RT Journal Article SR Electronic T1 Role of combined prenatal and postnatal paracetamol exposure on asthma development: the Czech ELSPAC study JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 349 OP 355 DO 10.1136/jech-2017-209960 VO 72 IS 4 A1 Piler, Pavel A1 Švancara, Jan A1 Kukla, Lubomír A1 Pikhart, Hynek YR 2018 UL http://jech.bmj.com/content/72/4/349.abstract AB Background Prenatal and postnatal paracetamol exposure has been previously associated with asthma development in childhood in Western populations. We explore the association between prenatal and postnatal paracetamol exposure and asthma development in a Central European sample of Czech children, suggesting possible additive effect of the both exposures. Furthermore, since aspirin had been used more widely during study data collection in Central Europe, we also compared asthma development for those exposed to paracetamol and aspirin.Methods We used data from 3329 children born in the 1990s as members of the prospective Czech European Longitudinal Study of Pregnancy and Childhood. Data about prenatal and postnatal paracetamol and aspirin exposure, and potential covariates were obtained from questionnaires completed by mothers. Data about incident asthma were obtained from paediatrician health records.Results 60.9% of children received paracetamol only postnatally, 1.5% only prenatally and 4.9% of children were exposed both during pregnancy and infancy. Prevalence of asthma in following population was 5% at 11 years. Being exposed to paracetamol both in prenatal and postnatal period was associated with asthma development (unadjusted OR 1.98, 95% CI 1.02 to 3.87). Being exposed only in the postnatal period was also significantly associated with increased risk of asthma. No association between prenatal exposure only and outcome was found. A higher but non-significant risk of asthma was observed for those whose mothers used paracetamol during pregnancy compared with those who used aspirin.Conclusions The main findings of this prospective birth cohort study add to previous observations linking prenatal and early postnatal paracetamol exposure to asthma development. However, the magnitude of effect is relatively modest, and therefore, we recommend paracetamol to remain the analgesic and antipyretic of choice throughout pregnancy and early childhood.