In Vitro Fertilization (IVF)
Our Pregnancy Rates & Outcomes
Ahead of the Centers for Disease Control and Prevention (CDC) and the Society for Assisted Reproductive Technology (SART)’s annual reports, which will include live birth rates but will not be available until 2016, here, we report the 2014 clinical IVF pregnancy rates for CHR.
These clinical pregnancy rates are reported with reference point embryo transfer. This means that only the women who made it to embryo transfer are included in the calculations. Women who did not reach embryo transfer are not reported, thus somewhat inflating pregnancy rates in comparison to rates calculated based on the number of cycles started. Pregnancy rates based on cycle start present outcomes based on “intent to treat,” and, especially in formal research studies, are considered the correct way of reporting pregnancy outcomes.
However, a large majority of CHR’s patients are the so-called “low-chance” patients. They enter IVF cycles fully aware that they may not reach embryo transfer. Many of our patients, therefore, are interested in knowing what their pregnancy chances are if they do reach embryo transfer. For this reason, clinical pregnancy rates are reported here with reference point embryo transfer, instead of IVF cycle start. Since CHR usually performs egg retrieval even with a single follicle in the case of “low-chance” patients, our cycle cancellation rate in fresh IVF cycles has also been relatively low, affecting the clinical pregnancy rates per cycle start to a relatively minor degree.
Against the background of rising ages for CHR’s patient population year after year (see pie chart), we are very proud that pregnancy rates in some age groups, nevertheless, still improved over the record 2013 results. Best evidence for the quality of CHR’s laboratory is the improvement in pregnancy rates of donor egg recipient cycles. Donor egg recipient cycles are not as age-dependent as fresh IVF cycles since almost all egg donors are very young. Egg donation results, therefore, best represent the quality of the embryology laboratory, as egg donors are of very similar age at all IVF centers. Pregnancy rates in donor recipient cycle increased from 51.7% in 2013 to 64.4% in 2014, a 25% improvement. These results are particularly remarkable because a good portion of these donor recipient cycles at CHR also undergo PGS for aneuploidy and/or gender selection, which somewhat reduces pregnancy chances.
As the pie chart above demonstrates, only 23% of CHR’s patients undergoing fresh IVF cycle in 2014 were under age 35. In a continuation of the trend of rising patient ages we have been witnessing for a good number of years now, more than half of our patients were above age 40; in fact, in 2014, a full 60% of our patients undergoing fresh IVF cycles were over 40. About 43% of the patients were above age 42.
Since these numbers do not include miscarriages (those data are not yet available for all 2014 patients), live birth rates, of course, will be lower. This data will be transmitted by year’s end to CDC and SART for public reporting.
Fresh IVF Cycle Pregnancy Rates
|Age (years)||Pregnancy rates (%)|
The table above and graph to the left summarize CHR’s 2014 clinical IVF pregnancy rates by age. As has been our practice, the reported pregnancy rates are clinical pregnancy rates. Clinical pregnancy rates are calculated by dividing the number of clinical pregnancies (pregnancies confirmed by ultrasound) by the number of patients undergoing embryo transfer. This means, as noted before, that in order to be included in the calculation, a patient had to have at least one embryo available for transfer.
Also of note, our clinical pregnancy rate calculations exclude the so-called chemical pregnancies. Chemical pregnancies are pregnancies that were diagnosed based on positive pregnancy test but did not continue to develop far enough to be seen on ultrasound. At CHR they are NOT counted as pregnancies.
Here presented age-specific clinical pregnancy rates are really nothing but remarkable, considering how adversely selected CHR’s patient population is. How extraordinary would CHR’s pregnancy rates be if the center served the same kind of patients most other IVF centers are treating!
One more point of importance: Above shown graphic representation of age-specific clinical pregnancy rates at CHR suggests outcome valleys at ages 36-37 and 43 years. As statisticians would note, they most likely represent statistical outliers (i.e., statistical flukes) because the general trend is exactly what would be expected, i.e., declining pregnancy rates with advancing female age.
There is, however, one quite remarkable exception, it appears—though additional years will have to confirm this trend. Because pregnancy rates demonstrated a steep decline after age 43, in 2014, CHR introduced a radically new IVF management protocol for women above age 43 involving earlier egg retrieval, based on research conducted at the center. We are pleased to note that, as a consequence of this new protocol, the center’s clinical pregnancy rate at age 44+ (which included women up to age 51) was almost identical to our pregnancy rate in 42 year-old patients. We see this as a remarkable accomplishment in an age group most of our colleagues don’t even try treating with use of their own eggs.
Clinical Pregnancy Rates for FET, Egg Donation and PGD Program
|Cycle type||Clinical pregnancy rates (%)|
|Frozen-thawed embryo transfer (FET) cycles||22.4|
|PGD cycles (all ages)||35.7|
The table above reports clinical pregnancy rates in other types of treatment cycles, including frozen-thawed cycles, egg donation cycles and in the preimplantation genetic diagnosis (PGD) program.
A few comments are warranted about these cycles: Considering the very adverse selection of CHR’s patient population, it is almost a miracle that CHR has any FET cycles. Older women and patients with low functional ovarian reserve (LFOR, another term for diminished ovarian reserve, or DOR), the two groups making up most of CHR’s patient population, usually have no or only very few embryos to freeze after transfers of fresh embryos are done. Moreover, the best embryos are usually transferred in fresh cycles, leaving second-best embryos for cryopreservation (freezing) and later FET. To see a 22.4% clinical pregnancy rate when these second-best embryos are transferred is, therefore, most satisfactory.
Finally, a word about CHR’s PGD cycles: Again, they involve relatively adversely selected patients, many of whom are much older than the typical patients undergoing PGD at most other IVF centers. Considering the additional manipulation of embryos required in association with PGD, CHR’s pregnancy rate in excess of 35%, is, therefore, also above expectations.
A few notable comparisons between 2013 and 2014
- In 2014, the number of patients over 44 undergoing fresh IVF cycles went up by 14%, pushing the age of CHR’s patient population further upward. As a proportion of all patients, those over 44 now represent almost a quarter. This is, of course, highly remarkable, considering that most IVF programs in the world don’t even accept patients at those ages into treatment with use of their own eggs!
- The percentage of women over 40 undergoing fresh IVF cycles at CHR hit in 2014 the all-time high of 60.9% - up from 53.0% in 2013.
- As a consequence, CHR treated a significantly more challenging patient population with more severe forms of LFOR/DOR.
- Our egg donation program pregnancy rates, which our team identified as likely one of the best center-to-center performance comparison indicators in a recently published CHR paper, improved significantly from 2013, reaching a respectable 64.4%.
Looking Ahead, and Some Cautions
Although 2014 was a remarkable year for CHR’s clinical program, we, again, do want to point out that statistical data in medicine always have to be interpreted with caution. No two patients are ever 100% alike, and looking at outcome data based on patient age alone is not always the best way to assess individual patient's pregnancy chances, especially for older women. This is one reason why we also offer a detailed guide to interpreting IVF pregnancy rates.
Here presented statistical outcome data mostly represent mean values. Reporting by mean value is a very appropriate way of presenting data when outcomes fall within a relatively narrow range. However, in women with very low ovarian reserve, whether due to premature ovarian aging (POA) or older age, the range of outcomes becomes quite wide. More importantly for these women, it needs to be noted that there is a significant risk of “ZERO” outcomes (i.e., no pregnancy chance). For example, if a patient has no eggs at oocyte retrieval, she, of course, has no chance of pregnancy in that cycle. The same applies to when she only has chromosomally abnormal embryos that cannot be transferred after preimplantation genetic diagnosis (PGD). Both of these risks rise with advancing female age, as well as increasing severity of LFOR/DOR.
We are not resting on our success. Continuous improvement of our treatment protocols has been driven by CHR’s considerable, and growing, research effort, and we are determined to push the horizons even further. Good examples are new treatment protocols we introduced in 2014 and 2015 including testosterone and human growth hormone (HGH) supplementation, as well as different timing of hCG trigger before egg retrieval for older women, as mentioned above. Other very promising studies under way involve changes in how the IVF laboratory treats immature eggs. All of these research initiatives should help us improve our understanding of the ovarian environment and of follicle development.
We are certain that 2015 results at CHR will be beneficially affected by these changes, as we continue fighting for every egg and embryo.