"You have unexplained infertility. IVF has a high chance of working for you."
Many of my patients report that their fertility specialist has told them this. But the data does not support this claim.
Problem number 1 - no UK data available
According to the Human Fertilisation and Embryo Authority (HFEA), in 2013 in the UK unexplained infertility accounted for 43% of all IVF cycles started and 20% of all ICSI cycles (IVF where the sperm is injected directly into the egg). See the table below (source: "Fertility treatment in 2013: trends and figures", Human Fertilisation and embryo authority, page 14)
In 2013, 49,636 women had a total of 64,600 cycles of IVF or ICSI (Source HFEA). So there are 10s of thousands of of women having IVF for unexplained infertility each year. However the HFEA do not break down success rates for unexplained infertility compared with all other causes of infertility. This in itself is a little odd.
However I managed to find a US website that does provide this comparison.
What I found was surprising.
Yes there is a slight difference between IVF success rates for explained vs unexplained infertility. But that difference is 2-3% across all age groups.
I'll say that again. Data comparing 190,000 IVF cycles in the US shows that there was only a 2-3% difference in success rate between unexplained infertility and all causes of fertility, including blocked fallopian tubes, endometriosis, hormone imbalances and whole range of other conditions.
The tables below are taken from the Society For Assisted Reproductive Technology in the US:
The first table below shows success rates for all causes of infertility. This data is for women using their own eggs.
This next table (below) shows success rates for fertility "unknown factor" infertility ie. unexplained infertility. Again this data is for women using their own eggs.
The link below is where I got this data. It is a tool provided by the Society For Assisted Reproductive Technology. It contains data from 190384 cycles of IVF performed in the US in 2014. You can compare success rates for different causes of infertility by clicking on the "filter" button in the top right hand corner:
https://www.sartcorsonline.com/rptCSR_PublicMultYear.aspx?ClinicPKID=0#patient-cumulative
These figures are from the US, however we can safely assume, due to the large volume of data, that the percentage difference between unexplained infertility and all other causes in the UK will be roughly similar.
Note: In the USA success rates are higher across the board than in the UK. For UK figures for IVF success rates by age, see below.
UK national average IVF success rates my age:
(source: "Fertility treatment in 2013: trends and figures", Human Fertilisation and embryo authority, page 29)
Note: Although this data is from 2011 and 2012, these are the latest figures available from the Human Fertilisation and Embryo Authority. This is due to the nine month wait to know the outcome of the IVF cycle and the time taken to verify and prepare the figures,