Approach to abdominal pain in hemodynamically stable pregnant patients without peritonitis in the emergency department*

HCG: human chorionic gonadotropin; IUP: intrauterine pregnancy; OB-GYN: obstetrics and gynecology; CT: computed tomography; MRI: magnetic resonance imaging; HELLP: hemolysis, elevated liver enzymes, and low platelets; CBC: complete blood count.

* Use this algorithm for a pregnant patient without peritoneal signs, shock/hemodynamic instability, or toxic appearance.

¶ Ultrasound indications are based on gestational age, previous documented IUP, and location of pain. Should evaluate for peritoneal free fluid and for the following:

• If <20 weeks gestation, undocumented IUP, and lower abdominal pain: evaluate for IUP
• If lower abdominal pain: also evaluate for peritoneal free fluid, adnexal/pelvic mass or torsion, and appendicitis
• If flank or right upper quadrant pain: evaluate for nephrolithiasis/hydronephrosis and gallstones/cholecystitis
• If >20 weeks gestation, can evaluate for all of the above and abruption and uterine rupture

Δ 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.

◊ Laboratory tests may include CBC, basic metabolic panel, lactate, liver enzymes, lipase, urinalysis, type and cross, and coagulation studies.

§ Suspect ectopic pregnancy if no IUP visualized and quantitative HCG is greater than discriminatory zone for HCG. Refer to UpToDate content on the approach to the patient with pregnancy of unknown location.

¥ 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 pregnancy.