IVF may be used to treat infertility due to oligospermia, tubal dysfunction, sperm antibodies, or endometriosis, and unexplained infertility.
FREMONT, CA: Assisted Reproductive Techniques (ARTs) include manipulating sperm and ova or embryos in vitro for the purpose of conception. ARTs can result in multifetal pregnancy, but the risk is much lower than that of managed ovarian stimulation. If there is a high risk of genetic abnormalities, the embryo will also be screened for defects before transition and implantation (preimplantation genetic testing).
In Vitro Fertilization (IVF)
IVF may be used to treat infertility due to oligospermia, tubal dysfunction, sperm antibodies, or endometriosis, and unexplained infertility. The procedure usually involves the following:
Controlled Ovarian Stimulation: Clomiphene along with gonadotropins or gonadotropins may be used on their own. A Gonadotropin-Releasing Hormone (GnRH) agonist or antagonist is often used to prevent premature ovulation. Human Chorionic Gonadotropin (hCG) is administered after adequate follicular growth to trigger final follicular maturation and ovulation. Conversely, a GnRH agonist may be used to trigger ovulation in women at increased risk of ovarian hyperstimulation syndrome.
Retrieval of Oocytes: About 34 hours after administration of hCG, oocytes are extracted by direct needle pinching of the follicle, typically transvaginally with ultrasound guidance or less generally laparoscopic. In certain centers, natural cycle IVF (in which a single oocyte is retrieved) is provided as an alternative; pregnancy rates with this procedure are lower than those with multiple oocyte recovery, but prices are lower, and success rates are increasing.
Fertilizations: Oocytes are inseminated in vitro. The semen sample is usually washed a few times with a tissue culture medium and is concentrated for motile sperm, which is then added to the oocyte-containing medium. At this point, intracytoplasmic sperm injection—a single sperm injection into each oocyte—may be performed at this stage, particularly if spermatogenesis is irregular in the male partner.
Embryo Culture: After sperm has been added, oocytes are cultivated for around 2 to 5 days.
Embryo Transfer: Only one or a handful of the resulting embryos are moved to the uterine cavity, minimizing the possibility of multifetal birth, with the highest IVF probability. The number of embryos transmitted is determined by the woman's age and the probability of reaction to IVF. Some or all embryos (mainly if women are at high risk of ovarian hyperstimulation syndrome) can be frozen in liquid nitrogen for transferal in a following cycle. There is a growing trend to put only one embryo at each transfer and freeze the remaining embryos for use in future cycles if there is no pregnancy.