To establish radiological characteristics of pneumonia during pregnancy and to investigate pregnancy outcomes in patients hospitalised due to pneumonia. Study design. A population-based study comparing all pregnancies of women with and without pneumonia between was conducted. The diagnosis of pneumonia was confirmed by chest radiograph. Multivariable logistic regression models were constructed in order to control for confounders. Results. During the study period, there were 181,765 deliveries, of which 160 were hospitalised due to pneumonia. The most common site of pneumonia was the left lower lobe (53.4%), followed by the right lower lobe (26.3%) and right middle lobe (8.3%); 9.8% were complicated with pleural effusion. Using a multivariable analysis, pneumonia was significantly associated with placental abruption (OR = 4.2; 95% CI 1.9-9.1), intrauterine growth restriction (IUGR; OR = 3.7; 95% CI 2.1-6.6), previous caesarean deliveries (CDs; OR = 2.6; 95% CI 1.8-3.7) and severe preeclampsia (OR = 2.6; 95% CI 1.2-5.7). Higher rates of low Apgar scores at 1 min (26.3% vs. 5.9%, < 50.001) and 5 min (10.6% vs. 2.6%, p < 0.001) were noted in the pneumonia group. No significant differences were noted between the groups regarding labour induction (23.8% vs. 27.9%, p = 0.240), non-progressive labour second stage (2.5% vs. 1.6%, p = 0.387) and post-partum haemorrhage (1.3% vs. 0.5%, p = 0.224). Furthermore, patients with pneumonia were significantly associated with preterm delivery (PTD,537 weeks) (35.6% vs. 7.7%, p50.001) and perinatal mortality (7.5% vs. 1.3%, p50.001). Pneumonia was found as an independent risk factor for PTD (OR = 5.4, 95% CI 3.8-7.7, p < 0.001), in a multivariable model controlling for IUGR, placental abruption and preeclampsia Controlling for possible confounding variables such as IUGR, gestational age at delivery, placental abruption and maternal age, using another multivariable model with perinatal mortality as the outcome variable, pneumonia was not identified as an independent risk factor for perinatal mortality (weighted OR = 0.9; 95% CI 0.4-1.9; p = 0.718). Conclusion. Maternal pneumonia is associated with adverse perinatal outcomes and specifically it is an independent risk factor for PTD. Keywords: Pregnancy, pneumonia, outcomes.