The advent of the laser has allowed the development of precision techniques to manipulate embryos for enhanced fertility. Laser-assisted hatching (LAH) can potentially enhance implantation/pregnancy rates or turn around a history of failure for embryos to implant themselves in the uterine wall.
Arizona Center for Fertility Studies strongly believes that laser technology is state of the art technology for any embryos that undergo Assisted Hatching (AH), embryo biopsy for Chromosome Abnormality / Single Gene Mutations or Gender or Sex Selection and prior to transferring Cryopreserved or Frozen Embryos FET).
Arizona Center for Fertility Studies embryologist, Andrew Barker, is one of a number of reproductive embryologists in the country that is highly skilled in using the laser on human embryos.
Laser-assisted hatching (LAH) is used to help the embryo hatch from its protective outer shell, the zona pellucida, and promote implantation in the uterine wall after embryo transfer. Laser-assisted hatching uses a highly focused infrared laser beam to remove a very small section of the zona pellucida, or outer wall of an embryo, in very precise increments. Prior to the clinical availability of the laser-assisted hatching, only mechanical or chemical methods could be used for assisted hatching of human embryos in clinical settings. Laser-assisted hatching requires less handling of the embryo than these other assisted hatching methods. Also, laser-assisted hatching is faster than the other methods and, therefore, the embryo spends less time outside the incubator.
Picture of a day 3 eight-cell embryo about to undergo laser-assisted hatching (arrow, round marker, indicates where the laser beam will penetrate the zona pellucida)
Laser-assisted hatching (LAH) is not currently recommended for routine use in all in-vitro fertilization patients, and several factors should be considered in determining candidates for laser-assisted hatching. These include age, hormonal status, embryo quality, number of in-vitro fertilization attempts, and whether frozen embryos are being implanted.
Laser-Assisted Biopsy (LAB) is used at Arizona Center for Fertility Studies to facilitate removal of a cell or blastomere from an embryo undergoing pre-implantation genetic diagnosis (PGD/PGS) for chromosome testing, single gene mutation testing or gender/sex selection. There are two current methods used for embryo biopsy:
Blastomere biopsy, the most common method of embryo biopsy, involves the removal of one blastomere when the embryo reaches the eight-cell stage, typically at the third day of development.
Video of Arizona Center for Fertility Studies embryologist doing assisted hatching using the laser to remove a single cell or blastomere for chromosome testing and sex selection.
Recently, trophectoderm biopsy is gaining popularity as an alternative method of embryo biopsy. Since trophectoderm cells are extra-embryonic tissue, they do not become part of the fetus but do become part of supporting structures, such as the placenta and membranes. Trophectoderm biopsy takes place at the blastocyst (day 5 or 6) stage of development, as the trophectoderm is beginning to herniate through the zona pellucida. Instead of removing an individual blastomere or cell, several trophectoderm cells are removed.
Video of Arizona Center for Fertility Studies embryologist doing a trophectoderm biopsy using the laser for chromosome testing and sex selection
As a result of our experience over the last several years doing 23-chromosome microarray; and now what seems to be conclusive evidence that embryos can "self-correct", Arizona Center for Fertility Studies strongly recommends only doing biopsies on day 5-6 embryos (blastocysts) using laser-directed TE (trophectoderm) biopsy. This means that after the blastocyst is biopsied, it will undergo cryopreservation and be transferred in a subsequent frozen embryo transfer (FET) the following cycle. Although this means that the couple will need to wait a cycle to do the transfer, there are a number of advantages of doing a TE biopsy as opposed to a day 3 biopsy.
In Arizona Center for Fertility Studies experience, all these advantages collectedly add up to higher success rates when using PGD/PGS, and is the reason Arizona Center for Fertility Studies now strongly recommends only doing TE biopsy, cryopreservation and subsequent next cycle FET on all patients undergoing PGD/PGS. The one exception is in our out of state patients, unless they can make a return trip. Our success rates are still very good with day 3 biopsy but Arizona Center for Fertility Studies would prefer day 5 TE biopsy.
Laser-Assisted Embryo Biopsy (LABis not currently recommended for routine use in all in-vitro fertilization patients, and several factors should be considered in determining candidates for LAB. Arizona Center for Fertility Studies strongly believes that Laser-Assisted Embryo Biopsy (LAB should be done on all embryos for the following indications:
Arizona Center for Fertility Studies believes that laser is safe for human embryos do to the patented Isotherm Rings™ on our laser that prevent potential harmful effects on blastomeres (the cells of the embryo) adjacent to the zona pellucida (wall of the embryo) due to heat from the laser drilling.
The Isotherm Rings™ appear on our embryologist's computer screen as a series of six concentric circles of varying colors (below) and indicate the maximum temperature reached at the ring diameter at various laser pulse durations (2nd picture below). At longer pulse duration, it is apparent that temperatures radiate farther into the center of the embryo, increasing the likelihood of blastomere damage. Arizona Center for Fertility Studies embryologist uses the orange ring (second from center) as an indicator of the drill hole size at the selected pulse duration.
With this interactive Isotherm Rings™ feature, Arizona Center for Fertility Studies can now "see" the heating and drill hole size and eliminate the temperature "guesswork."
The heat conduction into the embryo, as shown by the Isotherm Rings™, is based on published scientific algorithms that are built into the software. For increased embryo safety, the Isotherm Rings™ are hardwired and their specifications cannot be altered or deleted by users. With the Isotherm Rings™ you can be confident that what you see is accurate and determined according to scientific definitions, not by individual preference.
Compare the degree of heat penetration versus the drill hole size (orange ring) in the following animation that shows the degree of heat radiation at varying pulse durations.
Note how the heat penetrates further into the embryo as the pulse length increases. So even if the actual drill hole (orange ring) does not come close to the blastomeres, the blastomeres are exposed to the heat generated by the laser beam at longer pulse lengths. By using the Isotherm Rings™ feature of our laser, our embryologist can "see" the heat conduction prior to treatment and adjust the pulse length and embryo positioning accordingly, so as NOT to damage the embryo.
Arizona Center for Fertility Studies is excited about offering this new technology in human reproduction that has become the standard at our clinic.
Pictures and some text - Courtesy of Hamilton Thorne
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