This study aimed to determine if a best-practice alert (BPA) implementation increases the rate of smoking cessation during pregnancy and affects pregnancy outcomes associated with smoking. This was a pretest-posttest study design where a BPA was added to electronic medical records (EMR) of pregnant persons who reported active smoking. The BPA provided the 5A's method to conduct counseling on smoking cessation. The rates of smoking cessation during pregnancy were compared 1.5 years before and after implementation of the BPA. Secondary outcomes examined whether counseling on smoking cessation was done, the number of the counseling sessions during pregnancy, and obstetric outcomes associated with maternal smoking. After implementation of the BPA, the rate of smoking cessation in pregnancy increased from 17.5% prior to BPA implementation to 54.9% after BPA implementation (p < 0.001). The rate of counseling on smoking cessation increased from 66.6% prior to BPA implementation to 95.6% after BPA implementation, with an increase noted also in the number of smoking cessation counseling sessions. In multivariate analyses, after controlling for maternal demographic and clinical factors, BPA implementation was significantly associated with higher rates of smoking cessation (adjusted odds ratio [aOR]: 3.44, 95% confidence interval [CI]: 2.17-5.51), higher rates of documented smoking cessation counseling in the EMR (aOR: 12.44, 95% CI: 6.06-25.64), and higher odds of conducting the counseling more than once (aOR: 6.90 95% CI: 4.45-10.88). The rate of smoking cessation and number of times pregnant persons were counseled increased after implementation of a BPA. The BPA could be a useful EMR tool to increase smoking cessation rates during pregnancy. · Smoking during pregnancy is a maternal and fetal concern.. · Prenatal care offers the chance to address smoking.. · BPA increases rates of smoking counseling and cessation..