ART and IVF Technology PDF

## UNIT -IV: Applications of Biotechnology ### 4.1. Intrauterine Insemination In vitro fertilization and embryo transfer. Assisted Reproductive Technology (ART) refers to medical procedures or techniques used to help individuals or couples achieve pregnancy when they encounter difficulty conceiving...

## UNIT -IV: Applications of Biotechnology ### 4.1. Intrauterine Insemination In vitro fertilization and embryo transfer. Assisted Reproductive Technology (ART) refers to medical procedures or techniques used to help individuals or couples achieve pregnancy when they encounter difficulty conceiving naturally. These technologies are designed to overcome various infertility issues and may involve the manipulation of eggs, sperm, or embryos. ART has provided hope and solutions for many couples struggling with infertility. ### Causes of infertility: 1. **male infertility** - Oligospermia - low sperm count - Azoospermia - lack or low motile sperm 2. **female infertility** - Tubal infertility - Non functional ovaries - Non functional uterus - Idiopathic infertility ### Intrauterine Insemination The infertile women (due to endometriosis, idiopathic infertility) without blockage or damage to fallopian tubes can be effectively treated by intrauterine insemination. The women with adequate ovulation and below the age of 40 years are considered for IUI. - The women are usually super-ovulated by administering gonadotrophins. This results in multiple egg development. - The IUI is timed to coincide with ovulation - The semen is washed and the highly motile sperms are separated. - By using a thin and soft catheter, the sperms are placed either in the cervix or in uterine cavity. - The women subjects are advised to remain lying down for about 15-30 minutes following IUI. Insemination should be carefully timed for good success. If it is done, a little before the expected time of ovulation, the chances for fertilization are much higher. IUI is usually successful in the first 3-4 attempts. In any case, this approach is not recommended for more than a maximum of 6 ovulation cycles. The success rates of IUI vary considerably and are in the range of 15-30%. ## In Vitro Fertilization and Embryo Transfer (IVF and ET): In vitro fertilization broadly deals with the removal of eggs from a women, fertilizing them in the laboratory, and then transferring the fertilized eggs (zygotes) into the uterus a few days later. ### Indications for IVF: Infertility due to the following causes may be considered for IVF. - Failed ovulation induction - Tubal diseases - Cervical hostility - Endometriosis - Idiopathic infertility (in men and women). ### Ideal Subjects for IVF: Although it is not always possible to have a choice in the selection of subjects, the following criteria are preferred: - Woman below 35 years. - Presence of at least one functional ovary. - Husband with normal motile sperm count (i.e. normal seminogram). - The couple must be negative for HIV and hepatitis. ### Methodology of IVF: The in vitro fertilization broadly involves the following steps: - Induction of superovulation. - Monitoring of ovarian response. - Oocyte retrieval. - Fertilization in vitro. - Embryo transfer. ### Induction of Superovulation: It is well known that the success rate IVF is much higher when more embryos (3-5) are transferred. This is possible only with controlled ovarian hyper-stimulation (COH). The other advantages of COH include improvement in the quality of oocyte, control of ovulation timing, besides overcoming the ovulatory dysfunction. The following drug regimens are in use to induce superovulation. It is now common to use GnRH agonists to induce ovulation. These compounds act through a process called down regulation of the physiologic hypothalamic- pituitary-ovarian feedback mechanism to effectively suppress spontaneous ovulation. ### Monitoring of Ovarian Response: The follicular growth or ovarian response can be monitored by increase in serum estradiol level, increase in follicular diameter and thickening of endometrial bed. ### Oocyte Retrieval: The most common method for oocyte retrieval is carried out through vaginal route under ultrasound guidance. This method is simple and less invasive, and can be performed with analgesics only. It is easy to recognize the oocyte as a single cell surrounded by a mass of cumulus cells. The recovered oocytes are maintained in vitro culture for 4-6 hours. ### Fertilization in Vitro: The semen specimens are collected (just prior to oocyte retrival) via masturbation, processed, and incubated in protein-supplemented media for 3-4 hours prior to fertilization. The incubation results in sperm capacitation. The retrieved oocytes are also cultured in protein-supplemented media for about 6-8 hours. For the purpose of IVF, 50,000-1, 00,000 capacitated sperms are placed in culture with a single oocyte. The signs of fertilization may be demonstrated 16-20 hours later by the presence of two pronuclei within the developing embryo. There is no need to change the regime for a single failure of IVF. Many a times, success occurs in the subsequent cycles. The two most important criteria for the success of IVF are sperm density and motility. ### Embryo Transfer: Embryo at a stage between pronuclei and blastocyst stage are transferred. Conventionally, 4- 8 cell stage embryos are transferred between 48-60 hours following insemination. The transfer procedure is carried out by use of a catheter. Not more than three embryos are transferred (per cycle) to minimize multiple pregnancies. However, in the women above the age of 40 years, higher number of embryo may be transferred. (Note: Excess oocytes and embryos are cryopreserved for further use. This will reduce the cost, besides the risk of ovarian hyper stimulation). Luteal phase support is given by administration of progesterone for about two weeks. By this time, the diagnosis of pregnancy can be assessed by estimating human chorionic gonadotrophin (hCG). ### Success Rates of IVF: Success of IVF varies from programme to programme and within the same programme, the success rate is dependent on the correct diagnosis of the patient, and age. The overall pregnancy rate in IVF is in the range of 25-35% per oocyte retrieval. The take home baby rate is about 15-20% per procedure.