The last group was defined as the migraine control group, that is, a control group consisting of women with migraine who had not reported any triptan use during pregnancy. These subsets were created using

answers to questions regarding both triptan use and migraine in both GS-1101 research buy questionnaires 1 and 2 as long as the name of the triptan and the timing of either triptan use or migraine was specified. The pregnancy outcome of the exposed subgroups was compared with women who did not report any use of triptans at all. This group of women was defined as the nonmigraine control group. Drug therapy was classified and grouped according to the Anatomical Therapeutic Chemical Classification System developed by the World Health Organization.25 Outcome Variables.— The outcome variables were retrieved from the Medical Birth Registry of Norway and included primary outcome variables consisting of congenital malformations (yes/no) and other adverse pregnancy outcome variables consisting of survival (live birth, miscarriage/stillbirth, perinatal death, death during the first 12 months of life) (yes/no), birth weight <2500 g (yes/no), gestational age Protease Inhibitor Library <37 weeks (yes/no), Apgar scores <7 at 1 and 5 minutes (yes/no), atonic uterus (yes/no), prolonged labor (yes/no), and perinatal and/or postpartum blood loss >500 mL (yes/no). Possible Confounding Factors.— Possible confounding factors including

maternal sociodemographic and medical characteristics are categorized as shown in Tables 2 and 3, and those including maternal health and pregnancy complications are categorized as shown in Table 4. Statistical Analysis.— Individual logistic regression analyses were used to identify significant associations between triptan therapy, possible confounding factors and pregnancy outcomes. Different potential confounding GNA12 factors were chosen for each pregnancy outcome depending on clinical plausibility,

statistical significance, and the size of the outcome event rates. Confounding factors which were to be controlled for in the logistic regression analyses were chosen on the basis of theoretical clinical significance and initial Pearson’s χ2 analyses where the P value was <.25. During preliminary logistic regression analyses, potential confounding variables with a P value of >.5 were removed one by one excluding those instances where the coefficient change of the exposure variable was greater than 20%. The final logistic regression models for pregnancy outcomes were restricted to include statistically significant variables and clinically plausible interactions. The threshold for retaining these variables in the final logistic regression model was P < .05. Possible multicollinearity among the independent variables was identified using multiple regression analysis. The tolerance values for multicollinearity were set at >.5. Hosmer and Lemeshow goodness-of-fit tests >.