Valproate use in women aged 15–44 years: an observational study in general practice

BACKGROUND: Valproate is a known teratogen. In April 2018, the Medicines and Healthcare products Regulatory Agency (MHRA) restricted its use in women and banned use in pregnancy, except for epilepsy with no other effective treatment. To date, there is limited information on valproate prescribing within primary care. AIM: To characterise valproate prescribing to women of childbearing age, recorded advice or GP prescribed contraception, and recorded pregnancies. DESIGN & SETTING: A cross-sectional study of patients from all 141 general practices across three clinical commissioning groups (CCGs) in East London. METHOD: Women aged 15–44 years prescribed valproate between 1 October 2017 and 1 January 2020 were included. Exclusion criteria were early menopause, sterilisation procedures, or hysterectomy. Pseudonymised data on valproate indication, pregnancy, pre-conception, and contraception advice were retrospectively extracted from general practice consultation data. Data were analysed by quarter using univariate statistics. RESULTS: Of the total 1 042 463 registered patients, 344 women aged 15–44 years were prescribed valproate during the study period; 14 were excluded. There were 10 pregnancies during possible valproate exposure; one was terminated. During the study period, the number of women prescribed valproate significantly decreased (P = 0.003). The pregnancy rate decreased from 9.9/1000 on valproate before the MHRA April 2018 warning, to an average of 2.8/1000 afterwards. Recorded pre-conception and contraception advice increased by 79%, from 24% to 43%, of women prescribed valproate. CONCLUSION: With continued pregnancies in women aged 15–44 years prescribed valproate, patient education and foetal outcomes remain ongoing concerns. Further improvements are needed to ensure women make informed reproductive choices and safeguard future pregnancies from valproate exposure.