4. HOW MANY EGG CELLS ARE LOST EACH MONTH?
Every month, 20-30 egg cells are selected to begin to develop at the beginning of the cycle. It is well-established that AMH is actually one of the factors that causes 20-30 egg cells to be selected each month from the hundreds of thousands of egg cells that the ovary contains.
These egg cells were actually immature and are found in the primordial follicles. Immature egg cells are unable to fertilize, that is why they are called primordial. The primordial follicle is a self-contained unit found in the ovary.
After the egg is recruited or selected in the one or two follicles this month, it will move to the surface of the ovary.
FSH and LH are two hormones in the ovary that stimulate the primordial follicle and cause it to begin to mature.
This process takes 14 days until ovulation.
After ovulation, FSH and LH will actually cause the primordial follicle to be completely mature, and also assist the follicle to open up and release the matured egg contained in it. This mature egg can now be fertilized by sperm.
During the menstrual cycle, the FSH and LH will be released from the pituitary glands that will stimulate some of these 20-30 egg cells to begin to grow. The follicles that are more capable of responding to FSH and LH are the ones that will continue to grow.
In a natural cycle where no fertility medications are given, there is a limited amount of FSH and LH. So, only the best follicles will respond to these hormones. Of these follicles, there is usually one or two follicles that will continue to develop and mature and be released as matured eggs at the time of ovulation.
The largest follicle is called a dominant follicle, and that is the one that is most likely to ovulate.
When fertility medications are given, there will be much larger amounts of FSH and LH so that many more follicles will be able to respond, grow and develop until they are mature.
The other follicles will undergo a process called “ATRESIA” and they will be absorbed and disappear in the ovary.
Fertility medication contain FSH and LH. Gonal-F is FSH only while Menopur is FSH and LH.
In summary, fertility medications is the same FSH and LH found naturally in a woman’s body and in a natural menstrual cycle. These medications allow more follicles to develop and be available at the time of ovulation.
When these medications are given for IUI and IVF, most of the follicles that develop will increase in size at the same rate day-by-day.
In some cases, when we measure the number of follicles at the beginning of the cycle, we only see several. But after stimulation several days later, more follicles appear.
Several Conditions Patients should know about Fertility Medications
- Better follicles are more likely to respond to FSH and LH
- Better follicles will tend to grow at the same rate as other good follicles and be around the same size day after day during stimulation.
- Healthy follicles will usually grow 2 millimeters a day.
- Using fertility medication does not cause a patient to lose eggs. These medications only act on the follicles that have be selected to grow that month. All those follicles will be gone at the end of the month where we will stimulate them and use them to get pregnant or not.
Example:
A follicle measures 10 millimeters on day 5 of the stimulation. One can predict that on day 6, the healthy follicle will measure 12 millimeters, day 7 is 14 millimeters, day 8 is 16 millimeters, day 9 is 18 millimeters and day 10 is 20 millimeters – at which the hCG trigger can be given