University of Bristol University of Bristol Bristol, United Kingdom
Background: Antiseizure medications are prescribed for a number of indications that require maintenance to ensure safety of both mother and fetus during pregnancy. Understanding the trends in prescribing for antiseizure medications in pregnancy is an important starting point for assessing the association between these drugs and important safety outcomes including maternal, pregnancy and offspring outcomes.
Objectives: To examine antiseizure medication (ASM) prescription during pregnancy.
Methods:
Design: Population-based drug utilization study. Setting: UK primary and secondary care data, 1995-2018, from the Clinical Practice Research Datalink GOLD version. Population or Sample: 752,112 completed pregnancies among women registered for a minimum of 365 days with an ‘up to standard’ general practice prior to the estimated start of pregnancy and for the duration of their pregnancy.
Methods: We described ASM prescription across the study period, overall and by ASM indication, examined patterns of prescription during pregnancy including continuous prescription and discontinuation, and used logistic regression to investigate factors associated with those ASM prescription patterns. Main Outcome Measures: Prescription of ASMs during pregnancy and discontinuation of ASMs before and during pregnancy.
Results: ASM prescription during pregnancy increased from 0.6% of pregnancies in 1995 to 1.6% in 2018, driven largely by an increase in women with indications other than epilepsy. Epilepsy was an indication for 62.5% of pregnancies with an ASM prescription while non-epilepsy indications were present for 66.6%. Continuous prescription of ASMs during pregnancy was more common in women with epilepsy (64.3%) than in women with other indications (25.3%). Switching ASMs was infrequent (0.8% of ASM users). Factors predictive of discontinuation included age ≥35, higher social deprivation, more frequent contact with the GP and being prescribed antidepressants or antipsychotics.
Conclusions: ASM prescription during pregnancy increased between 1995 and 2018 in the UK. Patterns of prescription around the pregnancy period vary by indication and are predicted by several maternal characteristics.
