Clinical Trial Comparing Oral Versus Intravenous Cefuroxime in Pregnant Women with Pyelonephritis

Inclusion Criteria: * Pregnant women aged 18 years or older and less than 20 weeks of gestational age, determined by ultrasound or the date of last menstruation, who come to the HCPA emergency department with a clinical diagnosis of pyelonephritis in pregnancy, defined as: * Presence of lower back pain associated with * Dysuria with leukocyturia, or hematuria or nitrite in the urine test with at least one of the criteria below: * Leukocytosis (\> 14,000 leukocytes/mL) * Warm extremities, thready pulse, and tachycardia (HR \> 110 bpm) * Cyanosis and/or pallor * Tachypnea (RR \> 30 breaths/min) * Arterial hypotension (SBP \< 90mmHg) * Positive costovertebral angle tenderness * Urine culture with colony growth * Hyperthermia (≥ 37.8°C)" Exclusion Criteria: * Do not wish to participate in the project. * Used antimicrobials prior to hospitalization (3-day period). * those who are allergic to cefuroxime. * Have a urine culture antibiogram resistant to cefuroxime AND absence of clinical improvement (in this case, will be excluded as modified intention to treat). * Have a diagnosis other than pyelonephritis, for example, appendicitis. * those in septic shock, defined as: * the need for vasopressor to maintain a mean arterial pressure ≥ 65 mmHg and lactate \> 2 mmol/l or 2 points on qSOFA. qSOFA will be considered positive when at least two of the following clinical criteria are present: * Respiratory rate greater than or equal to 22 breaths per minute; * Altered level of consciousness (Glasgow Coma Scale score less than 15); * Systolic blood pressure less than or equal to 100 mmHg.