Background <p>Gabapentin is a newer-generation antiseizure medication (ASM) that is Food and Drug Administration (FDA)-approved for the treatment of postherpetic neuralgia and partial seizures. In addition, it is also widely prescribed off-label for other pain conditions, migraine prophylaxis, and psychiatric disorders. However, there is currently limited safety data for the use of gabapentin in pregnancy. Understanding how gabapentin use in pregnancy has changed over time will facilitate future safety studies. Here, we examine the trends of gabapentin utilization, prescribing patterns, and indications in pregnant people in Manitoba, Canada over a 20-year period.</p> Methods <p>A population-based cohort study was conducted using administrative health databases in Manitoba, from 1 April 1999 to 31 March 2019. Our data cohort captured all pregnant people living in Manitoba between 1999 and 2019. Pregnancy capture is based on administrative data identifying all pregnancies, including live births, stillbirths, miscarriages, and terminations. Inclusion criteria encompassed all pregnancies in Manitoba between 1999 and 2019 that met data completeness criteria; exclusion criteria were missing gestational age data or invalid records. Gabapentin use was defined as having at least one gabapentin prescription filled during the exposure period. The trends of utilization and indications for gabapentin prescriptions were examined in each pregnancy trimester as well as over the whole pregnancy term. Descriptive statistics were used to assess gabapentin prescriptions by prescriber specialty.</p> Results <p>The main outcome is gabapentin prescription fills during pregnancy. There were 0.30% (95% confidence interval [CI] 0.28–0.32%) of pregnancies exposed to gabapentin between the years 1999 and 2019 in Manitoba. Gabapentin use in pregnancy rose substantially by 38.6-fold, with use predominantly in the first trimester. Trend analysis revealed a significant increase in the 5-year utilization rates in all three trimesters. Pain was the most frequent indication (32.8%), followed by mood and personality disorders (17.4%). Among pain indications, back, joint, and soft tissue disorders (66.7%) were the most common. Among mood and personality disorders, anxiety (70.4%) was the most common. Prescribers were predominantly general practitioners (77.8%).</p> Conclusions <p>Gabapentin use during pregnancy in Manitoba has increased substantially over the past two decades, predominantly in the first trimester, and is largely prescribed by general practitioners for off-label indications, including pain and mood disorders. Given the limited safety data in pregnancy, these findings underscore the need for ongoing pharmacovigilance and future safety studies to inform clinical decision-making for pregnant people and their children.</p>