What are the Steps in PGD?
Step 1: Initial Assessment and Counselling
Once the couple shows their wish to have a balanced family or their infertility specialist assessed them to be at risk of giving birth to a child with inheritable genetic disorders, they are advised to go for a PGD procedure. Before starting the procedure patients are counseled about their hormonal profile and ovarian reserve and its effect and chances on Conception. Sufficient ovarian reserve allows better chances of conception with PGD procedure. Women with low ovarian reserve produce a limited number of eggs in response to the drugs given for stimulation of ovaries during the PGD cycle. Less number of eggs retrieval might result in the formation of fewer embryos that are suitable for pre-gestation gender selection or genetic diagnosis.
Step 2: Stimulation of the Ovaries
After a complete pre-requisite assessment, ovarian stimulation is started on Day 2 or Day 3 of the Menstrual Cycle. Injections for ovarian stimulation are administering daily at a specific time along with some oral medicines. The process of ovarian stimulation typically goes for 9-12 days, with the aim of maturing the maximum number of follicles ideally above 10 in the count. During the stimulation period monitoring of developing follicles (eggs) is done on alternate days with transvaginal scan and blood test (for Estradiol level checking).
Step 3: Trigger Shot
Once the level of Estradiol Hormone and Number of Follicles reached the desired level, one last shot of Trigger Injection is given at night, approximately 36 hours prior to the transvaginal ovum pickup (TVOPU).
Detailed instructions are provided to the patient regarding transvaginal ovum pickup day.
Step 4: Egg Retrieval / Collection
After 36 hours of the trigger shot, the TVOPU procedure is done for Egg Retrieval in presence of a fully trained team of Consultants, an Anesthetist, an Operation Theater Nurse, staff, and Embryologists. It’s a day case procedure in which a patient is given light anesthesia, and eggs from ovaries are aspirated through an ovum pick needle, guided by transvaginal ultrasound. The egg collection process is carried out in operation theatre. The transvaginal ovum pick-up procedure usually takes 30 minutes to complete. Trained Embryologist (s) are given with aspirated follicles and they will confirm the total number of eggs retrieved.
Any discomfort that you may experience after the TVOPU procedure is normal to mild and will be effectively controlled by the administration of pain-killer injections.
Step 5: Fertilization of Eggs
The next step is the fertilization of eggs in a specialized IVF Lab. Fertilization is achieved by using the advanced techniques of intra-cytoplasmic sperm injection (ICSI). During ICSI, embryologist injects a single sperm into each egg under a high-powered microscope by using a special IVF-grade glass needle. The process of ICSI improves the chances of fertilization, especially, if the semen sample has low sperm count or low motility of sperm cells.
Step 6: Embryo Biopsy & PGD Testing
The day after your egg collection, Embryologists will check how many eggs have been successfully fertilized. Please be advises some of your eggs might not fertilize and 100% fertilization rate is not achieved all the time. On the 2nd day of egg retrieval, embryologists check how many fertilized eggs have started to divide into 2 cell or 4 cells.
On the 3rd day of egg retrieval further cell divisions lead to the formation of 6 cell or 8 cell embryos. Biopsy on the embryos is performed at this stage for removal of 1 or 2 cells from each embryo for identification of gender and any genetic disorder.
The same biopsy sample can be used for the identification of chromosomal abnormalities through PGS.
Step 7: Embryo Transfer
After successful PGD Testing, the patient is informed about the status of Embryos Gender and Detection of any abnormality. With the consent of the couple, Embryos of the desired gender are then transferred to IVF Theater.
The patient is provided with complete instructions regarding medicine usage and precautions.
Step 8: Preserving Extra Embryos
In most cases, extra embryos are produced beyond the ones that will be transferred to the uterus. Couples are provided with the option of freezing extra embryos with the rapid freezing method, to be used in the future. It also eases the path for couples to try again if their first attempt is not successful.
Preservation of embryos prevents the process of ovarian stimulation as was done during PGD. Also, if extra embryos are not of the desired sex this time, still these frozen embryos can be used in near future to further expand your family, since fertility potential declines with every passing day.
Step 9: Pregnancy Test
After fifteen days of successful embryo transfer, a pregnancy test of the patient is carried out. If the test comes out positive, it means implantation has occurred successfully.
The next step is the identification of the fetal heart through TVs.
