Approach to abdominal pain in pregnant patients with hemodynamic instability or peritonitis in the emergency department*

IV: intravenous; FHR: fetal heart rate; OB-GYN: obstetrics and gynecology; CXR: chest radiograph; ECG: electrocardiogram; CT: computed tomography; MRI: magnetic resonance imaging; HELLP: hemolysis, elevated liver enzymes, and low platelets; CBC: complete blood count; hCG: human chorionic gonadotropin; IUP: intrauterine pregnancy; IVC: inferior vena cava.

* Use this algorithm for a pregnant patient with peritoneal signs (eg, rigidity, involuntary muscle guarding, severe or rebound tenderness, pain with coughing or shaking stretcher), shock/hemodynamic instability, or toxic appearance.

¶ Laboratory tests include CBC, basic metabolic panel, lactate, liver enzymes, lipase, urinalysis, type and cross, coagulation studies, and quantitative hCG (if IUP has not been documented).

Δ Ultrasound should evaluate for:

• Intrauterine pregnancy
• Adnexal mass or pelvic mass
• Peritoneal free fluid
• Gallstones/cholecystitis
• Nephrolithiasis/hydronephrosis
• Pericardial effusion/tamponade
• IVC diameter and collapse (as indicator of fluid status)

◊ Digital vaginal examination should not be performed in a patient with vaginal bleeding after 20 weeks of gestation unless placenta previa has been excluded by ultrasound examination.

§ Antimicrobial choice is empiric and should be tailored to each individual. Reasonable options include vancomycin and either piperacillin-tazobactam, meropenem, cefepime and metronidazole, or gentamicin and metronidazole. Refer to UpToDate content on the evaluation and management of suspected sepsis and septic shock in adults for examples of other empiric strategies and dosing.

¥ The choice of imaging study or studies is best made jointly by the clinical (medical, surgical, obstetric) providers and the radiologist, who can sometimes modify the technique to minimize fetal risk without significantly compromising the information needed for maternal diagnostic evaluation and management. Refer to UpToDate content on diagnostic imaging in pregnant patients.