Anti-Bacterial Agents/therapeutic use; Gram-Negative Bacterial Infections/drug therapy; Gram-Positive Bacterial Infections/drug therapy; Infant, Very Low Birth Weight; Sepsis/drug therapy; Age of Onset; Blood Culture; Cesarean Section/statistics & numerical data; Chorioamnionitis/microbiology; Chorioamnionitis/physiopathology; Chorioamnionitis/surgery; Disease Management; Early Diagnosis; Female; Fetal Membranes, Premature Rupture/microbiology; Fetal Membranes, Premature Rupture/physiopathology; Fetal Membranes, Premature Rupture/surgery; Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/growth & development; Gram-Negative Bacteria/pathogenicity; Gram-Negative Bacterial Infections/cerebrospinal fluid; Gram-Negative Bacterial Infections/diagnosis; Gram-Negative Bacterial Infections/microbiology; Gram-Positive Bacteria/drug effects; Gram-Positive Bacteria/growth & development; Gram-Positive Bacteria/pathogenicity; Gram-Positive Bacterial Infections/cerebrospinal fluid; Gram-Positive Bacterial Infections/diagnosis; Gram-Positive Bacterial Infections/microbiology; Humans; Infant, Newborn; Intensive Care Units, Neonatal; Male; Obstetric Labor, Premature/microbiology; Obstetric Labor, Premature/physiopathology; Obstetric Labor, Premature/surgery; Pre-Eclampsia/microbiology; Pre-Eclampsia/physiopathology; Pre-Eclampsia/surgery; Pregnancy; Retrospective Studies; Sepsis/cerebrospinal fluid; Sepsis/diagnosis; Sepsis/microbiology