Abstract: Objective To study the influencing factors of intrauterine infection and analyze the clinical features of intrauterine infection in premature infants caused by placenta previa and premature rupture of membranes.
Methods A retrospective analysis was made in 262 cases of premature infants with intrauterine infection treated in neonatal wards from January 2017 to January 2019. The general data such as gender, gestational age, birth weight, and asphyxia were recorded, and the perinatal factors related to preterm birth were recorded. The clinical characteristics of infection caused by placenta previa were compared with those caused by premature rupture of membranes.
Results There are many factors leading to intrauterine infection in premature infants, and the top two most important perinatal factors were premature rupture of membranes and placenta previa (accounting for 51.2%), and the premature infants with intrauterine infection due to premature rupture of membranes mainly presented symptoms of non-specific infection, accounting for 52.4%. A small part of the infants had pneumonia related to intrauterine infection, and the ratio of infants needing ventilator support was very low (2.4%); however, pulmonary infection was the main infection in the premature infants with intrauterine infection due to placenta previa (62.0%), and the ratio of infants needing mechanical ventilation was significantly increased, nearly one-third of them(32.0%), the difference being statistically significant (P=0.033).
Conclusion Premature infants born with placenta previa need to be specially alert to intrauterine infectious pneumonia and need active respiratory support.

Key words: Intrauterine infection, Placenta previa, Premature rupture of membranes, Premature infant