Fertility

About: Fertility is a research topic. Over the lifetime, 29988 publications have been published within this topic receiving 681106 citations.

Causes of male infertility: a 9-year prospective monocentre study on 1737 patients with reduced total sperm counts.

Abstract: STUDY QUESTION What are the primary causes of severe male factor infertility? SUMMARY ANSWER Although 40% of all patients showed primary causes of infertility, which could be subdivided into three groups based on the severity of their effect, ~75% of oligozoospermia cases remained idiopathic. WHAT IS KNOWN ALREADY There are few large-scale epidemiological studies analyzing the causes of male factor infertility. STUDY DESIGN, SIZE, DURATION A prospective clinical-epidemiological study was conducted at the Andrology Centre, Tartu University Hospital between 2005 and 2013, recruiting male partners of couples failing to conceive a child for over ≥12 months. Among 8518 patients, 1737 (20.4%) were diagnosed with severe male factor infertility. A reference group of fertile controls was comprised of 325 partners of pregnant women. PARTICIPANTS/MATERIALS, SETTING, METHODS The mean age of infertility patients and fertile controls was 33.2 ± 7.3 and 31.7 ± 6.3 years, respectively. All participants were examined using a standardized andrology workup, accompanied by a structured medical interview. Hormonal analysis included serum FSH, LH and testosterone. Semen quality was determined in accordance to the World Health Organization recommendations. Cases with spermatozoa concentrations of ≤5 million/ml were screened for chromosomal aberrations and Y-chromosomal microdeletions. MAIN RESULTS AND THE ROLE OF CHANCE The primary cause of infertility was defined for 695 of 1737 patients (~40%). The analyzed causal factors could be divided into absolute (secondary hypogonadism, genetic causes, seminal tract obstruction), severe (oncological diseases, severe sexual dysfunction) and plausible causal factors (congenital anomalies in uro-genital tract, acquired or secondary testicular damage). The latter were also detected for 11 (3.4%) men with proven fertility (diagnoses: unilateral cryptorchidism, testis cancer, orchitis, mumps orchitis). The causal factors behind the most severe forms of impaired spermatogenesis were relatively well understood; causes were assigned: for aspermia in 46/46 cases (100%), for azoospermia in 321/388 cases (82.7%), and for cryptozoospermia in 54/130 cases (41.5%). In contrast, 75% of oligozoospermia cases remained unexplained. The main cause of aspermia was severe sexual dysfunction (71.7% of aspermia patients). Azoospermia patients accounted for 86.4% of all cases diagnosed with secondary hypogonadism and 97.1% of patients with seminal tract obstruction. Of patients with a known genetic factor, 87.4% had extreme infertility (azoo-, crypto- or aspermia). The prevalence of congenital anomalies in the uro-genital tract was not clearly correlated with the severity of impaired sperm production. Previously defined 'potential contributing factors' varicocele and leukocytospermia were excluded as the primary causes of male infertility. However, their incidence was >2-fold higher (31.0 vs 13.5% and 16.1 vs 7.4%; P < 0.001) in the idiopathic infertility group compared to controls. In addition, the proportions of overweight (or obese) patients and patients suffering from a chronic disease were significantly increased in almost all of the patient subgroups. LIMITATIONS REASONS FOR CAUTION The study included only subjects with reduced total spermatozoa counts. Thus, these findings cannot be automatically applied to all male factor infertility cases. WIDER IMPLICATIONS OF THE FINDINGS The novel insights and improved clarity achieved in the comprehensive analysis regarding the absolute, causative and plausible factors behind male infertility, as well as the 'potential contributing factors', will be valuable tools in updating the current clinical guidelines. The study highlights knowledge gaps and reiterates an urgent need to uncover the causes and mechanisms behind, and potential treatments of, oligozoospermic cases, representing the majority of idiopathic infertility patients (86.3%). STUDY FUNDING/COMPETING INTERESTS The project was financed by the EU through the ERDF, project HAPPY PREGNANCY, no. 3.2.0701.12-004 (M.P., M.L.) and the Estonian Research Council: grants PUT181 (M.P.) and IUT34-12 (M.L.). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. We have no competing interests to declare. TRAIL REGISTRATION NUMBER: Not applicable.

Completing the fertility transition in the developing world: The role of educational differences and fertility preferences

Abstract: This study summarizes patterns of educational differentials in wanted and unwanted fertility at different stages of the fertility transition. The data are from Demographic and Health Surveys in 57 less developed countries. As the transition proceeds, educational differentials in wanted fertility tend to decline and differentials in unwanted fertility tend to rise. An assessment of fertility patterns in developed and less developed countries with low fertility concludes that these differentials are likely to remain substantial when less developed countries reach the end of their transitions. This conclusion implies that the educational composition of the population remains a key predictor of overall fertility in late transitional countries and that low levels of schooling can be a cause of stalling fertility.

Perpetual postponers? Women's, men's and couple's fertility intentions and subsequent fertility behaviour.

Abstract: In this article data from the British Household Panel Study (BHPS) are used to analyse gender differences in fertility intentions, and the correspondence between fertility intentions and subsequent fertility behaviour. By exploiting couple-level data, we examine whether partners have conflicting preferences for future fertility. Focusing on women who remain childless in their thirties we look at socio-demographic factors related to the intention to remain childless, or to start a family later on in life. By following up women over time, the characteristics of women who go on to have a child later on in life are considered. The importance of having a partner and the fertility intention of that partner in predicting whether a birth will occur are also examined.

Men's body mass index and infertility

Abstract: Background In men, excess weight may be linked with altered testosterone, estradiol levels, poor semen quality and infertility. We investigated whether higher BMI among men is associated with infertility and if so, to what extent that effect might be mediated by altered sexual function. Methods A retrospective cohort study of pregnancies from 1999 through 2005 based within the Norwegian Mother and Child Cohort Study (MoBa). Questionnaires assessed mother's and father's height and weight and time to pregnancy. Our sample comprises 26 303 planned pregnancies. Couples were considered infertile if they took >or=12 months to achieve pregnancy or received infertility treatment. Results After adjusting for the woman's BMI, coital frequency and the ages and smoking habits of both partners, the odds ratio for infertility was 1.20 for overweight men [BMI 25-29.9; 95% confidence interval (CI) = 1.04-1.38] and 1.36 for obese men (BMI 30-34.9; 95% CI = 1.13-1.63) relative to men with low-normal BMI (20.0-22.4). When BMI was divided into eight categories, there was a trend of increased infertility with increased male BMI. The effect of men's BMI was nearly identical when coital frequency was not included indicating that the effect is not mediated by sexual dysfunction in heavier men. Conclusions This study adds further support that men with excess body weight are at increased risk of infertility. Values may be underestimated because the most severe cases, couples who do not conceive, are not included in this birth cohort. Research is needed to see if weight loss improves fertility for these men.

Human semen quality in the new millennium: a prospective cross-sectional population-based study of 4867 men

Abstract: Objectives Considerable interest and controversy over a possible decline in semen quality during the 20th century raised concern that semen quality could have reached a critically low level where it might affect human reproduction. The authors therefore initiated a study to assess reproductive health in men from the general population and to monitor changes in semen quality over time. Design Cross-sectional study of men from the general Danish population. Inclusion criteria were place of residence in the Copenhagen area, and both the man and his mother being born and raised in Denmark. Men with severe or chronic diseases were not included. Setting Danish one-centre study. Participants 4867 men, median age 19 years, included from 1996 to 2010. Outcome measures Semen volume, sperm concentration, total sperm count, sperm motility and sperm morphology. Results Only 23% of participants had optimal sperm concentration and sperm morphology. Comparing with historic data of men attending a Copenhagen infertility clinic in the 1940s and men who recently became fathers, these two groups had significantly better semen quality than our study group from the general population. Over the 15 years, median sperm concentration increased from 43 to 48 million/ml (p=0.02) and total sperm count from 132 to 151 million (p=0.001). The median percentage of motile spermatozoa and abnormal spermatozoa were 68% and 93%, and did not change during the study period. Conclusions This large prospective study of semen quality among young men of the general population showed an increasing trend in sperm concentration and total sperm count. However, only one in four men had optimal semen quality. In addition, one in four will most likely face a prolonged waiting time to pregnancy if they in the future want to father a child and another 15% are at risk of the need of fertility treatment. Thus, reduced semen quality seems so frequent that it may impair the fertility rates and further increase the demand for assisted reproduction.