OBJECTIVES: To explore women's experiences of over-the-counter and prescription medication advice and use during pregnancy. DESIGN: A study design consisting of an online survey and nested in-depth interviews with a subsample of participants. We analysed data from survey free-text responses and in-depth interviews using thematic analysis. Quantitative survey data is published elsewhere. SETTING: The UK. PARTICIPANTS: Women were eligible if living in the UK, aged 16-45 years, were pregnant or had been pregnant in the last 5 years regardless of pregnancy outcome. A total of 7090 women completed the survey, and 34 women who collectively had experienced 68 pregnancies were subsequently interviewed. RESULTS: Medication prescribing and use during pregnancy was common. The prescribing, dispensing and taking of some advised medications were restricted through women's or prescribers' fear of fetal harm. Lack of adherence to national prescribing guidance, conflicting professional opinion and poor communication resulted in maternal anxiety, avoidable morbidity and women negotiating complex and distressing pathways to obtain recommended medications. In contrast, some women felt overmedicated and that pharmacological treatments were used without exploring other options first. CONCLUSION: Increased translation of national guidance into practice and greater personalisation of antenatal care are needed to improve the safety, efficacy and personalisation of prescribing in pregnancy.