Are oral contraceptive use and pregnancy complications risk factors for atopic disorders among offspring?

Maternal oral contraceptive pill use and the risk of atopic diseases in the offspring: A systematic review and meta-analysis

Studies of maternal oral contraceptive pill (OCP) exposure and the offspring's risk of atopic diseases are of current interest due to concerns about widespread use of OCP before or during pregnancy.We evaluated whether maternal OCP exposure is associated with an increased risk of atopic diseases by reviewing the literature and performing a meta-analysis. The PubMed and Embase databases were searched to identify potential studies for inclusion. Three common atopic outcomes were included: asthma, eczema, and rhinitis.We found 693 titles, abstracts, and citations, and 6 studies were included in this analysis. A meta-analysis revealed that maternal OCP exposure was associated with higher odds of asthma (odds ratio [OR] 1.1; 95% confidence interval [CI] 1.02-1.19; P = .014), rhinitis (OR 1.34; 95% CI 1.07-1.68; P = .011) during childhood, whereas there was no association with eczema (OR 1.17; 95% CI 0.81-1.68; P = .383). This analysis was limited by the small number of studies included and the limited adjustments for the possible confounders in the studies.Current evidence suggests that maternal OCP exposure increases the risk for respiratory allergic diseases (asthma and rhinitis) in the offspring, but not for eczema. Given the few studies included, future larger, prospective studies that control for important confounders are needed to verify our findings.

Periconception endogenous and exogenous maternal sex steroid hormones and risk of asthma and allergy in offspring: protocol for a systematic review and meta-analysis

INTRODUCTION

Pregnancy is associated with several hormonal changes which influence the developing fetus. Variations in maternal endogenous hormones and prepregnancy use of hormonal preparations have been linked to asthma and allergy in the offspring, but findings are inconsistent. We plan to undertake a systematic review to synthesise the evidence on the association between endogenous and exogenous maternal sex hormones and the risk of asthma and allergy in the offspring.

METHODS AND ANALYSIS

We will search Medline, Embase, Cochrane Library, Institute of Scientific Information Web of Science, Cumulative Index of Nursing and Allied Health, Scopus, Google Scholar, Allied and Complementary Medicine Database, Global Health, Psychological Information (PsycINFO), Centre for Agriculture and Bioscience (CAB) International and WHO Global Health Library from inception until 2016 to identify relevant studies on the topic. Additional studies will be identified by searching databases of proceedings of international conferences, contacting international experts in the field and searching the references cited in identified studies. We will include analytical epidemiological studies. Two researchers will independently screen identified studies, undertake data extraction and assess risk of bias in eligible studies, while a third reviewer will arbitrate any disagreement. We will use the Effective Public Health Practice Project tool to assess the risk of bias in the studies. We will perform a random-effects meta-analysis to synthesise the evidence. We will use the Grading of Recommendations Assessment, Development and Evaluation approach to rate the strength and quality of the overall evidence with respect to each outcome.

ETHICS AND DISSEMINATION

Ethical approval is not required since the study is a systematic review of published literature. Our findings will be reported in a peer-reviewed scientific journal.

PROSPERO REGISTRATION NUMBER

CRD42016048324.

Preconceptional exposure to oral contraceptive pills and the risk of wheeze, asthma and rhinitis in children

BACKGROUND

The prevalence of maternal oral contraceptive pills (OCP) use and that of childhood asthma are high in western countries. The aim of this study is to examine the association of OCP use with childhood wheeze and allergic diseases in Japan.

METHODS

Relevant data were extracted from a hospital based birth cohort study named as Tokyo-Children's Health, Illness and Development Study (T-CHILD) of which questionnaire conducted during pregnancy included maternal history and duration of OCP use. To identify wheeze and allergic diseases in the children, the questionnaire of the International Study of Asthma and Allergies in Childhood (ISAAC) was used. Logistic regression models were applied to estimate those association and adjustments were made for maternal history of allergy, maternal education level, maternal age at pregnancy, maternal BMI, maternal smoking during pregnancy, mode of delivery, gestational age at delivery, daycare attendance, number of previous live births, and gender of child.

RESULTS

OCP use was associated with ever wheeze (adjusted odds ratio [aOR], 1.62; 95% confidence interval [CI], 1.10-2.40), current wheeze (aOR, 1.59; 95% CI, 1.01-2.50), ever asthma (aOR, 1.65; 95% CI, 1.02-2.65), and ever rhinitis (aOR, 1.90; 95% CI, 1.30-2.80). Compared with no prior OCP use, using OCP for more than three months statistically increased the odds of ever wheeze (P = 0.012), current wheeze (P = 0.035), and ever rhinitis (P = 0.002).

CONCLUSIONS

Our findings suggest that maternal OCP use has a role in the development of wheeze, asthma and rhinitis in children. Extended use of OCP is likely to increase the risk of wheeze and rhinitis.

Oral contraceptive pill use before pregnancy and respiratory outcomes in early childhood

BACKGROUND

Oral contraceptive pills (OCPs) are often used soon before, and sometimes during, pregnancy. A few studies have suggested that OCP use before pregnancy may increase risks for childhood respiratory outcomes, but data are inconclusive. No studies have analyzed the two types of OCPs, estrogen-progestin combined pills and progestin-only pills, separately.

METHODS

In the Norwegian Mother and Child Cohort Study (MoBa), we prospectively examined associations of OCP use before pregnancy, by type, with lower respiratory tract infections in 60,225 children followed to 6 months old, lower respiratory tract infections and wheezing in 42,520 children followed to 18 months old, and asthma in 24,472 children followed to 36 months old. We used logistic regression to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) crudely and with adjustment for a wide range of potential confounders.

RESULT

Combined pills were used much more commonly than progestin-only pills. Taking combined pills before pregnancy was not associated with lower respiratory tract infections, wheezing, or asthma. Progestin-only pill use in the year before pregnancy had a slight positive association with wheezing at 6-8 months old [adjusted OR (95% CI) = 1.19 (1.05-1.34)].

CONCLUSION

Our finding that combined pill use before pregnancy was not related to respiratory outcomes should provide reassurance to the vast majority of mothers using OCPs before becoming pregnant. The small association with progestin-only pill use and early respiratory outcomes may reflect uncontrolled confounding or other bias. Nonetheless, it does suggest that these two types of pills should be examined separately in future analyses of respiratory and other childhood outcomes.

Developments in the field of allergy in 2009 through the eyes of Clinical and Experimental Allergy

In 2009 the journal published in the region of 200 papers including reviews, editorials, opinion pieces and original papers that ran the full gamut of allergic disease. It is instructive to take stock of this output to determine patterns of interest and where the cutting edge lies. We have surveyed the field of allergic disease as seen through the pages of Clinical and Experimental Allergy (CEA) highlighting trends, emphasizing notable observations and placing discoveries in the context of other key papers published during the year. The review is divided into similar sections as the journal. In the field of Asthma and Rhinitis CEA has contributed significantly to the debate about asthma phenotypes and expressed opinions about the cause of intrinsic asthma. It has also added its halfpennyworth to the hunt for meaningful biomarkers. In Mechanisms the considerable interest in T cell subsets including Th17 and T regulatory cells continues apace and the discipline of Epidemiology continues to invoke a steady stream of papers on risk factors for asthma with investigators still trying to explain the post-second world war epidemic of allergic disease. Experimental Models continue to make important contributions to our understanding of pathogenesis of allergic disease and in the Clinical Allergy section various angles on immunotherapy are explored. New allergens continue to be described in the allergens section to make those allergen chips even more complicated. A rich and vibrant year helpfully summarized by some of our associate editors.

Prevalence and risk factors of wheeze in Dutch infants in their first year of life

Factors operating in the first year of life are critical in determining the onset and persistence of wheezing in preschool children. This study was designed to examine the prevalence and risk factors of wheeze in the first year of life in Dutch infants. This was a population-based survey of 13-month-old infants visiting well baby clinics for a scheduled immunization. Parents/caregivers completed a standardized validated questionnaire on respiratory symptoms in the first year of life and putative risk factors. The independent influence of these factors for wheeze was assessed by multiple logistic regression analysis. A total of 1,115 questionnaires were completed. Wheeze ever (with a prevalence in the first year of life of 28.5%) was independently associated with male gender, eczema, sibs with asthma, any allergic disease in the family, day care, damp housing, and asphyxia. Recurrent wheeze (prevalence 14.5%) showed independent associations with eczema, sibs with asthma, and day care. In addition to these factors, severe wheeze (prevalence 15.4%) was also associated with premature rupture of membranes during birth, and with damp housing. Wheeze is common during the first year of life, and places a major burden on families and the health care system. Factors associated with wheeze are mainly related to markers of atopic susceptibility, and to exposure to infections. The strongest modifiable risk factor for wheeze in the first year of life is home dampness. Interventions to reduce home dampness to reduce wheeze in infancy should be examined.

Previous maternal oral contraception and the risk among subsequent offspring of asthma diagnosis in early childhood

Previous maternal use of the oral contraceptive pill (OCP) has been linked with asthma in subsequent offspring and has been implicated in the increased prevalence of childhood asthma in recent decades. We conducted a matched case-control study to test the hypothesis that maternal OCP used close to conception is associated with asthma in the offspring, particularly in children with coexistent eczema. We examined maternal OCP exposure in relation to asthma in the offspring (n = 6730) compared with offspring with no asthma (n = 6730) further stratifying by eczema, age group, treatment category and gender of the offspring. Maternal use of OCP was classified as: no OCP use in the 2 years prior to conception; past OCP use within 2 years but >6 months before conception; and recent OCP use within 6 months of conception. The adjusted odds ratio (OR) for asthma in the offspring was 1.16 [95% confidence interval 1.06, 1.27] among mothers who were recent users of the OCP when compared with mothers who had not used the OCP. Past OCP use was not associated with asthma in the offspring. In the stratified analyses, we observed weak but statistically significant associations between recent maternal OCP use and asthma in the offspring among children: without a history of eczema (adjusted OR 1.22 [1.09, 1.36]), those aged < or = 3 years (adjusted OR 1.24 [1.12, 1.37]), those not on treatment for their asthma (adjusted OR 1.33 [1.12, 1.58]) and among females (adjusted OR 1.34 [1.13, 1.51]). We did not find convincing evidence for a causal relationship between maternal OCP used close to conception and asthma in the offspring. The small statistically significant associations were not among children with characteristic features of asthma such as those with eczema and may be due to bias, uncontrolled confounding or chance.

Early-life environment, developmental immunotoxicology, and the risk of pediatric allergic disease including asthma

Incidence of childhood allergic disease including asthma (AD-A) has risen since the mid-20th century with much of the increase linked to changes in environment affecting the immune system. Childhood allergy is an early life disease where predisposing environmental exposures, sensitization, and onset of symptoms all occur before adulthood. Predisposition toward allergic disease (AD) is among the constellation of adverse outcomes following developmental immunotoxicity (DIT; problematic exposure of the developing immune system to xenobiotics and physical environmental factors). Because novel immune maturation events occur in early life, and the pregnancy state itself imposes certain restrictions on immune functional development, the period from mid-gestation until 2 years after birth is one of particular concern relative to DIT and AD-A. Several prenatal-perinatal risk factors have been identified as contributing to a DIT-mediated immune dysfunction and increased risk of AD. These include maternal smoking, environmental tobacco smoke, diesel exhaust and traffic-related particles, heavy metals, antibiotics, environmental estrogens and other endocrine disruptors, and alcohol. Diet and microbial exposure also significantly influence immune maturation and risk of allergy. This review considers (1) the critical developmental windows of vulnerability for the immune system that appear to be targets for risk of AD, (2) a model in which the immune system of the DIT-affected infant exhibits immune dysfunction skewed toward AD, and (3) the lack of allergy-relevant safety testing of drugs and chemicals that could identify DIT hazards and minimize problematic exposure of pregnant women and children.

Prevalence and associated factors of allergic rhinitis and atopic dermatitis in children

Allergic disorders are the chronic diseases of greatest pediatric morbidity, affecting over 25 % of the pediatric population. Indeed, this situation has been referred to as an "allergic epidemic". In comparison with asthma, atopic dermatitis and allergic rhinitis have been less extensively investigated, although this does not mean that they should be regarded as minor disorders but rather as alterations that affect the quality of life of the patients and their families, which generate considerable direct and indirect costs. Despite an important research effort, the reason for this allergic epidemic is not well known. These are multifactor disorders without a single causal agent, in which the most important component is the genetic predisposition of the patient (atopy), modulated by environmental factors, exposure to allergens, infections and irritants, among others. A confounding element is the fact that the concept of allergic diseases encompasses phenotypes of rhinitis, atopic dermatitis or asthma in which no IgE-mediated atopic mechanism is demonstrated, and which can manifest in a way similar to true allergic phenotypes. Differentiation between the two is difficult to establish on the basis of self-administered questionnaires alone, in the absence of a precise etiological diagnosis. The present article reviews the numerous factors suggested to be responsible for the increase in allergic diseases recorded in the last few decades, and for the differences in prevalence observed among centres. For most of these factors the results published in the literature are contradictory, in some cases due to a lack of control of the associated interacting or confounding factors. Consensus exists for only some of these causal factors, such as the established parallelism between the increase in allergic diseases and the reduction in infectious processes on one hand, and the increase in particles generated by diesel fuel combustion on the other. In addition, the implicated factors could act differently (and in some cases even antagonically) upon atopy and on the different disease phenotypes, thereby complicating the study of these interactions even further.

Environmental factors and allergic disorders

Despite numerous studies on possible associations between environmental exposure and allergic disorders, any conclusions made remain a matter of controversy. We conducted a review of evidence in relation to environmental and nutritional determinants and wheeze, asthma, atopic dermatitis, and allergic rhinitis. Identified were 263 articles for analysis after consideration of 1093 papers that were published since 2000 and selected by electronic search of the PubMed database using keywords relevant to epidemiological studies. Most were cross-sectional and case-control studies. Several prospective cohort studies revealed inconsistent associations between various environmental factors and the risk of any allergic disorder. Therefore, the evidence was inadequate to infer the presence or absence of a causal relationship between various environmental exposures and allergic diseases. However, evidence is suggestive of positive associations of allergies with heredity. Because almost all the studies were performed in Western countries, the application of these findings to people in other countries, including Japan, may not be appropriate. Further epidemiological information gained from population-based prospective cohort studies, in particular among Japanese together with other Asians, is needed to assess causal relationships between various environmental factors and allergic diseases.

Asthma prevalence, family size, and birth order

BACKGROUND

Asthma prevalence may be reduced in large families. The hygiene hypothesis suggests that older siblings protect their younger siblings from asthma through a modulating effect on the still-maturing immune system. If the hygiene hypothesis is correct, asthma prevalence should be inversely related to birth order. The objective of this study was to examine the relationship between asthma prevalence, and family size and birth order.

METHODS

The medical records of 531,116 Israeli military conscripts were reviewed. The association between number of children in the family and the prevalence of asthma, and between birth order and the prevalence of asthma was assessed. Odds ratios for asthma by birth order and family size, adjusted for each other, were calculated.

RESULTS

Asthma was diagnosed in 26,833 male subjects (8.6%) and 15,079 female subjects (6.9%). Asthma prevalence was inversely related to the number of children in the family (p < 0.001). Among subjects who were the only child in the family, the prevalence of asthma was 7.3%. The prevalence increased to 8.95% among subjects from families with three siblings, and then progressively decreased as the number of siblings increased, and reached a trough of 0.58% in conscripts from families of 15 to 20 siblings. Asthma prevalence was similar for all birth orders.

CONCLUSIONS

In families with four or more children, asthma prevalence is inversely related to the number of children in the family. Asthma prevalence is similar for all birth orders. The similar asthma prevalence for all birth orders challenges the hygiene hypothesis as the mechanism for the decreased asthma prevalence in large families.

Does the pill make a difference? Previous maternal use of contraceptive pills and allergic diseases among offspring

BACKGROUND

Maternal use of oral contraceptive pills (OCPs) might increase the prevalence of allergic diseases among offspring. The aim of the study was to clarify if there are differences between OCP types in this association.

METHODS

Primary outcomes were asthma, allergic rhinitis and atopic eczema among 1182 children (618 asthmatic and 564 controls) aged 5-6 years.

RESULTS

Maternal previous use of desogestrel, gestodene or cyproterone acetate before pregnancy, each combined with ethinyloestradiol (EO), increased the risk of allergic rhinitis among offspring compared with those children whose mothers had not used OCPs (OR 1.67, 95% CI 1.07-2.59, P < 0.024), and this risk was increased mainly in those children with parental allergy (OR 1.78, 95% CI 1.11-2.86, P < 0.018), especially in boys (OR 2.12, 95% CI 1.17-3.84, P < 0.014). No associations were observed between maternal use of OCPs before pregnancy and asthma or atopic eczema among offspring. The association between the previous use of OCPs and allergic rhinitis was not mediated through maternal sex steroid levels during early pregnancy, but women who had used more androgenic types of progestin formulas had higher serum levels of progesterone during early pregnancy.

CONCLUSION

Maternal previous use of desogestrel, gestodene or cyproterone acetate before pregnancy, each combined with EO, increased the risk of allergic rhinitis among offspring compared with those children whose mothers had not used OCPs and this risk was detected mainly in boys and in children with parental allergy.

Treating allergic rhinitis in pregnancy

Numerous pregnant women suffer from allergic rhinitis, and particular attention is required when prescribing drugs to these patients. In addition, physiologic changes associated with pregnancy could affect the upper airways. Evidence-based guidelines on the management of allergic rhinitis have been published. Medication can be prescribed during pregnancy when the apparent benefit of the drug is greater than the apparent risk. Usually, there is at least one "safe" drug from each major class used to control symptoms. All glucocorticosteroids are teratogenic in animals but, when the indication is clear (for diseases possibly associated, such as severe asthma exacerbation), the benefit of the drug is far greater than the risk. Inhaled glucocorticosteroids (eg, beclomethasone or budesonide) have not been incriminated as teratogens in humans and are used by pregnant women who have asthma. A few H1-antihistamines can safely be used as well. Most oral decongestants (except pseudoephedrine) are teratogenic in animals. There are no such data available for intranasal decongestants. Finally, pregnancy is not considered to be a contraindication for the continuation of immunotherapy.