Interpreting Success Rates
Assisted reproduction pregnancy outcomes can be measured per cycle started, per egg collection or per embryo transfer. Merrion Fertility Clinic rates are measured ‘per embryo transfer’.
Rates are also different for fresh and frozen cycles. Generally, rates are higher for fresh cycles.
- ‘Fresh’ cycle: transfer of an embryo that was never frozen (cryopreserved)
- ‘Frozen’ cycle: transfer of an embryo that has been frozen and subsequently thawed for use in a ‘Frozen Embryo Transfer’ (FET)
How Success Rates are Reported
Outcomes of assisted reproduction treatment can be reported as:
- Positive Pregnancy Test – 2-3 week stage
- Clinical Pregnancy – 8-12 week stage, visible by ultrasound scan
- Live Birth – 9 months (full term) or earlier (premature)
Due to the high risk of miscarriage in the early weeks of pregnancy, we measure our success rates based on the later stages: Clinical Pregnancy and Live Birth.
Positive pregnancy tests will always be the highest, then clinical pregnancy rates, then live birth.
It is important to check for this terminology when looking at success rates. ‘Pregnancy rates’ is a vague term, as it is unclear if this refers to a positive pregnancy test or a clinical pregnancy.
Our Success Rates at Merrion Fertility Clinic
Our ICSI and IVF success rates consistently rank well above the European average, as published by the European Society for Human Reproduction & Embryology (ESHRE) and the Human Fertilisation & Embryology Authority (HFEA) in the UK.
One of the main influences on success rates is female patient age, but as you can see from the table above, this is not the only factor. Other influences include diagnosis, previous pregnancy history, medical history etc.
FET Success Rates
A frozen embryo transfer (FET) cycle involves thawing frozen embryos and transferring them back to the womb. While success rates with FET cycles have traditionally been slightly lower than fresh cycles, recent advances in embryo freezing techniques have greatly improved outcomes.
In 2019, our clinical pregnancy rates per frozen embryo transfer was 38.3%.
Multiple Pregnancy Rates
At Merrion Fertility Clinic, we believe in optimising your chances of a healthy pregnancy and baby by promoting single embryo transfer (SET) and keeping twin pregnancies at a minimum. Twin pregnancies are much higher risk for the babies and the mother.
We are very proud of our low multiple pregnancy rate. In 2019, only 5.6% of our pregnancies resulted in a multiple pregnancy. This is compared to a U.K. rate of 10% and a U.S. rate of 12.3% (2017).
Live Birth Rates
At Merrion Fertility Clinic, we believe it is vital to publish transparent and up-to-date details such as multiple pregnancy rates and live birth rates. Live birth rates are always lower than clinical pregnancy rates (the figures given on most fertility clinic websites), but this is the information which is of most importance to our patients.
Live birth rates or “take-home baby rates” cannot be reported until all women have delivered. Our live birth rates for 2018 are exceptional by international standards, ranking well above UK live birth rates, and also compares very favourably with those in the US, widely regarded as having the best rates internationally.
Merrion Fertility Clinic is the only fertility clinic in Ireland that reports its success rates on a yearly basis in an official clinical publication.
Our ART figures and success rates are published in the National Maternity Hospital Clinical Report.