PGT and IVF: the procedure
The PGT procedure starts upon completion of the preparatory tests. This information leaflet explains the several steps.
The initial interview
An interview will take place before the start of the first PGT procedure.
The IVF physician, gynaecologist or a specialist nurse:
- discusses the course of the procedure with you
- determines which medications you should use and when to use them
- provides instructions on how you can selfadminister the necessary hormone injections and makes appointments with you for check-ups.
The IVF treatment
In IVF, fertilisation occurs in the laboratory by combining egg cells and sperm cells. The IVF treatment consists of the following steps:
- A few weeks before the start of the IVF treatment, the woman starts taking the contraceptive pill.
- The treatment begins by selfadministering the first hormone injections, which are necessary to stop your own hormone production.
- After 12 to 14 days, you will selfadminister FSH injections. These injections help the egg cells to mature.
- During the treatment several ultrasound scans will be made to monitor the maturity of the follicles.
- If there are sufficient follicles (usually after 10 to 14 days), the follicular puncture follows: under sedation, the fluid containing the egg cells is extracted from the follicles. Gynaecologists refer to this as ‘harvesting egg cells’. A follicular puncture takes 15 to 30 minutes.
- After the follicular puncture, the egg cells are fertilised in the IVF laboratory by combining them with the man’s sperm cells. After the egg cells have been fertilised in the IVF laboratory, they begin to multiply. When the egg cells have multiplied, they are called embryos. After three to five days, the embryo consists of an average of 8 to 60 cells.
In order to perform the subsequent PGT analysis a biopsy must be performed to extract one or more cells from the embryo. A tiny opening is created in the shell surrounding the embryo with a laser beam. One or more cells are then extracted from the embryo through a thin needle.
The cell or cells removed are examined in the laboratory to determine whether an embryo may have the disorder. There are two types of biopsy procedures: the blastomere biopsy and the TE biopsy.
A blastomere biopsy is performed on the third day after fertilisation. One cell is removed (two, in some cases). When the PGT analysis has been performed, an embryo without the genetic predisposition to the disease that you wish to prevent will be transferred back into the womb.
A trophectoderm or TE biopsy takes place on the fifth or sixth day after fertilisation. Several cells are removed. When the PGT test has been performed, one of the embryos which has been identified as unaffected by the disorder, will be transferred back into the womb.
The preimplantation genetic test
In PGT, the cells obtained from the biopsy are tested for the genetic disorder forming the underlying reason for the procedure. This test of the cells always takes place in Maastricht and takes 24 hours to four weeks, depending on the indication. Based on the analysis, a decision is made regarding which embryos are eligible
for transfer back into the womb.
Depending on the duration of the PGT analysis, in some cases a fresh transfer is performed in a blastomere biopsy: the best-quality embryo without the disorder is then transferred back into the womb without being frozen beforehand.
The other embryos without the disorder are frozen should the first procedure be unsuccessful, or if the couple have expressed the wish for a second child.
If the PGT takes longer, all embryos are frozen after the biopsy.
In a TE biopsy all embryos are frozen after the biopsy. Following the genetic test, one of the embryos without the disorder will be thawed and then transferred back into the womb. The other embryos without the disorder will in this case also be stored.