For a study, researchers sought to describe the trends in delivery hospitalization among patients aged 11–19 years, as well as the related comorbidities and outcomes. Deliveries to patients aged 11–54 years were found in the 2000–2018 National Inpatient Sample for this repeated cross-sectional research. Joinpoint regression estimated average yearly percent change with 95% CI for deliveries to patients aged 11–14 years and 15–19 years. The relationship between delivery and other comorbid conditions in patients aged 11–19 years was investigated. The association between delivery and unfavorable maternal outcomes in patients aged 11–19 years was studied using unadjusted and adjusted logistic regression models, using unadjusted and adjusted odds ratios (aORs) as impact variables. From 2000 to 2018, an estimated 73,198,153 delivery hospitalizations were included, including 88,363 to patients aged 11–14 years and 6,359,331 to patients aged 15–19 years. From 2000 to 2018, the proportion of delivery hospitalizations among patients aged 11–14 years fell from 2.1 to 0.4 per 1,000 (average annual percent change 7.8%, 95% CI −8.5% to −7.2%). From 2000 to 2018, births to patients aged 15–19 years declined from 11.5% to 4.8% of all deliveries (average annual percent change 4.9%, 95% CI 5.6 % to 4.3%). Obesity, mental health disorders, drug use disorder, asthma, and pregestational and gestational diabetes all rose considerably among patients aged 11–19 years over the research period. Severe maternal morbidity (average annual percent change 2.4%, 95% CI 1.6–3.1%), postpartum hemorrhage (average annual percent change 2.4%, 95% CI 1.4–3.4%), a cesarean delivery (average annual percent change 1.3%, 95% CI 0.9–1.7%), and hypertensive disorders of pregnancy (average annual percent change 3.3%, 95% CI 2.8–3.8%) all increased significantly from 2000 to 2018. Deliveries to patients aged 11–14 years were associated with an increased risk of severe maternal morbidity (aOR 1.73, 95% CI 1.49–2.00), hypertensive disorders of pregnancy (aOR 1.79, 95% CI 1.71–1.88), and postpartum hemorrhage (aOR 1.37, 95% CI 1.27–1.49) compared to deliveries to patients aged 20–54 years. Deliveries among patients aged 11–19 years have reduced, while comorbidity and the risk of bad outcomes have increased.