Population Fertility Research Articles

The influence of type 1 diabetes mellitus on spermatogenic gene expression

Routine semen analysis found no differences in diabetic men; however, mRNA profiles showed changes in the expression of genes involved in oxidative stress.

Fecundity reduction and aging in fertile women population in the period 1990-2004 in Chile

Chile is in the advanced stage of demographic transition with a low natural growth and a progressively aging population. To analyze births by range of maternal age and to establish if population aging is expressed in the women's fertile age range. Trend analysis of births and age-specific birth rates in the period 1990-2004, in the Chilean women population of reproductive age. Raw data were obtained from the Vital Statistics Yearbooks of the National Institute of Statistics. Trends were studied by linear regression and Generalized Estimating Equation (GEE). The general trend of births descended significantly from 1999 to 2004 (r: -0.996; p <0.001). Births significantly decreased in the range of ages from 20 to 34 years. There was an increase in the range of ages from 35 to 44 and from 10 to 14 years. The age-specific birth rate declined in all ranges, with the exception of women aged 10 to 14 years. The number of women increased significantly at all age ranges, except for the 20-24 year-old range where no significant change was observed and the 25-29 year-old range that experienced a significant reduction. In the period from 1990 to 2004, there was a significant reduction of births and age-specific birth rates in Chile. There was also an increased birth rate among women aged 35 to 44 years and an aging of the fertile women population.

Reducción de la fecundidad y envejecimiento de la población de mujeres chilenas en edad fértil: 1990-2004

Chile is in the advanced stage of demographic transition with a low natural growth and a progressively aging population.To analyze births by range of maternal age and to establish if population aging is expressed in the women's fertile age range.Trend analysis of births and age-specific birth rates in the period 1990-2004, in the Chilean women population of reproductive age. Raw data were obtained from the Vital Statistics Yearbooks of the National Institute of Statistics. Trends were studied by linear regression and Generalized Estimating Equation (GEE).The general trend of births descended significantly from 1999 to 2004 (r: -0.996; p <0.001). Births significantly decreased in the range of ages from 20 to 34 years. There was an increase in the range of ages from 35 to 44 and from 10 to 14 years. The age-specific birth rate declined in all ranges, with the exception of women aged 10 to 14 years. The number of women increased significantly at all age ranges, except for the 20-24 year-old range where no significant change was observed and the 25-29 year-old range that experienced a significant reduction.In the period from 1990 to 2004, there was a significant reduction of births and age-specific birth rates in Chile. There was also an increased birth rate among women aged 35 to 44 years and an aging of the fertile women population.

Women's fertility and mortality in late mid life: A comparison of three contemporary populations

Evolutionary theory suggests a trade-off between reproduction and somatic maintenance implying a negative relationship between parity and longevity, at least in natural fertility populations. In populations in which fertility control is usual, there are also a number of mechanisms that may link reproductive careers and later mortality, but evidence of associations between women's fertility patterns and their later life health has been judged inconclusive due to varying controls for socio-economic characteristics and marital status. Here, we build on three recent studies that followed a common framework to investigate associations between women's parity and timing of first and last birth with mortality in late middle age in three contemporary developed counties, Norway, England and Wales, and the USA. Data were drawn from whole population registers (Norway); a large census-based record linkage study (England and Wales), and a nationally representative survey linked to death records (USA). Results show that teenage childbirth was associated with higher mortality risks in late middle age in all three countries. Risks of death were significantly raised among nulliparous women in Norway and England and Wales, and also raised (although not significantly so) for childless US women. However, although higher parity was associated with a slight mortality disadvantage in England and Wales and the USA, the reverse seemed the case in Norway. These finding suggest that in populations in which fertility control is usual, contextual factors influencing the relative costs and benefits of childbearing may influence associations between fertility histories and later mortality.

Fertility transition and population ageing in the Asian and Pacific region

During the past half century, the world has witnessed a remarkable decline in total fertility rates (TFRs) from a high level of 5 children per woman in the period 1950-1955 to 2.8 children per woman in the period 2000-2005. While the fertility transition was already well under way in Europe, North America, and Australia and New Zealand during the period 1950-1955, TFR was very high in the Asian region, at about 6 children per woman. Fertility continued to decline in Europe, from a TFR of 2.7 in the period 1950-1955 to replacement level (2.1 children per woman) during the 1970s. TFR is now far below replacement level in Europe.

Population dynamics in an age of declining fertility

The population of the world has more than tripled during the twentieth century. The apparatus of technical demography has been fruitfully employed to study the causes and implications of this growth. However, at century’s end, fertility levels in Europe, North America, and East Asia have declined to levels below those necessary for long-term population replacement (United Nations, 1997). The tools of technical demography are also useful for studying growth prospects in low fertility populations, although they have been less frequently used for this purpose. This paper discusses two features of population dynamics in low fertility populations. The first involves a decomposition of the intrinsic rate of natural growth into a fertility and a mortality component. The lesson is that there are sharply “increasing returns” to fertility reductions in terms of their impact on long-term growth rates. A particular absolute decline in the number of children per woman will have larger and larger impacts on the rate of population growth as fertility levels fall. The second lesson is that, with reference to the situation that is or will soon be facing most of the industrialized world, there is a momentum to population decline that is exactly analogous to the better-publicized momentum of population growth. The first lesson merely involves presenting and interpreting some wellestablished formulas. The second takes advantage of several new expressions. Although migration is an additional factor of population growth in lowfertility countries, we choose to focus on fertility and assume that populations are closed to migration.

The problem of infertility in high fertility populations: Meanings, consequences and coping mechanisms in two Nigerian communities

This paper examines how socio-economic contexts shape local meanings of infertility, how the prevalence of infertility affects these meanings, and how the above affect community responses, life experiences and infertility treatment-seeking behaviors in two African communities. The paper is based on interdisciplinary research conducted among the Ijo and the Yakurr people of southern Nigeria that included a survey of approximately 100 infertile women and a matching sample of 100 fertile women, as well as in-depth ethnographic interviews with infertile and fertile women in two communities: Amakiri in Delta State and Lopon in Cross River State. In-depth interview results show that female infertility is more problematic among the Ijo in Amakiri, where kinship is patrilineal (traced through the father's side), than among the Yakurr in Lopon, where kinship is double unilineal (traced through both parents). Childless women in Ijo society are not only disadvantaged economically but are prevented from attaining full adult womanhood. They therefore leave the community more often than other members. In Lopon there is also a strong preoccupation with fertility as a central fact of life, but infertile women receive support from maternal kin as well as voluntary associations serving as support groups. Our survey data confirm that there are significant differences between the life experiences of infertile and fertile women and between the infertile women of the two communities. The overall findings indicate that while there are variations in the extent to which infertility is considered problematic, the necessity for a woman to have a child remains basic in this region. Motherhood continues to define an individual woman's treatment in the community, her self-respect and her understanding of womanhood.

A critical assessment of the role of antiphospholipid antibodies in infertility

Antiphospholipid antibodies (aPL) are a family of autoantibodies that are associated with pregnancy complications including stillbirth and recurrent miscarriage. Infertile women, and those with recurrent IVF implantation failure, have an increased incidence of aPL (22% and 30%, respectively) compared with a healthy, fertile population (1–3%). Despite this increased incidence, aPL are not predictive of an adverse outcome from IVF. In this review we critically assess the literature in this field, which we believe to be awash with poorly designed studies. Our main criticism is that studies have not examined the fertility outcomes for individual aPL, but rather have examined outcomes for women with between one and eight different aPL. The wide range of antibodies tested and collectively analyzed means that any clinically relevant effects of a specific antibody would be undetectable, if such effects exist. It is also difficult to envisage how aPL present in the maternal blood might damage zygotes or embryos in order to induce infertility. We review the experimental data, looking at possible mechanisms by which aPL might induce infertility. Despite the multiplicity of studies we demonstrate in this review that the question of whether aPL are associated with, or cause, reduced fertility remains unanswered. We also demonstrate that there is no evidence that supposedly aPL-induced infertility or implantation failure after IVF can be treated with pharmacological interventions.

The ageing of population in Kanjiza municipality

The aging of population in Vojvodina Province is one of the main political, national and economical issues. This paper presents the demographic situation in municipality of Kanjiza, researching the age structure. The aging is one of the most important demographic characteristics, which analyses the stage of development of a certain population. The consequence of low birthrate and emigrations in municipality of Kanjiza during the last 30- 40 years, is that the population in 1971. was in fourth stage of demographic development. The age structure in this paper is presented through the ageing of population, ageing index, age ratio, age group up to 20 year (young population) and age groups over 60 (old population), part of fertile and active population. .

Chromosomal Abnormalities in Miscarriages after Different Assisted Reproduction Procedures

About 10–15% of all recognised pregnancies end in spontaneous abortion and around 60% of these show a chromosomal abnormality. The finding of an abnormal karyotype allows one to avoid unnecessary and controversial testing and treatment, providing accurate reproductive and genetic counselling to the couple. Consequently, chromosome study of products of conception (POC) is routinely performed in our Institute, starting from 2002. Cytogenetic analysis on spontaneous metaphases, obtained using direct method, was successfully performed on a total of 277 cases: 133 from patients who underwent assisted reproductive technology (ART) and 144 samples from infertile couples that had natural conceptions (NC). An abnormal karyotype was observed in 84 (63.2%) cases after ART and in 103 (71.5%) after NC demonstrating that the ART group doesn't seem subjected to a higher cytogenetic risk due to the application of technical procedures and higher than the expected risk in the fertile population. Moreover we did not observe a significant difference in the incidence of chromosome anomalies between intracytoplasmic sperm injection (ICSI) (61.5%) and in vitro fertilisation (IVF) (54.5%). However, in the ICSI with testicular sperm extraction (ICSI-TESE) group, 80% of the cases were abnormal with 50% showing triploid/tetraploid karyotypes. Chromosomal abnormalities were present in 54.5% of miscarriages which occurred after ICSI with cryo-preserved oocytes (cryo-ICSI) and in 85.7% after intra-uterine insemination (IUI). To our knowledge this study analysed the largest number of POCs after ART and NC in an infertile population. Moreover, for the first time the cytogenetic results of POC from different ART procedures were included.

The frequency distribution of allelic variation in exon 10 of the FSH receptor gene in infertility patients from different ethnical backgrounds, a large population study from the Netherlands

OBJECTIVE: Studies on the frequency distribution of the follicle stimulating hormone receptor (FSHR) polymorphisms report conflicting results not only within fertile and infertile populations, but also between males and females. It has been suggested that ethnicity might influence these outcomes. Therefore, the aim of this study was to determine the frequency distribution of the FHSR polymorphisms, at position 680 of exon 10, within a large group of infertility patients from different ethnical backgrounds.DESIGN: Retrospective cohort study.MATERIALS AND METHODS: We studied 2001 patients (1771 women and 230 men) of different ethnic origin (Caucasian, Asian, Hindustani, Creole and Mediterranean). FSH receptor single nucleotide polymorphisms (SNPs) at codon 680 of exon 10 were determined by restriction fragment length polymorphism of amplicons generated by PCR. Genotypes were compared with serum FSH levels and between different ethnical groups.RESULTS: We found a significantly lower percentage of Asians to have the Ser680Ser receptor variant compared to Caucasians and Mediterranean's. FSH levels did not differ between either the various ethnical groups, or the different FSH receptor polymorphisms.CONCLUSIONS: In our study population the Ser680Ser receptor variant is less common in the Asian subgroup compared to Caucasians and Mediterranean's. These data indicate that when comparing allelic frequency distributions of the FSHR polymorphism variants one should account at least for ethnical background. FSH levels did not differ between FSHR polymorphisms or between ethnical groups. OBJECTIVE: Studies on the frequency distribution of the follicle stimulating hormone receptor (FSHR) polymorphisms report conflicting results not only within fertile and infertile populations, but also between males and females. It has been suggested that ethnicity might influence these outcomes. Therefore, the aim of this study was to determine the frequency distribution of the FHSR polymorphisms, at position 680 of exon 10, within a large group of infertility patients from different ethnical backgrounds. DESIGN: Retrospective cohort study. MATERIALS AND METHODS: We studied 2001 patients (1771 women and 230 men) of different ethnic origin (Caucasian, Asian, Hindustani, Creole and Mediterranean). FSH receptor single nucleotide polymorphisms (SNPs) at codon 680 of exon 10 were determined by restriction fragment length polymorphism of amplicons generated by PCR. Genotypes were compared with serum FSH levels and between different ethnical groups. RESULTS: We found a significantly lower percentage of Asians to have the Ser680Ser receptor variant compared to Caucasians and Mediterranean's. FSH levels did not differ between either the various ethnical groups, or the different FSH receptor polymorphisms. CONCLUSIONS: In our study population the Ser680Ser receptor variant is less common in the Asian subgroup compared to Caucasians and Mediterranean's. These data indicate that when comparing allelic frequency distributions of the FSHR polymorphism variants one should account at least for ethnical background. FSH levels did not differ between FSHR polymorphisms or between ethnical groups.

Age-specific ovarian function

It has been suggested that approximately 10% of females demonstrate premature ovarian aging. In younger women the diagnosis is frequently overlooked, since ovarian function parameters often still lie within ranges that are traditionally considered normal. Age-specific ovarian testing normalizes ovarian function parameters according to age. Such testing can, therefore, detect subtle ovarian abnormalities at earlier stages. Timely diagnosis of premature ovarian aging mandates the understanding of age-specific ovarian function testing. Among active infertility patients such testing reveals a far higher prevalence of premature ovarian aging risk than in a general population, the highest in youngest patients and a declining risk as women age. Since patient populations at different fertility centers vary in severity of ovarian compromise, center-based, age-specific ovarian function tests are not universally applicable. Such universally applicable function tests can only be defined in normal, fertile populations...

Screening for cystic fibrosis in an egg donation program

OBJECTIVE: Cystic fibrosis (CF) is an autosomic recessive disease with a prevalence of 1/2500 livebirths. Given this high prevalence and the severity of the disease, ACOG recommends CF screening in all couples preconceptionally. ASRM guidelines state that testing for CF carrier status should be preformed on all donors, whereas evaluation of karyotype is not required. The purpose of this study was to assess the incidence of CF carrier status in egg donors and in partners of egg recipients and to determine the incidence of chromosomal abnormalities in egg donors. DESIGN: Prospective clinical study in a private IVF center. MATERIALS AND METHODS: CF carrier status was tested in 77 prospective egg donors and 127 recipient partners screened in our egg donation program from January 2007 to April 2008. All donors were of Spanish nationality, most native of Canary Islands. The 19 mutations most frequently encountered in our region were tested in all prospective donors. Of the 127 recipients 84 were of Spanish nationality, most native of Canary Islands, and 43 were Italians. CF screening in recipient partners included different numbers of mutations depending on the reference laboratory. All prospective donors had a chomosomal analysis performed. RESULTS: Three of the 77 donors screened were CF carriers (3.8%) and were not accepted in the program. The following mutations were found: ΔF508, R553X and Y148T. Two of the 127 partners were CF carriers (1.6%), both with the mutations ΔF508. No chromosomal abnormalities were detected in prospective donors. CONCLUSIONS: These results stress the importance of CF screening of egg donors to prevent transmission of this disease. Although Spanish law does not specifically include CF screening among the obligatory tests for donors, the high incidence of the CF carrier status in our donor population indicates that all programs should include CF in their screening. These data also indicate that testing for the CF carrier status should be extended to the fertile population as a preconceptional test either in the female or in the male partner. On the other hand it is probably unnecessary to perform a karyotype in all donors.

Baseline expression profile of meiotic-specific genes in healthy fertile males

To establish the quantitative gene-expression profile of nine meiotic genes involved in synapsis and chromosome cohesion (SYCP1, SPO11, MSH4, MSH5, MLH1, MLH3, PMS2, STAG3, and REC8) in healthy fertile males. Prospective study. Research university laboratory and clinical andrology service. Twenty healthy males of proven fertility underwent a vasectomy procedure and four infertile patients with Sertoli cell-only syndrome (SCOS). Analysis of testicular biopsies from 20 fertile males and four SCOS patients. Quantitative gene expression by real-time polymerase chain reaction in testicular biopsies. Four of the nine genes under study (PMS2, MLH3, MLH1, and REC8) are expressed in both fertile males and SCOS patients. The remaining five genes are only (SYCP1, SPO11, MSH4, and MSH5) or mainly (STAG3) expressed in fertile males, and thus they could be considered meiotic-specific genes. All genes analyzed are expressed at similar levels among fertile individuals Gene expression levels reported in this study could be considered the gene expression profile of fertile population, and could be used to compare with the expression pattern of infertile patients. Expression of meiotic-specific genes could be used as a clinical diagnosis tool to ascertain the origin of some cases of idiopathic male infertility and sterility.

Chromosome heteromorphisms: an impact on infertility

Cytogenetic heteromorphisms are described as heritable variations at specific chromosomal regions without a proven impact on phenotype. We compared the presence of chromosome heteromorphisms in the karyotypes of two patient groups. The first group of patients consisted of 276 individuals of 138 infertile couples. The second group, consisted of 1,130 amniocentesis samples. This group was considered to be a sample of the fertile population, as the fetus being karyotyped is the result of a spontaneous pregnancy. Fetal karyotyping was made due to the standard indications for prenatal diagnosis, such as abnormal maternal serum screening results. Eighteen infertile patients (6.52%) and twenty fetuses (1.77%) were found to have chromosome heteromorphisms. The difference between the two groups was statistically significant (p < 0.0001). These results are consistent with other similar studies that suggest the yet undefined relationship between chromosome heteromorphisms and infertility.

Reproductive conflict and the separation of reproductive generations in humans

An enduring puzzle of human life history is why women cease reproduction midway through life. Selection can favor postreproductive survival because older females can help their offspring to reproduce. But the kin-selected fitness gains of helping appear insufficient to outweigh the potential benefits of continued reproduction. Why then do women cease reproduction in the first place? Here, we suggest that early reproductive cessation in humans is the outcome of reproductive competition between generations, and we present a simple candidate model of how this competition will be resolved. We show that among primates exhibiting a postreproductive life span, humans exhibit an extraordinarily low degree of reproductive overlap between generations. The rapid senescence of the human female reproductive system coincides with the age at which, in natural fertility populations, women are expected to encounter reproductive competition from breeding females of the next generation. Several lines of evidence suggest that in ancestral hominids, this younger generation typically comprised immigrant females. In these circumstances, relatedness asymmetries within families are predicted to give younger females a decisive advantage in reproductive conflict with older females. A model incorporating both the costs of reproductive competition and the benefits of grandmothering can account for the timing of reproductive cessation in humans and so offers an improved understanding of the evolution of menopause.

A new estimate of permanent sterility by age: Sterility defined as the inability to conceive

The proportion of couples permanently sterile beyond a certain age is an important component of the reproductive process. Unless medical assistance is used, this age is the upper bound of the fecund period. Most estimates of sterility by age of the woman have been derived from natural fertility populations, in which the number of births and the timing of the last birth (of the complete reproductive history) were not controlled by the couples. Because data on these populations do not include pregnancies not ending in a live birth, the sterility estimates apply to the proportion of couples unable to conceive and to have a live birth. For this reason, it is useful to have an estimate of sterility based on the risk of conceiving, independently of the fate of the pregnancy. Using this new estimate, sterility increases with age much more slowly than with most previous estimates.

Gender Differences in Endothelial Progenitor Cells and Cardiovascular Risk Profile

Endothelial progenitor cells (EPCs) participate in vascular homeostasis and angiogenesis. The aim of the present study was to explore EPC number and function in relation to cardiovascular risk, gender, and reproductive state. As measured by flow-cytometry in 210 healthy subjects, CD34(+)KDR(+) EPCs were higher in fertile women than in men, but were not different between postmenopausal women and age-matched men. These gender gradients mirrored differences in cardiovascular profile, carotid intima-media thickness, and brachial artery flow-mediated dilation. Moreover, EPCs and soluble c-kit ligand varied in phase with menstrual cycle in ovulatory women, suggesting cyclic bone marrow mobilization. Experimentally, hysterectomy in rats was followed by an increase in circulating EPCs. EPCs cultured from female healthy donors were more clonogenic and adherent than male EPCs. Treatment with 17beta-estradiol stimulated EPC proliferation and adhesion, via estrogen receptors. Finally, we show that the proangiogenic potential of female EPCs was higher than that of male EPCs in vivo. EPCs are mobilized cyclically in fertile women, likely to provide a pool of cells for endometrial homeostasis. The resulting higher EPC levels in women than in men reflect the cardiovascular profile and could represent one mechanism of protection in the fertile female population.

Prevalence of Sperm in the Post-Ejaculatory Urine of Fertile and Subfertile Men

The purpose of this study was to determine the prevalence of sperm within post-ejaculatory urine in both fertile and infertile men. Fifteen men of proven fertility and 66 non-azoospermic men being evaluated for infertility were recruited in two academic centers. Laboratory studies included a semen analysis and the examination of post-ejaculate urine for the presence and concentration of sperm. The median total urine sperm count for the fertile group (26.6 million) was not significantly greater than the infertile group (8.3 million, P = 0.63). The median percentage of total sperm (urine plus semen) present in urine for the fertile group (14.8%) was not different from that in the infertile group (15.3%, P = 0.36). Sperm were found in the urine of 73% of fertile and 65% of infertile patients (P = 0.54). The prevalence of sperm in the post-ejaculatory urine in the fertile population is similar to that in infertile patients, which suggests that a great deal more information is needed to interpret this test in the management of these patients.

Population and population policy: French model

Generations born today, or at least are trying to be, are scarcer than before all over the world. This decrease in the number of children is affecting modern societies in many spheres. If it was to be supported by efficient policies, it could be the source of a general improvement of life conditions. However, if this phenomenon continues or becomes drastic, it could ultimately lead to slower or faster demographic ageing, which could endanger many social heritages. Public intervention must, in that case, impinge much deeper, but without guarantees for a complete, if not permanent, success. The introductory part of the article is dedicated to the concept "demographic revolution" which was developed in 1934 by the French politician and demographer Adolphe Landry, in order to mark the development of a demographic regime which is characterized by a universally accepted practice of birth control, which represents a response for the essential concern for life standard improvement, not only for the parents but their children as well. But then, birth control is the primary cause of population ageing. The article further presents some of the most striking traits of the current French demographic situation, as its future development. France has a positive balance of population exchange with the remaining part of the world, as most of the Western European countries, but still the greatest part of its demographic increase is obtained from a larger number of births than deaths. Because of this, France is often seen as a real demographic paradise in Europe, whose population is decreasing and ageing. This image is certainly flattering, but it is becoming very contradictory after an analysis of long-term trends of fertility indicators and population ageing. The third part of the article, with the situation in France in focus, investigates the modalities and limitations of activities which a society, faced with demographic ageing and decreasing number of children, can apply: policies or simple "adjusting along the way" to demographic processes measures; policies and measures which are more intervening - even in the completely private sphere of birth-giving, and directed towards the limitation of some very unfavorable effects and not towards the change of strongly expressed tendencies of population ageing.