Table 4. 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).
Unadjusted | Age adjusted† | |||||
Timeframe of exposure§ | SAB | Fetus-days$ | HR | (95% CI) | HR | (95% CI) |
None | 4,408 | 6,656,492 | 1.0 | ref | 1.0 | ref |
Pre-conception only | 13 | 17,954 | 1.0 | 0.6; 1.6 | 1.0 | 0.6; 1.7 |
Both pre-conception and early pregnancy | 17 | 21,657 | 1.0 | 0.6; 1.7 | 1.1 | 0.7; 1.7 |
Early pregnancy only | 5 | 2,796 | 2.6 | 1.1; 6.5 | 2.7 | 1.1; 6.6 |
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.