Preimplantation Genetic Diagnosis (PGD) plus MicroSort® is a powerful combination when used for Family Balancing.
The use of PGD and MicroSort® may be combined to create a more efficient method for family balancing than using either approach alone.
Sperm that has been sorted through MicroSort® may by used to fertilize eggs retrieved from a woman in an IVF cycle. Since MicroSort® is performed first; most of the sorted sperm used for fertilization of the eggs retrieved through IVF will carry either an X chromosome (female) or a Y chromosome (male), depending on the couple’s choice. In this way, more embryos (fertilized eggs) of the desired gender are likely to be produced. A genetic test (PGD) is then performed on these early embryos to determine which are male or female with an accuracy of up to 99%. Embryos of the desired gender are transferred to the woman’s uterus.
Many couples opt through PGD to additionally screen their embryos for certain chromosomal abnormalities (i.e. Down syndrome) or familial genetic diseases. Data from GIVF and elsewhere suggest that on average approximately 60% of all embryos are chromosomally abnormal. This risk can be higher or lower depending on certain factors such as maternal age. PGD screened embryos have a lower spontaneous loss rate and a reduced risk of chromosome abnormality.
Consider the following two examples of couples interested in family balancing:
Couple A elects IVF and PGD for family balancing (female) but declines MicroSort®. In this example, ten embryos are generated in the course of their IVF cycle. On average, 5 male and 5 female embryos would be expected since there is typically a 50% chance to have either a boy or girl in any pregnancy. However, it may be determined through PGD that some of their embryos are chromosomally abnormal and the couple could on average have only 2-3 normal female embryos available for transfer.
Couple B elects IVF and PGD for family balancing (female) with MicroSort®. Ten embryos are also generated in the course of their IVF cycle. Significantly, since MicroSort® sperm was used for fertilization, the couple desiring a female could expect on average 8 or 9 of the embryos to be female, since sorts for females generally result in 85-90% X-bearing sperm. As with Couple A, PGD may determine some of the embryos are chromosomally abnormal. However, since Couple B started with a greater total number of female embryos, they could anticipate having approximately twice the number of normal female embryos available for transfer. Thus, MicroSort® used in concert with IVF and PGD provides a greater chance for having normal embryos of the desired gender available for transfer and cryopreservation.
What Other New IVF Technique Might Interest You?
- In vitro maturation (IVM)
- Personal Egg Banking (Elective Oocyte Cryopreservation)
- Intra-cytoplasmic sperm injection (ICSI)
- Microfertilization - IMSI
- Avoiding sickle-cell anemia
- Zona pellucida measurement
- Assisted hatching
- Assessment of Embryo Reproductive Potential (ERP)
Dr Paraschos participated in the world's first PGD.