Aims
Paracetamol is commonly consumed by pregnant women, even though recent data have questioned its safety. Having chronic medical diseases (CMDs) may influence the prevalence of use during pregnancy. We aimed to assess the prevalence and patterns of use 3 months prior to pregnancy and in the first trimester among women with and without CMDs and the potential influence of CMDs on frequent use in the first trimester.

Methods
We used patient-reported data from the Copenhagen Pregnancy Cohort from 1 October 2013 to 23 May 2019 with information on CMDs and paracetamol use. Prevalence and patterns of use were assessed descriptively and by multivariable logistic regression models.

Results
We included 24 019 pregnancies. Use of paracetamol prior to and in early pregnancy was significantly higher among women with CMDs compared to women without (40.7% vs. 35.8% and 9.1% vs. 5.1%, respectively). Women with CMDs were 2.7 times more likely to have a frequent intake compared to women without [aOR 2.69 (95% CI 2.05–3.32)]. Migraine, rheumatoid arthritis and mental disease were associated with a higher use of paracetamol [aOR 4.39 (3.20–6.02), aOR 4.32 (2.41–7.72) and aOR 2.74 (1.67–4.49), respectively].

Conclusions
Women with CMDs had a higher paracetamol use before and during pregnancy than women without CMDs. Women with migraine, rheumatoid arthritis and mental disease showed the highest risk of frequent use. This study highlights the importance of discussing pain relief in pregnancy and evaluating the influence of maternal CMDs when assessing adverse effects of paracetamol use during pregnancy.