Objective To analyze clinical characteristics of severe community-acquired pneumonia during pregnancy and its outcomes, and to explore the relevant risk factors. Methods From September 2012 to September 2017,324 398 pregnancies admitted in 7 tertiary hospitals were included. Clinical data of 33 cases of pregnancies with severe community-acquired pneumonia(severe pneumonia group)and 214 cases of pregnancies with common community-acquired pneumonia (control group) were reviewed retrospectively, including the clinical information, manifestations, laboratory examinations and pregnancy outcomes. Relevant risk factors were analyzed by multivariate logistic regression analysis. Results (1) General data: pregnancies with severe community-acquired pneumonia accounted for 0.010%(33/324 398) of hospitalized pregnancies, the gestational age of two groups were(28±8)and(23±8)weeks, body mass index were(21.7±2.1)and(25.5±3.4)kg/m2, rate of low income were 54.5%(18/33)and 31.8%(68/214), respectively. The differences between two groups were all statistically significant(all P<0.05). No significant differences were found in age, pregnancy and parity times, rate of main pregnant complications such as diabetes and hypertension, educational level, asthma and onset seasons between two groups(all P>0.05). (2)Clinical data: the severe pneumonia group had significantly higher incidence of fever [100.0%(33/33)vs 75.2%(161/214)], shortness of breath(90.9% vs 16.8%)compared with the control group(all P<0.05).The median peripheral leukocytes counts were 12.3×109/L and 10.2×109/L, the hemoglobin level were(84±18) and(107±14)g/L,the albumin level were(26±4)and(37±3)g/L, the median serum urea nitrogen level were 3.7 and 2.4 mmol/L,the serum creatinine level were(72±25)and(45±11)μmol/L, respectively in two groups. The differences were all statistically significant (all P<0.05). No significantly statistical differences were found in coagulation indicator and cardiac function between two groups(all P>0.05).(3) Treatments: in severe pneumonia group, 12 patients(36.4%,12/33)needed invasive mechanical ventilation, 9 patients(27.3%,9/33)needed non-invasive mechanical ventilation, average time of mechanical ventilation was(7±4)days;8 patients(24.2%,8/33)with septic shock needed vasoactive drugs. However, there was no patient in control group needing mechanical ventilation and vasoactive drugs.(4)Pregnant outcomes: one patient(3.0%,1/33)died in the severe pneumonia group, while no death occurred in the control group. The hospital stay between two groups were(15.1±4.1)and(7.0±1.9)days, the rates of abortion and stillbirth between two groups were 42.4%(14/33)and 3.3%(7/214), the rates of premature were 10/19 and 6.3% (13/207), the rates of cesarean were 15/19 and 43.0%(89/207), the rates of low birth weight newborn were 17/19 and 14.0%(29/207), the rates of infected newborn were 15/19 and 10.1%(21/207), the birth weights were(2 165±681)and(3 102±400)g, respectively. The differences between two groups were all statistically significant(all P<0.05).(5)Multivariate logistic regression analysis demonstrated that anemia, low body mass index, hypoproteinemia were risk factors for severe pneumonia in pregnancy(all P<0.05). Conclusions Pregnancy with severe community-acquired pneumonia may be complicated by multiple organ dysfunctions, lead to adverse outcomes. Anemia, malnutrition are risk factors for pregnancy with severe pneumonia. Active and effective treatment may improve its prognosis.