In vitro fertilization is the procedure in which sperm and eggs are allowed to fertilize outside the body in the laboratory. After fertilization, one or more fertilized eggs are introduced into the uterus of a woman, where they may implant in the wall of the uterus and develop. The excess fertilized eggs can be preserved for future use through cryopreservation. This technique was first used to treat women with blocked, damaged, or absent fallopian tubes. Nowadays this technique is used to treat many cases of infertility. The basic steps involved in IVF treatment include ovarian stimulation, egg retrieval, fertilization, embryo culture, and embryo transfer.
After 34 to 37 hrs of hCG (human chorionic gonadotropin) injection, an egg from the ovary is retrieved by minor surgery under anesthesia, using an ultrasound guide. Eggs are prepared by stripping from the surrounding cells. At the same time, sperm preparation is also carried out in special media. For each egg, 10000 – 1,00,000 sperms are needed and the eggs and sperms are brought together for fertilization. The fertilized egg or the zygote is then allowed to divide and form 8 celled blastomere, which is transferred into the uterus for further growth.
The embryo transfer technique is the transfer of an embryo with more than 8 celled blastomere stage into the uterus.
