|OVERALL PGS Frozen Pos HCG||78.3%||231||295||550||176||76.2%||283||51.5%|
|FET-2 Embryo w/PGS-Pos HCG||83.3%||195||234||489||150||76.9%||256||52.4%|
|FET-1 Embryo w/PGS- Pos HCG||59.0%||36||61||61||26||72.2%||27||44.3%|
Around 60 patients have frozen embryos that have undergone PGS testing, are chromosome normal, and are planning to do FET (frozen embryo transfer) in the next future. ACFS expects similar results in these patients, as above, with a FET with 2 embryo transfer. Also, a number of these patients are older (>37 years old) and have done two stimulation cycles in an attempt to improve their success rates (see #3 below). One important change in the last two years is a decrease in miscarriage rates and a subsequent increase in implantation rates in what ACFS feels is directly related to a proactive approach to miscarriage prevention prior to embryo transfer.
ACFS data for the last four years (August 2011- July 2015) clearly supports our continuing experience that PGS (preimplantation screening) improves pregnancy rates, ongoing pregnancies (clinical pregnancy) and decreases miscarriage rates. ACFS experience during the last four years has also noticed some interesting trends:
If a women is able to transfer 2 chromosomally normal day 5 embryos, pregnancy rates are increased by almost 15% (14.57%). Without PGS testing, pregnancy rates are 71.43% with a FET or frozen embryo transfer (ACFS no longer does fresh transfers because of the lower pregnancy rates , up to 30%, in putting embryos back in a physiologically overstimulated cycle that they were gotten from). ACFS believes that FET without PGS data is biased because many embryos that are chromosomally abnormal "stall out" in culture and never reach the blastocyst stage and therefore are not cryopreserved (or frozen). Even if they reach the blastocyst stage and are frozen, there are decreased survival rates when thawed for embryos that are chromosomally abnormal. Thus, the freeze-thaw process acts as a "screen and/or selects" for normal embryos. In other words, if the embryo survives the freeze-thaw process, there is a suggestion that this embryo has an increased chance of being chromosomally normal. ACFS is currently engaged in a clinical study looking at this data and preliminary data suggests it to be accurate.
One very important and interesting trend found by ACFS, is the much higher pregnancy rates with transferring 2 embryos as opposed to transferring 1 embryo. This is especially true for women 37 or older. Most one embryo transfers are either in younger patients who want a "zero" risk of twins or older patients (37 or older) who only have 1 chromosome normal embryo to transfer. Some young patients do not do chromosome testing, whereas almost all of the older patients do. In the above data, most of the 1 embryo transfers without PGS are in young patients (66.67% pregnancy rate); whereas 1 embryo transfer with PGS is in older patients (42.86%).
It is ACFS belief, that although chromosome testing goes a long way to "eliminating" age as a factor, the data shows that if a younger patient transfers 2 chromosome normal embryos and the older patient (37 or over) transfers 2 chromosome normal embryos; both will have the 83.3% success rates, but the younger patient is at increased risk of twins (28%) whereas the older patient (37 or over) will get a singleton (one baby). This suggests that although chromosome testing (PGS) goes a long way to "wipe out" age as a factor, there are still "age-related" factors in the embryo of an older patient. This data strongly suggests that the goal is to transfer 2 day 5 (blastocyst) chromosome normal embryos especially in older patients. In light of this information, ACFS recommends that patients 37 or older consider two stimulation cycles with freezing the eggs on the first attempt. By doing two stimulation cycles, ACFS will have twice as many eggs/embryos; therefore having twice as many embryos that undergo PGS screening.
An important point in this decision is to know that ACFS success rates with frozen eggs is the same as with fresh eggs. Also, by doing two stimulation cycles, with freezing the first set of eggs, as opposed to doing two complete IVF attempts, ACFS saves you around $6000-7000- by only having to do one fertilization procedure (ICSI), one advanced culture to blastocyst stage (day 5) and only one PGS (preimplantation) testing. The down side of two stimulation cycles is that you may not need to do them and one stimulation cycle will be enough to have a successful outcome. In women 37 and older that have a high resting follicle count (BAF- basal antral follicle count), low FSH and high AMH, may be fine with only one stimulation attempt because they are predicted to make a high number of eggs/embryos (if stimulated appropriately, which they will be).
Although clinical pregnancies (evidence of a gestational sac at 6+ week ultrasound) are similar with FET with or without PGS, ACFS data shows a 9-10% decrease in miscarriage rates with PGS testing; as well as eliminating the risk of a Down's pregnancy and/or other chromosome abnormalities. Also FET (frozen embryo transfer), without PGS testing, is again bias. Most embryos that are chromosomally abnormal do not even implant and/or if they do, result in an increased risk of miscarriage (70-80% of miscarriages are do to the embryo being chromosomally abnormal). This is evidenced by the fact that implantation rates with FET with PGS are 41.28% and FET without PGS are 29.58%
Patients are cautioned regarding making comparisons of success rates between IVF clinics based on the clinic - specific data reports released by the Society for Assisted Reproductive Technology ( SART ) and the Centers for Disease Control ( CDC ). Although SART issues a statement that specific clinic data should not be used for comparison, the fact is that they are used by patients and clinics alike for that purpose. There are many factors that influence IVF success rates and many variables exist among individual clinics that make comparisons almost impossible based on the released data. Some of these problems of the clinic - specific data reports include:
These are only some of the examples that can be listed that clearly invalidate comparisons between IVF clinics based on the released SART clinic - specific data reports.
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