CLEP_A_245040 579..587

Holly Michelle Crowe 1 Lauren Anne Wise 1 Amelia Kent Wesselink Kenneth Jay Rothman Ellen Margrethe Mikkelsen Henrik Toft Sørensen 3 Allan Jay Walkey 4 Elizabeth Elliott Hatch 1Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA; 2RTI International, Raleigh, NC 27709, USA; 3Department of Clinical Epidemiology, Aarhus University, Aarhus N 8200, Denmark; 4Boston University School of Medicine, Boston, MA 02118, USA Purpose: Asthma has been positively associated with irregular menses and infertility in some studies, but data are limited on the relation between asthma medication use and fecundability (i. e., average per-cycle probability of conception among non-contracepting couples). This study examines the extent to which a history of asthma, asthma medication use, and age at first asthma diagnosis are associated with fecundability among female pregnancy planners. Participants and Methods: Pregnancy Study Online (PRESTO) is an ongoing, web-based preconception cohort study of couples aged 21–45 years from North America. Between July 2013 and July 2019, a total of 10,436 participants enrolled in PRESTO, and 8286 were included in the present analysis. At study enrollment, women reported whether they had ever been diagnosed with asthma and, if so, the year they were first diagnosed. Women who reported ever being diagnosed with asthma were asked about medication use, including medication type and frequency of use. Participants completed follow-up questionnaires every 8 weeks for up to 12months or until pregnancy. Proportional probabilities regressionmodels were used to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders. Fecundability ratios below 1.00 indicate reduced probability of conception. Results: There was little association between a history of asthma diagnosis or asthma medication use and fecundability. Compared with no history of asthma, the FR for ever-diagnosis of asthma with medication use was 1.02 (95% CI: 0.91–1.15) and for ever-diagnosis of asthma without medication use was 1.00 (95% CI: 0.91–1.09). Highest intensity asthma medication use (daily plus extra dosing for symptoms), combination inhaled corticosteroid and long-acting betaagonist inhaler use, and a first diagnosis of asthma after age 17 years were associated with small reductions in fecundability. Conclusion: The present study provides little evidence that asthma or asthma medication use is adversely associated with fecundability.