Patterns and predictors of analgesic use in pregnancy: a longitudinal drug utilization study with special focus on women with migraine

BACKGROUND Few studies have investigated the drug utilization patterns and factors predicting drug use in pregnant women with migraine. This longitudinal drug utilization study aimed to describe patterns of analgesic use in a sample of Norwegian pregnant women according to their migraine history, and to identify predictors for analgesic use among these women. METHODS Pregnant women giving birth at Akershus University Hospital between 2008 and 2010 were recruited at ultrasound examination in gestational week 17. Data were collected by questionnaires in gestational weeks 17 and 32, and at 8 weeks postpartum, and linked to birth records. Women were grouped into four categories according to migraine history: no migraine history, previous migraine history, recent migraine history (within 1 year prior to pregnancy) and migraine in pregnancy. Patterns of use of analgesics were analyzed descriptively. Multivariable logistic regression was used to identify factors predicting analgesic use. RESULTS Out of 1981 women, 5.0% reported having migraine in pregnancy, 13.2% had a recent history of migraine, 11.5% had a previous history of migraine, and 68.8% reported no history of migraine. Analgesic use declined during pregnancy. Many women switched from triptans and non-steroidal anti-inflammatory drugs to paracetamol, which constituted most of the analgesic use. Factors associated with analgesic use included recent migraine history (OR 1.6, 95% CI 1.2-2.2), more severe headache intensity (OR 1.3, 95% CI 1.3-1.4), smoking (OR 1.9, 95% CI 1.1-3.3) and multiparity (OR 1.4, 95% CI 1.1-1.7). CONCLUSIONS Women with migraine stop or switch medications during pregnancy. Analgesic use in pregnancy is affected by migraine characteristics and intensity, and also by socio-demographic factors. Clinicians should bear this in mind when giving advice on adequate management of migraine in pregnancy and safe analgesic use.