Future fertility technology
While fertility technology is improving all the time, our children may still have a tough time conceiving when they're older, writes our fertility expert Dr Richard Fisher.
Encouraging a generation of adolescents to think about their future fertility is not an easy task, especially when the only thing many of them can think about is how not to get pregnant. However, when we began Fertility Associates in 1987, one of our earliest moves was to appoint a teacher to visit schools and start a discussion about fertility. The focus of her role was to promote scientific and ethical discussions among young people about what were then developing new technologies, such as IVF.
Interestingly, the overwhelming feedback from these students, no matter what their socio-economic or educational background, was that they almost all envisioned a future life that involved family, children and grandchildren. But today's adolescents may be surprised to hear their likely chances of future fertility are by no means guaranteed, despite ongoing advances in science and technology.
FERTILITY IN DECLINE
The biggest threats to having a baby now are age, weight and unknown environmental factors that appear to be reducing both sperm production and quality. Let's begin by looking at age. As women get older, there is a slow, steady decline in the chance of pregnancy per month until around the mid-thirties, when the decline speeds up. Most women in their mid-thirties will take longer to conceive than they would like but they do get pregnant. Fertility issues arise in the 15% of couples who have another problem besides age, which turns into a critical issue.
Weight at either end of the spectrum will also play a greater role in sub-fertility in the future. The obesity epidemic not only threatens the long-term health and welfare of both sexes but will also lead to substantially lower rates of fertility. Overweight and obese women take longer to conceive, have more irregular periods and are more difficult to treat than those of normal weight when they present with infertility. Overweight and obese men have lower sperm counts, less active sperm and the time to conception increases. There is good evidence from IVF pregnancy rates that as the weight of the male partner increases, there's less chance of conception and a higher chance of miscarriage. Given that many overweight or obese women have partners who are similarly affected, the combined effects are truly significant.
At the other end of the weight scale, there is clear evidence that adolescents who are light, either because of eating disorders or excessive exercise, place themselves at risk of dysfunctional hormone production in the future. The seriousness of illnesses such as anorexia are well recognised but more subtle presentations, often signaled by a lack of periods through adolescence, are more difficult to approach. Teenage girls with irregular menstrual cycles who are lighter than their peers should be seeking advice early.
Although declining sperm counts, which are occurring worldwide, have yet to be shown to have a significant effect on the fertility of the community, there is now plenty of research looking at the potential cause of this decline. Speculation about environmental factors and in particular environmental oestrogens from food or insecticides are another prime suspect. It will be some time yet, however, before the causes become clear.
Preserving fertility will also be important when caring for young people with cancer. Now that the survival rates for cancer in young people have improved dramatically, and most will survive to lead high quality lives, the preservation of fertility, which might be affected by cancer treatments, will become more important. The storage of sperm before treatment in young men or boys and the storage of eggs or ovarian tissue in women will offer opportunities for conception later if treatment damages the production of sperm or eggs. Storage will not always be necessary but a discussion around the future risks and benefits will become part of the management of cancer. Like all developments, at the moment these treatments offer an opportunity but not a guarantee of outcome. Continuing research and development will lead to significant improvements.
Having treatment for infertility is never an easy experience. Anything we can do to limit the pool of people who require intervention in their lives to reach their goal of having a child should be embraced. Changing the average age of first pregnancy would make the biggest contribution possible to reducing the instance of sub-fertility overall. At Fertility Associates we see many women in their late 30s when the issue of conception becomes really stressful, not because of underlying disease but because of age alone. Changing the age a woman comes to us for help will of course require significant change in our attitudes around planning for a family and may be a reversion to previous times when earlier conception was the norm. This is unlikely to happen without a significant effort at all levels of society, including changes in our working practice and better childcare. But perhaps the most important change needed to encourage couples to start their family earlier is in men's attitude to early commitment to long-term relationships, rather than the prolonged adolescence now not uncommonly seen.
One can't expect any of these changes to happen quickly but we should be teaching our children that conception doesn't always come easily and that earlier conception maximises the chances.
WHAT'S HAPPENING IN THE LAB
Science is making great inroads, however it will not solve fertility issues outright and no matter how clever the treatment, success will always be limited by age and weight. That said, there are some exciting developments we'll see more of in coming years.
It is likely that treatment will become more complex rather than less, but as a consequence of this, the chance of success will be greater. Simple interventions we currently use, such as improving the ability to ovulate or the quality of ovulation, will remain. As will the next line of intervention which involves getting more sperm and more eggs in the right place at the right time by physically introducing sperm into the uterus in combination with ensuring that an extra egg or two are made. However, the likelihood of either of these treatments improving success rates is limited as one is relying on assisting the function of normal biological systems, when these systems might be the cause of the delay in the first place.
In vitro fertilisation (IVF) pregnancy rates have remained static for the past 10 years but changes in protocols surrounding drug stimulation to produce more eggs will make the physical treatment for patients much easier in years to come.
Let's look at what is happening in the laboratory. We already know that most embryos created in a laboratory setting will not implant in the uterus. As clinicians, our challenge is to select the embryos that are most likely to implant successfully and this is one area where we'll see big improvements. The most likely "first cab off the rank" will be techniques that allow the biopsy of a small number of cells of embryos that have developed to a stage of development called blastocyst. Many blastocysts currently being replaced are chromosomally abnormal and will never implant and develop beyond the very early stages. Technology will allow us to make better embryo selections and therefore raise the chances of a successful pregnancy.
This is not a test about selecting particular abnormalities but will simply exclude those embryos from replacement into the uterus that have no chance of implantation at all.
It means fewer embryos will need to be replaced, to result in the same number of babies. Not only will this make the process more efficient, it will make the number of interventions that a woman will need to undergo significantly fewer.
As well as selecting better embryos, we'll also be able to grow better embryos. The fact is eggs obtained through IVF have a lesser chance of fertilisation and implantation than eggs released naturally. Despite our best efforts the environment in the lab is clearly not optimal. But research is being done internationally into ways in which embryo culture can be maximised, with changes in culture medium, methods of culture and processes involved in looking after embryos in those vital few days. Good science will ensure better outcomes.
I think with the growing confidence about success rates for IVF, the conservatism we have shown for many years about its use will diminish over the next 10 years. Part of this process will be the reassurance gained from continuing ongoing follow-up of children conceived from IVF which shows their long-term health and welfare is not compromised.
All current research is reassuring and if it continues, the relatively slow progress through investigation and management will speed up. After an initial assessment of the cause and an attempt to fix whatever the cause is, if there is a simple treatment available it will be tried for a short period of time. If it is not successful relatively quickly then treatment will progress to IVF. But science will not overcome biology.
The best way to improve the fertility of our population will be for couples to conceive earlier than they currently do. It's also important that they are in the best health they can be when they try to conceive. We also need to recognise that science will not be the answer to sub-fertility. It is where to turn to when unexpected factors limit a couple's hopes of parenthood.
If you're looking to get pregnant, there are things you can do to increase your chances of conception. Dr Richard Fisher explains more in his articles 'When IVF Doesn't Work', 'The New IVF' and 'Public and private options' .
Dr Richard Fisher (CNZM, FRCOG, FRANZCOG, CREI) is Adjunct Professor in the Liggins Institute. He set up Fertility Associates in 1987 with Freddie Graham and is now New Zealand's foremost spokesperson on infertility issues. In 2009, Richard was made a Companion of the New Zealand Order of Merit for his services to medicine. For more information on fertility issues go to http://www.fertilityassociates.co.nz/.
AS FEATURED IN ISSUE 17 OF OHbaby! MAGAZINE. CHECK OUT OTHER ARTICLES IN THIS ISSUE BELOW