Interpreting IVF clinic success rates in context
There has been much talk in the media about IVF clinic success rates and the language used by clinics to express average results. We know that about 25 per cent of women or couples who commence a single IVF cycle will take home a baby. We know that the average couple who has an IVF baby requires more than one treatment cycle.
One of the reasons that IVF clinic success rates are so complicated to explain to individuals or couples is that the couple 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 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 individual 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 the Australian & New Zealand Assisted Reproduction Database (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:
- If a woman is older than 35 years (and especially if she is older than 40)
- There is more than one reason for a person or couple’s infertility(e.g. a woman is older than 35 and/or has a low number of eggs)
- A person or couple have had more than three 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: Cannot be corrected 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 using eggs donated by 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. This process is known as egg freezing.
The best path to avoid infertility is to plan to start a family earlier in life if you are in a position to do so.
Most high quality IVF programs allow embryos to develop to a phase that is known as the blastocyst stage (around five days of maturity) before they are frozen. The reason for this is to be able to identify embryos that have failed to develop properly. By doing this, it is hoped that embryos that are transferred have a higher chance of becoming a baby (30-40 per cent). The reason that success rate per blastocyst transferred is higher than success rate per cycle is simply that not every couple that starts an IVF cycle can produce a blastocyst that is suitable for implantation into a woman.
Couples lucky enough to create several embryos can have more than one embryo transfer from a single IVF cycle. This means that a person or couple, over time, may be able to take home more than one baby from a single cycle. As a result, 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 per cent 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 and some couples never will. The chance of having a baby from a normal tested embryo will never approach 100 per cent. Even with normal genes there are other complex reasons as to why 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 changes and more conservative and less costly fertility treatment measures may in fact be more appropriate for some people.
Article by Dr Raelia Lew. Raelia is working with VARTA in 2016 as part of her certification in reproductive endocrinology and infertility from the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZOG).