The Laboratory – Fertilization
Conventional IVF Fertilization
involves a process wherein the eggs from the female are retrieved from her ovaries and are fertilized with sperm taken from the male outside the natural habitat which is the uterus/womb. The fertilized embryo is then allowed to grow in a lab for several days following the fertilization, usually 3-5 days, and then implanted back into the female’s uterus for the rest of the gestation period. The entire process usually takes from a few weeks to a few months depending on the type and nature of embryo transfer.
Several other procedures are routinely used with the IVF to ensure higher rates of success. These include medications and treatment protocols for improving the quality of eggs, sperms, and the embryo transfer.
ICSI – Intracytoplasmic Sperm Injection
An Intracytoplasmic Sperm Injection is an advanced reproductive procedure wherein a single sperm is directly injected into the egg to cause fertilization. This is accomplished in an embryology lab and is one of two fertilization methods that can be used during IVF. The sperm to be injected is selected using sperm morphology and its forward movement. Aspirated from the sperm drop into an ICSI needle and then injected into an egg.
The Laboratory – Embryo Development
Cleavage vs Blastocyst
Cleavage stage embryos are not growing in size, but the cells are getting divided within itself. This is usually on day 3 of the embryo transfer. By day 5 the embryos will move from the cleavage stage to the blastocyst stage with two types of cells – baby making ones, and the placenta forming ones. By day 5, the embryo is growing up quickly. From just division, the embryo is now actually growing.
Pre-Implantation Genetic Diagnosis involves testing an embryo before it implants for a specific, known genetic disorder. Pre-Implantation Genetic Diagnosis is used so that embryos unaffected by the disorder can be returned to the uterus. Pre-Implantation Genetic Diagnosis is prescribed for someone who has or is a carrier of a known genetic disorder. While a Pre-Implantation Genetic Screening may be recommended for someone with recurrent miscarriage, someone who is older or whose ovaries do not work as well as expected, or someone with multiple failed fertility treatments.
Without a Pre-Implantation Genetic Diagnosis, embryos would have been chosen based only on their visual quality and morphology, which cannot distinguish chromosomally normal embryos from abnormal embryos. Thus, this aims at improving pregnancy and live birth rates by screening your embryos for chromosomal abnormalities. Couples can identify embryos carrying a genetic disease or chromosomal abnormality, thus avoiding the difficult choice of abortion.
The Basics of Preimplantation Genetic Testing
PGT-A: Preimplantation Genetic Testing for Aneuploidy
This helps the doctors determine the number of chromosomes within IVF embryos.
PGT-M: Preimplantation Genetic Testing for Single-gene Defects
This is performed at the blastocyst stage to ascertain any genetic disorders with the embryo.
PGT-SR: Preimplantation Genetic Testing for Chromosomal Structural Rearrangements
This tests for determining the size or arrangement of chromosomes and is helpful to ascertain the risk of parents passing along faulty genetic mutations.