The influence of betamethasone on the feto-placental unit: a preliminary report

Genetic and environmental factors in the aetiology of hypospadias

This article reviews the current evidence and knowledge of the aetiology of hypospadias. Hypospadias remains a fascinating anomaly of the male phallus. It may be an isolated occurrence or part of a syndrome or field defect. The increasing use of assisted reproductive techniques and hormonal manipulation during pregnancy may have been associated with an apparent rise in the incidence of hypospadias. Genetic studies and gene analysis have suggested some defects that could result in hypospadias. New light has also been thrown on environmental factors that could modulate candidate genes, causing altered development of the male external genitalia.

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.

Environmental and genetic contributors to hypospadias: a review of the epidemiologic evidence

This review evaluates current knowledge related to trends in the prevalence of hypospadias, the association of hypospadias with endocrine-disrupting exposures, and the potential contribution of genetic susceptibility to its etiology. The review focuses on epidemiologic evidence. Increasing prevalence of hypospadias has been observed, but such increases tend to be localized to specific regions or time periods. Thus, generalized statements that hypospadias is increasing are unsupported. Owing to the limitations of study designs and inconsistent results, firm conclusions cannot be made regarding the association of endocrine-disrupting exposures with hypospadias. Studies with more rigorous study designs (e.g., larger and more detailed phenotypes) and exposure assessment that encompasses more breadth and depth (e.g., specific endocrine-related chemicals) will be critical to make better inferences about these important environmental exposures. Many candidate genes for hypospadias have been identified, but few of them have been examined to an extent that enables solid conclusions. Further study is needed that includes larger sample sizes, comparison groups that are more representative of the populations from which the cases were derived, phenotype-specific analyses, and more extensive exploration of variants. In conclusion, examining the associations of environmental and genetic factors with hypospadias remain important areas of inquiry, although our actual understanding of their contribution to hypospadias risk in humans is currently limited.

Maternal corticosteroid use and hypospadias

OBJECTIVE

To explore whether women who reported corticosteroid use during pregnancy were more likely to deliver an infant with hypospadias than women who did not.

STUDY DESIGN

The analysis encompassed data on deliveries with an estimated due date between 1997 and 2004 from the National Birth Defects Prevention Study, a large population-based, case-control study conducted in the United States. Included were 1165 cases of moderate to severe hypospadias and 3000 nonmalformed male controls.

RESULTS

The mothers of 39 cases (3.3%) and 62 controls (2.1%) reported using a corticosteroid medication during the period extending from 4 weeks before conception to 14 weeks after conception. The odds ratio (OR) for any corticosteroid exposure versus no corticosteroid exposure was 1.6 (95% confidence interval [CI] = 1.1 to 2.5); after adjustment for maternal race/ethnicity, education, age, and study site, it was 1.3 (95% CI = 0.8 to 2.0). Analyses by route of administration and specific component suggest that elevated ORs occurred only for nasal spray/inhaled corticosteroids (OR = 1.5; 95% CI = 0.9 to 2.6).

CONCLUSIONS

Maternal use of corticosteroid medications was weakly associated with risk of hypospadias, but the association was negligible after adjustment for potential confounders.

Maternal corticosteroid use and orofacial clefts

OBJECTIVE

The purpose of this study was to examine whether maternal corticosteroid use during pregnancy is associated with delivering an infant with an orofacial cleft.

STUDY DESIGN

This study included data on deliveries from the National Birth Defects Prevention Study, which is a population-based case-control study. Exposures were assessed by telephone interviews for mothers of 1141 cases with cleft lip +/- cleft palate (CLP), 628 with cleft palate (CP), and 4143 controls.

RESULTS

Mothers of 33 infants with CLP (2.9%), mothers of 6 infants with CP (1.0%), and 72 control subjects (1.7%) reported corticosteroid use from 4 weeks before through 12 weeks after conception. The crude odds ratio for "any" vs "no" use was 1.7 (95% CI, 1.1-2.6) for CLP and 0.5 (0.2-1.3) for CP. When analyzed by route of administration and medication components, odds ratios for CLP tended to be elevated, and odds ratios for CP tended to be close to 1.

CONCLUSION

Our results suggest a moderately increased risk of CLP among women who use corticosteroids during early pregnancy.