Unadjusted and age-adjusted hazard ratios and 95% confidence intervals for the association between Letigen* use and spontaneous abortion (SAB) in the Danish National Birth Cohort (1996–2002).

*Letigen is composed of 20 mg ephedrine and 200 mg caffeine.†Adjusted for maternal age using the following categories: 15–19, 20–24, 30–34, 35–39, 40–46 with 25–29 as the referent.§Pre-conception includes the 4 weeks prior to last menstrual period through gestational age 2 completed weeks; early pregnancy includes gestational age 3–13 completed weeks.$Observed fetus days at risk (i.e. time from entry to outcome, censoring, or end of risk period).Abbreviations: HR, hazard ratio; CI, confidence interval.