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Henri Leridon

Publications and source records attributed to Henri Leridon.

6 recordsLinked to original sources
PubMed2004

Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment.

BACKGROUND: Maternal age is an important factor in reproduction. Can assisted reproduction technologies (ART) fully compensate for the decline in fertility with age? METHODS: We used a computer simulation (Monte Carlo) model of reproduction, combining the monthly probabilities of conceiving, the risk of miscarriage and the probability of becoming age-dependently permanently sterile. RESULTS: Under natural conditions, 75% of women starting to try to conceive at age 30 years will have a conception ending in a live birth within 1 year, 66% at age 35 years and 44% at age 40 years. Within 4 years the success rates will be respectively 91, 84 and 64%. If women turn to ART after 4, 3 or 2 years respectively without conception, and if the rate of success is as observed after two cycles of insemination in IVF, ART makes up for only half of the births lost by postponing a first attempt of pregnancy from age 30 to 35 years, and <30% after postponing from 35 to 40 years. CONCLUSIONS: Even if we relax some of the assumptions, ART in its present form cannot make up for all births lost by the natural decline of fertility after age 35 years.

Computer Simulation↗
PubMed2004

Towards less confusing terminology in reproductive medicine: a proposal.

The use of the term 'infertility' and related terms in reproductive medicine is reviewed. Current terminology is found to be ambiguous, confusing, and misleading. We recommend that the fertility investigation report of a couple should consist of statements concerning description, diagnosis, and prognosis. The description concerns the duration of nonpregnancy before consulting the clinician. A system for prognostic grading is proposed. The fertility investigation report forms the basis for further action, including the possibility of waiting with treatment in case of almost normal or only slightly reduced fertility. The use of the terms 'infertility', 'subfertility', and 'fecundity' is not necessary, and it is recommended to avoid them.

Humans↗
PubMed2003

Contraception: from accessibility to efficiency.

BACKGROUND: Despite the widespread use of medical contraception in France, the prevalence of abortion remains stable. A cross-sectional population-based survey was designed to study the characteristics of current contraceptive use in France, the different types of contraceptive failure, and the reasons reported for not using contraception. METHODS: A representative sample of 14 704 French households was randomly selected from the telephone directory. All women who in the last 5 years had had an abortion or whose last pregnancy was unintended were selected (n = 1034), whilst a fraction (n = 1829) of the other women were randomly selected. Altogether, 2863 women answered the questionnaire. RESULTS: Only 2.7% of the women aged 18-44 years who did not wish to conceive and were sexually active did not use any contraception. However, 33% of pregnancies were estimated to be unplanned, of which 50% ended in an abortion. A total of 65% of the reported unplanned pregnancies occurred among women using contraception (21% the pill, 9% IUD, 12% condoms, 23% other method). The main reasons given for these contraceptive failures were the misuse of the methods or the failure of the partner to withdraw. Reasons for not using any contraception go beyond a simple lack of information. CONCLUSIONS: The importance of-and the reasons mentioned for-contraceptive failure show a misadaptation between women's contraceptive needs and the method they use. Improving the training of family planning providers remains a major goal to ensure that women use a contraceptive method that fits their social and sexual lifestyle.

Abortion, Induced↗
PubMed2002

[The many states of aging: a meeting and some demographic aspects].

With an expectation of life at birth of 27 years in the middle of the 18th century, 21% of males reached their 60th birthday with a remaining expectation of life of 12 years. Under the conditions of mortality of 1950, in France, 70 percent could celebrate their 60th birthday, and they had still 15 years (only) to live on the average. This last figure started increasing after 1950: the expectancy of life at age 60 is now over 20 years, and it will exceed 25 years around 2050 (for women, the mean will be 31 years). Longevity is an individual capacity. It is now increasing fast, and becomes more and more responsible for the ageing of the population (the rise in the proportion of older persons in the population). We now try to forecast the number of centenarians, and even of super-centenarians (aged 110 years and more), and speculate about the maximum life span. We are in fact entering an entirely new era, when three, four, even five generations can survive simultaneously. Are we prepared to it? The French Ministers for Research and for Social affairs set up a Committee of 15 members (chaired by Henri Leridon) to prepare a National Meeting of Researchers on Ageing, in order to review the situation of research in France on this issue and to make proposals for organising and orienting new studies. The life span of human species, as well as the one of individuals, is undoubtedly depending upon genetic factors. But interactions with environmental factors and with behaviour also play a major role. To be able to disentangle these complex associations, it will be necessary to combine the work of biologists, clinicians and social sciences specialists. The main conclusions of the June 2001 meeting are reported here, together with some orientations of demographic research on mortality at oldest ages and the limits of longevity.

Aged↗