In vitro fertilization involves different steps. The first steps are the collection of oocytes and sperms.
Collection of Oocytes:
Oocytes for in vitro fertilization are mainly collected from females during their natural or induced ovulation cycle.
The time of natural ovulation is determined by monitoring the rise in the level of luteinizing hormone (LH) either in urine or in blood and the ova are recovered.
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Ovulation may be stimulated by the administration of clomiphene. This approach yields several oocytes from a female, which increases the chances of success of in vitro fertilization.
Follicle development can be arrested at the optimum stage by administration of LCG so that the ova are not released. The oocytes can be collected by laparoscopy at a convenient time.
It is critical to determine the time of ovulation precisely particularly when laparoscopy is to be done for oocyte can be recovered, while if it is done 6 hours or more prior to ovulation, fertilization may not occur unless oocyte are incubated under specified conditions to allow them to mature.
The time of ovulation is estimated on the basis of temperature chart of the donor female, change the cervical mucus score (which is related to follicle development) oestrogen level in blood or urine, level of luteinizing hormone (LHG) in blood or urine and determination of the follicle size using ultra sound imaging. Plasma progesterone levels are also monitored since they begin to increase 24 hours prior to LH surge in stimulated ovulation cycle.
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Recovery of oocyte is the most convenient and efficient by laparoscopic equipment, which permits the visualization of ovary through a monitor, aspiration (suction) of the follicular fluid containing the oocyte and the necessary surgical manipulation of ovary sensors, laparoscopic scissors and/or aspiring apparatus inserted into the abdomen of female via a suitable tube. This procedure involves minimum surgical interventions, causes very little damage to the ovary and is quite convenient.
Collection of Sperms:
The semen is connected about 60-90 minutes prior to fertilization, liquefied and centrtifused. The sperm pallet so formed is re-suspended in culture medium and incubated for 30-60 minutes at 37 degree celsius.
A sample of spermatozoa is taken from the surface of the medium for fertilization since the most active sperms are located there. The semen is collected from the prospective male. If this is not possible either due to low sperm counts of the semen or due to lack of motive sperms semen may be collected from a suitable male.