct 14th day of our cycle, over the next 14th day if there is no pregnancy then a girl will resume her menses which is a failure to conceive. If it happens regularly then the girl will have a regular menstruation cycle of 28-30 days. And if a girl is having the irregular menstrual cycle, then the ovulation is not happening correctly on time. So this is known as Ovulatory disorders. Now, what happens after the ovulation round.

Once the egg is released, it is caught by fallopian tubes. Fallopian tube has finger like projection and the eggs are normally kept on the last part of the tubes. Now when the couples meet, the sperm is released in the vagina. The sperms have basically the head, body and the tale. As I had mentioned earlier, once the ovulation happens, the eggs do not have any tale, so it needs a tube to collect it an d store it in the tube. The sperms will move into the uterine cavity and move into the fallopian tube and have to reach the other part of the tube. So at this point, the sperms will be reaching the egg.

There are certain criteria for normal semen. So when do we know that it is a fertile semen for which there are some criteria like the volume should be atleast more than 1.5 ml ejaculate.And the sperm count should be more than 15 million per ml of sperm. Because of the tale fraction of the mortality, there should be active mortality of the sperm for more than 30%. So when the sperm enters the egg, the process is called Fertilization. And the egg and the sperm will fuse to form an Embryo. The early embryo is called Zygote which is a single cell. So when this forms, the embryo has to divide. In that tube the embryo undergoes division. So in that cell, the embryo will divide into 2 cells, 4 cells, 8 cells. As the embryo is progressively dividing, the tube is going to push the embryo back slowly into the uterine cavity. During this process of egg maturation, the follicle growth, the ovulation, there is another process happening in the uterus.

So here is the uterus and this is the Uterine bed. So, as the follicles are increasing in size, so it produces a hormone called estrogen which is actually acting on the uterine bed. And the uterine bed is ready, there is an increase in thickness for an embryo to come here. And once the ovulation happens, there is a pregnancy favouring hormone called Progesterone which is increasing in the second half of the menstrual cycle. When this comes, there is a lot of blood flow coming to the uterine bed. So this is the time when the embryo is actually reaching the uterine bed. This process, when the embryo reaches the uterine bed and when the embryo sticks to the uterine bed, this process is called Implantation. Basically what is happening here is the blood collection between the uterus and the embryo. That is how the nutrients from the mother's body are transferred to the embryo which grows further and establishes a pregnancy.

So when the couples conceive, these are the things which have to happen in a natural way for them to conceive. Now what happens when they do not conceive when they try for more than a year after the marriage and still unable to conceive, so we evaluate the problems. Evaluation of problem depends on the steps which I have told.