IVF 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 2015, here, we report the 2013 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.
Rates based on cycle start present outcomes based on “intent to treat,” and, especially in 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 are fully aware that they may not reach embryo transfer. Our patients, therefore, are interested in knowing what their chances to conceive are if they do reach embryo transfer. For this reason, clinical pregnancy rates are reported here with reference point embryo transfer. Since CHR usually performs egg retrieval even with a single follicle in the case of “low-chance” patients, our IVF cycle cancellation rate in fresh cycles has also been relatively low, affecting the clinical pregnancy rates per cycle start (“intent to treat”) to a relatively minor degree.
In almost all age categories, CHR’s 2013 IVF pregnancy rates exceeded our 2012 results. Against the background of our patients’ seemingly ever-rising median age, we are very proud of this continuous improvement.
As the pie chart above demonstrates, only about 20% of CHR’s patients undergoing fresh IVF cycle in 2013 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. Astonishingly, nearly 20% of patients using their own eggs were over age 44, yet still achieved a very respectable clinical pregnancy rate of 14.5% if they reached embryo transfer.
Since these numbers do not include miscarriages (those data are not yet available for all 2013 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
The table above and graph to the left summarize CHR’s 2013 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 diagnosed based on positive pregnancy test, but which did not continue to develop far enough to be seen on ultrasound.
Here presented age-specific numbers are really remarkable, considering the adversely selected patient population in which they were achieved. One has to wonder how extraordinary CHR’s pregnancy rates would be if the center served the same kind of patients most other IVF centers are treating!
Clinical Pregnancy Rates for FET, Egg Donation and PGD Program
The table below reports clinical pregnancy rates in other types of treatment cycles, including frozen-thawed cycles, egg donation cycles and in CHR’s Preimplantation Genetic Diagnosis (PGD) Program.
A few comments are warranted about these cycles as well: 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), the two groups making up most of CHR’s patient population, usually have no or very few embryos to freeze after fresh transfers are done. Moreover, the best embryos are usually transferred in fresh cycles, leaving second-best embryos for cryopreservations and later FET. To see a 40.0% clinical pregnancy rates when these second-best embryos are transferred is, therefore, really remarkable.
CHR’s oocyte donor cycle pregnancy rate also needs some explanation. Once again, CHR’s egg donation cycles are often performed in women of significantly advanced age, a good number above age 50. In older women, CHR strongly recommends transfer of a single embryo because the risks of twin pregnancy in older women are significant. In younger women, in contrast, we consider the twin pregnancy risks as acceptable, and do not hesitate to transfer 2 embryos if the patient has no medical contraindications to twin pregnancies.
Practically, this means that here reported donor cycle pregnancy rate of 51.7% represents the mean of both patient groups. Women who get only a single embryo transferred in a fresh donor cycle have a pregnancy chance in the 40-45% range, while women who have two embryos from egg donors transferred will have a pregnancy chance above 60%.
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. Considering the additional manipulation of embryos required in association with PGD, CHR’s pregnancy rates around 35%, are, therefore, also beyond expectations.
A few notable comparisons between 2012 and 2013
- As the graph on the right demonstrates, the number of patients younger than 36 years declined by about 10%, while the number of patients above 36 increased significantly. Of particular note, the number of patients over age 41 increased by more than 33%. This continuing demographic shift, again, increased the median age even further in 2013.
- As a consequence, CHR treated a significantly more challenging patient population with more severe forms of DFOR.
- In 2013, women 44 and above were actually among the largest age group undergoing non-donor IVF cycles at CHR.
- Overall pregnancy rates for fresh IVF cycles improved by 5.5 percentage points over 2012, a 22.7% improvement year over year from 2012.
Conclusions and Cautions
Though 2013 was truly 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 asses individual patient's pregnancy chances, especially for older women.
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 significant. 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 woman has no eggs at oocyte retrieval, she, of course, has no chance of pregnancy in that cycle. The same applies to when a woman 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.
While our IVF pregnancy rates were quite remarkable in 2013, 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 initiated in 2014, which will help us to better understand the ovarian environment and follicle development, involving testosterone and human growth hormone (HGH) supplementation. Other very promising studies under way involve changes in the IVF laboratory.
Last Updated: May 1, 2014