When introduced a decade ago, patient-facing price transparency tools had low use rates and were largely not associated with changes in spending. Little is known about how such tools are used by pregnant individuals in anticipation of childbirth, a shoppable service with increasing out-of-pocket spending. To measure changes over time in the patterns and characteristics of use of a price transparency tool by pregnant individuals, and to identify the association between price transparency tool use, coinsurance, and childbirth spending. This descriptive cross-sectional study of 2 cohorts used data from a US commercial health insurance company that launched a web-based price transparency tool in 2010. Data on all price transparency tool queries for 2 periods (January 1, 2011, to December 31, 2012, and January 1, 2015, to December 31, 2016) were obtained. The sample included enrollees aged 19 to 45 years who had a delivery episode during 2 periods (November 1, 2011, to December 31, 2012, or November 1, 2015, to December 31, 2016) and were continuously enrolled for the 10 months prior to delivery (N = 253 606). Access to a web-based price transparency tool that provided individualized out-of-pocket price estimates for vaginal and cesarean deliveries. The primary outcomes were searches on the price transparency tool by delivery mode (vaginal or cesarean), timing (first, second, or third trimester), and individual characteristics (age at childbirth, rurality, pregnancy risk status, coinsurance exposure, area educational attainment, and area median household income). Another outcome was the association of out-of-pocket childbirth spending with price transparency tool use. The sample included 253 606 pregnant individuals, of whom 131 224 (51.7%) were in the 2011 to 2012 cohort and 122 382 (48.3%) were in the 2015 to 2016 cohort. In the 2015 to 2016 cohort, the mean (SD) age was 31 years (5.2 years) and most individuals had coinsurance for delivery (94 251 [77.0%]). Price searching increased from 5.9% in the 2011 to 2012 cohort to 13.0% in the 2015 to 2016 cohort. In the 2015 to 2016 cohort, 43.9% of searchers' first price query was in their first trimester. The adjusted probability of searching was lower for individuals with a high-risk pregnancy due to a previous cesarean delivery (11.5%; 95% CI, 11.0%-12.1%) vs individuals with low-risk pregnancy (13.4%; 95% CI, 12.9%-14.0%). Use increased monotonically with coinsurance, from 9.2% (95% CI, 8.7%-9.8%) among individuals with no coinsurance to 15.0% (95% CI, 14.4%-15.5%) among individuals with 11% or higher coinsurance. After adjusting for covariates, searching was positively associated with out-of-pocket delivery episode spending. Among patients with 11% coinsurance or higher, early and late searchers spent more out of pocket ($59.57 [95% CI, $33.44-$85.96] and $73.33 [95% CI, $32.04-$115.29], respectively), compared with never searchers. The results of this cross-sectional study indicate that the proportion of pregnant individuals who sought price information before childbirth more than doubled within the first 6 years of availability of a price transparency tool. These findings suggest that price information may help individuals anticipate their out-of-pocket childbirth costs.