This article aimed to evaluate whether a substance-related diagnosis (SRD; i.e., alcohol, opioids, cannabis, stimulants, nicotine) predicts the likelihood and co-occurrence of preterm (20-37 weeks' gestation) and cesarean delivery.This study reviewed electronic health record data on women (aged 18-44 years) who delivered a single live or stillbirth at ≥ 20 weeks of gestation from 2012 to 2019. Women with and without an SRD were matched on key demographic characteristics at a 1:1 ratio. Adjusting for covariates, odds ratios and 95% confidence intervals were calculated.Of the 19,346 deliveries, a matched cohort of 2,158 deliveries was identified. Of these, 1,079 (50%) had an SRD, 280 (13%) had a preterm delivery, 833 (39%) had a cesarean delivery, and 166 (8%) had a co-occurring preterm and cesarean delivery. An SRD was significantly associated with preterm and cesarean delivery (AOR = 1.84 [95% CI, 1.41-2.39], p-value= <0.0001; AOR = 1.51 [95% CI, 1.23-1.85], p-value= <0.0001). An alcohol-related diagnosis (AOR = 1.82 [95% CI, 1.01-3.28], p-value= 0.0471), opioid-related diagnosis (AOR = 1.94 [95% CI, 1.26-2.98], p-value= 0.0027), stimulant-related diagnosis (AOR = 1.65 [95% CI, 1.11-2.45], p-value= 0.0142), and nicotine-related diagnosis (AOR = 1.54 [95% CI, 1.05-2.26], p-value= 0.0278) were associated with co-occurring preterm and cesarean delivery.Pregnant women with an SRD experienced disproportionally higher odds of preterm and cesarean delivery compared to pregnant women without an SRD. Substance-type predicts the type of delivery outcome. An SRD in pregnant women should be identified early to reduce potential harm through intervention and treatment.