Pregnant women are regarded as a unique group due to the distinct immunological condition that pregnancy produces, which makes pregnant women more susceptible to respiratory infections like coronavirus disease 2019 (COVID-19) and its consequences. During pregnancy, many viral infections have been recognized to increase the risk of adverse obstetrical outcomes such as preterm delivery. The purpose of this study was to investigate the effects of COVID-19 infection on preterm birth in pregnant women in the Al-Qassim region of Saudi Arabia. This retrospective cohort study was conducted in Saudi Arabia between December 2019 to October 2021. The target subjects were pregnant women with live singleton gestations who underwent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) testing for COVID-19 infection during their delivery hospitalization. Data gathered included patient demographic information, clinical characteristics, and pregnancy outcomes. Data were analyzed using R version 4.1.1 (R Core Team (2021); R Foundation for Statistical Computing, Vienna, Austria). A total of 381 pregnant women were included. The median maternal age of women was 31.0 years (IQR: 27.0, 35.0) and the median BMI value was 30.5 kg/m2 (IQR: 26.9, 34.8). The most common comorbidities were diabetes (7.1%) and asthma (4.5%). A known history of preterm birth was prevalent among 2.9%. Of the participants,13.6% had a prenatal COVID-19 infection, of whom 57.7% had their infections resolved. The prevalence of positive PCR testing was 13.6%. Preterm birth occurred in 46 women (12.1%, 95%CI 9.1-15.9). Preterm birth was significantly associated with having a maternal age of ≥35 years, having high frequencies of parity, and having a past history of preterm birth, as well as having a history of hypertension and diabetes. Preterm birth was not significantly associated with having a confirmed COVID-19 infection at delivery. It was shown that preterm birth is evident among women with COVID-19 infection. Preterm birth is significantly associated with old age, multiparity, and a history of preterm delivery. Preterm birth is not significantly associated with having a confirmed COVID-19 infection at delivery. More research regarding infection-related adverse effects is advised and should be highlighted.