How to Interpret Results
We understand that clinic success rates are important when choosing which IVF Unit to attend. The Hull IVF Unit has a long history of success, with pregnancy and live birth rates above or consistent with the national average success rate across all clinics.
The Human Fertilisation and Embryology Authority (HFEA) publish success rates for every licensed clinic. Although the results are usually updated every 6 months, there is at least a nine month wait required before outcomes are known and the results then need to be verified for accuracy, hence the data presented often relates to treatments conducted two years prior. We present data here from the HFEA and more recent clinical data.
The results show the number of treatments cycles carried out in a particular year and the number of clinical pregnancies and live births. However, success rates can be shown in a number of different ways and we understand that this can be confusing.
For example the data may be presented to show;
- How likely it is that each treatment cycle started (fertility drugs started or embryos thawed) will lead to a clinical pregnancy or live birth. However not all cycles started will result in embryos being available for transfer. A cycle could be abandoned or postponed for several reasons (inappropriate response to stimulation, no eggs collected or embryos created, or for the purpose of fertility preservation and oocyte/ embryo freeze requirements)
- Or how likely it is that an embryo transfer cycle of one or two embryos will result in a pregnancy or live birth.
- Or how likely each embryo transferred during treatment will lead to a live birth. This takes into account how many embryos have been transferred in a cycle and therefore results can appear lower than ‘per cycle’ because two embryos can be transferred in some cycles. For example 4 women start fertility drugs, 1 woman ops not to have embryos transferred, of the 3 who have embryos transferred 1 has two embryos replaced and the other women have single embryos replaced, two achieve pregnancies, resulting in the delivery of twins and a singleton respectively. The clinical pregnancy data could be reported as 2/4 per cycle started, 2/3 per embryo transfer cycle or 3/4 per embryo transferred. The live birth data could be reported as 2/4 live birth events per cycle started or 3/4 live births per embryo replaced.
- Live births may be presented as live birth events (i.e. the number of patients with live births) or the actual number of live births (i.e. number of babies born).
- A Clinical Pregnancy (CP) is defined as one in which at least one foetal heartbeat has been detected by ultrasound at around 6 weeks of pregnancy.
Multiple pregnancy is the single biggest risk of fertility treatment to both mother and baby. The birth of a single, healthy child is the safest, most desirable outcome of fertility treatment.
Therefore it is important to look for clinics that have a high proportion of single births, as well as a good overall success rate. The Hull IVF Unit has consistently low multiple birth rates.
For this reason we report here firstly whether treatment results in a live birth and secondly whether the live birth is composed of a single baby, twins or triplets.
Page Last Modified: 7th November 2017