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1.
J Urol ; 187(4): 1363-8, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22341293

ABSTRACT

PURPOSE: Although varicocele size has an inverse relationship with baseline semen parameters and a direct relationship with seminal reactive oxygen species in infertile patients, to our knowledge the effect of varicocele grade in fertile men is unknown. We evaluated the impact of varicocele grade on seminal parameters, testicular size and seminal reactive oxygen species in fertile men. MATERIALS AND METHODS: We prospectively evaluated 194 men from July 2004 to April 2010. Of the men 156 were fertile and classified by presence of varicocele. A total of 38 infertile patients with varicocele as the only identifiable cause of infertility comprised the control group. Physical examination, semen parameters and seminal reactive oxygen species were compared between the groups. RESULTS: Of 156 fertile men 43 (24.3%) had clinical varicocele, which was grade 1 to 3 in 22, 11 and 10, respectively. The remaining 113 men (72.7%) had no varicocele. Infertile men had smaller testes, decreased semen parameters and higher seminal reactive oxygen species than the fertile groups. Testicular size, reactive oxygen species and semen parameters did not differ between fertile men with vs without varicocele. Fertile men with varicocele grade 3 had higher seminal reactive oxygen species than those with lower grade varicocele. As varicocele grade increased, seminal reactive oxygen species increased and sperm concentration decreased. CONCLUSIONS: Although fertile men have more efficient defense mechanisms to protect against the consequences of varicocele on testicular function, these mechanisms may not be sufficient in those with varicocele grade 3. Further research is needed to clarify whether they are at increased risk for future infertility.


Subject(s)
Reactive Oxygen Species/analysis , Semen Analysis , Semen/chemistry , Testis/pathology , Varicocele , Adult , Fertility , Humans , Male , Organ Size , Prospective Studies , Varicocele/classification
2.
Urology ; 73(4): 887-91; discussion 891-2, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19201456

ABSTRACT

INTRODUCTION: The management of nonpalpable testicular masses is a challenging task, and coexisting infertility can further complicate the treatment decisions. We present our technique for microsurgical organ-sparing resection of incidental nonpalpable testicular nodules combined with microdissection for testicular sperm extraction and tissue cryopreservation in azoospermic patients. TECHNICAL CONSIDERATIONS: Five infertile patients with azoospermia presented with nonpalpable hypoechoic testicular masses that were detected by ultrasonography and underwent organ-sparing surgery. The testis was delivered through an inguinal incision, and the blood circulation was interrupted with a vascular clamp placed on the spermatic cord. Sludged ice was used to prevent warm ischemia, and a temperature probe was used to control the temperature at 12 degrees-15 degrees C. Real-time reflex ultrasonography was used to locate the tumor, and a stereotaxic hook-shaped needle was inserted under ultrasound guidance. The needle was placed adjacent to the tumor to guide the microsurgical resection. The tunica albuginea was incised over the tumor, which was dissected and removed, along with the adjoining parenchymal tissue. Frozen section studies were performed and, if malignancy was confirmed, biopsies of the tumor cavity margins and remaining parenchyma were obtained to ensure the absence of residual tumor. Microdissection was performed for excision of selected enlarged tubules that were processed and cryopreserved. CONCLUSIONS: We present a technique for microsurgical organ-sparing resection of testicular tumor and sperm extraction that can be used in selected infertile patients with azoospermia in whom incidental masses have been diagnosed by ultrasonography. This conservative approach should be especially considered for patients with a solitary testis or bilateral tumors.


Subject(s)
Azoospermia/surgery , Cryopreservation , Microsurgery , Testicular Neoplasms/surgery , Tissue and Organ Harvesting , Adult , Azoospermia/complications , Humans , Male , Testicular Neoplasms/complications , Urologic Surgical Procedures, Male/methods
3.
Fertil Steril ; 91(3): 925-8, 2009 Mar.
Article in English | MEDLINE | ID: mdl-18644594

ABSTRACT

OBJECTIVE: To describe a subinguinal technique of microsurgical testicular biopsy performed during subinguinal varicocelectomy in men with nonobstructive azoospermia. DESIGN: Prospective clinical study. SETTING: Andrology laboratory at tertiary care hospital. Male infertility section, department of urology, at tertiary care hospital. PATIENT(S): Ten azoospermic men with clinical varicocele. INTERVENTION(S): Subinguinal microsurgical testicular biopsy and microsurgical varicocele repair. MAIN OUTCOME MEASURE(S): Safety, feasibility, and effectiveness of subinguinal testicular biopsy during varicocele repair. RESULT(S): All testes were easily delivered through the subinguinal incision, and testicular biopsies were successfully performed under microscopic view. After a median follow-up of 9 months, none of the patients had any discomfort, pain, or presented with testicular atrophy. No intraoperative or postoperative complications were observed. There was no incidence of wound infection or scrotal hematoma. CONCLUSION(S): The subinguinal approach is a safe and effective option for testicular biopsy during varicocele repair in men with nonobstructive azoospermia. This technique may be an attractive alternative to traditional biopsy because it obviates scrotal violation.


Subject(s)
Azoospermia/surgery , Biopsy/methods , Microsurgery , Testis/surgery , Urologic Surgical Procedures, Male/methods , Varicocele/surgery , Adult , Azoospermia/etiology , Azoospermia/pathology , Biopsy/adverse effects , Feasibility Studies , Humans , Male , Microsurgery/adverse effects , Prospective Studies , Testis/pathology , Time Factors , Treatment Outcome , Urologic Surgical Procedures, Male/adverse effects , Varicocele/complications , Varicocele/pathology , Young Adult
4.
Urology ; 71(3): 490-4, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18342194

ABSTRACT

OBJECTIVES: The effects of advancing paternal age on the male reproductive system are well known, but its effects on fecundity remain controversial. Although oxidative stress is associated with poor semen quality and function, a relationship with advancing male age has not been established. The objective of this study was to analyze the relationship between male age and seminal reactive oxygen species (ROS) levels in men presenting for voluntary sterilization. METHODS: We prospectively evaluated 98 fertile men who were candidates for vasectomy. These were divided into 2 age groups: less than 40 years (n = 78) and 40 or more years (n = 20). We used 46 infertile patients as positive controls. Standard semen analysis, seminal leukocyte count and ROS levels were measured in all samples. Fertile men with leukocytospermia were excluded. RESULTS: The mean age of the men was 35.1 +/- 5.6 years. Men 40 years and older had significantly higher ROS levels compared with younger men (P <0.001). We observed a positive correlation between seminal ROS levels and age (r = 0.20; P = 0.040). In addition, ROS was negatively correlated with sperm concentration (r = -0.48; P <0.001) and motility (r = -0.21; P = 0.030). CONCLUSIONS: Reactive oxygen species levels are significant higher in seminal ejaculates of healthy fertile men older than 40 years. ROS levels in whole ejaculate are significantly correlated to age among fertile men. Because ROS are clearly implicated in the pathogenesis of male infertility, these data suggest that delayed fatherhood may reduce the chances of pregnancy as men become progressively less fertile with age.


Subject(s)
Fertility , Reactive Oxygen Species/analysis , Semen/chemistry , Adult , Age Factors , Humans , Infertility, Male/metabolism , Male , Prospective Studies
5.
Fertil Steril ; 90(4): 1103-8, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18022168

ABSTRACT

OBJECTIVE: To investigate: 1) the impact of clinical varicocele on reactive oxygen species (ROS) levels in neat and washed semen in a proven fertile population; and 2) the correlation between ROS levels, testicular volume, and varicocele grade in the same population of fertile men. DESIGN: Prospective controlled clinical study. SETTING: Andrology laboratory at tertiary-care hospital. PATIENT(S): One hundred fourteen healthy fertile men (81 normal fertile and 33 fertile with clinical varicocele) and 30 infertile patients (control subjects). INTERVENTION(S): Standard semen analysis and measurement of sperm ROS production. MAIN OUTCOME MEASURE(S): Seminal parameters, seminal ROS levels, seminal leukocyte levels, clinical varicocele, and testis size. RESULT(S): Thirty-three of the 114 (29%) fertile men had clinical varicocele (grade 1, n = 14; grade 2, n = 11; and grade 3, n = 8), and the remaining 81 (71%) had a normal physical examination. Levels of ROS and semen quality did not differ significantly between the fertile men with or without varicocele. No significant differences in ROS levels in neat and washed semen were observed compared with fertile men with grades 2 and 3 varicocele and with fertile men with varicocele grade 1. The ROS levels in neat and washed semen were not significantly correlated with varicocele grade in fertile men. No significant correlations between ROS levels and testis volume were observed between the fertile groups. CONCLUSION(S): The presence of clinical varicocele in fertile men is not associated with higher seminal ROS levels or abnormal semen parameters. Levels of ROS are not correlated with varicocele grade or testis volume in the same population of fertile men.


Subject(s)
Fertility , Infertility, Male/metabolism , Reactive Oxygen Species/metabolism , Semen/metabolism , Testis/metabolism , Testis/pathology , Varicocele/metabolism , Adult , Humans , Male , Organ Size
6.
Int Braz J Urol ; 33(5): 603-21, 2007.
Article in English | MEDLINE | ID: mdl-17980058

ABSTRACT

Oxidative stress (OS) in the reproductive tract is now a real entity and concern due to the potential harmful effects of high levels of reactive oxygen species (ROS) on sperm number, motility, quality, and function including damage to sperm nuclear DNA. Evaluation of OS related damage to non-functional sperm is highly relevant as intracytoplasmic sperm injection (ICSI) technique, an effective therapy for severe male factor infertility, bypasses the majority of reproductive tract deficiencies. Despite the controversial findings in the existing literature, there is now enough evidence to show that sperm DNA damage is detrimental to reproductive outcomes. In addition, spermatozoa of infertile men are suggested to carry more DNA damage than do the spermatozoa from fertile men. Besides impairment of fertility such damage is likely to increase the transmission of genetic diseases during the assisted reproductive procedures. Standardization of protocols to assess reactive oxygen species and DNA damage is very important in introducing these tests in such clinical practice. Thus evaluation of seminal ROS levels and extent of sperm DNA damage especially in an infertile male may help develop new therapeutic strategies and improve success of assisted reproductive techniques (ART).


Subject(s)
DNA Damage/physiology , Infertility, Male/physiopathology , Oxidative Stress/physiology , Reactive Oxygen Species/metabolism , Spermatozoa/pathology , Chromatin/pathology , Humans , Infertility, Male/etiology , Infertility, Male/metabolism , Male , Sperm Count , Sperm Motility/physiology
7.
Int. braz. j. urol ; 33(5): 603-621, Sept.-Oct. 2007. ilus
Article in English | LILACS | ID: lil-470211

ABSTRACT

Oxidative stress (OS) in the reproductive tract is now a real entity and concern due to the potential harmful effects of high levels of reactive oxygen species (ROS) on sperm number, motility, quality, and function including damage to sperm nuclear DNA. Evaluation of OS related damage to non-functional sperm is highly relevant as intracytoplasmic sperm injection (ICSI) technique, an effective therapy for severe male factor infertility, bypasses the majority of reproductive tract deficiencies. Despite the controversial findings in the existing literature, there is now enough evidence to show that sperm DNA damage is detrimental to reproductive outcomes. In addition, spermatozoa of infertile men are suggested to carry more DNA damage than do the spermatozoa from fertile men. Besides impairment of fertility such damage is likely to increase the transmission of genetic diseases during the assisted reproductive procedures. Standardization of protocols to assess reactive oxygen species and DNA damage is very important in introducing these tests in such clinical practice. Thus evaluation of seminal ROS levels and extent of sperm DNA damage especially in an infertile male may help develop new therapeutic strategies and improve success of assisted reproductive techniques (ART).


Subject(s)
Humans , Male , DNA Damage/physiology , Infertility, Male/physiopathology , Oxidative Stress/physiology , Reactive Oxygen Species/metabolism , Spermatozoa/pathology , Chromatin/pathology , Infertility, Male/etiology , Infertility, Male/metabolism , Sperm Count , Sperm Motility/physiology
8.
J Androl ; 28(4): 613-20, 2007.
Article in English | MEDLINE | ID: mdl-17409462

ABSTRACT

Although reactive oxygen species (ROSs) are clearly implicated in the pathogenesis of male infertility, few studies have attempted to define the basal levels of ROSs in fertile men. Levels of ROSs are highly influenced by the presence of leukocytes and are associated with decreased seminal parameters. The objective of our study was to determine the normal ROS reference values in neat and washed semen of a fertile population and to correlate the leukocyte concentrations with seminal parameters. We evaluated 114 fertile men seeking vasectomy and 47 subfertile patients as a positive control. All samples were subjected to semen analysis and Endtz testing; chemiluminescence assay was used to determine ROS levels. All seminal parameters were significantly higher in the fertile men than in the subfertile patients. In nonleukocytospermic samples, ROS levels were lower in the fertile men than in the subfertile patients in neat (0.29 [0.18, 0.54] vs 0.94 [0.38, 1.51]) (P = .001) and washed semen (5.73 [1.90, 14.71] vs 23.4 [9.46, 115.55]) (P = .001). Similarly, in samples with leukocytes (Entdz, less than 1 x 10(6)/mL), ROS levels were lower in the fertile men in neat (0.75 [0.27, 1.71] vs 2.0 [0.97, 27.41]) (P = .001) and washed semen (15.85 [4.18, 62.16] vs 239.83 [33.4, 1193.75]) (P < .0001). As expected, samples with leukocytes had significantly higher ROS values in washed and neat semen. In the fertile population, ROSs were positively correlated with leukocytes and negatively correlated with sperm count and motility. In semen samples without leukocytes, the normality cutoff of ROSs was 0.55 x 10(4) counted photons per minute with 76.4% area under the curve (AUC) in the neat samples and 10.0 x 10(4) counted photons per minute with 77% AUC in the washed samples. In semen samples with leukocytes, the cutoff for ROSs in neat samples was 1.25 with 72.7% AUC and 51.5 with 81% AUC in the washed samples. We defined the cutoff levels of ROSs in a fertile population. Seminal leukocyte levels below 1 x 10(6)/mL were associated with increased ROSs. ROS levels were positively correlated with leukocytes and negatively correlated with sperm motility and concentration. Patients with normal seminal parameters and lower seminal leukocyte levels may benefit from therapeutic interventions that improve semen quality.


Subject(s)
Fertility/physiology , Reactive Oxygen Species/metabolism , Semen/physiology , Spermatozoa/physiology , Cross-Sectional Studies , Humans , Male , Reference Values , Sperm Count , Sperm Motility , Spermatozoa/cytology
9.
J Androl ; 28(4): 528-32, 2007.
Article in English | MEDLINE | ID: mdl-17287456

ABSTRACT

In spite of prompt diagnosis and either orchiectomy or preservation of the affected testis, infertility remains a significant sequel to testicular torsion. The objective of this study was to evaluate the late endocrine profile, seminal parameters, and antisperm antibody levels after testicular torsion. We also analyzed the impact of orchiectomy or detorsion on the organ fate. Of 24 patients evaluated after testicular torsion, 15 were treated with orchiectomy (group 1) and 9 were treated with orchiopexy (group 2). All subjects were assessed by semen analysis, endocrine profile (levels of follicle-stimulating hormone, luteinizing hormone, and testosterone), and seminal antisperm antibody levels. A group of 20 proven fertile men was used as the control. Median ischemia time in group 1 (48 hours) was significantly higher than in group 2 (7 hours). Both groups demonstrated decreases in sperm count and morphology compared with controls. Group 1 showed a significantly higher motility than group 2 (P = .02). Group 1 also showed a significantly better morphology by World Health Organization and Kruger criteria than group 2 (P = .01). All patients presented endocrine profiles within the normal range, and no significant differences in antisperm antibody levels were detected between the groups. However, a trend for higher levels was found in patients treated for testicular torsion, regardless of the fate of the testis. Moreover, no significant correlation was found between antisperm antibody levels and age at torsion, ischemia time, seminal parameters, or treatment applied. In conclusion, we found that after torsion patients maintain late hormonal levels within the normal range. Testicular fate did not have any correlation with the formation of antisperm antibodies. Although sperm quality was preserved in most of the patients with the exception of sperm morphology, patients treated with orchiectomy presented better motility and morphology compared with the detorsion group. Further studies may clarify whether maintenance of a severely ischemic testicle may impair testicular function.


Subject(s)
Autoantibodies/blood , Semen/physiology , Spermatic Cord Torsion/surgery , Spermatozoa/immunology , Testis/surgery , Adolescent , Adult , Follicle Stimulating Hormone/blood , Functional Laterality , Humans , Luteinizing Hormone/blood , Male , Orchiectomy , Sperm Count , Sperm Motility , Spermatic Cord Torsion/blood , Spermatic Cord Torsion/immunology , Testosterone/blood
10.
Fertil Steril ; 85(4): 954-60, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16580380

ABSTRACT

OBJECTIVE: To evaluate semen characteristics, testicular volume, and hormonal levels of normal fertile men requiring vasectomy for sterilization. DESIGN: Retrospective study. SETTING(S): Academic medical centers. PATIENT(S): A total of 889 patients underwent a vasectomy for sterilization. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Semen volume, sperm concentration, motility, and morphology according to the World Health Organization (WHO); complex motion parameters evaluated by computer-assisted semen analyzer; FSH, LH, and T levels; and both testicular volumes. RESULT(S): When compared with the WHO values, 87.2% of the patients presented normal sperm morphology below the normal level. The other semen parameters (semen volume, pH, sperm concentration, and sperm motility) differed from the WHO parameters in 6%-32.2% of patients. Semen volume and sperm concentration presented a progressive increase according to the duration of sexual abstinence. However, patients with 5 days or more of abstinence had a decrease in sperm motility. Mean testicular size had the strongest correlation with serum FSH levels, total sperm count, and sperm concentration. CONCLUSION(S): Low sperm motility and morphology were found in men who request a vasectomy for sterilization. Semen volume and sperm concentration present a progressive increase and sperm motility a decrease according to the duration of sexual abstinence. Sperm concentration had stronger correlations with testicular size than did sperm quality. Therefore, the WHO normal values need to be reconsidered.


Subject(s)
Semen , Sperm Count/trends , Spermatozoa/pathology , Testis/pathology , Vasectomy , Adult , Aged , Humans , Male , Middle Aged , Organ Size/physiology , Retrospective Studies , Semen/physiology , Sperm Motility/physiology , Spermatozoa/physiology , Testis/physiology , Vasectomy/statistics & numerical data
11.
São Paulo med. j ; 123(4): 161-166, jul. 2005. tab
Article in English | LILACS | ID: lil-414411

ABSTRACT

CONTEXTO E OBJETIVO: Estudos recentes têm demonstrado diferenças regionais e populacionais quanto a características do sêmen. O objetivo foi estabelecer valores de referência para análise seminal e verificar o efeito da idade, tempo de abstinência sexual, sazonalidade, hábito de fumar e consumo de cafeína sobre as características do sêmen de indivíduos férteis. TIPO DE ESTUDO E LOCAL: Estudo prospectivo, na Divisão de Clínica Urológica do Hospital das Clínicas, Universidade de São Paulo. MÉTODOS: Entre setembro de 1999 e agosto de 2002, 500 homens férteis requisitando vasectomia com propósitos de esterilização voluntária foram solicitados a coletar uma amostra de sêmen antes da vasectomia. Avaliamos efeitos da idade, abstinência sexual, sazonalidade, consumo de cigarros e café nas características seminais. RESULTADOS: Quando comparados aos valores da Organização Mundial de Saúde, 87,2 por cento dos pacientes apresentavam morfologia espermática abaixo do normal. Foi observado declínio significativo do volume seminal, motilidade e morfologia em pacientes acima de 45 anos. Em pacientes com cinco dias ou mais de abstinência, houve redução da motilidade. Valores mais baixos para concentração, motilidade e morfologia espermática foram observados no verão e os mais elevados no inverno. Não houve diferenças nos parâmetros seminais estudados de acordo com o hábito de fumar. Com relação ao consumo de café, pacientes que ingeriam seis ou mais xícaras/dia apresentaram maior motilidade espermática. CONCLUSAO: Houve baixa porcentagem de morfologia espermática normal. Apenas a morfologia espermática apresentou alto percentual de anormalidade se levado em consideração o padrão descrito pela Organização Mundial de Saúde. Foram identificadas diferenças nos parâmetros seminais de acordo com a idade, tempo de abstinência sexual, sazonalidade e consumo de café. Não houve diferenças de acordo com o hábito de fumar.


Subject(s)
Humans , Male , Adult , Middle Aged , Semen/physiology , Sperm Count , Sperm Motility/physiology , Vasectomy , Age Factors , Caffeine/pharmacology , Prospective Studies , Reference Values , Seasons , Semen/cytology , Semen/drug effects , Sexual Abstinence/physiology , Smoking/adverse effects , Time Factors
12.
Sao Paulo Med J ; 123(4): 161-6, 2005 Jul 07.
Article in English | MEDLINE | ID: mdl-16389413

ABSTRACT

CONTEXT AND OBJECTIVE: Recent studies have shown regional and population differences in semen characteristics. The objective was to establish reference values for semen analysis and to verify the effect that age, length of sexual abstinence, seasonality, smoking habits and coffee consumption have on fertile individuals' semen characteristics. DESIGN AND SETTING: Prospective study in the Urology Division, Hospital das Clínicas, Universidade de São Paulo. METHODS: Between September 1999 and August 2002, 500 fertile men requesting a vasectomy for sterilization purposes were asked to provide a semen sample before the vasectomy. We evaluated the effects of age, sexual abstinence, seasonality, smoking and coffee consumption on semen characteristics. RESULTS: Compared with World Health Organization values, 87.2% of the patients presented sperm morphology below the normal level. A significant decline in semen volume, sperm motility and sperm morphology in patients over 45 years of age was observed. In patients with 5 days or more of abstinence, there was reduced sperm motility. The lowest values for sperm concentration, motility and morphology were observed in summer and the highest in winter. No differences in semen parameters relating to smoking were detected. Patients who drank six or more cups of coffee per day presented higher sperm motility. CONCLUSIONS: Our sample had a very low percentage of normal sperm morphology. Only sperm morphology showed a high abnormality rate. Differences in semen parameters with regard to age, length of sexual abstinence, seasonality and coffee consumption were identified. No differences relating to smoking were detected.


Subject(s)
Semen/physiology , Sperm Count , Sperm Motility/physiology , Vasectomy , Adult , Age Factors , Caffeine/pharmacology , Humans , Male , Middle Aged , Prospective Studies , Reference Values , Seasons , Semen/cytology , Semen/drug effects , Sexual Abstinence/physiology , Smoking/adverse effects , Sperm Count/standards , Time Factors
13.
Rev Hosp Clin Fac Med Sao Paulo ; 58(3): 173-8, 2003.
Article in English | MEDLINE | ID: mdl-12894315

ABSTRACT

Evidence suggests that human semen quality may have been deteriorating in recent years. Most of the evidence is retrospective, based on analysis of data sets collected for other purposes. Measures of male infertility are needed if we want to monitor the biological capacity for males to reproduce over time or between different populations. We also need these measures in analytical epidemiology if we want to identify risk indicators, risk factors, or even causes of an impaired male fecundity-that is, the male component in the biological ability to reproduce. The most direct evaluation of fecundity is to measure the time it takes to conceive. Since the time of conception may be missed in the case of an early abortion, time to get pregnant is often measured as the time it takes to obtain a conception that survives until a clinically recognized pregnancy or even a pregnancy that ends with a live born child occurs. A prolonged time required to produce pregnancy may therefore be due to a failure to conceive or a failure to maintain a pregnancy until clinical recognition. Studies that focus on quantitative changes in fecundity (that does not cause sterility) should in principle be possible in a pregnancy sample. The most important limitation in fertility studies is that the design requires equal persistency in trying to become pregnant and rather similar fertility desires and family planning methods in the groups to be compared. This design is probably achievable in exposure studies that make comparisons with reasonable comparable groups concerning social conditions and use of contraceptive methods.


Subject(s)
Infertility, Male/epidemiology , Semen/physiology , Female , Fertility , Humans , Infertility, Male/etiology , Male , Pregnancy , Sperm Count
14.
Article in English | LILACS | ID: lil-342138

ABSTRACT

Evidence suggests that human semen quality may have been deteriorating in recent years. Most of the evidence is retrospective, based on analysis of data sets collected for other purposes. Measures of male infertility are needed if we want to monitor the biological capacity for males to reproduce over time or between different populations. We also need these measures in analytical epidemiology if we want to identify risk indicators, risk factors, or even causes of an impaired male fecundity-that is, the male component in the biological ability to reproduce. The most direct evaluation of fecundity is to measure the time it takes to conceive. Since the time of conception may be missed in the case of an early abortion, time to get pregnant is often measured as the time it takes to obtain a conception that survives until a clinically recognized pregnancy or even a pregnancy that ends with a live born child occurs. A prolonged time required to produce pregnancy may therefore be due to a failure to conceive or a failure to maintain a pregnancy until clinical recognition. Studies that focus on quantitative changes in fecundity (that does not cause sterility) should in principle be possible in a pregnancy sample. The most important limitation in fertility studies is that the design requires equal persistency in trying to become pregnant and rather similar fertility desires and family planning methods in the groups to be compared. This design is probably achievable in exposure studies that make comparisons with reasonable comparable groups concerning social conditions and use of contraceptive methods


Subject(s)
Humans , Male , Female , Pregnancy , Infertility, Male , Semen , Fertility , Infertility, Male , Sperm Count , Testis
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