Although the possibility of recovering the embryos by uterine flushing exists, is recommended to get them by IVF procedures. In addition, to minimize the risk of contamination with parental cells, it is advisable to perform an ICSI procedure, where the operator injects a single sperm into each egg devoid of granulosa cells and washed.
Women should receive hormonal medication to develop several mature follicles, which will be subsequently aspirated to retrieve the eggs.

The male must obtain a semen sample on the day of oocytes retrieval, otherwise the sample should be frozen previously.

The eggs and sperm are processed prior to the ICSI procedure. The fertilized eggs are then maintained in culture for five days.

When the embryos are obtained, a single cell is removed from each embryo under microscopic guidance and analyzed for the presence of genetic disorders. The diagnosis must be complete in one or two days, and only the unaffected embryos that reach the blastocyst stage are replaced in the female's uterus.

To remove one or two cells from the pre-embryo, first one must perforate the zona pellucida (ZP) to be able to insert the suction pipette and aspirate the blastomere.

The ZP opening can be made by different methods:

1) Mechanic: trying to cut a segment of zona pellucida with a micropipette
2) Chemical:  drilling with Tyrode acid solution and,
 

 

3) Laser Microsurgery: using modulated laser through the optical system of the microscope.
We prefer the later method because in a single step it allows the aspiration of the blastomere and is therefore safer for the embryo survival.

Previous to the biopsy, the pre-embryos are placed for 10 minutes on culture media without Ca and Mg to detach the cells. Then, they are transferred to microdrops under oil. With an inverted micromanipultive microscope with a 400X-Laser objective, the pre-embryo to be biopsed is positioned at the center of the field and fixed using a holding pipette.
One should choose a blastomere with one visible nucleus. The selected blastomere is positioned at 3 o'clock fixing the pre-embryo with a holding pipette at 9 o'clock. According to the size of the chosen cell to be removed, the adjacent ZP is perforate with one or two 15 milliseconds laser shot (infrared diode laser of 1,48 um).

Finally, with the suction pipette the cell is aspirated. The blastomeres removed are genetically tested using one of the following  methods: Fluorescence In Situ Hibridization (FISH), Comparative genomic hybridization array( aCGH ) and fluorescent  PCR (QF-PCR) for chromosomal abnormalities; and fluorescent PCR, minisequencing or linkage analysis for mendelian diseases.
You can see the demo-video to appreciate the easy handling when performing the blastomere biopsy using the laser equipment to drill the ZP.
Only pre-embryos that have reached 8-cell development on day 3 or the blastocyst stage on day 5 are biopsied. On day 3, only one cell is removed, while on day 5 several cells of the trophoectoderm can be obtained.