Assisted Reproductive Technology (ART)refers to using methods used to achieve pregnancy by artificial or partially artificial means, without sexual intercourse. These proceduresinclude all fertility treatments in which both eggs and sperm are handled, and also reproductive treatments involving a 3rd party, eg. a sperm donor. Such procedures do not include treatments in which only sperm are handled or procedures whereby a woman takes hormonal medicinal stimulate egg production.
The first step includes taking medical tests to diagnose infertility, and determine the best treatment to help a woman become pregnant. SomeAssisted Reproductive Technologytreatments are more time-consuming, invasive and expensive than others. For example, oneAssisted Reproductive Technologytreatment, resorted to when other means have not been successful, is Vitro Fertilization (IVF). It involves surgically removing eggs (ova) from a woman’s ovaries, fertilizing them with sperm in the laboratory, and returning them to the woman’s body or donating them to another woman.
There are no long-term health effets which have been linked to children born usingAssisted Reproductive Technologyprocedures. Most doctors, however, recommend such procedures as a last resort for having a baby. The success of any fertility procedures depends, in part on the female’s age.
Preimplantation Genetic Diagnosis,also known as embryo screening, is used in ART procedures, to screen for a variety of genetic and chromosomal abnormalities. Such a diagnosis is performed prior to embryo implantation, and sometimes prior to oocytes fertilization. For example, in IVF, it may be used to screen the oocytes or embryos before the ART procedures take place.
Preimplantation Genetic Diagnosismakes it highly likely that the baby will be free of the disease, and this means that selective pregnancy termination can be avoided. An oocyte or early-stage embryo has no symptoms of disease, however, may have a genetic condition that could lead to disease. They do need to be screened for genetic or other conditions. Procedures performed on sperm cells before fertilization may instead be referred to as sperm sorting, although the methods and purpose partly overlap with PGD.
The risk of having a pregnancy with a chromosomal irregularity is low (less than 2%). However, not all embryos produced have the required chromosomal composition to result in a successful pregnancy and birth. Most embryos will not develop or implant. By the time a woman is 40 years old, approx. 70% of a her embryos will lack the number of chromosomes required to result in a successful pregnancy. The risk of giving birth to a child with chromosomal abnormality is still relatively low, because many of the embryos will stop developing at an early stage or miscarry.
There are two basic types ofPreimplantation Genetic Diagnosistests. The first screens for individuals with a known risk of genetic disease, such as cystic fibrosis or muscular dystrophy. The second type of PGD test checks for common chromosomal irregularities related to advanced maternal age, repeated pregnancy loss and multiple IVF procedures.
Preimplantation Genetic Diagnosisis offered on a limited basis in some clinics. Also it requires advanced discussion and preparation with a fertility specialist. As this procedure is relatively new, so long-term studies on its success rate are not yet available.
