Alcohol binge drinking during pregnancy and cryptorchidism

Maternal alcohol intake in early pregnancy and biomarkers of fecundity in adult sons: A cohort study

Male fecundity may be largely determined through fetal programming and therefore potentially be sensitive to exposure to maternal alcohol intake during pregnancy. We investigated whether maternal alcohol intake in early pregnancy was associated with biomarkers of fecundity in adult sons. In total, 1058 sons from the Fetal Programming of Semen Quality (FEPOS) cohort nested in the Danish National Birth Cohort (DNBC) provided blood and semen samples at around 19 years of age. Information on maternal weekly average alcohol intake (0 drinks [ref], >0-1 drinks, >1-3 drinks, >3 drinks) and binge drinking episodes (intake of ≥5 drinks on one occasion: (0 [ref], 1-2, ≥3 episodes)) was self-reported at around gestational week 17. Outcomes included semen characteristics, testes volume and reproductive hormones. We found some small tendencies towards lower semen characteristics and an altered hormone level profile in sons of mother who had an intake of > 3 drinks/week in early pregnancy and sons of mother who had ≥ 3 episodes of binge drinking in pregnancy. However, the effect estimates were overall small and inconsistent and with no indication of a dose dependent association. Due to the limited number of mothers with a high weekly alcohol intake, we cannot exclude whether prenatal exposure to higher doses than 4.5 drinks/week of alcohol in early pregnancy might have a detrimental effect on the biomarkers of fecundity in adult sons..

Birth Defects Associated with Prenatal Alcohol Exposure-A Review

Since the recognition of fetal alcohol syndrome, alcohol has been accepted as a human teratogen. However, little is known about the relation between prenatal alcohol exposure and the spectrum of associated major birth defects. The objective of this review was to summarize data on the association of major congenital abnormalities and prenatal alcohol exposure. We included all major birth defects according to ICD-10 classification. We found that the strongest evidence to date lies in the research examining herniation (gastroschisis and omphalocele), oral clefts (cleft lip with or without palate and cleft palate) and cardiac defects. There is less consistent evidence supporting the association between prenatal alcohol exposure and anomalies of gastrointestinal system, diaphragmatic hernia, genitourinary system and neural tube defects. We found no material support for PAE and choanal atresia, biliary atresia or clubfoot.

Effects of the prenatal environment on cryptorchidism: A narrative review

Cryptorchidism, the absence of testes from the scrotum, is the most common genital disorder in boys and a risk factor for reduced fertility and testicular cancer. The mechanism responsible for cryptorchidism involves two discrete stages: a transabdominal and an inguinoscrotal phase. These phases of testicular descent are regulated by the prenatal sex hormone environment, including levels of testosterone, insulin-like factor 3, and calcitonin gene-related peptide. Environmental endocrine disruptors, which are unfavorable environmental factors, may also affect testicular descent through prenatal sex hormones. This review examined the effects of environmental factors, particularly environmental endocrine disruptors, such as phthalates, organochlorine pesticides, diethylstilbestrol, bisphenol A, dioxins/dioxin-like compounds, and perfluoroalkyl substances, and parental lifestyles on the risk of cryptorchidism. Although some studies have shown that environmental endocrine disruptors can affect testicular descent by changing the hormonal environment during the prenatal period, no significant association has been established between exposure to environmental endocrine disruptors and the incidence of cryptorchidism. Therefore, the role played by environmental endocrine disruptor exposure (if any) in the pathogenesis of cryptorchidism remains unknown. Further studies are needed to examine these issues.

Diagnosis and treatment of the intra-abdominal gonad in the pediatric population: Testes, ovaries, dysgenetic gonads, streaks, and ovotestes

BACKGROUND/PURPOSE

Pediatric surgical specialists are often confronted with the difficult task of identifying, diagnosing and managing intra-abdominal gonads in children. Ranging from the intra-abdominal cryptorchid testis to normal or pathologic ovaries and gonads in disorders of sexual development, all intra-abdominal gonads in the pediatric population pose different diagnosis and management challenges. Understanding the hormonal and fertility potential of the gonad and knowing its potential cancer risk is essential when deciding how to manage these patients. In addition, the ideal surgical management for each one of these patients is often debated.

METHODS

Descriptive literature review.

RESULTS/CONCLUSION

Herein, we reviewed gonadal formation, common etiologies, diagnosis and management of intra-abdominal testes, pathologic ovaries and gonads in disorders of sexual development. Fertility potential and cancer risk for each were also reviewed and how both affect surgical management of the gonad.

TYPE OF STUDY/LEVEL OF EVIDENCE

Review Article, Level V.

Lifestyle in pregnancy and cryptorchidism in sons: a study within two large Danish birth cohorts

Purpose

Cryptorchidism is the most frequent congenital malformation in boys and is associated with low sperm count, infertility and testicular cancer. Unhealthy maternal lifestyle during pregnancy such as smoking, high prepregnancy body mass index (BMI) as well as alcohol and caffeine intake may constitute possible risk factors for cryptorchidism, but results from the few previous studies are conflicting. We aimed to explore the association between maternal lifestyle factors and occurrence of cryptorchidism in sons.

Patients and methods

The Danish National Birth Cohort and the Aarhus Birth Cohort provided information on maternal lifestyle from early pregnancy. Data were linked to several Danish health registers, multiple imputation was used to handle missing data and Cox proportional hazards models were used to adjust for potential confounders.

Results

In total, 85,923 boys were included, and of them, 2.2% were diagnosed with cryptorchidism. We observed the strongest associations between maternal tobacco smoking and prepregnancy BMI and cryptorchidism. Sons of women who smoked 10–14 cigarettes/day had the highest hazard ratio (HR) for cryptorchidism (1.37; 95% CI: 1.06–1.76), and for maternal BMI ≥30 kg/m², the HR was 1.32 (95% CI: 1.06–1.65). Binge drinking was associated with an HR <1, if the women had one or two episodes in pregnancy (HR: 0.81; 95% CI: 0.67–0.98). Average maternal alcohol intake and caffeine intake during pregnancy were not significantly associated with a higher occurrence of cryptorchidism detected at birth or later in life.

Conclusion

Maternal tobacco smoking, overweight and obesity in pregnancy were associated with higher occurrence of cryptorchidism in boys in this study.

Association of light-to-moderate alcohol drinking in pregnancy with preterm birth and birth weight: elucidating bias by pooling data from nine European cohorts

Women who drink light-to-moderately during pregnancy have been observed to have lower risk of unfavourable pregnancy outcomes than abstainers. This has been suggested to be a result of bias. In a pooled sample, including 193 747 live-born singletons from nine European cohorts, we examined the associations between light-to-moderate drinking and preterm birth, birth weight, and small-for-gestational age in term born children (term SGA). To address potential sources of bias, we compared the associations from the total sample with a sub-sample restricted to first-time pregnant women who conceived within six months of trying, and examined whether the associations varied across calendar time. In the total sample, drinking up to around six drinks per week as compared to abstaining was associated with lower risk of preterm birth, whereas no significant associations were found for birth weight or term SGA. Drinking six or more drinks per week was associated with lower birth weight and higher risk of term SGA, but no increased risk of preterm birth. The analyses restricted to women without reproductive experience revealed similar results. Before 2000 approximately half of pregnant women drank alcohol. This decreased to 39% in 2000-2004, and 14% in 2005-2011. Before 2000, every additional drink was associated with reduced mean birth weight, whereas in 2005-2011, the mean birth weight increased with increasing intake. The period-specific associations between low-to-moderate drinking and birth weight, which also were observed for term SGA, are indicative of bias. It is impossible to distinguish if the bias is attributable to unmeasured confounding, which change over time or cohort heterogeneity.

Smoking and its association with cryptorchidism in Down syndrome

INTRODUCTION

Cryptorchidism is a common and prevalent condition in patients with Down syndrome. Environmental factors, such as smoking, can be associated with malformations during fetal development. The study of the prevalence of cryptorchidism and its association with parental tobacco use in Down syndrome can contribute to alert health care professionals, patients and family members regarding the prevention of the harms caused by cryptorchidism and its possible predisposing factors.

OBJECTIVE

To evaluate the prevalence of cryptorchidism in Down syndrome and its association with maternal and paternal smoking.

METHOD

Forty (40) patients of a public clinic specialized in Down syndrome were evaluated, using a semi-structured questionnaire for evaluation of antecedents and sociodemographic characteristics, as well as physical and complementary examinations.

RESULTS

Cryptorchidism was observed in 27.5% of the patients (95CI 15.98-42.96). Of these, 55% (5/9) were the children of mothers who smoked during pregnancy, and 19.35% (6/31) were the children of mothers who did not smoke during pregnancy (OR = 5.26 [95CI 1.06-25.41]; p=0.032). Similarly, paternal smoking was also observed in greater frequency among the parents of cryptorchid patients compared with subjects with descended testis, 63.36% (7/11) and 31.03% (9/29), respectively (OR = 3.89 [95CI 0.91-16.73]; p=0.060).

CONCLUSION

The prevalence of cryptorchidism is high in patients with Down syndrome. We can show a strong association between smoking parents and the occurrence of cryptorchidism, especially when it comes to maternal smoking.

Risk factors for cryptorchidism

Undescended testis - known as cryptorchidism - is one of the most common congenital abnormalities observed in boys, and is one of the few known risk factors for testicular cancer. The key factors that contribute to the occurrence of cryptorchidism remain elusive. Testicular descent is thought to occur during two hormonally-controlled phases in fetal development - between 8-15 weeks (the first phase of decent) and 25-35 weeks gestation (the second phase of descent); the failure of a testis to descend permanently is probably caused by disruptions to one or both of these phases, but the causes and mechanisms of such disruptions are still unclear. A broad range of putative risk factors have been evaluated in relation to the development of cryptorchidism but their plausibility is still in question. Consistent evidence of an association with cryptorchidism exists for only a few factors, and in those cases in which evidence seems unequivocal the factor is likely to be a surrogate for the true causal exposure. The relative importance of each risk factor could vary considerably between mother-son pairs depending on an array of genetic, maternal, placental and fetal factors - all of which could vary between regions. Thus, the role of causative factors in aetiology of cryptorchidism requires further research.

Developmental origins of male subfertility: role of infection, inflammation, and environmental factors

Male gamete development begins with the specification of primordial cells in the epiblast of the early embryo and is not complete until spermatozoa mature in the epididymis of adult males. This protracted developmental process involves extensive alteration of the paternal germline epigenome. Initially, epigenetic reprogramming in fetal germ cells results in removal of most DNA methylation, including parent-specific epigenetic information. The germ cells then establish sex-specific epigenetic information through de novo methylation and undergo spermatogenesis. Chromatin in haploid germ cells is repackaged into protamines during spermiogenesis, providing further widespread epigenetic reorganization. Finally, after fertilization, epigenetic reprogramming in the preimplantation embryo is necessary for regaining totipotency. These events provide substantial windows during which epigenetic errors either may be corrected or may occur in the germline. There is now increasing evidence that environmental factors such as exposure to toxicants, the parents' and individual's diet, and even infectious and inflammatory events in the male reproductive tract may influence epigenetic reprogramming. This, together with other damage inflicted on the germline chromatin, may result in negative consequences for fertility and health. Large epidemiological birth cohort studies have yielded insight into possible causative environmental factors. Together with experimental animal studies, a clearer view of environmental impacts on fetal development and their intergenerational and even transgenerational effects on reproductive health has emerged and is reviewed in this article.

Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility

It is predicted that Japan and European Union will soon experience appreciable decreases in their populations due to persistently low total fertility rates (TFR) below replacement level (2.1 child per woman). In the United States, where TFR has also declined, there are ethnic differences. Caucasians have rates below replacement, while TFRs among African-Americans and Hispanics are higher. We review possible links between TFR and trends in a range of male reproductive problems, including testicular cancer, disorders of sex development, cryptorchidism, hypospadias, low testosterone levels, poor semen quality, childlessness, changed sex ratio, and increasing demand for assisted reproductive techniques. We present evidence that several adult male reproductive problems arise in utero and are signs of testicular dysgenesis syndrome (TDS). Although TDS might result from genetic mutations, recent evidence suggests that it most often is related to environmental exposures of the fetal testis. However, environmental factors can also affect the adult endocrine system. Based on our review of genetic and environmental factors, we conclude that environmental exposures arising from modern lifestyle, rather than genetics, are the most important factors in the observed trends. These environmental factors might act either directly or via epigenetic mechanisms. In the latter case, the effects of exposures might have an impact for several generations post-exposure. In conclusion, there is an urgent need to prioritize research in reproductive physiology and pathophysiology, particularly in highly industrialized countries facing decreasing populations. We highlight a number of topics that need attention by researchers in human physiology, pathophysiology, environmental health sciences, and demography.

Maternal gestational smoking, diabetes, alcohol drinking, pre-pregnancy obesity and the risk of cryptorchidism: a systematic review and meta-analysis of observational studies

Background

Maternal gestational smoking, diabetes, alcohol drinking, and pre-pregnancy obesity are thought to increase the risk of cryptorchidism in newborn males, but the evidence is inconsistent.

Method

We conducted a systematic review and meta-analysis of studies on the association between maternal gestational smoking, diabetes, alcohol drinking, and pre-pregnancy obesity and the risk of cryptorchidism. Articles were retrieved by searching PubMed and ScienceDirect, and the meta-analysis was conducted using Stata/SE 12.0 software. Sensitivity analysis was used to evaluate the influence of confounding variables.

Results

We selected 32 articles, including 12 case—control, five nested case—control, and 15 cohort studies. The meta-analysis showed that maternal smoking (OR = 1.17, 95% CI: 1.11–1.23) or diabetes (OR = 1.21, 95%CI: 1.00–1.46) during pregnancy were associated with increased risk of cryptorchidism. Overall, the association between maternal alcohol drinking (OR = 0.97, 95% CI: 0.87–1.07), pre-pregnancy body mass index (OR = 1.02, 95% CI: 0.95–1.09) and risk of cryptorchidism were not statistically significant. Additional analysis showed reduced risk (OR = 0.89, 95% CI: 0.82–0.96) of cryptorchidism with moderate alcohol drinking during pregnancy. No dose—response relationship was observed for increments in body mass index in the risk of cryptorchidism. Sensitivity analysis revealed an unstable result for the association between maternal diabetes, alcohol drinking and cryptorchidism. Moderate heterogeneity was detected in studies of the effect of maternal alcohol drinking and diabetes. No publication bias was detected.

Conclusion

Maternal gestational smoking, but not maternal pre-pregnancy overweight or obesity, was associated with increased cryptorchidism risk in the offspring. Moderate alcohol drinking may reduce the risk of cryptorchidism while gestational diabetes may be a risk factor, but further studies are needed to verify this.

In utero exposure to alcohol and puberty in boys: a pregnancy cohort study

OBJECTIVES

Epidemiological studies have raised concerns about the reproductive consequences of in utero exposure to alcohol. Maternal lifestyle factors have been associated with altered pubertal development, but the impact of prenatal alcohol exposure on male puberty is unknown. Thus, the objective was to explore whether prenatal alcohol exposure alters pubertal development in boys.

SETTING

Follow-up of a Danish pregnancy cohort.

PARTICIPANTS

Sons (N=2522) of women who were enrolled in a Danish pregnancy cohort between 1984 and 1987.

PRIMARY AND SECONDARY OUTCOME MEASURES

Indicators of pubertal development, assessed by age at first nocturnal emission, voice break, acne and regular shaving.

RESULTS

We found a tendency towards a later age at first nocturnal emission and voice break following in utero exposure to binge drinking. Boys exposed to ≥5 binge drinking episodes during pregnancy experienced their first nocturnal emission 7.3 months (95% CI -2.8 to 17.4) later and voice break 4.9 months (95% CI -0.6 to 10.4) later than the unexposed boys. Results for average weekly alcohol consumption were in the same direction, but differences were smaller and not statistically significant.

CONCLUSIONS

We found no strong support for the hypothesis that in utero exposure to weekly alcohol consumption is a risk factor for altered pubertal development, but a tendency towards delayed pubertal development among boys exposed to binge drinking during fetal life was observed. Longitudinal studies, with data collected as children go through puberty, are needed to explore this further.

Prenatal ethanol exposure delays the onset of spermatogenesis in the rat

BACKGROUND

During late prenatal and early postnatal life, the reproductive system in males undergoes an extensive series of physiological and morphological changes. Prenatal ethanol (EtOH) exposure has marked effects on the development of the reproductive system, with long-term effects on function in adulthood. The present study tested the hypothesis that prenatal EtOH exposure will delay the onset of spermatogenesis.

METHODS

Development of the seminiferous tubules and the onset of spermatogenesis were examined utilizing a rat model of fetal alcohol spectrum disorder (FASD). Male offspring from ad libitum-fed control (C), pair-fed (PF), and EtOH-fed (prenatal alcohol exposure [PAE]) dams were terminated on postnatal (PN) days 5, 15, 18, 20, 25, 35, 45, and 55, to investigate morphological changes through morphometric analysis of the testes from early neonatal life through young adulthood.

RESULTS

PAE males had lower relative (adjusted for body weight) testis weights compared with PF and/or C males from PN15 through puberty (PN45). In addition, fewer gonocytes (primordial germ cells) were located on the basal lamina on PN5, while more of those touching the basal lamina were dividing in PAE compared with PF and C males, suggesting delayed cell division and migration processes. As well, the percentage of tubules with open lumena was lower in PAE compared with PF and C males on PN18 and 20, and PAE males had fewer primary spermatocytes per tubule on PN18 and round spermatids per tubule on PN25 compared with C males. Finally, the percentage of tubules at stages VII and VIII, when mature spermatids move to the apex of the epithelium and are released, was lower in PAE compared with PF and/or C males in young adulthood (PN55).

CONCLUSIONS

Maternal EtOH consumption appears to delay both reproductive development and the onset of spermatogenesis in male offspring, with effects persisting at least until young adulthood.

Accuracy of cryptorchidism diagnoses and corrective surgical treatment registration in the Danish National Patient Registry

PURPOSE

In recent years several Danish studies of the etiology, time trends and long-term health consequences of cryptorchidism have relied on diagnoses and surgical treatments registered in the National Patient Registry. We evaluated the diagnostic accuracy of these registry data.

MATERIALS AND METHODS

According to the Danish National Patient Registry, 16,168 males were diagnosed with cryptorchidism and 9,244 surgical treatments for cryptorchidism were performed between January 1, 1995 and October 10, 2009. We randomly selected 500 diagnosed cases, of which 284 had been managed surgically. We requested the medical records from the departments making the diagnoses and performing the surgery.

RESULTS

We successfully retrieved medical records for 452 diagnosed cases (90%) and 249 operations (88%). Overall positive predictive value of a registry diagnosis of cryptorchidism was 80% (95% CI 77-84) using the testicular position described by the physician performing the clinical examination as the gold standard. Similarly the positive predictive value of the surgical treatment registration was 99% (95% CI 98-100) using the type of procedure performed.

CONCLUSIONS

The data on cryptorchidism in the Danish National Patient Registry are quite accurate. In etiological research the limited misclassification will in most cases only slightly attenuate estimates of the true relative association. Thus, the registry has the potential to serve as a valuable research tool, although caution should be exercised when studying time trends or geographical differences.

Safety concerns regarding binge drinking in pregnancy: a review

BACKGROUND

There is ongoing debate about the risks to the fetus associated with maternal binge drinking. This makes it difficult to counsel patients about the potential risks associated with their use of alcohol during pregnancy.

METHODS

This article reviews the literature on animal and human studies regarding binge drinking (four to five drinks at one time in humans, or the equivalent in laboratory animals).

RESULTS

Animal studies provide evidence that high doses of alcohol over a short period of time can be more damaging than lower doses over a long period of time. Human data are more inconsistent, especially in terms of the association with malformations. Although neurobehavioral effects are the most commonly reported adverse outcome, some studies do not find such an association. Conclusions are confounded by the design of many studies, which fail to document pattern and total amount of alcohol consumption at one time. In addition, it has been suggested there is a bias against the null effect in publications.

CONCLUSION

Although the evidence in humans is not conclusive, the incidence of binge exposures in pregnancy is high, and it appears prudent to counsel patients to avoid this exposure whenever possible. Women inadvertently exposed to a single binge episode of alcohol early in the first trimester before pregnancy recognition can be reassured that the risks for adverse effects in their baby are likely low if they are able to discontinue use for the duration of the pregnancy. Unfortunately, there may be some residual fetal risk.

Regional differences and temporal trends in male reproductive health disorders: semen quality may be a sensitive marker of environmental exposures

The decline in semen quality has been the subject of an animated debate. A recent prospective study now irrefutably shows a decline in semen quality in men from Finland, a country that previously boasted good semen quality. Semen quality has, in some countries, reached a level where a considerable fraction of young men are at risk of fertility problems. Impaired semen quality, testicular cancer, cryptorchidism and hypospadias are risk factors for each other, and the testicular dysgenesis syndrome (TDS) has been put forward to explain the observations. This syndrome implies that the four disease entities share the same patho-physiological etiology caused by disturbed testicular development in early fetal life. It seems likely that the rapid rise in TDS-associated conditions can, at least partly, be explained by environmental factors. Animal studies provide strong evidence that manmade chemicals can disrupt the hormone dependent pathways responsible for fetal gonadal development, subsequently leading to TDS-like symptoms. In humans, fetal exposure to endocrine disrupting substances may play a role, although genetic factors are probably also involved. Recent studies indicate that exposure to endocrine disrupters also in adulthood may affect semen quality and reproductive hormones. Causal relationships are inherently difficult to establish in humans, and a clear connection between the disorders and specific toxicants has not been established. It seems likely that the cumulative effects of various low-dose exposures to endocrine disrupters in our environment are responsible for the adverse effects in the male reproductive system. Semen quality may be the most sensitive marker of adverse environmental exposures, and we suggest that standardized surveillance studies of semen quality are continued or initiated to monitor the combined effects of various preventive actions.

Prospective study on the prevalence and associated risk factors of cryptorchidism in 6246 newborn boys from Nice area, France

To assess the incidence and risk factors of cryptorchidism in Nice area. A 3-year prospective study was conducted at two maternity wards involving neonatal screening of boys born ≥34weeks of amenorrhoea. Methodology was strict with examination at birth, 3 and 12months by the same paediatrician. Two strictly matched controls were included for each case. Information on child and parents (medical history, pregnancy, lifestyle) was recorded using medical chart and self-administered questionnaires. A total of 102 of 6246 boys were born with cryptorchidism (prevalence 1.6%, 95 included). Half of them were still cryptorchid at three and 12months with, however, 10% of secondary re-ascent (recurrent cryptorchidism) at 12months, justifying long-term follow-up. Cryptorchidism at birth was associated with instrumental delivery, inguinal hernia and urogenital malformations, particularly micropenis and paternal history of cryptorchidism. Our results suggest that maternal exposure to anti-rust or phthalates could be a risk factor, whereas eating fruits daily seemed somewhat protective. Prevalence of cryptorchidism in our area is on the lower bracket compared with other countries, and is associated with both familial and environmental risk factors.

Testicular descent: INSL3, testosterone, genes and the intrauterine milieu

Complete testicular descent is a sign of, and a prerequisite for, normal testicular function in adult life. The process of testis descent is dependent on gubernacular growth and reorganization, which is regulated by the Leydig cell hormones insulin-like peptide 3 (INSL3) and testosterone. Investigation of the role of INSL3 and its receptor, relaxin-family peptide receptor 2 (RXFP2), has contributed substantially to our understanding of the hormonal control of testicular descent. Cryptorchidism is a common congenital malformation, which is seen in 2-9% of newborn boys, and confers an increased risk of infertility and testicular cancer in adulthood. Although some cases of isolated cryptorchidism in humans can be ascribed to known genetic defects, such as mutations in INSL3 or RXFP2, the cause of cryptorchidism remains unknown in most patients. Several animal and human studies are currently underway to test the hypothesis that in utero factors, including environmental and maternal lifestyle factors, may be involved in the etiology of cryptorchidism. Overall, the etiology of isolated cryptorchidism seems to be complex and multifactorial, involving both genetic and nongenetic components.

Maternal alcohol consumption during pregnancy and semen quality in the male offspring: two decades of follow-up

BACKGROUND

Concurrent alcohol exposure has been associated with reduced fecundity, but no studies have estimated the effect of prenatal alcohol exposure on male fecundity. The aim of this study was to investigate the association between maternal alcohol consumption during pregnancy, semen quality and levels of reproductive hormones in young, adult men.

METHODS

From a Danish pregnancy cohort established in 1984-1987, 347 sons were selected for a follow-up study conducted in 2005-2006. Semen and blood samples were analyzed for conventional semen characteristics and reproductive hormones, respectively, and results were related to prospectively self-reported information on maternal alcohol consumption during pregnancy.

RESULTS

The sperm concentration decreased with increasing prenatal alcohol exposure. The adjusted mean sperm concentration among sons of mothers drinking >or=4.5 drinks per week during pregnancy was 40 (95% CI: 25-60) millions/ml. This concentration was approximately 32% lower compared with men exposed to <1.0 drink per week, who had a sperm concentration of 59 (95% CI: 44-77) millions/ml. The semen volume and the total sperm count were also associated with prenatal alcohol exposure; sons prenatally exposed to 1.0-1.5 drinks per week had the highest values. No associations were found for sperm motility, sperm morphology or any of the reproductive hormones, including testosterone.

CONCLUSIONS

These results indicate that prenatal exposure to alcohol may have a persisting adverse effect on Sertoli cells, and thereby sperm concentration. If these associations are causal they could explain some of the reported differences between populations and long-term changes in semen quality.