The goal of this study was to describe patterns of selective serotonin reuptake inhibitor (SSRI) use during pregnancy in a US cohort (2005-2014) of > 1 million commercially insured women using administrative claims. We used international classification of disease (ICD-9) diagnosis and procedure and current procedural terminology codes in the OptumLabs® Data Warehouse to identify deliveries (including losses) among US women aged 15-45 (n= 1,061,023). SSRI dispensings that overlapped with the timing of pregnancy were identified using national drug codes in linked pharmacy claims. Demographic characteristics were imputed based on residential location, census data, and consumer information. We investigated patterns by trimester, agent, and demographic subgroups. A total of 46,087 of women (4.34%) were dispensed SSRIs during the estimated pregnancy period. Sertraline was the most common overall and had the highest initial use after trimester 1, including women who switched from another SSRI, although dispensing for > 1 SSRI during pregnancy was uncommon. Use of vilazodone was rare and had the highest discontinuation after trimester 1, followed by paroxetine. SSRI use was more common among women who were older, White, college-educated, higher income (≥ $100,000), or resided in the Midwest. Paroxetine and dispensings for > 1 SSRI were more common in lower education subgroups. White women had the highest proportion of use in all trimesters of pregnancy, whereas Hispanic women had the lowest. Among commercially insured US women, SSRI use during pregnancy differed by agent and demographics. More research is needed to understand whether these differences are due to symptom reporting, cultural beliefs, and/or physician preferences.