Showing papers on "Fertility published in 2001"

Sperm Morphology, Motility, and Concentration in Fertile and Infertile Men

Abstract: Background Although semen analysis is routinely used to evaluate the male partner in infertile couples, sperm measurements that discriminate between fertile and infertile men are not well defined. Methods We evaluated two semen specimens from each of the male partners in 765 infertile couples and 696 fertile couples at nine sites. The female partners in the infertile couples had normal results on fertility evaluation. The sperm concentration and motility were determined at the sites; semen smears were stained at the sites and shipped to a central laboratory for an assessment of morphologic features of sperm with the use of strict criteria. We used classification-and-regression-tree analysis to estimate threshold values for subfertility and fertility with respect to the sperm concentration, motility, and morphology. We also used an analysis of receiver-operating-characteristic curves to assess the relative value of these sperm measurements in discriminating between fertile and infertile men. Results The su...

International variability of ages at menarche and menopause: patterns and main determinants.

Abstract: 1 Abstract The purpose of this study was to review published studies on the variability of age at menarche and age at menopause throughout the world, and to identify the main causes for age variation in the timing of these events. We first present a summary table including mean (or median) values of the age at menarche in 67 countries, and of the age at menopause in 26 countries. General linear models showed that mean age at menarche was strongly linked to the mean female life expectancy, suggesting that one or several variables responsible for inequalities in longevity similarly influ- enced the onset of menarche. A closer examination of the data revealed that among several variables reflecting living conditions, the factors best explain- ing the variation in age at menarche were adult illiteracy rate and vegetable calorie consumption. Because adult illiteracy rate has some correlation with the age at which children are involved in physical activities that can be detri- mental in terms of energy expenditure, our results suggest that age at menar- che reflects more a trend in energy balance than merely nutritional status. In addition, we found the main determinant of age at menopause to be the mean fertility. This study thus suggests that, on a large scale, age at menarche is mainly determined by extrinsic factors such as living conditions, while age at menopause seems to be mainly influenced by intrinsic factors such as the re- productive history of individuals. Finally, these findings suggest that human patterns cannot be addressed solely by traditional, small-scale investigations on single populations. Rather, complementary research on a larger scale, such as this study, may be more appropriate in defining some interesting ap- plications to the practical problems of human ecology.

Contribution of environmental factors to the risk of male infertility

Abstract: BACKGROUND: An increasing number of reports suggest that chemical and physical agents in the environment, introduced and spread by human activity, may affect male fertility in humans. We investigated the relationships between exposure to environmental agents and seminal characteristics, and the concentrations of reproductive hormones in the serum of men seeking infertility treatment. METHODS: We studied 225 male partners from consecutively recruited couples, who had their first infertility consultation between 1995 and 1998, in the Litoral Sur region of Argentina, one of the most productive farming regions in the world. RESULTS: A multivariate logistic regression model showed that exposure to pesticides and solvents is significantly associated with sperm threshold values well below the limit for male fertility. We also found that men exposed to pesticides had higher serum oestradiol concentrations, and that men exposed to solvents had lower LH concentrations than non-exposed men. All of these effects were greater in men with primary infertility than in men with secondary infertility. CONCLUSION: We have shown that environmental factors contribute to the severity of infertility, and that this may worsen the effects of pre-existing genetic or medical risk factors.

Optimal age at motherhood. Theoretical and empirical considerations on postponement of maternity in Europe

Abstract: The age at which women become mothers has increased to an all time high in most European countries in the past decennia. This increase of age at first birth is the main explanatory variable for the rapid decrease in fertility in European countries which has occurred at different points of time earlier in North and West Europe than in South Europe. To understand the development of the period fertility rate it is therefore crucial to understand the determinants of optimal age at maternity. This paper reviews empirical and theoretical literature and tries to give suggestions on future research directions. The econometric so called timing and spacing literature has used current female wages and male incomes as the main explanatory variables. However, theoretical research identifies on the one hand consumption smoothing, and on the other hand career planning of the woman as the main explanations to the postponement of maternity.

Fertility, Education, and Development: Evidence from India

Abstract: A large body of Indian and international evidence points to the role of increasing female education in lowering fertility. Questions have been raised however about the nature and interpretation of this evidence. Several studies have found little evidence of a positive link between womens education and "female autonomy" while other studies report no significant correlation between female education and fertility. This article attempts to address these issues by examining the determinants of fertility in India in a multivariate framework using district-level panel data linking two censuses 1981 and 1991. The panel aspect of the data permits controlling for district-specific effects that might otherwise produce a spurious correlation between fertility and various explanatory variables. Even after controlling for district effects womens education and child mortality emerge as the most important factors explaining fertility differences across the country and over time. Moreover low levels of son preference also contribute to lower fertility. By contrast general indicators of modernization and development such as urbanization poverty reduction and male literacy bear no significant association with fertility decline.

The Density of Social Networks and Fertility Decisions: Evidence From South Nyanza District, Kenya

Abstract: Demographers have argued increasingly that social interaction is an important mechanism for understanding fertility behavior Yet it is still quite uncertain whether social learning or social influence is the dominant mechanism through which social networks affect individuals’ contraceptive decisions In this paper we argue that these mechanisms can be distinguished by analyzing the density of the social network and its interaction with the proportion of contraceptive users among network partners Our analyses indicate that social learning is most relevant with high market activity; in regions with only modest market activity, however, social influence is the dominant means by which social networks affect women’s contraceptive use

Psychosocial characteristics of infertile couples: a study by the `Heidelberg Fertility Consultation Service'

Abstract: BACKGROUND: The aim of the study was to identify differences in psychological characteristics between couples with fertility disorders, especially idiopathic infertility, and a representative sample. MATERIAL AND METHODS: A total of 564 couples was examined using psychological questionnaires pertaining to sociodemographic factors, motives for wanting a child, dimensions of life satisfaction and couple relationships, physical and psychic complaints, and a personality inventory. RESULTS: Specific to our sample was the high educational level of the couples, and the large number with idiopathic infertility (27% of all diagnoses). There were no remarkable differences in psychological variables between the infertile couples and a representative sample, except that the infertile women showed higher scores on the depression and anxiety scales. Couples with idiopathic infertility showed no remarkable differences in the questionnaire variables compared with couples with other medical diagnoses of infertility. CONCLUSIONS: A typical psychological profile for infertile couples could not be identified using standardized psychometric rating methods. This may be an effect of the specific characteristics of our sample. For some couples, the infertility crisis can be seen as a cumulative trauma, which indicates that these couples have a marked need for infertility counselling.

Did the association between fertility and female employment within OECD countries really change its sign

Abstract: Recent literature finds that in OECD countries the cross-country correlation between the total fertility rate and the female labor force participation rate, which until the beginning of the 1980s had a negative value, has since acquired a positive value. This result is (explicitly or implicitly) often interpreted as evidence for a changing sign in the time-series association between fertility and female employment within OECD countries. This paper shows that the time-series association between fertility and female employment does not demonstrate a change in sign. Instead, the reversal in the sign of the cross-country correlation is most likely due to a combination of two elements: First, the presence of unmeasured country-specific factors and, second, country-heterogeneity in the magnitude of the negative time-series association between fertility and female employment. However, the paper does find evidence for a reduction in the negative time-series association between fertility and female employment after about 1985.

Births: final data for 1999.

Abstract: OBJECTIVES This report presents 1999 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal characteristics (medical risk factors, weight gain, tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS Descriptive tabulations of data reported on the birth certificates of the 3.96 million births that occurred in 1999 are presented. RESULTS Overall birth and fertility rates changed less than 1 percent in 1999. Teenage birth rates fell 2 to 6 percent. The rate for women aged 20-24 years declined slightly, while rates for women in their late twenties and their thirties rose 2 to 3 percent each. The number of births to unmarried women, the birth rate, and the percent of births that were to unmarried women each rose 1 percent or less. Smoking by pregnant women overall dropped again, but rose among women aged 18-24 years. Improvements in prenatal care utilization continued. The cesarean delivery rate increased for the third year after declining for 7 consecutive years. The proportion of multiple births continued to rise; however, higher order multiple births (e.g., triplets, quadruplets) declined for the first time in over a decade, following increases of 13 percent per year during 1990-98. The percent low birthweight remained at 7.6 percent, while preterm births rose to 11.8 percent. These trends are in large part the result of increases in multiple births.

Late Marriage and Less Marriage in Japan

Abstract: FOLLOWING WORLD WAR II, the mean age at marriage in Japan (as measured by the singulate mean age at marriage) remained fairly stable until 1975, when it suddenly began to increase Between 1975 and 1995, singulate mean age at marriage increased from 245 to 277 years for women and from 276 to 307 years for men, making Japan one of the latest-marrying populations in the world Over the same period, the proportion who will never marry, calculated from age-specific first-marriage probabilities pertaining to a particular calendar year, increased from 5 to 15 percent for women and from 6 to 22 percent for men-a far cry from the universal-marriage society of earlier years While of great interest in their own right, these marriage trends have gained attention also because they account for more than half of Japan's resumed fertility decline since 1973 (Ogawa and Retherford 1993b) This fertility decline has been substantial Between 1975 and 1999 the total fertility rate fell from 19 to 13 children per woman That fertility is now well below replacement level and still falling has caused much public concern in Japan The trend toward late marriage and less marriage has come about because of a confluence of interrelated economic, social, and cultural changes, including remarkable educational gains by women, massive increases in the proportion of women who work for pay outside the home, major changes in the structure and functioning of the marriage market, extraordinary increases in the prevalence of premarital sex, and far-reaching changes in values relating to marriage and family life In this article we describe these changes and assess their effects on age at marriage and the proportion never marrying in Japan

Mass education and fertility transition

Abstract: The relationship between the spread of mass education and fertility-limiting behavior is examined. Existing theories relating education to fertility limitation are integrated, including those relating the presence of educational opportunity to fertility decline, theories relating women's education to their fertility behavior, and theories relating children's education to the fertility behavior of their parents. Using survey data from a sample of 5,271 residents of 171 neighborhoods in rural Nepal, the individual-level mechanisms linking community-level changes in educational opportunity to fertility behavior are tested. A woman's proximity to a school during childhood dramatically increases permanent contraceptive use in adulthood. This finding is largely independent of whether the woman subsequently attended school, whether her husband attended school, whether she lived near a school in adulthood, and whether she sent her children to school. Strong fertility limitation effects were also found for husband's education and for currently living near a school. These effects were independent of other education-related measures. The largest education-related effect is for sending children to school

Sperm morphological defects related to environment, lifestyle and medical history of 1001 male partners of pregnant women from four European cities

Abstract: BACKGROUND: Recently, differences in semen quality have been found among the partners of pregnant women from four European cities: Turku, Copenhagen, Edinburgh and Paris. METHODS: During this study, slides from the four centres were subjected to a centralized assessment of sperm morphology. The percentages of sperm defects were recorded using a multiple-entry classification enabling the calculation of the multiple anomalies index (MAI), which is the mean number of anomalies per abnormal sperm. The relationships between various sperm abnormalities and self-reported data on medical history, lifestyle and occupational factors were examined. RESULTS: Significant differences in the MAI and most of the sperm defects were found between the four cities, and more abnormalities were found in spring than in winter. An increase in some sperm abnormalities was related to medical treatment of the mother during pregnancy, higher birthweight and previous treatment for cryptorchidism. Significant variations of several sperm defects were related to stress, weekly working time, occupational posture and metal welding, suggesting directions for further exposure studies. CONCLUSION: The present study indicated that the detailed assessment of sperm abnormalities is a useful biomarker of the effect of various external factors which may qualitatively affect human spermatogenesis.

Fertility and social interaction

Abstract: This chapter investigates whether colleagues’ fertility influences women’s transitions to parenthood. I draw on LinkedEmployer–Employee data (1993–2007) from the German Institute for Employment Research comprising 33,119 female co-workers in 6,579 firms. Results from discrete-time hazard models reveal social interaction e ects on fertility among women employed in the same firm. In the year after a colleague gave birth, transition rates to first pregnancy double. This e ect declines over time and vanishes after two years. Further analyses suggest that the influence of colleagues’ fertility is mediated by social learning.

Fertility after bilateral cryptorchidism. Evaluation by paternity, hormone, and semen data.

Abstract: Purpose: Evaluation of the fertility of a cohort of formerly bilaterally cryptorchid men in comparison with a group of formerly unilaterally cryptorchid men, and a group of control

Sexual Intercourse and Pregnancy Among African American Girls in High-Poverty Neighborhoods: The Role of Family and Perceived Community Environment

Abstract: Data are used from a random sample of African American families in impoverished Chicago neighborhoods to address two questions: How well do modeling, supervision, and marital transition hypotheses explain the relationship between family structure and early sexual debut and pregnancy for disadvantaged Black female adolescents? Do higher levels of social support from parents and neighborhood adults decrease the risk of sexual activity for youth in poor communities? Support for each hypothesis is contingent upon the family transition experienced and specific sexual outcome examined. Living in any type of married household reduces the risk of sexual debut and pregnancy. Stronger parent-child relationships are associated with delayed sexual onset, whereas the risk of pregnancy is reduced when adolescents report more working adults in their social networks.

The High Fertility of College Educated Women in Norway: An Artefact of the Separate Modelling of Each Parity Transition

Abstract: College education has a positive impact on birth rates, net of age and duration since previous birth, according to models estimated separately for second and third births. There are also indications of such effects on first-birth rates, in the upper 20s and 30s. Whereas a high fertility among the better-educated perhaps could be explained by socioeconomic or ideational factors, it might just as well be a result of selection. When all three parity transitions are modelled jointly, with a common unobserved factor included, negative effects of educational level appear. On the whole, the effects are less clearly negative for women born in the 1950s than for those born in the 1940s or late 1930s. The cohorts from the 1950s show educational differentials in completed fertility that are quite small and to a large extent stem from a higher proportion of childlessness among the better-educated. Second-birth progression ratios are just as high for the college educated as for women with only compulsory education, and the third-birth progression ratios differ very little. This reflects weakly negative net effects of education after first birth and spill-over effects from the higher age at first birth, counterbalanced by differential selectivity of earlier parity transitions.

Cohort Reproductive Patterns in Low‐Fertility Countries

Abstract: This paper presents a comprehensive picture of levels and trends of contemporary fertility in low-fertility countries of Europe North America Oceania and East Asia. Cohort fertility approach was applied to study the changes in womens childbearing patterns. Among the various findings it is noted that the levels trends and age patterns of cohort fertility for women born between 1930 and 1960 in Western countries differed from those in the formerly socialist countries. In most Western countries the decline of completed cohort fertility has been in progress starting with women born in the 1930s and women born around 1960 are likely to complete their fertility with values decidedly below the replacement level. While in the formerly socialist countries completed cohort fertility remained within narrow bands and was relatively steady starting with the cohorts born in the 1930s until the cohorts of the late 1950s; thereafter completed cohort fertility declined from one cohort to the next for women born during the late 1950s and early 1960s. In almost all industrialized and postindustrial societies women born during the 1960s and early 1970s are experiencing lower fertility at comparable ages than women born earlier.

Relationship of Bull Fertility to Sperm Nuclear Shape

Abstract: The relationship between sperm nuclear shape and bull fertility was determined. Two groups of bulls, 3 per group, were selected. Bulls differed in fertility based on lifetime nonreturn rates. Digital images of propidium iodide-stained sperm from each bull were collected and shape-evaluated by Fourier harmonic amplitudes 0 to 5. A discriminant function (P < .05) was constructed based on harmonic amplitudes and the 2 fertility groups. When individual sperm were classified as being of high or lower fertility, the percentage of each bull's sperm placed in the high-fertility group had a linear relationship (r = .89, P < .05) with fertility. To construct a plot of mean sperm shapes, a novel technique to automatically orient and identify the anterior tip of the sperm head was developed. The mean nuclear shape of high-fertility sperm was more elongated and tapered than those of lower fertility. A discriminant function (P < .05) was also constructed that separated the 6 bulls into 2 groups based only on the harmonic amplitudes or sperm nuclear shape. The bulls were correctly classified into the 2 fertility groups. A comparison of sperm chromatin structure analysis (SCSA) and harmonic amplitudes found that overall size variance, anterior roundness, and posterior taperedness of sperm nuclei were related to chromatin stability (P < .05). Some of the differences observed in sperm nuclear shape between the high- and lower-fertility bulls may be explained by varying levels of chromatin stability. However, sperm nuclear shape appears to contain additional information from chromatin stability alone. In this particular study, with 6 bulls, all with good chromatin quality, sperm nuclear shape was a better predictor of bull fertility.

The High Fertility of College Educated Women in Norway: An Artefact of the 'Piecemeal Approach'

Abstract: College education has a positive impact on birth rates, net of age and duration since previous birth, according to models estimated separately for second and third births. There are also indications of such effects on first-birth rates, in the upper 20s and 30s. Whereas a high fertility among the bettereducated perhaps could be explained by socioeconomic or ideational factors, it might just as well be a result of selection. When all three parity transitions are modelled jointly, with a common unobserved factor included, negative effects of educational level appear. On the whole, the effects are less clearly negative for women born in the 1950s than for those born in the 1940s or late 1930s. The cohorts from the 1950s show educational differentials in completed fertility that are quite small and to a large extent stem from a higher proportion of childlessness among the better-educated. Second-birth progression ratios are just as high for the college educated as for women with only compulsory education, and the third-birth progression ratios differ very little. This reflects weakly negative net effects of education after first birth and spill-over effects from the higher age at first birth, counterbalanced by differential selectivity of earlier parity transitions. (201 words)

Children’s experience of family disruption and family formation : Evidence from 16 FFS countries

Abstract: In this paper, we present a number of descriptive measures on children’s experience of family disruption and family formation. We use data from the Fertility and Family Surveys of 15 European count ...

Review of unexplained infertility and obstetric outcome: a 10 year review

Abstract: BACKGROUND: Increased maternal and fetal risks have been reported in pregnancies following unexplained infertility. Our aims were to examine the obstetric and perinatal outcome of singleton pregnancies in couples with unexplained infertility and explore the impact of fertility treatment. METHODS: Women with unexplained infertility were identified from the Aberdeen Fertility Clinic Database. Their unit numbers were matched against the Aberdeen Maternity and Neonatal Databank (AMND) in order to extract obstetric records of those women with subsequent pregnancy outcomes. The general obstetric population served as a control group. RESULTS: Women with unexplained infertility were older [30.8 versus 27.9 years, 95% confidence interval (CI) for difference = + 2.4 to + 3.4] and more likely to be primiparous (59 versus 40%, 95% CI = + 1.3 to + 1.9). After adjusting for age and parity they had a higher incidence of pre-eclampsia, abruptio placentae, preterm labour, emergency Caesarean section and induction of labour in comparison with the general population (P < 0.05). Perinatal outcome did not differ between women with unexplained infertility and those of the general population. The multiple pregnancy rate was 5.4% higher following fertility treatment than in women who conceived spontaneously (95% CI = + 2.8 to + 9.7). CONCLUSIONS: Women with unexplained infertility are at higher risk of obstetric complications which persist even after adjusting for age, parity and fertility treatment. The reasons are however unclear and merit further study.

Child Labor, Fertility and Economic Growth

Abstract: This paper explores the evolution of child labor, fertility, and human capital in the process of development. In early stages of development the economy is in a development trap where child labor is abundant, fertility is high and output per capita is low. Technological progress, however, increases gradually the wage differential between parental and child labor, thereby inducing parents to substitute child education for child labor and reduce fertility. The economy takes-off to a sustained growth steady-state equilibrium where child labor is abolished and fertility is low. Prohibition of child labor expedites the transition process and generates Pareto dominating outcome.

Use of GnRH Analogs for Functional Protection of the Ovary and Preservation of Fertility during Cancer Treatment in Adolescents

Abstract: Objective. Recent success in polychemotherapy (PCT) in adolescent female cancer patients has become a source of concern for specialists who also strive to preserve fertility. We studied whether gonadotropin-releasing hormone (GnRH) analogs could prevent the early onset of ovarian insufficiency postchemotherapy and protect fertility. Methods. The patients were divided into three groups: Control group 1 (Group A), premenarchal patients aged 3 to 7.5 years (n 5 5), were not given GnRH analogs administered prior to PCT. Postmenarchal patients (Group B), aged 14.7 to 20 years (n 5 12) with normal menstrual rhythm and ovulatory cycles, received treatment with GnRH analogs prior to PCT. Control group 2 (Group C), postmenarchal patients aged 15.9 to 20 years (n 5 4), received PCT but no GnRH analog protection. All groups received the PCT regimens CAVPE, CVPP, ABVD, TAMO, ARA-C, and MTT. In group B, leuprolide acetate inhibition was obtained with a depot injection administered each month before and during treatment with PCT. To accelerate the timing of ovarian regression, a subcutaneous injection (0.2 mg) was administered simultaneously. Results. In Group A, patients had spontaneous menarche between the ages of 12 and 17.9 years, followed by normal menstruation and ovulatory cycles. Three patients became pregnant. After GnRH analog withdrawal, Group B patients continued with normal ovulatory cycles. Two patients became pregnant. Group C patients presented hypergonadotrophic hypoestrogenic amenorrhea. Conclusion. GnRH analog treatment before and during PCT enhances ovarian function and preserves adolescent fertility. The results must be confirmed in a larger study. © 2001 Academic Press

Genetic and Environmental Correlations Among Female Fertility Traits and Milk Production in Different Parities of Swedish Red and White Dairy Cattle

Abstract: The main objective of this study was to estimate genetic correlations between fertility and production traits in first, second and third lactations as well as between fertility traits measured in the same way at different ages. The fertility traits studied were: number of inseminations per service period, number of treatments for reproductive disturbances, interval between first and last inseminations, interval between calving and first insemination, and interval between calving and last insemination. Early milk production was measured as the average of the energy-corrected milk yield at the second and third monthly testdays in a lactation. The number of records was approximately 450 000, 350 000, 180 000 and 75 000 in the heifer period, first, second, and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and sire of the cow was applied. To reduce the effect of ongoing selection, 305-days kg protein production in first lactation was include...

The incorporation of fertility indices in genetic improvement programmes

Abstract: In recent years there has been considerable genetic progress in milk production. Yet, increases in yield have been accompanied by an apparent lengthening of calving intervals, days open, days to first heat and a decline in conception rates, which appears to be both at the genetic and phenotypic level. Fertility has a high relative economic value compared to production traits such as protein, making it attractive to include in a breeding programme. To do this there needs to be genetic variance in fertility. Measures of fertility calculated from service dates have a small genetic compared to phenotypic variance, hence heritability estimates are small, typically less than 5%, although coefficients of genetic variance are comparable to those of production traits. Heritabilities of commencement of luteal activity determined using progesterone profiles are generally higher, and have been reported as being from 0.16 to 0.28, which could be because of a more precise quantification of genetic variance, as management influences such as delaying insemination and heat detection rates are excluded. However, it might not be the use of progesterone profiles alone, as days to first heat observed by farm staff has a heritability of 0.15. The most efficient way to breed for improved fertility is to construct a selection index using the genetic and phenotypic parameter estimates of all traits of interest in addition to their respective economic values. Index traits for fertility could include measures such as calving interval, days open, days to first service, or days to first heat but there may also be alternative measures. Examples include traits related to energy balance, such as live weight and condition score (change), both of which have higher heritabilities than fertility measures and have genetic correlations of sufficient magnitude to make genetic progress by using them feasible. To redress the balance between fertility and production, some countries already publish genetic evaluations of fertility including: Denmark, Finland, France, Germany, Israel, The Netherlands, Norway and Sweden.