What is my chance of having a baby with IVF? Interpreting IVF clinic success rates in context

Posted on 17 November 2016

There has been much talk in the media about IVF clinic success rates and the language used to express average results. We know from the averages that about 25% of couples who commence a single IVF cycle will have a baby. We know that the average couple who have an IVF baby require more than one treatment cycle.
One of the reasons that IVF clinic success rates are so complicated to explain to couples is the simple fact that they themselves may not be average.
Factors that influence IVF outcomes
There are many factors that influence IVF outcomes, some that we can’t change (like maternal and paternal age) and others that may be modifiable. Modifiable factors may be lifestyle related (like obesity and being overweight, smoking and drug use) or medical (like optimising endometriosis management, hormonal regulation and diabetes control).
For this reason, there is no replacement for a detailed individualised medical fertility assessment from a qualified fertility specialist before you embark on your IVF journey.
Who exactly is average?
There are couples who are likely to be more successful than average in an IVF cycle. This is because IVF is a stronger solution for combating some fertility problems compared to others. An example of factors that may be associated with higher chance of success include maternal age younger than 35, a good ovarian reserve (high egg number), and cases where male factor infertility or physical blockage (or absence) of the fallopian tubes is the major obstacle identified. In these cases, your fertility specialist may indicate that your chance of having a baby from IVF treatment may be higher than average success rates published by ANZARD.
Some couples may be less likely to have a baby in an IVF cycle than average. Reasons for this may include the following factors:
• Maternal age > 35 and especially >40 years
• Multiple reasons for infertility identified (e.g. advanced maternal age and low egg number)
• More than 3 previous IVF cycles which have not resulted in a live birth
In these cases, your fertility specialist may communicate that your chance of having a baby through IVF is well below average.
Poor egg quality: Uncorrectable by IVF
IVF technology does not correct for age related poor egg quality. A major problem that all women face over the age of 35 is that not every egg can be a baby. Over 40 years, it is important to realise that most eggs can’t. IVF technology in the setting of poor egg quality is much less successful. Women who have been unable to have a baby with their own eggs can improve their chance of having a baby dramatically by having a younger egg donor. Women can electively choose to freeze younger healthy eggs for the future to give themselves a finite number of additional opportunities to have a baby. The best path to avoid infertility is to plan to have started a family earlier in life.
Frozen embryos
Most high quality IVF programs have moved to culturing embryos to the blastocyst stage before freezing. The reason for this is to “select out” embryos that fail to make it to the day 5 stage in culture. By doing this, it is hoped that embryos that are transferred have a higher chance of being a baby (30-40%). The reason that success rate per blastocyst transferred is higher than success rate per cycle is simply that not every couple that commence an IVF cycle can produce a blastocyst to transfer.
Couples lucky enough to create several embryos can have more than one sequential embryo transfers from a single IVF cycle. Cumulative success rates (live births) for couples in this group may be higher than average.
Preimplantation genetic screening of embryos
An embryo that has been tested and found to be genetically normal has an up to 50% chance of being a baby. It is important to realise that for many couples, it may take several IVF cycles to find such an embryo an some couples never will. The chance of having a baby from a normal tested embryo will never approach 100% – as even with normal genes there are other complex reasons that implantation and embryo development may not occur normally.
Advice to couples
Couples considering IVF treatment should seek expert advice, as reported average success rates from IVF may not reflect their own chance of having a baby through IVF. Being thoroughly assessed is also an important step in determining whether IVF is the right treatment path to take, as other options like health and lifestyle optimisation and more conservative fertility treatment measures may in fact be more appropriate for some people.


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