Table of contents
How do eggs mature in the natural cycle?
In the natural cycle, when the leading follicle reaches a diameter of 18-22 mm on day 14-15 of the menstrual cycle, there is a surge of LH (luteinizing hormone) for the final maturation of the egg and ovulation. The process of maturation of the ovum is very important in genetics, because in the ovum there is a distribution of genetic material and preparation for fertilization by a sperm. Thus, 23 of the 46 chromosomes remain in the egg cell to unite with the 23 chromosomes of the sperm and transfer the genetic material correctly to the future child.
Why use the final egg maturation and ovulation trigger in the IVF program?
In reproductive medicine, hCG (human chorionic gonadotropin), which is very similar to LH and performs the function of egg maturation and ovulation, is used to stimulate the growth of follicles for the purpose of final egg maturation. Follicle puncture to obtain oocytes takes place 36 hours after the subcutaneous injection of the final egg maturation trigger. After receiving the eggs, the embryologist assesses their quality and maturity, after which their fertilization with sperm occurs. An embryologist can only fertilize mature eggs after confirming the distribution of chromosomes in the polar body.
MII
МІ
Ооцит GV
Subsequently, with the development of new protocols for stimulating the growth of follicles and the possibility of vitrification (freezing) of eggs and embryos, GtRH (a-GnRH) agonist drugs began to be used as a trigger for the final maturation of eggs. This group has a number of advantages, as it completely avoids the risk of developing hyperstimulation syndrome. This group of drugs has the advantage that it directly stimulates the rise of own LH in the pituitary gland and, accordingly, the physiological maturation of oocytes.
Normally, the percentage of expected mature eggs after the puncture of follicles with a diameter of 18-22 mm should be more than 75-90% after the introduction of the ovulation trigger in the IVF program. There are situations when, after the puncture of the follicles, embryologists ascertain the empty follicle syndrome (absence of an egg after the puncture of the follicle) or signs of immature eggs (removal of the egg without full maturation at the stage of GV, MI).
In this case, it is necessary to analyze the follicular growth stimulation protocol to determine the cause.
What is the Double Trigger or Double Oocyte Maturation Induction Protocol?
Many clinical data and our experience prove the effectiveness of using a “double trigger” of final oocyte maturation (hCG + GnRH agonist) in this case. In this case, hCG will act directly on the ovary and follicles, when aHnRH will promote the rise of LH in the pituitary gland and the final maturation of eggs in a double way. This will make it possible to increase the number of obtained mature eggs and, accordingly, embryos of good quality. This method is of great importance in improving the effectiveness of IVF programs.