What are the next steps for a patient with right pelvic pain, bleeding, and a possible pregnancy?

Right Pelvic Pain with Bleeding and Possible Pregnancy

This patient requires immediate assessment for ectopic pregnancy, which is a life-threatening emergency that occurs in up to 13% of symptomatic ED patients with first-trimester bleeding and pain. 1, 2

Immediate Initial Steps

Stabilize the patient first:

• Assess vital signs (blood pressure and pulse rate) to determine hemodynamic stability 1
• Establish IV access if the patient shows any signs of instability 3
• For unstable patients with hemorrhagic shock, initiate immediate resuscitation with fluids and blood products 3

Obtain critical diagnostic tests immediately:

• Quantitative β-hCG (serum pregnancy test) to confirm pregnancy 3, 2
• Complete blood count to assess for anemia from bleeding 2
• Blood type and Rh status (for potential anti-D immunoglobulin administration if Rh-negative) 1, 3

Diagnostic Imaging Approach

Perform pelvic ultrasound regardless of β-hCG level:

• Transvaginal ultrasound is the preferred imaging modality and should be obtained even when β-hCG is below traditional discriminatory thresholds 1, 3
• The sensitivity of ultrasound for detecting intrauterine pregnancy with β-hCG below 1,500 mIU/mL is only 33%, but this modest diagnostic performance still provides valuable information for risk stratification 1
• Bedside ultrasound by emergency physicians can expedite diagnosis when available 1, 3
• Do not defer ultrasound based solely on β-hCG levels 3

The ultrasound will help determine:

• Presence or absence of intrauterine pregnancy 4, 2
• Presence of adnexal masses suggesting ectopic pregnancy 5, 2
• Free fluid in the pelvis or abdomen indicating possible rupture 4, 5

Interpreting Results and Next Steps

If ultrasound shows empty uterus with no intrauterine pregnancy:

• This is consistent with either very early pregnancy, miscarriage, or ectopic pregnancy 6
• Serial β-hCG measurements are critical: a viable pregnancy should show at least 53% rise in 2 days 6
• A spontaneous abortion shows 21-35% decline in 2 days 6
• A rise or fall slower than these thresholds is highly suggestive of ectopic pregnancy 6

If ectopic pregnancy is confirmed or highly suspected:

• Asymptomatic, hemodynamically stable patients with unruptured ectopic pregnancy may be candidates for medical management with methotrexate 2, 6
• Success rates with methotrexate are inversely related to baseline β-hCG values 6
• Surgical management (laparoscopy with salpingectomy or salpingostomy) is indicated for unstable patients or those with contraindications to methotrexate 2, 6

Critical Pitfalls to Avoid

Common diagnostic errors:

• Assuming normal pregnancy based on low β-hCG alone without ultrasound confirmation 3
• Deferring ultrasound because β-hCG is "too low" to see anything—even modest diagnostic yield is valuable 1, 3
• Missing rare presentations like pelvic wall ectopic pregnancy, which can present with minimal or resolved pain 5
• Failing to arrange concrete follow-up plans within 24-48 hours before discharge 3

For Rh-negative patients:

• Consider anti-D immunoglobulin administration for threatened abortion, complete abortion, or ectopic pregnancy 1, 3

Special Considerations for Right-Sided Pain

Right pelvic pain specifically raises concern for:

• Right tubal ectopic pregnancy (most common location) 2
• Right ovarian pathology that may be detected on ultrasound 4
• Rare presentations such as pelvic wall ectopic pregnancy adherent to right pelvic peritoneum 5

The combination of right pelvic pain, bleeding, and possible pregnancy mandates urgent evaluation with β-hCG and transvaginal ultrasound to rule out ectopic pregnancy, as delay in diagnosis can result in tubal rupture, hemorrhagic shock, and maternal death. 2, 6