Associations of asthma and asthma medication use with fecundability and prolonged time to pregnancy (>12 months)
| Fecundability# odds ratio | Prolonged TTP odds ratio | |||||
| Unadjusted | Adjusted (model 1¶) | Adjusted (model 2+) | Unadjusted | Adjusted (model 1¶) | Adjusted (model 2+) | |
| Non-asthmatic (n=4511) | 1 | 1 | 1 | 1 | 1 | 1 |
| Asthmatic (n=1106) | ||||||
| Former (n=450) | 1.12 (1.01–1.24) | 1.02 (0.92–1.14) | 1.00 (0.89–1.13) | 0.84 (0.61–1.15) | 0.97 (0.70–1.34) | 0.89 (0.62–1.28) |
| Current (n=656) | ||||||
| SABA only (n=421) | 0.95 (0.85–1.06) | 0.85 (0.76–0.95) | 0.85 (0.75–0.96) | 1.10 (0.82–1.47) | 1.26 (0.92–1.73) | 1.30 (0.93–1.81) |
| ICS±LABA (n=235) | 1.01 (0.87–1.16) | 0.93 (0.81–1.08) | 0.98 (0.84–1.15) | 1.07 (0.72–1.57) | 1.20 (0.80–1.79) | 1.08 (0.69–1.71) |
Data are presented as odds ratio (95% CI) unless otherwise stated. TTP: time to pregnancy; SABA: short-acting β-agonist; ICS: inhaled corticosteroids; LABA: long-acting β-agonist; BMI: body mass index. #: fecundability was defined as the average per-cycle probability of conception; ¶: model 1 factors were maternal BMI, maternal age, recruitment site, socioeconomic status, ethnicity (Caucasian/other), polycystic ovary syndrome (yes/no), smoking status (yes/no) and age at menarche; +: model 2 factors were the same as model 1 plus paternal BMI and paternal age.