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Objective: To compare the risk of acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and contact with specialist healthcare services for coronavirus disease 2019 (COVID‐19) between pregnant and non‐pregnant women. Population or sample: All women ages 15–45 living in Norway on 1 March 2020 (n = 1 033 699). Methods: We linked information from the national birth, patient, communicable diseases and education databases using unique national identifiers. Main outcome measure: We estimated hazard ratios (HR) among pregnant compared to non‐pregnant women of having a positive test for SARS‐CoV‐2, a diagnosis of COVID‐19 in specialist healthcare, or hospitalisation with COVID‐19 using Cox regression. Multivariable analyses adjusted for age, marital status, education, income, country of birth and underlying medical conditions. Results: Pregnant women were not more likely to be tested for or to a have a positive SARS‐CoV‐2 test (adjusted HR 0.99; 95% CI 0.92–1.07). Pregnant women had higher risk of hospitalisation with COVID‐19 (HR 4.70, 95% CI 3.51–6.30) and any type of specialist care for COVID‐19 (HR 3.46, 95% CI 2.89–4.14). Pregnant women born outside Scandinavia were less likely to be tested, and at higher risk of a positive test (HR 2.37, 95% CI 2.51–8.87). Compared with pregnant Scandinavian‐born women, pregnant women with minority background had a higher risk of hospitalisation with COVID‐19 (HR 4.72, 95% CI 2.51–8.87). Conclusion: Pregnant women were not more likely to be infected with SARS‐CoV‐2. Still, pregnant women with COVID‐19, especially those born outside of Scandinavia, were more likely to be hospitalised. Pregnant women are at increased risk of hospitalisation for COVID‐19. Pregnant women are at increased risk of hospitalisation for COVID‐19. [ABSTRACT FROM AUTHOR]

Introduction: This study assessed prevalence and time trends of pre-pregnancy obesity in immigrant and non-immigrant women in Norway and explored the impact of immigrants' length of residence on pre-pregnancy obesity prevalence., Material and Methods: Observational data from the Medical Birth Registry of Norway and Statistics Norway for the years 2016-2021 were analyzed. Immigrants were categorized by their country of birth and further grouped into seven super regions defined by the Global Burden of Disease study. Pre-pregnancy obesity was defined as a body mass index ≥30.0 kg/m 2 , with exceptions for certain Asian subgroups (≥27.5 kg/m 2 ). Statistical analysis involved linear regressions for trend analyses and log-binomial regressions for prevalence ratios (PRs)., Results: Among 275 609 pregnancies, 29.6% (N = 81 715) were to immigrant women. Overall, 13.6% were classified with pre-pregnancy obesity: 11.7% among immigrants and 14.4% among non-immigrants. Obesity prevalence increased in both immigrants and non-immigrants during the study period, with an average yearly increase of 0.62% (95% confidence interval [CI]: 0.55, 0.70). Obesity prevalence was especially high in women from Pakistan, Chile, Somalia, Congo, Nigeria, Ghana, Sri Lanka, and India (20.3%-26.9%). Immigrant women from "Sub-Saharan Africa" showed a strong association between longer residence length and higher obesity prevalence (≥11 years (23.1%) vs. <1 year (7.2%); adjusted PR = 2.40; 95% CI: 1.65-3.48), particularly in women from Kenya, Eritrea, and Congo., Conclusions: Prevalence of maternal pre-pregnancy obesity increased in both immigrant and non-immigrant women from 2016 to 2021. Several immigrant subgroups displayed a considerably elevated obesity prevalence, placing them at high risk for adverse obesity-related pregnancy outcomes. Particular attention should be directed towards women from "Sub-Saharan Africa", as their obesity prevalence more than doubled with longer residence., (© 2024 The Author(s). Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Introduction: The prevalence of congenital heart disease (CHD) among women of reproductive age is rising. We aimed to investigate the risk of preeclampsia and adverse neonatal outcomes in pregnancies of mothers with CHD compared to pregnancies of mothers without heart disease., Material and Methods: In a nationwide cohort of pregnancies in Norway 1994-2014, we retrieved information on maternal heart disease, the course of pregnancy, and neonatal outcomes from national registries. Comparing pregnancies with maternal CHD to pregnancies without maternal heart disease, we used Cox regression to estimate the adjusted hazard ratio (aHR) for preeclampsia and log-binomial regression to estimate the adjusted risk ratio (aRR) for adverse neonatal outcomes. The estimates were adjusted for maternal age and year of childbirth and presented with 95% confidence intervals (CIs)., Results: Among 1 218 452 pregnancies, 2425 had mild maternal CHD, and 603 had moderate/severe CHD. Compared to pregnancies without maternal heart disease, the risk of preeclampsia was increased in pregnancies with mild and moderate/severe maternal CHD (aHR1.37, 95% CI 1.14-1.65 and aHR 1.62, 95% CI 1.13-2.32). The risk of preterm birth was increased in pregnancies with mild maternal CHD (aRR 1.33, 95% CI 1.15-1.54) and further increased with moderate/severe CHD (aRR 2.49, 95% CI 2.03-3.07). Maternal CHD was associated with elevated risks of both spontaneous and iatrogenic preterm birth. The risk of infants small-for-gestational-age was slightly increased with mild maternal CHD (aRR 1.12, 95% CI 1.00-1.26) and increased with moderate/severe CHD (aRR 1.63, 95% CI 1.36-1.95). The prevalence of stillbirth was 3.9 per 1000 pregnancies without maternal heart disease, 5.6 per 1000 with mild maternal CHD, and 6.8 per 1000 with moderate/severe maternal CHD. Still, there were too few cases to report a significant difference. There were no maternal deaths in women with CHD., Conclusions: Moderate/severe maternal CHD in pregnancy was associated with increased risks of preeclampsia, preterm birth, and infants small-for-gestational-age. Mild maternal CHD was associated with less increased risks. For women with moderate/severe CHD, their risk of preeclampsia and adverse neonatal outcomes should be evaluated together with their cardiac risk in pregnancy, and follow-up in pregnancy should be ascertained., (© 2024 The Author(s). Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Introduction: Tanzania has a high adolescent birth rate and many sexually active adolescents do not have access to effective contraception. Teenage pregnancy is considered a high-risk pregnancy. Furthermore, it leads to social inequalities for both mother and offspring., Methods: We conducted semistructured interviews with 12 adolescent mothers during their stay in the postnatal ward of the maternity department of a tertiary hospital in Zanzibar. The study took place between November and December 2022. Data were then analyzed qualitatively., Results: The main theme that emerged from the interview data was that pregnancy seemed to affect the lives of young girls in a negative way. The majority of pregnancies were unplanned, and the girls reported low family planning uptake. Another recurring theme was that girls had many οbstacles in their education prior to pregnancy, which left them uncertain about their future. Finally, despite the advice of local doctors, the majority of the girls received minimal prenatal care, mostly because they did not regard obstetric care to be a priority., Conclusions: Adolescent pregnancy remains an important public health issue in Tanzania, despite significant measures by authorities to reduce it. Educational changes and professional opportunities as well as family planning services may enable young girls to achieve professional and personal goals while delaying motherhood into adulthood., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Triantafyllidi et al.)

Objective: To assess the impact of COVID-19 on pregnancy-related healthcare utilisation and differences across social groups., Design: Nationwide longitudinal prospective registry-based study., Setting: Norway., Participants: Female residents aged 15-50 years (n=1 244 560)., Main Outcome Measures: Pregnancy-related inpatient, outpatient and primary care healthcare utilisation before the COVID-19 pandemic (prepandemic: 1 January to 11 March 2020), during the initial lockdown (first wave: 12 March to 3 April 2020), during the summer months of low restrictions (summer period: 4 April to 31 August 2020) and during the second wave to the end of the year (second wave: 1 September to 31 December 2020). Rates were compared with the same time periods in 2019., Results: There were 130 924 inpatient specialist care admissions, 266 015 outpatient specialist care consultations and 2 309 047 primary care consultations with pregnancy-related diagnostic codes during 2019 and 2020. After adjusting for time trends and cofactors, inpatient admissions were reduced by 9% (adjusted incidence rate ratio (aIRR)=0.91, 95% CI 0.87 to 0.95), outpatient consultations by 17% (aIRR=0.83, 95% CI 0.71 to 0.86) and primary care consultations by 10% (aIRR=0.90, 95% CI 0.89 to 0.91) during the first wave. Inpatient care remained 3%-4% below prepandemic levels throughout 2020. Reductions according to education, income and immigrant background were also observed. Notably, women born in Asia, Africa or Latin America had a greater reduction in inpatient (aIRR=0.87, 95% CI 0.77 to 0.97) and outpatient (aIRR 0.90, 95% CI 0.86 to 0.95) care during the first wave, compared with Norwegian-born women. We also observed that women with low education had a greater reduction in inpatient care during summer period (aIRR=0.88, 95% CI 0.83 to 0.92), compared with women with high educational attainment., Conclusion: Following the introduction of COVID-19 mitigation measures in Norway in March 2020, there were substantial reductions in pregnancy-related healthcare utilisation, especially during the initial lockdown and among women with an immigrant background., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Importance: Data about the safety of vaccines against SARS-CoV-2 during pregnancy are limited., Objective: To examine the risk of adverse pregnancy outcomes after vaccination against SARS-CoV-2 during pregnancy., Design, Setting, and Participants: This registry-based retrospective cohort study included 157 521 singleton pregnancies ending after 22 gestational weeks from January 1, 2021, until January 12, 2022 (Sweden), or January 15, 2022 (Norway). The Pregnancy Register in Sweden and the Medical Birth Registry of Norway were linked to vaccination and other registries for identification of exposure and background characteristics., Exposures: Data on mRNA vaccines-BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna)-and 1 viral vector vaccine-AZD1222 (AstraZeneca)-were collected from national vaccination registries., Main Outcomes and Measures: The risk of preterm birth and stillbirth was evaluated using Cox regression models, with gestational day as the time metric and vaccination as a time-dependent exposure variable. The risk of small for gestational age, low Apgar score, and neonatal care admission was evaluated using logistic regression. Random-effects meta-analysis was used to combine results between countries., Results: Among the 157 521 singleton births included in the study (103 409 in Sweden and 54 112 in Norway), the mean maternal age at the time of delivery was 31 years, and 28 506 (18%) were vaccinated against SARS-CoV-2 (12.9% with BNT162b2, 4.8% with mRNA-1273, and 0.3% with AZD1222) while pregnant. A total of 0.7%, 8.3%, and 9.1% of individuals delivering were vaccinated during the first, second, and third trimester, respectively. Vaccination against SARS-CoV-2 was not significantly associated with increased risk of preterm birth (6.2 vs 4.9 per 10 000 pregnancy days; adjusted hazard ratio [aHR], 0.98 [95% CI, 0.91 to 1.05]; I2 = 0%; P for heterogeneity = .60), stillbirth (2.1 vs 2.4 per 100 000 pregnancy days; aHR, 0.86 [95% CI, 0.63 to 1.17]), small for gestational age (7.8% vs 8.5%; difference, -0.6% [95% CI, -1.3% to 0.2%]; adjusted OR [aOR], 0.97 [95% CI, 0.90 to 1.04]), low Apgar score (1.5% vs 1.6%; difference, -0.05% [95% CI, -0.3% to 0.1%]; aOR, 0.97 [95% CI, 0.87 to 1.08]), or neonatal care admission (8.5% vs 8.5%; difference, 0.003% [95% CI, -0.9% to 0.9%]; aOR, 0.97 [95% CI, 0.86 to 1.10])., Conclusions and Relevance: In this population-based study conducted in Sweden and Norway, vaccination against SARS-CoV-2 during pregnancy, compared with no SARS-CoV-2 vaccination during pregnancy, was not significantly associated with an increased risk of adverse pregnancy outcomes. The majority of the vaccinations were with mRNA vaccines during the second and third trimesters of pregnancy, which should be considered in interpreting the findings.

Objective: To compare the risk of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and contact with specialist healthcare services for coronavirus disease 2019 (COVID-19) between pregnant and non-pregnant women., Population or Sample: All women ages 15-45 living in Norway on 1 March 2020 (n = 1 033 699)., Methods: We linked information from the national birth, patient, communicable diseases and education databases using unique national identifiers., Main Outcome Measure: We estimated hazard ratios (HR) among pregnant compared to non-pregnant women of having a positive test for SARS-CoV-2, a diagnosis of COVID-19 in specialist healthcare, or hospitalisation with COVID-19 using Cox regression. Multivariable analyses adjusted for age, marital status, education, income, country of birth and underlying medical conditions., Results: Pregnant women were not more likely to be tested for or to a have a positive SARS-CoV-2 test (adjusted HR 0.99; 95% CI 0.92-1.07). Pregnant women had higher risk of hospitalisation with COVID-19 (HR 4.70, 95% CI 3.51-6.30) and any type of specialist care for COVID-19 (HR 3.46, 95% CI 2.89-4.14). Pregnant women born outside Scandinavia were less likely to be tested, and at higher risk of a positive test (HR 2.37, 95% CI 2.51-8.87). Compared with pregnant Scandinavian-born women, pregnant women with minority background had a higher risk of hospitalisation with COVID-19 (HR 4.72, 95% CI 2.51-8.87)., Conclusion: Pregnant women were not more likely to be infected with SARS-CoV-2. Still, pregnant women with COVID-19, especially those born outside of Scandinavia, were more likely to be hospitalised., Tweetable Abstract: Pregnant women are at increased risk of hospitalisation for COVID-19., (© 2021 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.)

Objective: Some studies of women with polycystic ovary syndrome (PCOS) report increased prevalence of hypertensive disorders in pregnancy, while others do not. Several of these studies do not control for obesity. We aimed to study whether PCOS is associated with hypertensive disorders in pregnancy and whether it is dependent on body mass index (BMI)., Study Design: We present a cross-sectional analysis of 3732 women from Denmark, Estonia, Iceland, Norway and Sweden, born in 1945-72, who participated in the Respiratory Health In Northern Europe (RHINE) study and answered an extensive women's health questionnaire on menstruation, PCOS, infertility, pregnancy history and childbirth. The main outcome measurement was hypertensive disorders of pregnancy. We adjusted for smoking, age, infertility treatment and study center. Effect modification by BMI was assessed., Results: PCOS was related to hypertensive disorders in pregnancy with a relative risk (RR) of 1.62 (95% CI 1.09-2.42). This relationship was found among underweight women with a BMI of <18.5 kg/m 2 [RR = 5.2 (95% CI 1.66-16.5)] and obese women with a BMI of ≥30 kg/m 2 [RR = 2.36 (95% CI 1.29-4.31)], but not among normal-weight women, BMI 18.5-25 kg/m 2 [1.08 (0.53-2.20)], or overweight women, BMI 25-30 kg/m 2 [1.24 (0.50-3.08)] (p-interaction = 0.041)., Conclusion: Polycystic ovary syndrome is associated with hypertensive disorders in pregnancy. This association only occurs among underweight and obese women and not among normal-weight and slightly overweight women., (Copyright © 2018 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.)

Background: Whereas it is generally accepted that maternal environment plays a key role in child health, emerging evidence suggests that paternal environment before conception also impacts child health. We aimed to investigate the association between children's asthma risk and parental smoking and welding exposures prior to conception., Methods: In a longitudinal, multi-country study, parents of 24 168 offspring aged 2-51 years provided information on their life-course smoking habits, occupational exposure to welding and metal fumes, and offspring's asthma before/after age 10 years and hay fever. Logistic regressions investigated the relevant associations controlled for age, study centre, parental characteristics (age, asthma, education) and clustering by family., Results: Non-allergic early-onset asthma (asthma without hay fever, present in 5.8%) was more common in the offspring with fathers who smoked before conception {odds ratio [OR] = 1.68 [95% confidence interval (CI) = 1.18-2.41]}, whereas mothers' smoking before conception did not predict offspring asthma. The risk was highest if father started smoking before age 15 years [3.24 (1.67-6.27)], even if he stopped more than 5 years before conception [2.68 (1.17-6.13)]. Fathers' pre-conception welding was independently associated with non-allergic asthma in his offspring [1.80 (1.29-2.50)]. There was no effect if the father started welding or smoking after birth. The associations were consistent across countries., Conclusions: Environmental exposures in young men appear to influence the respiratory health of their offspring born many years later. Influences during susceptible stages of spermatocyte development might be important and needs further investigation in humans. We hypothesize that protecting young men from harmful exposures may lead to improved respiratory health in future generations., (© The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association)

Background: There is limited and conflicting evidence on the effect of menopause on asthma., Objectives: We sought to study whether the incidence of asthma and respiratory symptoms differ by menopausal status in a longitudinal population-based study with an average follow-up of 12 years., Methods: The Respiratory Health in Northern Europe study provided questionnaire data pertaining to respiratory and reproductive health at baseline (1999-2001) and follow-up (2010-2012). The study cohort included women aged 45 to 65 years at follow-up, without asthma at baseline, and not using exogenous hormones (n = 2322). Menopausal status was defined as nonmenopausal, transitional, early postmenopausal, and late postmenopausal. Associations with asthma (defined by the use of asthma medication, having asthma attacks, or both) and respiratory symptoms scores were analyzed by using logistic (asthma) and negative binomial (respiratory symptoms) regressions, adjusting for age, body mass index, physical activity, smoking, education, and study center., Results: The odds of new-onset asthma were increased in women who were transitional (odds ratio, 2.40; 95% CI, 1.09-5.30), early postmenopausal (odds ratio, 2.11; 95% CI, 1.06-4.20), and late postmenopausal (odds ratio, 3.44; 95% CI, 1.31-9.05) at follow-up compared with nonmenopausal women. The risk of respiratory symptoms increased in early postmenopausal (coefficient, 0.40; 95% CI, 0.06-0.75) and late postmenopausal (coefficient, 0.69; 95% CI, 0.15-1.23) women. These findings were consistent irrespective of smoking status and across study centers., Conclusions: New-onset asthma and respiratory symptoms increased in women becoming postmenopausal in a longitudinal population-based study. Clinicians should be aware that respiratory health might deteriorate in women during reproductive aging., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Rationale: There is some evidence that maternal smoking increases susceptibility to personal smoking's detrimental effects. One might question whether early life disadvantage might influence susceptibility to occupational exposure., Objectives: In this cross-sectional study we investigated respiratory symptoms, asthma and self-reported chronic obstructive pulmonary disease (COPD) as related to working as a cleaner in Northern European populations, and whether early life factors influenced susceptibility to occupational cleaning's unhealthy effects., Methods: The RHINE III questionnaire study assessed occupational cleaning in 13,499 participants. Associations with respiratory symptoms, asthma and self-reported COPD were analysed with multiple logistic regressions, adjusting for sex, age, smoking, educational level, parent´s educational level, BMI and participating centre. Interaction of occupational cleaning with early life disadvantage (maternal smoking, severe respiratory infection <5 years, born during winter months, maternal age at birth >35 years) was investigated., Main Results: Among 2138 ever-cleaners the risks of wheeze (OR 1.4, 95% CI 1.3-1.6), adult-onset asthma (1.5 [1.2-1.8]) and self-reported COPD (1.7 [1.3-2.2]) were increased. The risk increased with years in occupational cleaning (adult-onset asthma: ≤1 year 0.9 [0.7-1.3]; 1-4 years 1.5 [1.1-2.0]; ≥4 years 1.6 [1.2-2.1]). The association of wheeze with cleaning activity ≥4 years was significantly stronger for those with early life disadvantage than in those without (1.8 [1.5-2.3] vs. 1.3 [0.96-1.8]; pinteraction 0.035)., Conclusions: Occupational cleaners had increased risk of asthma and self-reported COPD. Respiratory symptom risk was particularly increased in persons with factors suggestive of early life disadvantage. We hypothesize that early life disadvantage may increase airway vulnerability to harmful exposure from cleaning agents later in life.

Background: Selection bias is a systematic error in epidemiologic studies that may seriously distort true measures of associations between exposure and disease. Observational studies are highly susceptible to selection bias, and researchers should therefore always examine to what extent selection bias may be present in their material and what characterizes the bias in their material. In the present study we examined long-term participation and consequences of loss to follow-up in the studies Respiratory Health in Northern Europe (RHINE), Italian centers of European Community Respiratory Health Survey (I-ECRHS), and the Italian Study on Asthma in Young Adults (ISAYA)., Methods: Logistic regression identified predictors for follow-up participation. Baseline prevalence of 9 respiratory symptoms (asthma attack, asthma medication, combined variable with asthma attack and/or asthma medication, wheeze, rhinitis, wheeze with dyspnea, wheeze without cold, waking with chest tightness, waking with dyspnea) and 9 exposure-outcome associations (predictors sex, age and smoking; outcomes wheeze, asthma and rhinitis) were compared between all baseline participants and long-term participants. Bias was measured as ratios of relative frequencies and ratios of odds ratios (ROR)., Results: Follow-up response rates after 10 years were 75% in RHINE, 64% in I-ECRHS and 53% in ISAYA. After 20 years of follow-up, response was 53% in RHINE and 49% in I-ECRHS. Female sex predicted long-term participation (in RHINE OR (95% CI) 1.30(1.22, 1.38); in I-ECRHS 1.29 (1.11, 1.50); and in ISAYA 1.42 (1.25, 1.61)), as did increasing age. Baseline prevalence of respiratory symptoms were lower among long-term participants (relative deviations compared to total baseline population 0-15% (RHINE), 0-48% (I-ECRHS), 3-20% (ISAYA)), except rhinitis which had a slightly higher prevalence. Most exposure-outcome associations did not differ between long-term participants and all baseline participants, except lower OR for rhinitis among ISAYA long-term participating smokers (relative deviation 17% (smokers) and 44% (10-20 pack years))., Conclusions: We found comparable patterns of long-term participation and loss to follow-up in RHINE, I-ECRHS and ISAYA. Baseline prevalence estimates for long-term participants were slightly lower than for the total baseline population, while exposure-outcome associations were mainly unchanged by loss to follow-up.

Objective: Evaluating the validity of pre-eclampsia registration in the Medical Birth Registry of Norway (MBRN) according to both broader and restricted disease definitions., Design: Retrospective nested cohort study., Setting: Multicenter study., Population: In this study, two cohorts of women with pre-eclamptic pregnancies registered in the MBRN were selected. Study group 1 contained 966 pregnancies from 1967 to 2002. Concomitant participation in the Nord-Trøndelag Health Study 2 was required. Study group 2 comprised 1138 pregnancies recorded in 1967-2005, examined as a pre-eclampsia biobank was established., Methods: Diagnostic criteria vary. The broader criteria for pre-eclampsia, used by the MBRN, are one measurement of hypertension and proteinuria (Criterion A). Criteria used internationally today require two measurements of hypertension and proteinuria (Criterion B). The diagnostic validities in Study groups 1 and 2 were judged against medical records according to Criterion A and B, respectively., Main Outcome Measures: Positive predictive value (PPV) and trend analyses., Results: The diagnosis was confirmed in 88.3% of pregnancies in Study group 1, and in 63.6% in Study group 2. PPV was high for Study group 1 throughout the period. For Study group 2, results improved significantly after 1986., Conclusions: This study ascertains high PPV of pre-eclampsia in the MBRN using broader traditional criteria, although the PPV decreases through assessment using restricted modern criteria. This illustrates how inclusion of direct measurements may improve registration of complex disorders defined by changing diagnostic criteria., (© 2013 Nordic Federation of Societies of Obstetrics and Gynecology.)

Rationale: There is little knowledge of variations in respiratory symptoms during the menstrual cycle in a general population, and potential modifying factors are not investigated., Objectives: To investigate menstrual cycle variation in respiratory symptoms in a large general population, using chronobiology methodology, and stratifying by body mass index (BMI), smoking, and asthma status., Methods: A total of 3,926 women with regular cycles less than or equal to 28 days and not taking exogenous sex hormones answered a postal questionnaire regarding the first day of their last menstruation and respiratory symptoms in the last 3 days. Moving 4-day means were computed to smooth uneven records of daily sampling; best-fitting 28-day composite cosine curves were applied to each time series to describe rhythmicity., Measurements and Main Results: Significant rhythmic variations over the menstrual cycle were found in each symptom for all subjects and subgroups. Wheezing was higher on cycle Days 10-22, with a midcycle dip near the time of putative ovulation (approximately Days 14-16) in most subgroups. Shortness of breath was higher on days 7-21, with a dip just before midcycle in many subgroups. Cough was higher just after putative ovulation for subjects with asthma, BMI greater than or equal to 23 kg/m(2), and smokers, or just before ovulation and menses onset for low symptomatic subgroups., Conclusions: Respiratory symptoms varied significantly during the menstrual cycle and were most frequent from the midluteal to midfollicular stages, often with a dip near the time of ovulation. The patterns varied by BMI, smoking, and asthma status. These relations link respiratory symptoms with hormonal changes through the menstrual cycle and imply a potential for individualized chronotherapy for respiratory diseases.

Gender differences in respiratory health have, in recent years, been the focus of considerable scientific effort. This paper reviews recent literature on respiratory health in women in relation to age at menarche, menstrual cycle, irregular menstruation, polycystic ovarian syndrome, menopause and exogenous sex hormones. This literature provides substantial evidence that hormonal status plays an important role for respiratory health in women. Effects of hormonal status on the airways often appear to be heterogeneous and recent literature in particular suggests that the interplay between hormonal and metabolic factors is important. A view to developmental factors may also be relevant for the understanding of respiratory health according to hormonal status in women. Further knowledge of respiratory health in women holds interesting potential for intervention and personalized treatment.

Rationale: hormonal and metabolic status appears to influence lung health in women, and there are findings suggesting that early menarche may be related to asthma, cardiovascular disease, diabetes, and breast cancer., Objectives: this study investigates whether age at menarche is related to adult lung function and asthma., Methods: among participants in the European Community Respiratory Health Survey II, 3,354 women aged 27-57 years from random population samples in 21 centers responded to a questionnaire concerning women's health (1998-2002). Of these women, 2,873 had lung function measurements, 2,136 had measurements of bronchial hyperreactivity, and 2,743 had IgE measurements. Logistic, linear, and negative binomial regression analyses included adjustment for age, height, body mass index, education, smoking, family size, and center., Measurements and Main Results: FEV(1) and FVC were lower and asthma was more common in women with early menarche. Women reporting menarche at age 10 years or less, as compared with women with menarche at age 13 years (reference category), had lower FEV(1) (adjusted difference, -113 ml; 95% confidence interval [CI], -196 to -33 ml) and FVC (-126 ml; 95% CI, -223 to -28 ml); also lower FEV(1) expressed as a percentage of the predicted value (-3.28%; 95% CI, -6.25 to -0.30%) and FVC expressed as a percentage of the predicted value (-3.63%; 95% CI, -6.64 to -0.62%). Women with early menarche more often had asthma symptoms (odds ratio, 1.80; 95% CI, 1.09-2.97), asthma with bronchial hyperreactivity (odds ratio, 2.79; 95% CI, 1.06-7.34), and higher asthma symptom score (mean ratio, 1.58; 95% CI, 1.12-2.21)., Conclusions: women with early menarche had lower lung function and more asthma in adulthood. This supports a role for metabolic and hormonal factors in women's respiratory health.

Background: Studies on perimenstrual asthma are inconsistent, and different methodologies limit comparisons., Objective: To investigate cyclic variations in bronchial hyperreactivity (BHR) to methacholine in premenopausal women in a population-based cohort and assess effect modification by oral contraceptives (OCs)., Methods: Day of menstruation cycle at the time of methacholine challenge was calculated in 571 menstruating women without hormonal treatment, age 28 to 58 years, on the basis of questionnaire data from the Swiss cohort study on Air Pollution And Lung Disease In Adults (SAPALDIA) cohort 2001/2002. A window of risk was defined 3 days before and after the first day of menstruation. Logistic and linear regression analyses were performed adjusting for main predictors of BHR and stratifying for asthma status. The impact of OCs was studied in the same sample enlarged by 130 women taking OCs., Results: The prevalence of BHR was 13% (fall of > or =20% in FEV(1) up to a maximal cumulative dose of 2 mg), and 6% had asthma. A total of 143 women had undergone methacholine challenge within the risk window. We observed a significant increase in BHR within the window of risk (odds ratio [OR], 2.3; 95% CI, 1.27-4.29). A cyclic association pattern was confirmed by trigonometric functions. Effect modification by asthma status and oral contraceptive use was found, with lower OR in subjects without asthma and OR <1 in women using OCs., Conclusion: The data provide evidence of a systematic variation in BHR during the menstruation cycle, supporting the hypothesis of a hormonal influence. OCs appear to have a protective effect. Cyclicity of BHR could be of clinical importance in view of future medication recommendations and timing of respiratory function tests in women., (Copyright (c) 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: Emerging evidence suggests that sex steroid hormones may influence airways obstruction, and that metabolic status may modify potential effects., Objective: This study investigated the association between use of oral contraceptive pills (OCPs) and asthma in a Nordic-Baltic population-based study, while taking into account possible interplay with body mass index (BMI)., Methods: Postal questionnaires were sent to subjects in Denmark, Estonia, Iceland, Norway, and Sweden from 1999 to 2001 (response rate in women, 77%). Pregnant women, women using hormone replacement therapy, and women >45 years were excluded. Analyses included 5791 women 25 to 44 years old, of whom 961 (17%) used OCP. Logistic regression analyses included adjustment for smoking, irregular menstruation, BMI, age, type of dwelling, and center., Results: Oral contraceptive pills were associated with increased risk for asthma (odds ratio, 1.42; 95% CI, 1.09-1.86), asthma with hay fever (1.48; 1.08-2.03), wheeze with shortness of breath (1.27; 1.02-1.60), hay fever (1.25; 1.06-1.48), and >/=3 asthma symptoms (1.29; 1.05-1.58). The findings were consistent between centers. The associations were present only among normal weight women (BMI 20-25 kg/m(2), asthma: 1.45; 1.02-2.05) and overweight women (BMI >25kg/m(2): 1.91; 1.20-3.02), but not among lean women (BMI <20 kg/m(2): 0.41; 0.12-1.40). Interaction between BMI and OCP in association with asthma was significant (P(interaction) < .05)., Conclusions: Women using oral contraceptive pills had more asthma. This was found only in normal weight and overweight women, indicating interplay between sex hormones and metabolic status in effect on the airways. The findings originate from a cross-sectional postal survey and should be interpreted with caution; it is recommended that asthma symptoms are included in clinical trials of oral contraception.