No association between maternal pre-pregnancy obesity and risk of hypospadias or cryptorchidism in male newborns

Maternal PM2.5 exposure and hypospadias risk in Chinese offspring: Insights from a nationwide surveillance-based study

Research on the association between maternal PM2.5 exposure and hypospadias risk in male offspring, particularly in highly polluted areas, has been limited and inconsistent. This study leveraged data from China's National Population-based Birth Defects Surveillance System spanning the years 2013 to 2019, and employed sophisticated machine learning models to estimate daily PM2.5 levels and other pollutants for mothers at a 1-km resolution and a 6-km buffer surrounding maternal residences. Multivariate logistic regression analyses were performed to evaluate the relationship between PM2.5 exposure and hypospadias risk. For sensitivity analyses, stratification analysis was conducted, and models for one-pollutant and two-pollutants, as well as distributed lag nonlinear models, were constructed. Of the 1194,431 boys studied, 1153 cases of hypospadias were identified. A 10 μg/m3 increase in maternal PM2.5 exposure during preconception and the first trimester was associated with an elevated risk of isolated hypospadias, with Odds Ratios (ORs) of 1.102 (95% CI: 1.023-1.188) and 1.089 (95% CI: 1.007-1.177) at the 1-km grid, and 1.122 (95% CI: 1.034-1.218) and 1.143 (95% CI: 1.048-1.246) within the 6-km buffer. Higher quartiles of PM2.5 exposure were associated with increased odds ratios compared to the lowest quartile. These findings highlight a significant association between PM2.5 exposure during the critical conception period and an elevated risk of isolated hypospadias in children, emphasizing the need for targeted interventions to reduce PM2.5 exposure among expectant mothers.

Maternal Diabetes and Risk of Hypospadias: A Systemic Review and Meta-Analysis

INTRODUCTION

This study aimed to investigate the association between maternal diabetes and the risk of hypospadias in male infants, as the relationship between them remains uncertain.

METHODS

To comprehensively evaluate the association between pregestational diabetes mellitus and gestational diabetes mellitus with hypospadias, we conducted a systematic review and meta-analysis. A thorough literature search was conducted, encompassing relevant publications published prior to January 2023. Crude odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated using a random-effects model.

RESULTS

Our meta-analysis comprised a total of 13 studies, 11 of which investigated the relationship between pregestational diabetes mellitus and hypospadias, while 9 studies explored the association between gestational diabetes mellitus and hypospadias. Notably, these investigations yielded compelling evidence of significant positive associations between pregestational diabetes mellitus and hypospadias (OR = 1.51, 95% CI = 1.13-2.03), as well as between gestational diabetes mellitus and hypospadias (OR = 1.18, 95% CI = 1.04-1.35).

CONCLUSION

Our findings suggest that both pregestational diabetes mellitus and gestational diabetes mellitus are associated with an increased risk of hypospadias in offspring. Further investigations are needed to explore the optimal range of blood glucose during pregnancy that minimizes the risk of congenital malformation in the fetus, as well as to develop more effective measures for glycemic control in pregnant women.

Parental smoking and risk of hypospadias: An updated meta-analysis of observational studies

Background

Inconsistent relationships have been shown between cigarette smoking and hypospadias in offspring. The purpose of this study was to summarize epidemiological evidence to evaluate the relationship between parental smoking and the risk of hypospadias.

Methods

Up until October 2022, PubMed, EMBASE, Web of Science, and the Cochrane Library were systematically searched for qualified research. The summary RRs and 95% CIs were calculated using either a fixed-effects or a random-effects model. There were subgroup analyses undertaken to identify potential sources of heterogeneity.

Results

44 studies with 16,637,830 participants were included in our meta-analysis. Overall, maternal active smoking [risk ratio (RR) = 0.94; 95% confidence interval (CI): 0.90-0.99; P < 0.01] was significantly associated with the risk of hypospadias. And neither paternal smoking (RR = 1.00; 95% CI: 0.86-1.15) nor maternal passive smoking (RR = 0.91; 95% CI: 0.60-1.23) was associated with the risk of hypospadias.

Conclusion

Our study discovered an association between maternal active smoking and a decreased risk of hypospadias, which may be due to the effect of smoking on androgen. However, as numerous studies have proved that cigarette smoking during pregnancy increases the risk of overall birth abnormalities in offspring, quitting cigarettes before pregnancy positively influences the health of offspring and should be advocated worldwide.

Systematic review registration

[www.crd.york.ac.uk/prospero], identifier [CRD42022319378].

Maternal smoking during pregnancy and the risk of congenital urogenital malformations: A systematic review and meta-analysis

BACKGROUND

Investigations regarding the association between maternal smoking and specific urogenital teratogenesis exist. However, an integrated systematic review and meta-analysis studying the relationship by encompassing the whole urogenital system is essential.

OBJECTIVE

Even though many studies about inborn urogenital malformations have been conducted, its etiologic factors and exact pathogenesis are still unclear. Our aim is to assess the risk of congenital urogenital malformations in offspring of smoking pregnant women.

RESULTS

The meta-analysis, covering 41 case-control and 11 cohort studies, suggested that maternal smoking was associated with an increased risk of urogenital teratogenesis (odds ratio [OR] = 1.13, 95% confidence interval [CI]: 1.04-1.23, p = 0.005), cryptorchidism (OR = 1.18, 95%CI: 1.12-1.24, p = 0.0001), hypospadias (OR = 1.16, 95%CI: 1.01-1.33, p = 0.039), and kidney malformations (OR = 1.30, 95%CI: 1.14-1.48, p = 0.0001). Moreover, paternal smoking during the mother's pregnancy was also significantly associated (OR = 1.26, 95%CI: 1.03-1.55, p = 0.028). The association between smoking > 10 cigarettes/day was evident but was not significant (OR = 1.24, 95%CI:0.81-1.88, p = 0.323).

CONCLUSION

Our results showed that maternal smoking during pregnancy increased the risk of congenital urogenital malformations. In numerous epidemiological studies, maternal smoking during pregnancy has a significant role in fetal development. Therefore, quitting tobacco use may be an effective method for reducing the risk of congenital urogenital malformation in pregnant women.

A systematic review of quantitative bias analysis applied to epidemiological research

BACKGROUND

Quantitative bias analysis (QBA) measures study errors in terms of direction, magnitude and uncertainty. This systematic review aimed to describe how QBA has been applied in epidemiological research in 2006-19.

METHODS

We searched PubMed for English peer-reviewed studies applying QBA to real-data applications. We also included studies citing selected sources or which were identified in a previous QBA review in pharmacoepidemiology. For each study, we extracted the rationale, methodology, bias-adjusted results and interpretation and assessed factors associated with reproducibility.

RESULTS

Of the 238 studies, the majority were embedded within papers whose main inferences were drawn from conventional approaches as secondary (sensitivity) analyses to quantity-specific biases (52%) or to assess the extent of bias required to shift the point estimate to the null (25%); 10% were standalone papers. The most common approach was probabilistic (57%). Misclassification was modelled in 57%, uncontrolled confounder(s) in 40% and selection bias in 17%. Most did not consider multiple biases or correlations between errors. When specified, bias parameters came from the literature (48%) more often than internal validation studies (29%). The majority (60%) of analyses resulted in >10% change from the conventional point estimate; however, most investigators (63%) did not alter their original interpretation. Degree of reproducibility related to inclusion of code, formulas, sensitivity analyses and supplementary materials, as well as the QBA rationale.

CONCLUSIONS

QBA applications were rare though increased over time. Future investigators should reference good practices and include details to promote transparency and to serve as a reference for other researchers.

Effects of Overweight and Obesity in Pregnancy on Health of the Offspring

Overweight and obesity in pregnancy confer a wide range of risks on mother, fetus, and offspring throughout their lives. In addition to compounding many common pregnancy complications, including both iatrogenic preterm delivery and cesarean delivery, obesity is associated with multiple fetal anomalies, metabolic sequelae including diabetes and obesity, allergy and asthma, attention-deficit disorder, and likely many other challenges for the offspring. As targeted interventions are being developed, encouraging solid nutrition and exercise in women of childbearing age may stave off risks and mitigate obesity in the next generation.

Interaction between CYP1A1/CYP17A1 polymorphisms and parental risk factors in the risk of hypospadias in a Chinese population

Hypospadias (HS) is a common congenital malformation of the genitourinary tract in males and its etiology is viewed as multifactorial, and studies about gene-environment interaction in the etiology of HS are rare. A total of 152 cases and 151 controls were selected in the present study. Information before and during pregnancy from questionnaires finished by mothers of subjects were extracted, and the relating data were analyzed to determine the risk factors of HS. Meanwhile, maternal genomic DNA was genotyped for the single nucleotide polymorphisms (SNPs) of CYP1A1 rs1048943 and CYP17A1 rs4919686. Results of multivariable logistic regression analyses showed that several factors were associated with hypospadias risk. Analysis of the distributions of SNPs in CYP1A1 and CYP17A1 genes showed that the mutant genotype CC (OR = 4.87) of CYP1A1 rs1048943, and mutant genotype CC (OR = 5.82), recessive genotype AC + CC (OR = 2.17) and allele C (OR = 1.77) of CYP17A1 rs4919686 significantly increased the risk of HS. In addition, the additive gene-environment interactions were also found in several models. Several maternal risk factors that are associated with HS risk can interact with CYP1A1/CYP17A1 polymorphisms, which lead to infants vulnerable to occurrence of HS in Chinese populations.

Maternal smoking during pregnancy and risk of cryptorchidism: a systematic review and meta-analysis

The risk factors for undescended testes in male infants and the underlying pathogenesis still remain unclear. The aim of this study is to identify the relationship between maternal smoking during pregnancy and risk of cryptorchidism. A systematic review was conducted using appropriate search terms to identify articles pertaining to maternal smoking during pregnancy and risk of cryptorchidism. Entries up to December 23, 2017 were taken into consideration, without any language or regional restriction. The crude ORs and their 95% CIs were computed by using the fixed-effect model. Twenty studies involving 111,712 infants were included in our meta-analysis. The risk of having a male infant with cryptorchidism was significantly different between mothers who smoked during pregnancy and those who did not (pooled crude OR 1.18, 95% confidence interval [CI] 1.12-1.24, p < 0.00001).Conclusion: Our findings suggest that smoking during pregnancy increased the risk of cryptorchidism by 1.18 times. Further investigations that are well-designed, multicentric studies measuring variables, such as the number of cigarettes smoked in a day and the stage of pregnancy during which the mothers smoked, are necessary to precisely determine the relationship between maternal smoking and risk of cryptorchidism. What is Known: • Preterm and low birth weight have been definitively shown to be risk factors for cryptorchidism. • The relationship between with maternal smoking during pregnancy and risk of cryptorchidism remains controversial all the time. What is New: • Mothers who smoked during pregnancy had a 1.18 times higher risk of having a child with cryptorchidism as compared to those who did not smoke. • Evidence has been found that maternal smoking during pregnancy is a definitive risk factor for cryptorchidism.

Hypertensive Disorders of Pregnancy and Genital Anomalies in Boys: A Danish Nationwide Cohort Study

BACKGROUND

Although congenital abnormalities in the male reproductive tract are common, their causes remain poorly understood. We studied associations between hypertensive disorders of pregnancy (pregestational hypertension, gestational hypertension, and preeclampsia) and the genital anomalies, cryptorchidism (undescended testes), and hypospadias (ventrally displaced urethral meatus).

METHODS

We established a population of 1,073,026 Danish boys born alive between 1 January 1978 and 31 December 2012. By means of Cox regression analyses, we estimated hazard ratios with 95% confidence intervals for cryptorchidism and hypospadias according to type and severity of hypertensive disorder. Further, we used restricted cubic spline analyses to investigate the association between gestational age at onset of severe and moderate preeclampsia and the two genital anomalies.

RESULTS

We found associations between pregestational hypertension and cryptorchidism (HR: 1.3; 95% CI = 1.1, 1.6) and hypospadias (HR: 1.7; 95% CI = 1.3, 2.3), whereas gestational hypertension was only associated with cryptorchidism (HR: 1.2; 95% CI = 1.1, 1.4). Boys of mothers with preeclampsia had the highest occurrence of cryptorchidism and hypospadias, increasing with preeclampsia severity. Women with HELLP syndrome faced the highest risk of having a child with both cryptorchidism (HR: 2.1; 95% CI = 1.4, 3.2) and hypospadias (HR: 3.9; 95% CI = 2.5, 6.1). Further, the occurrence increased with early onset of preeclampsia diagnosis.

CONCLUSIONS

These findings support the hypotheses that preeclampsia and genital anomalies share common etiologic factors and that placental dysfunction and androgen deficiency in early pregnancy are important in the etiology of male genital anomalies.

Family and neighborhood socioeconomic inequality in cryptorchidism and hypospadias: A nationwide study from Sweden

OBJECTIVES

To examine whether there is an association between neighborhood deprivation and incidence of cryptorchidism and hypospadias, after accounting for family-level and individual-level sociodemographic characteristics.

METHODS

All boys born in Sweden between January 1, 2001 and December 31, 2010 were followed. Data were analyzed by multilevel logistic regression, with family-level and individual-level characteristics at the first level and level of neighborhood deprivation at the second level.

RESULTS

During the study period, among a total of 497,584 boys, 8,584 (1.7%) and 3,704 (0.7%) were diagnosed with cryptorchidism and hypospadias, respectively. Cumulative rates for cryptorchidism and hypospadias increased with increasing levels of neighborhood deprivation. In the study population, 1.5 per 100 and 2.0 per 100 boys, in the least and most deprived neighborhoods were diagnosed with cryptorchidism and 0.7 per 100 and 0.9 per 100 boys were diagnosed with hypospadias. Incidence of hospitalization for cryptorchidism and hypospadias increased with increasing neighborhood-level deprivation across all family-level and individual-level sociodemographic categories. The odds ratio (OR) for cryptorchidism and hypospadias for those living in high-deprivation neighborhoods versus those living in low-deprivation neighborhoods was 1.13 (95% confidence interval [CI] = 1.05-1.21) and 1.24 (95% CI = 1.12-1.37). High neighborhood deprivation remained significantly associated with higher odds of hypospadias after adjustment for family-level and individual-level sociodemographic characteristics (OR = 1.20, 95% CI = 1.08-1.35).

CONCLUSIONS

This study is the largest so far on neighborhood influences on cryptorchidism and hypospadias. Our results suggest that neighborhood deprivation is associated with a moderate incidence of hypospadias independent of family-level and individual-level sociodemographic characteristics.

Maternal Diabetes Mellitus and Genital Anomalies in Male Offspring: A Nationwide Cohort Study in 2 Nordic Countries

BACKGROUND

Pre-existing diabetes has been associated with an increased risk of congenital malformations overall, but studies on genital anomalies in boys are conflicting and possible causal mechanisms are not well understood. Previous studies have mainly assessed pregestational and gestational diabetes in combination. Yet considering the vulnerable time windows for the genital anomalies, associations could well differ between types of diabetes and between the 2 genital anomalies and we therefore aimed to study this further.

METHODS

A population-based cohort study of 2,416,246 singleton live-born boys from Denmark (1978-2012) and Sweden (1987-2012) was carried out using Danish and Swedish register-based data. Using Cox regression models, we estimated hazard ratios for hypospadias and cryptorchidism according to maternal diabetes. We considered type and severity of diabetes, as well as timing of diagnosis in relation to birth.

RESULTS

Pregestational type 1 diabetes was associated with a higher risk of both genital anomalies. The highest risks were seen for boys of mothers with diabetic complications (hazard ratio for hypospadias = 2.33 [95% confidence interval, 1.48, 3.66] and hazard ratio for cryptorchidism = 1.92 [95% confidence interval, 1.39, 2.65]). Gestational diabetes was associated with slightly increased risks of both genital anomalies.

CONCLUSIONS

These results are consistent with the hypothesis that poor glycemic control may interfere with fetal genital development in the critical early period of organogenesis. Given the widespread and increasing occurrence of diabetes, these results are of public health importance.

Maternal hypertension and hypospadias in offspring: A systematic review and meta-analysis

BACKGROUND

Several studies have reported an association between maternal hypertensive disorders and hypospadias in offspring; however there is still debate on the role of maternal hypertension and preeclampsia on this relatively common congenital malformation. Therefore, we conducted a systematic review and meta-analysis to comprehensively evaluate the relationship between these frequent maternal conditions and hypospadias in offspring.

METHODS

Fifteen articles meeting the eligibility criteria were identified in our search and included in the analysis. A meta-analysis was conducted and pooled odds ratio (OR) estimates were calculated separately for hypertension and preeclampsia using meta-analysis. We also conducted several secondary analyses, including (a) studies conducted before versus after January 1, 1998; (b) studies in United States versus other countries; and (c) studies that accounted for ≥3 versus fewer or no potential confounders, among others.

RESULTS

Significant positive associations were observed between hypertension and hypospadias (OR 1.68; 95% CI 1.46-1.93), as well as preeclampsia and hypospadias (OR 2.18; 95% CI 1.63-2.91). The direction and magnitude of effect was comparable for the majority of secondary analyses conducted.

CONCLUSIONS

Our results indicate that maternal hypertensive disorders are positively associated with hypospadias in offspring. Further research is needed to better understand the mechanisms involved, and to ultimately develop public health strategies geared toward prevention of hypospadias.

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.

Maternal Overweight and Obesity and Genital Anomalies in Male Offspring: A Population-Based Swedish Cohort Study

BACKGROUND

Overweight and obese pregnant women face higher risk of several critical birth outcomes, including an overall increased risk of congenital abnormalities. Only few studies have focused on associations between maternal overweight and the genital anomalies in boys, cryptorchidism and hypospadias, and results are inconclusive.

METHODS

We performed a population-based cohort study and assessed the associations between maternal body mass index (BMI) in early pregnancy and occurrence of cryptorchidism and hypospadias. All live-born singleton boys born in Sweden from 1992 to 2012 were included. From the Swedish Patient Register, information on cryptorchidism and hypospadias was available. Data were analysed using Cox proportional hazards regression adjusted for potential confounders. Mediation analyses were performed to estimate how much of the association between BMI and genital anomalies were mediated through obesity-related diseases.

RESULTS

Of the 1 055 705 live-born singleton boys born from 1992 to 2012, 6807 (6.4 per 1000) were diagnosed with hypospadias and 16 469 (15.6 per 1000) were diagnosed with cryptorchidism, of which 9768 (9.3 per 1000) underwent corrective surgery for cryptorchidism. We observed dose-response associations between maternal BMI and hypospadias and cryptorchidism. Boys of mothers with BMI ≥40.0 kg/m² had the highest adjusted hazard ratios for hypospadias (HR 1.35, 95% confidence interval [CI] 1.04, 1.76) and cryptorchidism (HR 1.25, 95% CI 1.00, 1.58). A substantial proportion of the associations between BMI and the genital anomalies were mediated through preeclampsia.

CONCLUSION

This large register-based study adds to the current literature and indicates that the occurrence of hypospadias and cryptorchidism increase with maternal overweight and obesity severity.

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.

Maternal Exposure to Domestic Hair Cosmetics and Occupational Endocrine Disruptors Is Associated with a Higher Risk of Hypospadias in the Offspring

Pregnant women are exposed to various chemical products at home and at work. Some of these products contain endocrine-disrupting chemicals (EDCs) such as cosmetics, pesticides, industrial chemicals, heavy metals, plastics or medications that could alter sexual differentiation and increase the risk of hypospadias. We evaluated maternal occupational and household exposures that could constitute risk factors for hypospadias. From 2011 to 2014, we enrolled 57 full-term newborns with hypospadias and three randomly selected controls per case (162 control newborns), matched for gestational age, from 11 maternity units in Picardy, France. Neonatal and parental data were collected at birth (personal characteristics, maternal lifestyle, and medical history). Maternal occupational exposure was assessed by a job-exposure matrix for EDCs from a job history questionnaire completed by mothers. Odds ratios (OR) and 95% confidence intervals (CI) were calculated with univariate and multivariable logistic regression, and adjusted for relevant covariates. Multivariate analysis showed a strong association between hypospadias and potential maternal occupational exposure to EDCs and maternal household use of hair cosmetics (OR 6.1, 95% CI: 1.1–34.9; OR: 9.6, 95% CI: 1.4–66.1, respectively). Our results suggest that maternal occupational exposure to EDCs is a risk factor for hypospadias and suggests a possible influence of household use of hair cosmetics during early pregnancy on the incidence of hypospadias in the offspring. A larger study with more accurate exposure assessment should evaluate the impact of EDCs in hair cosmetics on the incidence of hypospadias.

Maternal hypertension and risk for hypospadias in offspring

Hypospadias is one of the most common birth defects in male infants. Maternal hypertension is a suspected risk factor; however, few previous studies have addressed the possibility of reporting bias, and several previous studies have not accounted for hypospadias severity. We analyzed data from the Texas Birth Defects Registry for 10,924 nonsyndromic cases and statewide vital records for deliveries during 1999-2009, using Poisson regression. After adjustment for potential confounders, hypospadias was associated with maternal hypertension (adjusted prevalence ratio: 1.5, 95% confidence interval: 1.4-1.7). Similar associations were observed with gestational and pregestational hypertension, including separate analyses restricted to the subset of cases with severe (second- or third-degree) hypospadias. All of these associations were also similar among the subset of cases with isolated hypospadias (without additional birth defects). To evaluate the potential for bias due to potential hypertension misclassification, we repeated our analyses using logistic regression, comparing the cases to controls with other birth defects. In these analyses, the associations with gestational hypertension were similar, but adjusted associations with pregestational hypertension were no longer observed. Our findings support an association between gestational hypertension and hypospadias in offspring, but also suggest that previously observed associations with pregestational hypertension may have been inflated due to differential misclassification of hypertension (e.g., reporting bias). As gestational hypertension is recognized after hypospadias development, more research is needed to determine if this association reflects an increase in gestational hypertension risk secondary to hypospadias or if both conditions have shared risk factors (e.g., precursors of gestational hypertension). © 2016 Wiley Periodicals, Inc.

The Genetic and Environmental Factors Underlying Hypospadias

Hypospadias results from a failure of urethral closure in the male phallus and affects 1 in 200-300 boys. It is thought to be due to a combination of genetic and environmental factors. The development of the penis progresses in 2 stages: an initial hormone-independent phase and a secondary hormone-dependent phase. Here, we review the molecular pathways that contribute to each of these stages, drawing on studies from both human and mouse models. Hypospadias can occur when normal development of the phallus is disrupted, and we provide evidence that mutations in genes underlying this developmental process are causative. Finally, we discuss the environmental factors that may contribute to hypospadias and their potential immediate and transgenerational epigenetic impacts.

Maternal bereavement and cryptorchidism in offspring

BACKGROUND

Cryptorchidism (undescended testis) is a common anomaly with largely unexplained etiology. Animal studies have suggested maternal emotional stress as a potential risk factor, but this has not been studied in humans. We aimed to investigate whether maternal bereavement due to the death of a close relative in the antenatal period increases the occurrence of cryptorchidism in the offspring.

METHODS

In a population-based cohort, we studied death of a close relative as the exposure and cryptorchidism entries in nationwide medical registries as the outcome. Danish national registries included 898,961 (23,609 exposed) boys born from 1978 to 2008 with a maximum of 30 years of follow-up.

RESULTS

A total of 20,947 boys had cryptorchidism, of whom 13,524 also underwent corrective surgery. We found no increased occurrence of cryptorchidism in the offspring (hazard ratio = 1.02 [95% confidence interval = 0.92-1.14]). Results were similar when the diagnosis was verified with surgery. We adjusted for maternal and paternal age, birth year, and family history of cryptorchidism.

CONCLUSION

We observed no association between maternal bereavement before and during pregnancy and the occurrence of cryptorchidism in the offspring.

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.

Geographic analysis of individual and environmental risk factors for hypospadias births

BACKGROUND

Hypospadias is a relatively common birth defect affecting the male urinary tract. We explored the etiology of hypospadias by examining its spatial distribution in North Carolina and the spatial clustering of residuals from individual and environmental risk factors.

METHODS

We used data collected by the North Carolina Birth Defects Monitoring Program from 2003 to 2005 to estimate local Moran's I statistics to identify geographic clustering of overall and severe hypospadias, using 995 overall cases and 16,013 controls. We conducted logistic regression and local Moran's I statistics on standardized residuals to consider the contribution of individual variables (maternal age, maternal race/ethnicity, maternal education, smoking, parity, and diabetes) and environmental variables (block group land cover) to this clustering.

RESULTS

Local Moran's I statistics indicated significant clustering of overall and severe hypospadias in eastern central North Carolina. Spatial clustering of hypospadias persisted when controlling for individual factors, but diminished somewhat when controlling for environmental factors. In adjusted models, maternal residence in a block group with more than 5% crop cover was associated with overall hypospadias (odds ratio = 1.22; 95% confidence interval = 1.04-1.43); that is living in a block group with greater than 5% crop cover was associated with a 22% increase in the odds of having a baby with hypospadias. Land cover was not associated with severe hypospadias.

CONCLUSION

This study illustrates the potential contribution of mapping in generating hypotheses about disease etiology. Results suggest that environmental factors including proximity to agriculture may play some role in the spatial distribution of hypospadias. Birth Defects Research (Part A) 100:887-894, 2014. © 2014 Wiley Periodicals, Inc.

Maternal hypertension, medication use, and hypospadias in the National Birth Defects Prevention Study

OBJECTIVE

To investigate whether antihypertensive classes and specific medications in early pregnancy increase the risk of severe hypospadias and to assess prior associations detected for late-treated and untreated hypertension in the National Birth Defects Prevention Study.

METHODS

Using telephone interviews from mothers of 2,131 children with severe hypospadias and 5,129 nonmalformed male control children for 1997-2009 births in a population-based case-control study, we estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) with multivariable logistic regression. We adjusted P values to account for multiple testing.

RESULTS

Forty-eight (2.3%) case and 70 (1.4%) control mothers reported early pregnancy antihypertensive treatment, 45 (2.1%) case and 31 (0.6%) control mothers reported late treatment, and 315 (14.8%) case and 394 (7.7%) control mothers reported untreated hypertension. Selective β-blockers, centrally acting agents, renin-angiotensin system-acting agents, diuretics, and specific medications, methyldopa and atenolol, were not associated with hypospadias. Nonselective β-blockers (adjusted OR 3.22, 95% CI 1.47-7.05) were associated with hypospadias; however, P values adjusted for multiple testing were not statistically significant. We confirmed prior findings for associations between hypospadias and untreated hypertension (adjusted OR 2.09, 95% CI 1.76-2.48) and late initiation of treatment (adjusted OR 3.98, 95% CI 2.41-6.55). The increased risks would translate to severe hypospadias prevalences of 11.5, 17.7, and 21.9 per 10,000 births for women with untreated hypertension, nonselective β-blocker use, and late initiation of treatment, respectively.

CONCLUSION

Our study suggests a relationship between hypospadias and the severity of hypertension.

LEVEL OF EVIDENCE

II.

Review of genetic and environmental factors leading to hypospadias

Hypospadias is one of the most common congenital malformations, affecting about 4-6 males per 1000 male births, and ranging in severity from a urethral meatus that is slightly off-center to a meatus in the perineal area. Over the past three decades its prevalence may have increased due to changes in reporting of mild cases and/or increased survival of low birth weight infants due to improved neonatal care. However, despite the increasing numbers of males with hypospadias, the overall etiology remains unclear and likely multifactorial in nature. The purpose of this review article is to provide a comprehensive overview of the various factors implicated in hypospadias etiology, including genetic and environmental factors. In addition, we list syndromes in which hypospadias is a relatively common association and delineate the areas that require further investigation in an effort to understand this condition.

Pre-pregnancy body mass index in relation to infant birth weight and offspring overweight/obesity: a systematic review and meta-analysis

BACKGROUND

Overweight/obesity in women of childbearing age is a serious public-health problem. In China, the incidence of maternal overweight/obesity has been increasing. However, there is not a meta-analysis to determine if pre-pregnancy body mass index (BMI) is related to infant birth weight (BW) and offspring overweight/obesity.

METHODS

Three electronic bibliographic databases (MEDLINE, EMBASE and CINAHL) were searched systematically from January 1970 to November 2012. The dichotomous data on pre-pregnancy overweight/obesity and BW or offspring overweight/obesity were extracted. Summary statistics (odds ratios, ORs) were used by Review Manager, version 5.1.7.

RESULTS

After screening 665 citations from three electronic databases, we included 45 studies (most of high or medium quality). Compared with normal-weight mothers, pre-pregnancy underweight increased the risk of small for gestational age (SGA) (odds ratios [OR], 1.81; 95% confidence interval [CI], 1.76-1.87); low BW (OR, 1.47; 95% CI, 1.27-1.71). Pre-pregnancy overweight/obesity increased the risk of being large for gestational age (LGA) (OR, 1.53; 95% CI, 1.44-1.63; and OR, 2.08; 95% CI; 1.95-2.23), high BW (OR, 1.53; 95% CI, 1.44-1.63; and OR, 2.00; 95% CI; 1.84-2.18), macrosomia (OR, 1.67; 95% CI, 1.42-1.97; and OR, 3.23; 95% CI, 2.39-4.37), and subsequent offspring overweight/obesity (OR, 1.95; 95% CI, 1.77-2.13; and OR, 3.06; 95% CI, 2.68-3.49), respectively. Sensitivity analyses revealed that sample size, study method, quality grade of study, source of pre-pregnancy BMI or BW had a strong impact on the association between pre-pregnancy obesity and LGA. No significant evidence of publication bias was observed.

CONCLUSIONS

Pre-pregnancy underweight increases the risk of SGA and LBW; pre-pregnancy overweight/obesity increases the risk of LGA, HBW, macrosomia, and subsequent offspring overweight/obesity. A potential effect modification by maternal age, ethnicity, gestational weight gain, as well as the role of gestational diseases should be addressed in future studies.

Transient protection from heat-stress induced apoptotic stimulation by metastasis-associated protein 1 in pachytene spermatocytes

BACKGROUND

Deregulated thermal factors have been frequently implicated in the pathogenesis of male infertility, but the molecular basis through which certain responses are directed remain largely unknown. We previously reported that overexpression of exogenous Metastasis-associated protein 1 (MTA1) protects spermatogenic tumor cells GC-2spd (ts) against heat-induced apoptosis. To further dissect the underlying mechanism, we addressed here the fine coordination between MTA1 and p53 in pachytene spermatocytes upon hyperthermal stimulation.

METHODOLOGY/PRINCIPAL FINDINGS

High level of MTA1 expression sustained for 1.5 h in primary spermatocytes after heat stress before a notable decrease was detected conversely correlated to the gradual increase of acetylation status of p53 and of p21 level. Knockdown of the endogenous MTA1 in GC-2spd (ts) elevated the acetylation of p53 by diminishing the recruitment of HDAC2 and thereafter led to a dramatic increase of apoptosis after heat treatment. Consistent with this, in vivo interference of MTA1 expression in the testes of C57BL/6 mice also urged an impairment of the differentiation of spermatocytes and a disruption of Sertoli cell function due to the elevated apoptotic rate after heat stress. Finally, attenuated expression of MTA1 of pachytene spermatocytes was observed in arrested testes (at the round spermatid level) of human varicocele patients.

CONCLUSIONS

These data underscore a transient protective effect of this histone modifier in primary spermatocytes against heat-stress, which may operate as a negative coregulator of p53 in maintenance of apoptotic balance during early phase after hyperthermal stress.