Hum. Reprod. Advance Access originally published online on June 21, 2008
Human Reproduction 2008 23(9):2173-2174; doi:10.1093/humrep/den235
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Letters to the Editor |
Can assisted reproductive technologies help to offset population ageing?
1 Emeritus Professor Reproductive Medicine, University Utrecht, Utrecht 2 Department of Public Health, Erasmus MC, University Medical Center, Rotterdam, the Netherlands 3 Netherlands Interdisciplinary Demographic Institute, the Hague, the Netherlands
4 Correspondence address. E-mail: e.r.tevelde{at}wanadoo.nl
In the challenging paper by Hoorens et al. (2007)
which is a condensed version of a Rand Corporation Report by the same authors (Grant et al. 2006), the authors argue that the trend of population ageing as a result of decreasing birth rates and longer life-expectancies is a serious threat for most EU member states. They compare the situation of the UK and Denmark in 2002 with regard to the total fertility rate (TFR, the mean number of children per woman), the age of the mother at childbirth and the number of IVF cycles per million inhabitants. On the basis of the spontaneous and the IVF pregnancy rates, they construct a fertility model and demonstrate that if the access to IVF in the UK were increased to the much higher IVF capacity in Denmark, the TFR in the UK would increase by 0.04. Moreover, if all infertile couples would have access to IVF, the so-called ‘maximum TFR with ART’ (Fig. 1 and Table II) would rise by 0.20 in the UK and 0.17 in Denmark implying enormous rises in IVF capacity. Compared with other policy measures intended to increase national birth rates, these are considerable effects. The authors conclude that IVF and other assisted-reproductive technologies (ART) have the potential to increase birth rates, thereby helping to offset the trend of population ageing.
However, several of the results and conclusions of the study are based on inappropriate definitions and flawed assumptions. In Appendix A of the RAND Report, to which the article and its technical paragraph refer, the fertility definitions are given. Couples are fertile if a spontaneous pregnancy leading to live birth is achieved within 1 year after stopping birth control. In spite of having regular, unprotected intercourse, they do not conceive within that crucial period, they are to be considered as subfertile, which condition is potentially restorable by IVF. However, if IVF appears to be ineffective, the couple is to be categorized as sterile: with this male partner the woman will never conceive. These definitions imply (i) that IVF is indicated for all couples who do not conceive spontaneously within 1 year and (ii) that all couples, who do have a child after IVF, would have been otherwise childless. This view on fertility ignores the overwhelming evidence from the literature about the ability of couples to have a natural conception leading to live birth after 1, 2 or more years of unsuccessfully trying (Tietze, 1950; Leridon, 1977; Collins et al., 1983; Spira, 1986; Wood, 1989; van der Steeg et al., 2007 and many others). For example, about half of all the couples, who do not achieve a natural pregnancy within 1 year after stopping birthcontrol, will still do so during the following year (te Velde et al., 2000; Dunson and Baird, 2004). Applying IVF to all couples who have not become pregnant within 1 year is unnecessarily exposing many of them to the complications and side effects of a potentially risky treatment modality.
The authors do not seem to realize that the demographic advantage of early IVF—a higher TFR—for a considerable part is due to the high incidence of children from twin and triplet pregnancies after IVF (Andersen et al., 2006). Such children have a much higher probability of immaturity or prematurity associated with increased risks of infant mortality and morbidity after delivery and of cognitive problems and long-term handicaps later in life (Helmerhorst et al., 2004; Hille et al., 2007). In their cost–benefit analysis, the authors only include the direct costs of the IVF treatment, neglecting the much higher costs of the complications by premature and immature births, and the treatment-related complications for the mother (Collins, 2002).
In conclusion, we think that IVF is the most important treatment for couples who have no or little chance of conceiving naturally and that all these couples should have the opportunity to have IVF. However, early IVF is only indicated in the minority of couples: those who have a clearly identifiable cause of their infertility. Many couples need more time for realizing a natural pregnancy. Hoorens et al. grossly overestimate the impact of IVF as a policy measure to boost birth rates. If governments would follow their recommendations, this would have serious health consequences for mothers and children.
References
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Dunson DB, Baird DD, Colombo B. Increased infertility with age in men and women. Obstet Gynecol (2004) 103:51–56.[CrossRef][Web of Science][Medline]
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Wood J. Fecundity and natural fertility in humans. In: Reviews of Reproductive Biology—Milligen S, ed. (1989) Oxford: Oxford University Press. 61–109.
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