IVF Success Rates
Clinical pregnancies per embryo transferred, January to December 2018.
|Number of embryos transferred||154||43,652|
Live birth per embryo transferred, January to December 2018.
Number of embryos transferred
How to interpret these results:
How do clinical pregnancy success rates compare to live birth rates?
The figures used in the first table above represent clinical pregnancies, which are usually defined as when foetal heartbeats are seen by ultrasound. There is always a miscarriage rate which means that the live birth rates, as shown in the second table, will usually be lower than the clinical pregnancy rate. Our own results show no decline between pregnancy and live birth for certain age groups, this is simply because of the small numbers involved and we would always, regrettably, expect a decline when looking at larger numbers. The tables refers to fresh transfers only, which means that pregnancies from frozen embryos transferred in future cycles are not included.
Why is this time frame presented?
Live birth rates take time to collate. Pregnancies last around 9 months and then a year’s data is normally collated together. For this reason the latest national figures take a little longer to become available.
How does Concept Fertility rank against other fertility clinics?
It is worth noting what the HFEA (the fertility sector regulator) publishes: “it is not meaningful to directly compare clinics’ success rates” and “the majority of clinics perform around the national average”. We believe that our pregnancy statistics stack up very well against the national equivalents, especially as we do not operate a restrictive patient-selection or treatment-selection policy. The tables above show fantastic results for our clinic in some categories and poorer ones in others, this is also almost certainly a peculiarity caused by the small number of cycles involved and the best forecast for the result from any future cycle would be that it would be similar to the national average. Read on to know a little more about how the statistics are compiled:
Pregnancy / live birth statistics are affected by a clinic’s patient selection policy.
When patients come to us they ask us to help them have a baby. We advise them of the options and chances of success and then proceed with treatment if that is their wish. We do not have any patient selection criteria as long as the patient has a chance of success and our doctors agree. We don’t reject patients if their sperm or eggs, or some other element, suggests a poorer prognosis. Statistically, this means that our results could be predicted to expect a lower than average success rate and this is why we at Concept are happy to be consistent with the average.
Some of the selections are politically determined too. For example, in the table at the top, the national data includes NHS cycles. The NHS has its own patient and treatment selection criteria and these quite often vary between the different Health Authority regions. As the NHS does not offer all the treatment cycles to all the patients who want them, their selection criteria skew the predictive probabilities for the rest of the population and further muddy the statistical waters.
Pregnancy / live birth statistics are affected by a clinic’s treatment selection policy.
We suggest to patients the treatment which we think is best for them, not the treatment which is best for the clinic. This means that we perform high numbers of IUIs (intra-uterine inseminations) as well as IVF (in-vitro fertilisation) cycles and we also offer simple cycle monitoring. We also advise some patients that they should try naturally for a while longer. If we had pushed everyone towards IVF, or not offered the other treatments at all, one would have to reasonably assume that our IVF success rates would be higher because the resulting group of patients would have had, on average, simpler infertility problems.
How statistical choices affect pregnancy / live birth statistics (Success Rates).
There are many ways to define what success is: not just with whether a pregnancy is biochemical, clinical or live birth, but also relating to the number of embryos transferred, the multiple-birth rate and whether the clinic chooses, for example, to show cumulative success rates or multiple-cycle success rates. Sometimes you have to remind yourself of the phrase often attributed to Mark Twain “There Are Lies, Damned Lies and Statistics”.
How accurate are the mathematics?
Statistics are used as predictions and for any degree of accuracy there has to be a sufficient number of cases. The HFEA writes: “If there is only a small number of women in an age group it can make results appear to be very changeable, when expressed as a percentage… For this reason, we do not present percentages where the group size (for instance the number of cycles performed) is fewer than 50.” As Concept Fertility has a relatively small number of cycles in each age group, any percentage we publish could potentially be quite variable, so the numbers in our table should be seen as indicative only when used for predictions. This is illustrated in the above tables where some of our figures appear to be higher than the national average and some appear to be lower.
So, do useful statistics exist anywhere? Read on…