by Professor William Ledger
While the population of the world as a whole continues to rise, the population of Western Europe, Canada and parts of South East Asia is falling. The only two countries in Western Europe that are maintaining their population size are France and the Republic of Ireland. Across Europe the fertility rate fell below the replacement level in the mid-80’s. Canada’s total fertility rate (TFR) fell to 1.5 by 1995 and has remained there ever since.
The age distribution of a country is determined by three factors, namely, the level of net migration, the mortality rate and the fertility rate. The European Union has seen a net immigration, probably approaching a 17 million population increase in the last two decades; however, this trend has not been sufficient to maintain population size. Many immigrants will spend only a few years working in their host country, and will then return home to start their family. Hence their contribution to population size cannot be viewed as stable. Longevity has increased steadily during the 20th century, such that the average life expectancy increased from 43.5 to 75.4 years for males and from 46.0 to 81.4 years for women over the last 100 years. Since this trend will likely continue beyond 2050, we will be faced with an ageing population. Western Europe and Canada are not seeing sufficient births to meet population replacement needs. The TFR of most EU countries is well below replacement (2.1 children per couple) while Canada’s TFR is only 1.5. By 2015 the number of senior citizens in Canada will be greater than the number of school age children. By 2035, Canada will have a further decline in population unless provincial and federal governments establish policies which will ensure population growth.
Clearly, the major reason for the decline in birth rate is social. Couples are having fewer children for financial reasons, in order to establish a career, and to enjoy the many opportunities open to unattached young adults that are more difficult to access, and more expensive, with children. Perhaps ART can make a significant contribution to the TFR of the EU and Canada.
A brief analysis of the major causes of infertility shows the likelihood that involuntary infertility is on the increase. As the prevalence of sexually transmitted infections in young people continues to rise, it is likely that there will be an increased recognition of tubal blockage some 10 – 15 years later when this cohort tries to conceive. Anovulatory infertility may also become more common, following the trend for obesity which seems to unmask and worsen anovular polycystic ovary syndrome. Obesity has many negative influences and will again exert its effects on reproductive health some years after becoming a problem in children and young adults. Male infertility is likely increasing as well. However, the most significant trend in future fertility will be the effect of women deferring childbirth. UK data shows that over just 20 years the average age at first birth has risen by almost a decade. The picture is the same across Europe and in Canada. We now see the same trend with males – they too are becoming new parents for the first time at an older age.
Starting a family in middle age has many adverse consequences. The prevalence of ‘unexplained’ infertility rises dramatically as women age. Most of this ‘unexplained’ phenomenon is due to the decline in the quality of oocytes and is dramatically demonstrated by the increases in prevalence of Down Syndrome, and miscarriage in women over 35. Having an older father also puts a child at significant increased risk of ill health (Bray et al, 2006).
IVF practitioners will be all too familiar with the rapid reduction in pregnancy and live birth rates per cycle seen in patients over 35 (Templeton & Parslow ref). The reasons for this are many – older women make fewer follicles and have fewer oocytes at egg collection. Endometrial development may be impaired and more women have uterine problems that affect implantation. Egg quality is suboptimal, with lower fertilisation rates and lower quality embryos. Studies with preimplantation genetic screening have shown that, even if pregnancy is established, there are significantly higher chances of miscarriage, stillbirth and obstetric complications.
Accepting the apparent increase in the number of couples with involuntary infertility that will occur in Europe and in Canada in the next decade, how much benefit might treatment bring to the overall TFR of a country? In order to put this question into perspective, it is necessary to assess the contribution of existing governmental social policies on population size. Traditional solutions include:
- Lowering direct costs of children (eg, tax benefits, cash transfers)
- Increasing length of parental leave
- Increasing childcare for pre-school children
- Increasing part-time employment opportunities
While the impact of such policies on population size varies from country to country, none appear to offer a universal panacea (d’Addio & d’Ercole ref). In fact, studies that have been carried out on their effectiveness suggest that many such attempts to influence societal behaviour have little effect. Conversely, the effects of ART can easily be quantified – many Western countries have reliable data concerning the number of treatment cycles and live births achieved per year, allowing the net contribution of ART to TFR to be calculated. The costs of such treatments are also known. Jonathan Grant and the Rand Corporation (2006) have modelled the effect of increasing the number of IVF treatments in one EU country with a current low level of provision (UK) to levels seen in another with better provision of treatment (Denmark). IVF in UK contributes about 1.4% of live births, in Denmark about 4.2%. Their data show that a relatively modest increase in the number of treatment cycles would increase the TFR by 0.04, an increase equivalent to the effect expected if there were a 20% increase in UK Child Benefit.
Hence while funding IVF cannot be seen as the whole answer to the decline in European and Canadian populations, the message from demographic studies is that there needs to be a range of strategies and ART can be viewed as a cost effective component of an overall policy, bringing great benefit to infertile couples and helping to reverse the fall in TFR.
This logic has been accepted in certain countries, notably South Korea. South Korea has one of the lowest TFR in the World, with less than 1.2 births per woman. Their birth rate has fallen from 1 million per year in 1070 to less than 500,000 per year currently. The Korean government has responded to this challenge with a raft of policies, amongst which is generous funding for ART, enough to provide 50% of the cost to support 16,000 couples through ART in 2006 – 7, with treatment for 20,000 couples annually thereafter.
It is clear that couples respond to more generous State support by undertaking more IVF treatments, with improved conception rates. Governments concerned by population decline should study the Korean approach. To ignore the problem in 2007 will result in a greater disparity between wage earners (hence taxpayers) and retired people later, with obvious consequences for a nation.
ABOUT THE AUTHOR: Professor William Ledger, MB ChB, FRCOG of Sheffield, UK is Head of the Centre for Reproductive Medicine and Fertility, the Jessop Wing, Royal Hallamshire Hospital in Sheffield, UK and Professor of Obstetrics and Gynaecology.
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