Egg cell collection
Egg cell collection is carried out under ultrasound guidance. Ovarian follicles are punctured with a long needle, the liquid is collected to syringes and immediately forwarded to the IVF laboratory. The embryologist isolates cumuli, i.e. the complex of the egg cell and granulosa cells, from the remaining part of the liquid. These cumuli are then transferred to appropriate media and then to incubators.
Egg cell quality
In order to get fertilized, the egg must be in the proper stage of maturity. Following the purification of the egg cells from granulosa cells which are tasked with nourishing the oocytes, the embryologist can assess the maturity stage. Only egg cells in the MII stage, i.e. cells stopped in the prophase of the second meiotic division are in the proper maturity stage. However, typically in addition to MII cells, which usually account for 85% of all obtained cells, also the cells which do not qualify to the in vitro fertilization procedure are obtained. These are GV stage oocytes which account for 10% of all cells, MI (5%) and cells which underwent degeneration.
Oocyte in the stage of prophase I of meiotic division
– GV (germinal vesicle).
Oocyte in the stage of metaphase I of meiotic division – MI.
Absence of the first polar body.
DMature oocyte – MII.
A secondary oocyte forms just before ovulation and stops in the stage of second meiotic division.
The presence of the first polar body characterizes the mature egg cell.
Currently the most important parameters which play important role in the evaluation of the efficacy of the ART (Assisted Reproductive Technology) techniques in case of women are::
- age,
- ovarian reserve
- and age quality
It is known that chances for having a child decrease with age. The decrease in fertility is observed after 30 years of age, and after the age of 35 the chances for obtaining pregnancy drop by even 30%.
Currently the best fertility parameter is the determination of the anti-Müllerian hormone (AMH) level, which determines the pool and quality of egg cells. Determining the hormone’s level will allow to detect young female patients with decreased ovarian reserve, middle-age patients with good ovarian reserve and to exclude women without any chance for obtaining pregnancy. The advantage of AMH level determination is its consistency, irrespective of the cycle day. Current statistics show that women with the AMH level above 2.4 ng/mL have the best chances, while patients with AMH level below 0.2 ng/mL have the lowest chances.
The last parameter is egg quality. Egg quality is affected by various concomitant conditions. The example of such condition is endometriosis. It is a disease in which endometrium is in the other part of uterine cavity. Even the mild stage of this disease can have toxic effect on egg cells and decrease the endometrium’s ability for embryo implantation.