Maternal corticosteroid use and hypospadias

Exposure to corticosteroids in the first trimester is associated with an increased risk of urogenital congenital anomalies

STUDY QUESTION

Does maternal exposure to first trimester corticosteroids in IVF/ICSI treatment result in an increased risk of congenital anomalies?

SUMMARY ANSWER

Children born with the aid of IVF/ICSI whose mothers were treated with adjuvant corticosteroids during the first trimester had an increased risk of cryptorchidism, hypospadias and talipes.

WHAT IS KNOWN ALREADY

Maternal exposure to corticosteroids may increase the risk of congenital anomalies such as cleft palate and neural tube defects. However, the existing studies have conflicting outcomes, are underpowered, and do not study a population undergoing IVF/ICSI, a group known to be at increased risk of abnormalities.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort analysis covering Monash IVF fertility clinics in Melbourne, Australia assessed the outcomes of 12 426 live births from both fresh and frozen embryo transfers between 2010 and 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

There were 618 live births included in our study group of mothers exposed to corticosteroids (oral prednisolone or dexamethasone) during their IVF/ICSI treatment, with the remainder of births not exposed to steroids (control, n = 11 808). The primary outcome measured was the presence of congenital anomalies and secondary outcomes were birth weight and gestation length. Multivariate binary logistic regression was used to assess the independent effects of corticosteroid exposure and the freezing of embryos, with adjustment for maternal age at oocyte retrieval, smoking status, number of cycles taken, BMI, etiology of the infertility and the use of ICSI. Results are presented as incidence rate ratios (IRRs) with 95% CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

Amongst 12 426 live births, and 597 birth defects, multivariate logistic regression demonstrated there was an increased incidence in talipes equinovarus (1.33% vs 0.32%, adjusted IRR = 4.30, 95% CI = 1.93, 9.58; P < 0.001), hypospadias (0.66% vs 0.18%, adjusted IRR = 5.90, 95% CI = 2.09, 16.69; P = 0.001) and cryptorchidism (0.83% vs 0.19%, adjusted IRR = 5.53, 95% CI = 1.91, 15.42; P = 0.001) in the offspring of mothers exposed to corticosteroids compared to those who were unexposed. The incidence of neither neural tube defects nor cleft palate were significantly increased in babies exposed to corticosteroids. The sex ratio of infants exposed to corticosteroids during a fresh embryo transfer cycle significantly favored males but reverted to the normal sex ratio in infants conceived in frozen embryo transfer cycles.

LIMITATIONS, REASONS FOR CAUTION

This was a retrospective observational cohort study using administrative datasets with the potential for measurement error and unobserved confounding. Missing outcome data were obtained from patients using self-report leading to possible ascertainment bias. Given the rare incidence of some of the anomalies assessed, the study was underpowered to identify differences in abnormality rates for some specific anomalies.

WIDER IMPLICATIONS OF THE FINDINGS

The findings of this study, the largest of its kind, suggest that caution should be heeded when prescribing corticosteroids to women undergoing IVF/ICSI, given that this study has now identified three previously unassociated serious neonatal complications (talipes, hypospadias and cryptorchidism), plus a potential alteration in sex ratio. Physicians should be careful in using corticosteroids in the critical first trimester and should counsel patients regarding the potential risks of this treatment.

STUDY FUNDING/COMPETING INTEREST(S)

There was no funding sought or obtained for this study. K.T., V.T., B.V. and D.Z.-F. are employees or contractors to Monash IVF and hold a minority stock position in Monash IVF. R.J.W. reports no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Pharmacologic and Environmental Endocrine Disruptors in the Pathogenesis of Hypospadias: a Review

PURPOSE OF REVIEW

Endocrine disrupting chemicals (EDCs) potentially have a role in causing hypospadias malformation through modifiable in-utero exposure. Considering the emerging literature on the role of potential endocrine disrupting substances on the occurrence of hypospadias and the potential to inform public health efforts to prevent the occurrence of these malformations, we have summarized the current literature, identified areas of consensus, and highlighted areas that warrant further investigation.

RECENT FINDINGS

Pharmaceuticals, such as diethylstilbestrol, progestin fertility treatments, corticosteroids, and valproic acid, have all been associated with hypospadias risk. Data on exposure to dichlorodiphenyltrichloroethane and hexachlorobenzene pesticides, as well as non-persistent pollutants, particularly phthalates, is less consistent but still compelling. Improving exposure assessment, standardizing sample timing to relevant developmental windows, using clear case identification and classification schemes, and elucidating dose-response relationships with EDCs will help to provide clearer evidence. Promising directions for future research include identification of subgroups with genetic hypospadias risk factors, measurement of intermediate outcomes, and study of EDC mixtures that will more accurately represent the total fetal environment.

Anatomical Explanations of the Pathogenesis of Proximal Hypospadias

Aims:

The aim of this study was to try to explain the pathogenesis of proximal hypospadias based on anatomical and histological findings.

Methods:

During 9 years, we performed systematic biopsies (in the lateral areas of the urethral plate, as well as under this plate) in 81 patients treated for proximal hypospadias. The histological study was performed by routine coloring, hematoxylin and eosin, and Masson's trichrome, which colors the collagen fibers in blue, and monoclonal antibody against alpha-smooth muscle actin.

Results:

There is a fibrosis tissue abnormally present on the ventral side of the penis. This tissue consists of a mixture of fibrous connective tissue, nerve nets, short vessels, and smooth muscle fibers. The penis' dartos does not contain smooth muscle fibers. These fibers can come from a blood vessel or spongy tissue which existed during the neonatal period in the distal part of the penis before disappearing.

Conclusions:

The proximal hypospadias is due presumably to avascular necrosis of the distal part poorly vascularized of the corpus spongiosum.

What is the pathogenesis of proximal hypospadias?

OBJECTIVE

To report the information concerning the pathogenesis of proximal hypospadias and causes of curvature associated with it.

MATERIAL AND METHODS

From January 2009 to December 2015, 74 patients underwent repair of proximal hypospadias. In 70 patients we performed a systematic biopsies in the lateral areas of the urethral plate, as well as under this plate. The study of the histological structure of these areas was performed using routine staining with hematoxylin and eosin, and the Masson's trichrome which color the collagen fibers in blue and monoclonal antibody against alpha-smooth muscle actin.

RESULTS

This prospective study shows that the fibrotic tissue abnormally present on the ventral side of the penis consists of a mixture of fibrous connective tissue, nerve nets, short vessels, and smooth muscle fibers. In contrast to the scrotal dartos, penile dartos fascia does not contain smooth muscle fibers. Therefore, these fibers may come from a blood vessel or spongy tissue which existed during neonatal period in the distal part of the penis before disappearing. In addition, in 13 cases, the presence downstream of the urethral meatus, of a bifurcation of corpus spongiosum into two branches supposes that the corpus spongiosum is form by fusion around the urethra of two mesenchymal bodies. The arterial supply of this purely masculine formation originates from a new vascularization and it is probably, developed under secretion of androgens (angiogenic substances in target tissues).

CONCLUSION

These findings allow us to suggest that the proximal hypospadias is due to avascular necrosis of the distal part ie. poorly vascularized part of the corpus spongiosum.

Use of azathioprine and corticosteroids during pregnancy and birth outcome in women diagnosed with inflammatory bowel disease

BACKGROUND

The aim of this study was to describe prescription patterns for azathioprine and corticosteroids for pregnant women with inflammatory bowel diseases (IBD) before, during, and after pregnancy and to describe pregnancy outcomes.

METHODS

A cohort composed of all singleton pregnancies in Danish registries from 1996 to 2009 was divided by maternal IBD status: Crohn's disease (CD, n = 827), ulcerative colitis (UC, N = 1361), or no IBD diagnosis (background population, n = 814,231). The number of women with a prescription for azathioprine, local and systemic steroids within a 3-month period was computed for each of the pregnancy trimesters and the year before and after pregnancy. Outcomes of interest were stillbirth, perinatal mortality, low birth weight (LBW), preterm birth, and small for gestational age (SGA).

RESULTS

Number of prescriptions for azathioprine decreased just before and during pregnancy and increased after birth. Number of prescriptions for local and systemic corticosteroids decreased approximately 30% compared with before pregnancy and increased in the second trimester. There was an increased risk among mothers with IBD of LBW (adjusted odds ratio [adjOR]: CD: 2.25 [95% confidence interval {CI}, 1.74-2.91], UC: 1.81 [95% CI, 1.42-2.30]), preterm birth (adjOR: CD: 2.54 [95% CI, 2.04-3.15], UC: 1.86 [95% CI, 1.52-2.27]), and SGA (adjOR: CD: 1.99 [95% CI, 1.26-3.15], UC: 1.80 [95% CI, 1.18-2.75]).

CONCLUSION

Use of azathioprine and corticosteroids was often reduced or discontinued before or during early pregnancy followed by an increased use of corticosteroids later in pregnancy. Women diagnosed with IBD and with prescriptions for azathioprine and/or corticosteroids, have an increased risk of LBW, pre-term birth, and SGA. Birth Defects Research (Part A) 106:494-499, 2016. © 2016 Wiley Periodicals, Inc.

Maternal Stressors and Social Support and Risks of Delivering Babies With Gastroschisis or Hypospadias

We examined the association of maternal stressful life events and social support with risks of gastroschisis and hypospadias, using data from the National Birth Defects Prevention Study, a population-based case-control study of US births taking place in 2006-2011. We examined maternal self-reports of 7 life events and 3 sources of social support during the periconceptional period among mothers of 593 gastroschisis cases, 1,142 male hypospadias cases, and 4,399 nonmalformed controls. Responses to the questions on stressful life events were summed to form an index (higher is worse), as were responses to questions on social support (higher is better). We used logistic regression to estimate adjusted odds ratios and 95% confidence intervals. The adjusted odds ratios for gastroschisis for a 4-point increase in the stress index were 3.5 (95% confidence interval (CI): 2.6, 4.8) among nonteenage mothers (age ≥20 years) and 1.0 (95% CI: 0.5, 1.7) among teenage mothers (age <20 years). The odds ratio for hypospadias (among all mothers) was 0.8 (95% CI: 0.7, 1.1). Adjusted odds ratios for a social support score of 3 (versus 0) in the 3 respective groups were 0.6 (95% CI: 0.4, 1.0), 1.0 (95% CI: 0.5, 2.3), and 0.6 (95% CI: 0.4, 0.9). Given the lack of prior research on these outcomes and stress, results should be interpreted with caution.

Risk of congenital anomalies after exposure to asthma medication in the first trimester of pregnancy - a cohort linkage study

Objective

To examine the effect of maternal exposure to asthma medications on the risk of congenital anomalies.

Design

Meta‐analysis of aggregated data from three cohort studies.

Setting

Linkage between healthcare databases and EUROCAT congenital anomaly registries.

Population

519 242 pregnancies in Norway (2004–2010), Wales (2000–2010) and Funen, Denmark (2000–2010).

Methods

Exposure defined as having at least one prescription for asthma medications issued (Wales) or dispensed (Norway, Denmark) from 91 days before to 91 days after the pregnancy start date. Odds ratios (ORs) were estimated separately for each register and combined in meta‐analyses.

Main outcome measures

ORs for all congenital anomalies and specific congenital anomalies.

Results

Overall exposure prevalence was 3.76%. For exposure to asthma medication in general, the adjusted OR (adjOR) for a major congenital anomaly was 1.21 (99% CI 1.09–1.34) after adjustment for maternal age and socioeconomic position. The OR of anal atresia was significantly increased in pregnancies exposed to inhaled corticosteroids (3.40; 99% CI 1.15–10.04). For severe congenital heart defects, an increased OR (1.97; 1.12–3.49) was associated with exposure to combination treatment with inhaled corticosteroids and long‐acting beta‐2‐agonists. Associations with renal dysplasia were driven by exposure to short‐acting beta‐2‐agonists (2.37; 1.20–4.67).

Conclusion

The increased risk of congenital anomalies for women taking asthma medication is small with little confounding by maternal age or socioeconomic status. The study confirmed the association of inhaled corticosteroids with anal atresia found in earlier research and found potential new associations with combination treatment. The potential new associations should be interpreted with caution due to the large number of comparisons undertaken.

Tweetable abstract

This cohort study found a small increased risk of congenital anomalies for women taking asthma medication.

This cohort study found a small increased risk of congenital anomalies for women taking asthma medication.

Safety of topical corticosteroids in pregnancy

BACKGROUND

Topical corticosteroids are the most frequently prescribed dermatological treatment and are often used by pregnant women with skin conditions. However, little is known about their safety in pregnancy.

OBJECTIVES

To assess the effects of topical corticosteroids on pregnancy outcomes in pregnant women.

SEARCH METHODS

This is an update of a review previously published in 2009. We updated our searches of the following databases to July 2015: the Cochrane Skin Group Specialised Register, the Cochrane Pregnancy and Childbirth Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 6), MEDLINE, EMBASE, and LILACS. We also searched five trials registers and checked the reference lists of included studies, published reviews, articles that had cited the included studies, and one author's literature collection, for further references to relevant RCTs.

SELECTION CRITERIA

Randomised controlled trials and cohort studies of topical corticosteroids in pregnant women, as well as case-control studies comparing maternal exposure to topical corticosteroids between cases and controls when studies reported pre-specified outcomes. The primary outcomes included mode of delivery, major congenital abnormality, birth weight, and preterm delivery (delivery before 37 completed weeks gestation); the secondary outcomes included foetal death, minor congenital abnormality, and low Apgar score (less than seven at 5 min).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two authors independently applied selection criteria, extracted data, and assessed the quality of the included studies. A third author was available for resolving differences of opinion. A further author independently extracted data from included studies that were conducted by authors of this systematic review.

MAIN RESULTS

We included 7 new observational studies in this update, bringing the total number to 14, including 5 cohort and 9 case-control studies, with 1,601,515 study subjects.Most studies found no causal associations between maternal exposure to topical corticosteroids of any potency and pregnancy outcomes when compared with no exposure. These outcomes included: mode of delivery (risk ratio (RR) 1.04, 95% confidence interval (CI) 0.95 to 1.15, 1 cohort study, n = 9904, low quality evidence); congenital abnormalities, including orofacial cleft or cleft palate and hypospadias (where the urethral opening is on the underside of the penis) (RR 0.82, 95% CI 0.34 to 1.96, 2 cohort studies, n = 9512, low quality evidence; and odds ratio (OR) 1.07, 95% CI 0.71 to 1.60, 1 case-control study, n = 56,557); low birth weight (RR 1.08, 95% CI 0.86 to 1.36; n = 59,419, 4 cohort studies; very low quality evidence); preterm delivery (RR 0.93, 95% CI 0.81 to 1.08, 4 cohort studies, n = 59,419, low quality evidence); foetal death (RR 1.02, 95% CI 0.60 to 1.73, 4 cohort studies, n = 63,885, very low quality evidence); and low Apgar score (RR 0.84, 95% CI 0.54 to 1.31, 1 cohort study, n = 9220, low quality evidence).We conducted stratified analyses of mild or moderate potency, and potent or very potent topical corticosteroids, but we found no causal associations between maternal exposure to topical corticosteroid of any potency and congenital abnormality, orofacial clefts, preterm delivery, or low Apgar score. For low birth weight, although the meta-analysis based on study-level data was not significant for either mild to moderate corticosteroids (pooled RR 0.90, 95% CI 0.74 to 1.09, 3 cohort studies, n > 55,713) or potent to very potent corticosteroids (pooled RR 1.58, 95% CI 0.96 to 2.58, 4 cohort studies, n > 47,651), there were significant differences between the two subgroups (P = 0.04). The results from three of the individual studies in the meta-analysis indicated an increased risk of low birth weight in women who received potent to very potent topical corticosteroids. Maternal use of mild to moderate potency topical steroids was associated with a decreased risk of foetal death (pooled RR 0.70, 95% CI 0.64 to 0.77, 2 studies, n = 48,749; low quality evidence), but we did not observe this effect when potent to very potent topical corticosteroids were given during pregnancy (pooled RR 1.14, 95% CI 0.69 to 1.88, 3 studies, n = 37,086, low quality evidence).We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) Working Group approach to rate the overall quality of the evidence. Data from observational studies started at low quality. We further downgraded the evidence because of imprecision in low birth weight and inconsistency in foetal death. Lower quality evidence resulted in lower confidence in the estimate of effect for those outcomes.

AUTHORS' CONCLUSIONS

This update adds more evidence showing no causal associations between maternal exposure to topical corticosteroids of all potencies and pregnancy outcomes including mode of delivery, congenital abnormalities, preterm delivery, foetal death, and low Apgar score, which is consistent with the previous version of this review. This update provides stratified analyses based on steroid potency; we found no association between maternal use of topical corticosteroids of any potency and an increase in adverse pregnancy outcomes, including mode of delivery, congenital abnormality, preterm delivery, foetal death, and low Apgar score. Similar to the previous version of the review, this update identified a probable association between low birth weight and maternal use of potent to very potent topical corticosteroids, especially when the cumulative dosage of topical corticosteroids throughout the pregnancy is very large, which warrants further investigation. The finding of a possible protective effect of mild to moderate topical corticosteroids on foetal death could also be examined.

Use of asthma medication during pregnancy and risk of specific congenital anomalies: A European case-malformed control study

BACKGROUND

Pregnant women with asthma need to take medication during pregnancy.

OBJECTIVE

We sought to identify whether there is an increased risk of specific congenital anomalies after exposure to antiasthma medication in the first trimester of pregnancy.

METHODS

We performed a population-based case-malformed control study testing signals identified in a literature review. Odds ratios (ORs) of exposure to the main groups of asthma medication were calculated for each of the 10 signal anomalies compared with registrations with nonchromosomal, nonsignal anomalies as control registrations. In addition, exploratory analyses were done for each nonsignal anomaly. The data set included 76,249 registrations of congenital anomalies from 13 EUROmediCAT registries.

RESULTS

Cleft palate (OR, 1.63; 95% CI, 1.05-2.52) and gastroschisis (OR, 1.89; 95% CI, 1.12-3.20) had significantly increased odds of exposure to first-trimester use of inhaled β2-agonists compared with nonchromosomal control registrations. Odds of exposure to salbutamol were similar. Nonsignificant ORs of exposure to inhaled β2-agonists were found for spina bifida, cleft lip, anal atresia, severe congenital heart defects in general, or tetralogy of Fallot. None of the 4 literature signals of exposure to inhaled steroids were confirmed (cleft palate, cleft lip, anal atresia, and hypospadias). Exploratory analyses found an association between renal dysplasia and exposure to the combination of long-acting β2-agonists and inhaled corticosteroids (OR, 3.95; 95% CI, 1.99-7.85).

CONCLUSIONS

The study confirmed increased odds of first-trimester exposure to inhaled β2-agonists for cleft palate and gastroschisis and found a potential new signal for renal dysplasia associated with combined long-acting β2-agonists and inhaled corticosteroids. Use of inhaled corticosteroids during the first trimester of pregnancy seems to be safe in relation to the risk for a range of specific major congenital anomalies.

Risk factors for hypospadias in China

This case-controlled study was designed to evaluate the association between various baseline parental factors and the risk of hypospadias in China. Patients were selected from tertiary referral hospitals in Anhui, a province in mid-eastern China. A questionnaire was given to the parents of each patient. The final database included 193 cases and 835 controls. The incidence of additional coexistent anomalies was 13.0%, primarily cryptorchidism (9.8%). Ten patients (5.1%) were from families with genital anomaly, including five families (2.6%) with hypospadias. The risks of hypospadias was higher for children of mothers > 35 (odds ratio [OR] =1.47) and < 18 (OR = 2.95) years of age, and in mothers who had consumed alcohol (OR = 2.67), used drugs (OR = 1.53) and had an infection (OR = 1.87) during pregnancy. The risk of hypospadias was also higher when mothers (OR = 1.68) and fathers (OR = 1.74) were engaged in agriculture. Other factors assessed were not associated with the risk of hypospadias.

Similar causes of various reproductive disorders in early life

During the past few decades, scientific evidence has been accumulated concerning the possible adverse effects of the exposure to environmental chemicals on the well-being of wildlife and human populations. One large and growing group of such compounds of anthropogenic or natural origin is referred to as endocrine-disrupting chemicals (EDCs), due to their deleterious action on the endocrine system. This concern was first focused on the control of reproductive function particularly in males, but has later been expanded to include all possible endocrine functions. The present review describes the underlying physiology behind the cascade of developmental events that occur during sexual differentiation of males and the specific role of androgen in the masculinization process and proper organogenesis of the external male genitalia. The impact of the genetic background, environmental exposures and lifestyle factors in the etiology of hypospadias, cryptorchidism and testicular cancer are reviewed and the possible role of EDCs in the development of these reproductive disorders is discussed critically. Finally, the possible direct and programming effects of exposures in utero to widely use therapeutic compounds, environmental estrogens and other chemicals on the incidence of reproductive abnormalities and poor semen quality in humans are also highlighted.

Maternal medication and herbal use and risk for hypospadias: data from the National Birth Defects Prevention Study, 1997-2007

PURPOSE

To investigate associations between maternal use of common medications and herbals during early pregnancy and risk for hypospadias in male infants.

METHODS

We used data from the National Birth Defects Prevention Study, a multi-site, population-based, case-control study. We analyzed data from 1537 infants with second-degree or third-degree isolated hypospadias and 4314 live-born male control infants without major birth defects, with estimated dates of delivery from 1997 to 2007. Exposure was reported use of prescription or over-the-counter medications or herbal products, from 1 month before to 4 months after conception. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression, adjusting for maternal age, race/ethnicity, education, pre-pregnancy body mass index, previous live births, maternal subfertility, study site, and year.

RESULTS

We assessed 64 medication and 24 herbal components. Maternal uses of most components were not associated with an increased risk of hypospadias. A new associations was observed for venlafaxine (aOR 2.4; 95%CI 1.0, 6.0) [Correction made here after initial online publication.]. The previously reported association for clomiphene citrate was confirmed (aOR 1.9; 95%CI 1.2, 3.0). Numbers were relatively small for exposure to other specific patterns of fertility agents, but elevated aORs were observed for the most common of them.

CONCLUSIONS

Overall, findings were reassuring that hypospadias is not associated with most medication components examined in this analysis. New associations will need to be confirmed in other studies. Increased risks for hypospadias associated with various fertility agents raise the possibility of confounding by underlying subfertility.

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.

Aetiology of hypospadias: a systematic review of genes and environment

BACKGROUND

Hypospadias is a common congenital malformation of the male external genitalia. Most cases have an unknown aetiology, which is probably a mix of monogenic and multifactorial forms, implicating both genes and environmental factors. This review summarizes current knowledge about the aetiology of hypospadias.

METHODS

Pubmed was used to identify studies on hypospadias aetiology published between January 1995 and February 2011. Reference lists of the selected manuscripts were also searched to identify additional studies, including those published before 1995.

RESULTS

The search provided 922 articles and 169 articles were selected for this review. Studies screening groups of patients with hypospadias for single gene defects found mutations in WT1, SF1, BMP4, BMP7, HOXA4, HOXB6, FGF8, FGFR2, AR, HSD3B2, SRD5A2, ATF3, MAMLD1, MID1 and BNC2. However, most investigators are convinced that single mutations do not cause the majority of isolated hypospadias cases. Indeed, associations were found with polymorphisms in FGF8, FGFR2, AR, HSD17B3, SRD5A2, ESR1, ESR2, ATF3, MAMLD1, DGKK, MID1, CYP1A1, GSTM1 and GSTT1. In addition, gene expression studies indentified CTGF, CYR61 and EGF as candidate genes. Environmental factors consistently implicated in hypospadias are low birthweight, maternal hypertension and pre-eclampsia, suggesting that placental insufficiency may play an important role in hypospadias aetiology. Exogenous endocrine-disrupting chemicals have the potential to induce hypospadias but it is unclear whether human exposure is high enough to exert this effect. Other environmental factors have also been associated with hypospadias but, for most, the results are inconsistent.

CONCLUSIONS

Although a number of contributors to the aetiology of hypospadias have been identified, the majority of risk factors remain unknown.

Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects

BACKGROUND

Nausea and vomiting of pregnancy (NVP) occurs in up to 80% of pregnant women, but its association with birth outcomes is not clear. Several medications are used for the treatment of NVP; however, data are limited on their possible associations with birth defects.

METHODS

Using data from the National Birth Defects Prevention Study (NBDPS)-a multi-site, population-based, case-control study-we examined whether NVP or its treatment was associated with the most common noncardiac defects in the NBDPS (nonsyndromic cleft lip with or without cleft palate [CL/P], cleft palate alone [CP], neural tube defects, and hypospadias) compared with randomly selected nonmalformed live births.

RESULTS

Among the 4524 cases and 5859 controls included in this study, 67.1% reported first-trimester NVP, and 15.4% of them reported using at least one agent for NVP. Nausea and vomiting of pregnancy was not associated with CP or neural tube defects, but modest risk reductions were observed for CL/P (adjusted odds ratio [aOR] = 0.87; 95% confidence interval [CI], 0.77-0.98) and hypospadias (aOR = 0.84; 95% CI, 0.72-0.98). Regarding treatments for NVP in the first trimester, the following adjusted associations were observed with an increased risk: proton pump inhibitors and hypospadias (aOR = 4.36; 95% CI, 1.21-15.81), steroids and hypospadias (aOR = 2.87; 95% CI, 1.03-7.97), and ondansetron and CP (aOR = 2.37; 95% CI, 1.18-4.76), whereas antacids were associated with a reduced risk for CL/P (aOR = 0.58; 95% CI, 0.38-0.89).

CONCLUSIONS

NVP was not observed to be associated with an increased risk of birth defects; however, possible risks related to three treatments (i.e., proton pump inhibitors, steroids and ondansetron), which could be chance findings, warrant further investigation.

Value of the small cohort study including a physical examination for minor structural defects in identifying new human teratogens

Most known human teratogens are associated with a unique or characteristic pattern of major and minor malformations and this pattern helps to establish the causal link between the teratogenic exposure and the outcome. Although traditional case-control and cohort study designs can help identify potential teratogens, there is an important role for small cohort studies that include a dysmorphological examination of exposed and unexposed infants for minor structural defects. In combination with other study design approaches, the small cohort study with a specialized physical examination fulfills a necessary function in screening for new potential teratogens and can help to better delineate the spectrum and magnitude of risk for known teratogens.

Environmental factors in genitourinary development

PURPOSE

In the last century the world has experienced an increase in the use of industrial chemicals as well as possible increases in the prevalence of hypospadias and cryptorchidism. Because hormones regulate the fetal development of many organs, numerous investigations have explored the role of environmental factors in genitourinary growth. We summarize the data regarding endocrine disruptors in human genitourinary development.

MATERIALS AND METHODS

A PubMed literature search was performed for human studies from 2004 to 2009.

RESULTS

Few data exist on environmental influences on the kidneys, ureters or bladder. Studies on the influence of pesticides, vegetarian diets, diethylstilbestrol, oral contraceptives and corticosteroids on hypospadias have yielded varied conclusions. Phthalates appear to increase the odds of hypospadias and anogenital distance. The testicular dysgenesis syndrome postulates that cryptorchidism, hypospadias, poor semen quality and testicular cancer share a common environmental origin. In utero exposure to diethylstilbestrol has been shown to increase the risk of testicular dysgenesis syndrome. However, to our knowledge no other environmental factor has been shown to cause testicular dysgenesis syndrome. Some industrial chemicals as well as the pesticide dichloro-diphenyl-trichloroethane have detrimental effects on semen quality. In cases of documented industrial accidents, chemical exposure has also decreased the male-to-female birth ratio.

CONCLUSIONS

Data on chemical exposure are largely mixed and inconclusive. Studies of populations with high exposure rates due to industrial accidents or in utero exposure to diethylstilbestrol suggest that endocrine disruptors adversely affect genitourinary development.

Steroidogenesis in the fetal testis and its susceptibility to disruption by exogenous compounds

Masculinization depends on adequate production of testosterone by the fetal testis within a specific "masculinization programming window." Disorders resulting from subtle deficiencies in this process are common in humans, and environmental exposures/lifestyle could contribute causally because common therapeutic and environmental compounds can affect steroidogenesis. This evidence derives mainly from rodent studies, but because there are major species differences in regulation of steroidogenesis in the fetal testis, this may not always be a guide to potential effects in the human. In addition to direct study of the effects of compounds on steroidogenesis, information also derives from study of masculinization disorders that result from mutations in genes in pathways regulating steroidogenesis. This review addresses this issue by critically reviewing the comparative timing of production and regulation of steroidogenesis in the fetal testis of humans and of rodents and its susceptibility to disruption; where there is limited information for the fetus, evidence from effects on steroidogenesis in the adult testis is considered. There are a number of fundamental regulatory differences between the human and rodent fetal testis, most notably in the importance of paracrine vs. endocrine drives during masculinization such that inactivating LH receptor mutations block masculinization in humans but not in rodents. Other large differences involve the steroidogenic response to estrogens and GnRH analogs and possibly phthalates, whereas for other compounds there may be differences in sensitivity to disruption (ketoconazole). This comparison identifies steroidogenic targets that are either vulnerable (mitochondrial cholesterol transport, CYP11A, CYP17) or not (cholesterol uptake) to chemical interference.