Maternal use of Loratadine during pregnancy and risk of hypospadias in offspring

WITHDRAWN: Hypospadias induced by medications and environmental exposures- A scoping review

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Parental subfertility and hypospadias and cryptorchidism in boys: results from two Danish birth cohorts

OBJECTIVE

To study if parental subfertility is related to the occurrence of the male genital anomalies, cryptorchidism and hypospadias.

DESIGN

Population-based cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 80,220 singleton boys and their mothers from the Danish National Birth Cohort and the Aarhus Birth Cohort.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The two congenital anomalies; cryptorchidism and hypospadias, registered within the Danish National Patient Register up until December 31, 2012.

RESULT(S)

By means of Cox regression analyses, we found no associations between waiting time-to-pregnancy (TTP) and cryptorchidism or hypospadias among those who conceived spontaneously. The highest hazard ratio for cryptorchidism was seen among boys of couples with a TTP>12 months who conceived after fertility treatment (adjusted hazard ratio [aHR] 1.19, 95% confidence interval 0.92-1.55). For hypospadias, we found that boys of couples with a TTP>12 months who conceived after fertility treatment, had a 71% higher risk of hypospadias (aHR 1.71, [95% confidence interval 1.24-3.36]) as compared with boys of couples with a TTP<5 months.

CONCLUSION(S)

The findings from this study showed that boys of couples with TTP>12 months who conceived after fertility treatment, had a higher occurrence of hypospadias than boys conceived spontaneously of couples with a short TTP. Among those who conceived spontaneously, TTP was not associated with hypospadias or cryptorchidism. These findings indicate that fertility treatment or severity of subfertility is related to hypospadias.

Placental Weight and Male Genital Anomalies: A Nationwide Danish Cohort Study

The most consistently reported risk indicators for the male genital anomalies cryptorchidism and hypospadias are prematurity and low birth weight. Placental dysfunction has been hypothesized as a possible underlying cause, and an association between placental weight at birth and hypospadias has been indicated. In a population-based cohort of 388,422 Danish singleton boys born alive (1997-2008), we studied the association between placental weight and cryptorchidism and hypospadias. Missing data were handled with multiple imputation, and we estimated hazard ratios by means of Cox regression models. During follow-up, 1,713 boys were diagnosed with hypospadias and 6,878 with cryptorchidism (3,624 underwent corrective surgery). We observed an association between low placental weight and risk of both genital anomalies. Boys with a placental weight in the lowest decile (<10%) had higher risks of both cryptorchidism (hazard ratio = 1.52, 95% confidence interval: 1.31, 1.76) and hypospadias (hazard ratio = 1.97, 95% confidence interval: 1.59, 2.45) than boys in the reference decile (50.0-59.9%). In conclusion, we found higher risks of both genital malformations in boys born with a low placental weight. The relationship seemed stronger for hypospadias than for cryptorchidism. Taken together, our data support a role for placental dysfunction in the etiology of these anomalies.

The Danish National Patient Registry: a review of content, data quality, and research potential

Background

The Danish National Patient Registry (DNPR) is one of the world’s oldest nationwide hospital registries and is used extensively for research. Many studies have validated algorithms for identifying health events in the DNPR, but the reports are fragmented and no overview exists.

Objectives

To review the content, data quality, and research potential of the DNPR.

Methods

We examined the setting, history, aims, content, and classification systems of the DNPR. We searched PubMed and the Danish Medical Journal to create a bibliography of validation studies. We included also studies that were referenced in retrieved papers or known to us beforehand. Methodological considerations related to DNPR data were reviewed.

Results

During 1977–2012, the DNPR registered 8,085,603 persons, accounting for 7,268,857 inpatient, 5,953,405 outpatient, and 5,097,300 emergency department contacts. The DNPR provides nationwide longitudinal registration of detailed administrative and clinical data. It has recorded information on all patients discharged from Danish nonpsychiatric hospitals since 1977 and on psychiatric inpatients and emergency department and outpatient specialty clinic contacts since 1995. For each patient contact, one primary and optional secondary diagnoses are recorded according to the International Classification of Diseases. The DNPR provides a data source to identify diseases, examinations, certain in-hospital medical treatments, and surgical procedures. Long-term temporal trends in hospitalization and treatment rates can be studied. The positive predictive values of diseases and treatments vary widely (<15%–100%). The DNPR data are linkable at the patient level with data from other Danish administrative registries, clinical registries, randomized controlled trials, population surveys, and epidemiologic field studies – enabling researchers to reconstruct individual life and health trajectories for an entire population.

Conclusion

The DNPR is a valuable tool for epidemiological research. However, both its strengths and limitations must be considered when interpreting research results, and continuous validation of its clinical data is essential.

Antihistamines and birth defects: a systematic review of the literature

INTRODUCTION

Approximately 10 - 15% of women reportedly take an antihistamine during pregnancy for the relief of nausea and vomiting, allergy and asthma symptoms, or indigestion. Antihistamines include histamine H1-receptor and H2-receptor antagonists.

AREAS COVERED

This is a systematic evaluation of the peer-reviewed epidemiologic literature published through February 2014 on the association between prenatal exposure to antihistamines and birth defects. Papers addressing histamine H1- or H2-receptor antagonists are included. Papers addressing pyridoxine plus doxylamine (Bendectin in the United States, Debendox in the United Kingdom, Diclectin in Canada, Lenotan and Merbental in other countries) prior to the year 2001 were excluded post hoc because of several previously published meta-analyses and commentaries on this medication.

EXPERT OPINION

The literature on the safety of antihistamine use during pregnancy with respect to birth defects is generally reassuring though the positive findings from a few large studies warrant corroboration in other populations. The findings in the literature are considered in light of three critical methodological issues: i) selection of appropriate study population; ii) ascertainment of antihistamine exposures; and iii) ascertainment of birth defect outcomes. Selected antihistamines have been very well studied (e.g., loratadine); others, especially H2-receptor antagonists, require additional study before an assessment of safety with respect to birth defect risk could be made.

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.

Cryptorchidism and hypospadias in a cohort of 934,538 Danish boys: the role of birth weight, gestational age, body dimensions, and fetal growth

Early delivery and low birth weight are strong predictors of the urogenital anomalies cryptorchidism (undescended testis) and hypospadias. Understanding these associations may lead to important etiologic clues. Therefore, the authors revisited the prevailing hypotheses regarding fetal growth restriction as a risk factor for urogenital anomalies. They studied a population of 934,538 Danish boys born alive between January 1, 1980, and December 31, 2008. Cryptorchidism and hypospadias were associated with low weight-for-gestational-age, an indicator of fetal growth restriction, and furthermore the authors observed strong interaction with early delivery. Low birth weight in a singleton compared with the mean birth weight of all singleton brothers in the family or in a twin compared with the male co-twin was associated with higher risk of urogenital anomalies, suggesting an effect of relative fetal growth restriction within families. Contrary to previous reports, newborns' body dimensions assessed independently of birth weight were not associated with urogenital anomalies. The hypothesis that shared factors cause both fetal growth restriction and urogenital anomalies was supported by comparison of urogenital anomaly risks in singletons and twins and by patterns of cryptorchidism and hypospadias co-occurrence in individuals. These novel insights might also extend to other male reproductive conditions with prenatal etiology.

Use of antihistamine medications during early pregnancy and isolated major malformations

BACKGROUND

Antihistamines are commonly used during pregnancy. There is little evidence that they have teratogenic effects, but there are knowledge gaps with respect to newer products, as well as the relationship between specific antihistamines and specific birth defects.

METHODS

Using the National Birth Defects Prevention Study (1997-2003), the authors examined associations between maternal use of 14 antihistamines during early pregnancy and 26 isolated major birth defects. A Bayesian analysis incorporating prior knowledge about the relationships between antihistamines, birth defects, and measured covariates was conducted.

RESULTS

Of the 364 associations investigated, 24 had 95% posterior intervals excluding 1.0. All 24 associations were positive; 23 associations were of weak to moderate magnitude (posterior OR < 3.0) and one was strong (OR > 6.0) but very imprecise. Of the 24 associations, 20 were with noncardiac defects. Eight associations involved the antihistamine diphenhydramine.

CONCLUSIONS

The results of this study generally were consistent with no association between birth defects and antihistamine use during early pregnancy. Several of the findings might warrant further investigation, although the observed elevated associations should be interpreted in the context of the number of associations investigated and the analysis of retrospective, self-reported data.

Risk of hypospadias in offspring of women using loratadine during pregnancy: a systematic review and meta-analysis

BACKGROUND

Loratadine, a second-generation antihistamine, is commonly used to treat seasonal allergies. Some studies have suggested that use of loratadine by pregnant women increases the risk of hypospadias in male offspring.

OBJECTIVE

This meta-analysis was designed to assess the strength of the association between loratadine and hypospadias.

METHODS

To locate pertinent articles published in any language from January 1989 until August 2007, we searched electronic databases (MEDLINE, OVID, EMBASE, SCOPUS, TOXLINE Special, ReproTox, TERIS, CINAHL and others), conference proceedings and bibliographies. Studies were eligible for this analysis if they were cohort, case-control or case series studies that reported the incidence of hypospadias in the offspring of women who were or were not exposed to loratadine during pregnancy. Two authors independently extracted information on study design, participant characteristics, measures of outcome, control for potential confounding factors and risk estimates using a standardized data collection form. The Newcastle-Ottawa Scale was then used to assess the quality of each study. We used a random-effects meta-analysis model to combine the risk data.

RESULTS

In 1402 potentially relevant titles, we found three case-control studies and seven cohort studies that reported the incidence of hypospadias or other congenital malformations in offspring of women who did or did not use loratadine during pregnancy. Together the studies in our meta-analysis provided information about 453 053 male births in Brazil, Canada, Denmark, Israel, Italy, Sweden, the UK and the US.Of 2694 male infants born to women using loratadine, 39 (1.4%) had hypospadias. Of 450 413 male infants born to women not using loratadine, 4231 (0.9%) had hypospadias. Women who used loratadine during pregnancy were not significantly more likely to have a son with hypospadias (unadjusted odds ratio [OR] 1.27, 95% CI 0.73, 2.23; adjusted OR 1.28, 95% CI 0.69, 2.39).

CONCLUSION

The results of our systematic review and meta-analysis of controlled observational studies indicate that the use of loratadine during pregnancy does not significantly increase the risk of hypospadias in male offspring.

Factors associated with hypospadias in Asian newborn babies

AIMS

Previous studies reported an increasing temporal trend of hypospadias and a significant association with poor intrauterine growth. It remains unclear whether the association relates to birth weight, degree of prematurity or intra-uterine growth. The objective was to study the incidence of hypospadias and to examine the association with various risk factors.

METHODS

A retrospective case-control study was carried out of infants admitted to a neonatal unit from January 1st, 1999 to December 31st, 2005.

RESULTS

Of 6538 male live births, 27 (0.41%) infants had hypospadias. Incidence increased from 2.85 per thousand in 1999 to 6.89 per thousand in 2005. Hypospadias occurred significantly more frequently in babies born small for gestational age (SGA), in very low birth weight (VLBW) infants, those born preterm and to mothers with preeclampsia (PET). Logistic regression revealed that VLBW (OR 14.12, CI 5.48-36.39), maternal PET (OR 3.90, CI 1.50-10.14) and SGA (OR 3.23, CI 1.25-8.37) as independent risk factors.

CONCLUSIONS

Hypospadias is associated with VLBW, maternal PET and poor intra-uterine growth, but not with preterm birth. A rising trend in the incidence of hypospadias was noted in our population of Asian babies, suggesting a universal phenomenon.

No increased risk of infant hypospadias after maternal use of loratadine in early pregnancy

The original report published in 2001 on a possible association between maternal use of loratadine and an increased risk of infant hypospadias, based on data in the Swedish Medical Birth Register 1995-2001, has been followed up by continued surveillance in the same register. The original "signal" was based on 15 infants with hypospadias among 2780 loratadine-exposed infants born, representing an adjusted odd ratio of about 2.3, statistically significant. Since then another 10 cases have been identified, and 12.5 expected. For the period 2001-2004, another 1911 loratadine-exposed infants have been identified and only two had hypospadias (4 expected). Our present position is that the primary finding was a "signal" which had occurred by chance and the follow-up agrees with independent studies which indicate an absence of an association. This illustrates the care with which apparent statistically significant increases have to be handled when no prior hypothesis exists.