Prenatal exposure to loratadine in children with hypospadias: a nested case-control study within the Danish National Birth Cohort

Exposure to antazoline-naphazoline eye drops during pregnancy and the risk of congenital malformations: a Danish nationwide cohort study

PURPOSE

To investigate whether exposure to antazoline-naphazoline eye drops in the first trimester of pregnancy was associated with an increased risk of malformations in humans.

METHODS

All women giving live birth between 1997 and 2011 in Denmark were included in this nationwide cohort study. All women redeeming at least one prescription of antazoline-naphazoline eye drops during the first 84 days of pregnancy were identified. Logistic regression was used to estimate the odds ratios of malformations among exposed offspring compared to non-exposed offspring.

RESULTS

We identified 977 706 births between 1997 and 2011. A total of 3061 women (0.32%) were exposed to antazoline-naphazoline eye drops in the first trimester of pregnancy. The rate of congenital malformations was 3.0% (n = 93) in exposed offspring and 3.5% (n = 33 594) in unexposed offspring. First-trimester exposure to antazoline-naphazoline was not associated with major congenital malformations overall (odds ratio: 0.88, 95% confidence interval: 0.71-1.09) or with any specific major malformation. The number of redeemed prescriptions was unchanged during all trimesters of pregnancy as compared to before and after pregnancy (p < 0.05).

CONCLUSION

Exposure to antazoline-naphazoline eye drops in the first trimester of pregnancy appears not to be associated with increased teratogenic risk.

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.

Histamine, histamine receptors, and anti-histamines in the context of allergic responses

Histamine is a bioactive amine which is considered a key player in the allergic response. Thus, histamine receptor blockers (antihistamines) play an important role in the treatment of a number atopic diseases such as allergic rhinitis, conjunctivitis, and acute and chronic forms of urticaria. Histamine is produced by immune cells but also by bacteria in the gut. Beyond its role in the acute allergic response, histamine exerts numerous effects by binding to its 4 pleiotropic G-protein coupled histamine receptors. Here, we describe the roles of these histamine receptors and antihistamines in the human system, clinical applications, side effects, and novel concepts for the usage of antihistamines with different specificity based on guidelines and recommendations.

Statement of novelty: This review provides an overview of histamine receptors and links it to clinical relevance of antagonizing their action in clinical routine.

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.

Accuracy of the hypospadias diagnoses and surgical treatment registrations in the Danish National Patient Register

Purpose

The Danish National Health registers provide a valuable data source that offers unique opportunities for observational research, including studies on the congenital anomaly hypospadias. The accuracy of the diagnosis and surgical treatment registration of hypospadias in the Danish National Patient Register (DNPR) remains unknown.

Patients and methods

We randomly sampled 500 patients diagnosed with hypospadias in the DNPR from January 1, 1995 to December 31, 2012. Among these, 384 patients were also registered with surgical treatment for hypospadias. Medical records were collected and reviewed independently by two investigators. Any classification disagreements were resolved by consensus. Using the medical records as the gold standard, we estimated positive predictive values (PPVs) with 95% confidence intervals (CIs) for the hypospadias diagnoses and surgical treatment registrations overall, as well as for the clinical subtypes.

Results

We were able to retrieve medical records for 463 (92.6%) patients with hypospadias diagnoses and for 329 (85.7%) patients registered with surgical treatment. Presence of hypospadias was confirmed in 450 of 463 patients, yielding an overall PPV (95% CI) of 97.6% (95.8%–98.7%). For subtypes of hypospadias, the PPVs ranged between 37.5% and 72.7%. For surgical treatment of hypospadias, the overall PPV was 99.7% (97.9%–99.9%).

Conclusion

The validity of the registration of hypospadias diagnoses as well as surgical treatment for hypospadias in the DNPR is overall very high. For the specific subtypes of hypospadias diagnoses codes and the specific surgical treatment codes, the PPVs are lower and cautious use is warranted. However, the DNPR remains a valuable tool for future observational research on hypospadias.

Maternal endometriosis and genital malformations in boys: a Danish register-based study

OBJECTIVE

To investigate the association between maternal endometriosis and occurrence of the genital anomalies cryptorchidism and hypospadias in sons.

DESIGN

Population-based cohort study.

SETTING

Not applicable.

PATIENT(S)

All live-born singleton boys born from 1978 to 2012.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Cryptorchidism and hypospadias in boys based on information from the Danish National Patient Register.

RESULT(S)

The study included 1,073,026 live-born singleton boys. A total of 6,443 boys were sons of women diagnosed with endometriosis before pregnancy. Altogether, 27,342 boys were diagnosed with cryptorchidism, of whom 16,446 had corrective surgery. Hypospadias was diagnosed in 4,853 boys. As compared with unexposed boys, a tendency towards a slightly higher occurrence of cryptorchidism was observed among boys of women with endometriosis (adjusted hazard ratio [aHR] 1.18; 95% confidence interval [CI], 0.97, 1.44). When stratified by medically assisted reproduction (MAR) technologies, the association was slightly stronger among boys born to women with endometriosis who had conceived via MAR, yet it remained moderate and statistically insignificant (aHR 1.27; 95% CI, 0.86; 1.88). When women who conceived with MAR were excluded, the association between endometriosis and cryptorchidism disappeared. For hypospadias, we observed no association, either in the main analysis or the stratified analysis.

CONCLUSION(S)

The findings from this register-based study do not provide strong evidence for a higher occurrence of the studied genital anomalies among boys of women with endometriosis.

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.

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.

Assessment of antihistamine use in early pregnancy and birth defects

BACKGROUND

Several studies have reported an association between use of specific antihistamines in early pregnancy and certain specific birth defects.

OBJECTIVE

To test 16 previously hypothesized associations between specific antihistamines and specific birth defects, and to identify possible new associations.

METHODS

We used 1998-2010 data from the Slone Epidemiology Center Birth Defects Study, a multicenter case-control surveillance program of birth defects in North America. Mothers were interviewed within 6 months of delivery about demographic, reproductive, medical, and behavioral factors, and details on the use of prescription and nonprescription medications. We compared first trimester exposure to specific antihistamines between 13,213 infants with specific malformations and 6982 nonmalformed controls by using conditional logistic regression to estimate odds ratios and 95% confidence intervals (CIs), with adjustment for potential confounders, including indication for use.

RESULTS

Overall, 13.7% of controls were exposed to antihistamines during the first trimester. The most commonly used medications were diphenhydramine (4.2%), loratadine (3.1%), doxylamine (1.9%), and chlorpheniramine (1.7%). When estimates were stable, none supported the previously hypothesized associations. Among more than 100 exploratory comparisons of other specific antihistamine-defect pairs, 14 had odds ratios ≥1.5, of which 6 had 95% CI bounds excluding 1.0 before but not after adjustment for multiple comparisons.

CONCLUSION

Our findings do not provide meaningful support for previously posited associations between antihistamines and major congenital anomalies; at the same time, we identified associations that had not been previously suggested. We suspect that previous associations may be chance findings in the context of multiple comparisons, a situation that may also apply to our new findings.

A review of antihistamines used during pregnancy

Antihistamines are one of the most common drugs that are used extensively in various dermatological and nondermatological conditions. The use of H-1-antihistamines during pregnancy has been very controversial due to possible teratogenic effects of these drugs. None of the antihistamines available today have been categorized as safe during pregnancy. Control studies are available for certain first generation drugs regarding their safety in pregnancy, but the newer agents require further studies to be declared safer in pregnancy. A few drugs are comparatively safer to use in pregnancy than others. Every drug used in pregnancy carries a risk for teratogenicity and careful risk/benefit assessment should be done before prescribing them.

[Asthma and pregnancy. Review of the current literature and management according to the GINA 2006-2007 guidelines]

INTRODUCTION

Many pregnant women are asthmatics and maternal asthma is a source of questions and complications concerning both the progress of the pregnancy itself and the impact on the foetus. In this situation good asthma control is essential as the disease can deteriorate with acute exacerbations, possibly precipitated by reduction or even withdrawal of treatment on account of fear of teratogenicity.

BACKGROUND

Even though asthma treatments are not totally harmless during pregnancy, their use has been validated by several studies and guidelines. To help clinicians, we undertake here a review of the complications induced by maternal asthma and its medications, and then suggest management guidelines according to the most recent publications.

CONCLUSIONS

The risks and benefits of asthma treatments should be explained in a real partnership between the patient and her general practitioner and specialists (obstetrician, chest physician or allergist). In order to reduce complications to both mother and child, perfect control of asthma is required and inhaled steroids remain the treatment of choice for partially or uncontrolled asthma in the pregnant woman.

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.