How can we prevent ordering an abdominal X‑ray in a pregnant woman with abdominal pain before confirming her pregnancy status?

Prevention of Inadvertent Abdominal X-ray in Pregnant Women

To prevent ordering an abdominal X-ray in a pregnant woman before confirming pregnancy status, obtain a beta-human chorionic gonadotropin (β-hCG) test in all women of childbearing age presenting with abdominal pain before ordering any diagnostic imaging that involves ionizing radiation. 1, 2

Systematic Prevention Protocol

Pre-Imaging Pregnancy Screening

• Question all women of childbearing age about pregnancy status before any imaging procedure involving ionizing radiation. 3, 2, 4
• Obtain β-hCG measurement before ordering diagnostic imaging in premenopausal women to narrow the differential diagnosis and prevent inadvertent fetal radiation exposure. 1, 2
• A negative serum β-hCG essentially excludes pregnancy, as it becomes positive approximately 9 days after conception. 2
• For high-dose procedures like fluoroscopy, pregnancy testing within 72 hours is recommended unless medical urgency prevents it. 3, 2, 4

Alternative Imaging Pathway for Pregnant Patients

Once pregnancy is confirmed, follow this hierarchical approach:

First-line: Ultrasonography is the initial imaging modality for pregnant patients with acute abdominal pain because it lacks ionizing radiation. 1, 3, 2, 4

Second-line: MRI without gadolinium is the preferred alternative when ultrasound is inadequate or inconclusive, with excellent sensitivity and specificity (97% and 95%, respectively) for diagnosing appendicitis in pregnant women. 1, 3, 2, 4

Third-line: Plain abdominal X-ray may be appropriate (rated 4-6/9) specifically to evaluate for bowel perforation, as it delivers only 0.1-0.3 mGy to the fetus. 3, 4

Last resort: CT abdomen/pelvis should be avoided when possible but may be performed in life-threatening situations when the benefit clearly outweighs risk. 3, 4

Critical Safety Context

Radiation Safety Thresholds

• Fetal doses below 50 mGy cause no detectable increases in malformations, growth restriction, or fetal death. 3, 4
• The threshold for significant fetal damage is 100 mGy, and most diagnostic X-ray studies deliver far less than 20 mGy to the uterus. 3, 2, 4
• Plain abdominal radiography delivers only 0.1-0.3 mGy to the fetus—well below any threshold for concern. 3, 4

If Imaging Already Occurred

• The risk of delaying or avoiding necessary imaging poses greater danger to both mother and fetus than the radiation exposure itself. 3
• Counsel the patient that a single abdominal X-ray delivers radiation far below the 50 mGy safety threshold and is not associated with adverse fetal outcomes. 3, 2, 4
• Fetal doses below 100 mGy should not be considered a reason for terminating a pregnancy. 5

Common Pitfalls to Avoid

• Failure to ask about pregnancy status: This is the most common error leading to inadvertent fetal radiation exposure. 2, 6, 7
• Assuming menstrual history alone is sufficient: Always obtain objective β-hCG testing rather than relying solely on patient recall of last menstrual period. 1, 2
• Ordering CT when ultrasound or MRI would suffice: CT is not commonly used for evaluation of pelvic pain in the setting of a positive β-hCG and may be used inadvertently if the patient is inadequately screened for pregnancy. 2
• Creating unnecessary anxiety: Most diagnostic X-rays deliver radiation equivalent to only a few days of natural background exposure, and the risk of missing a serious maternal diagnosis far outweighs the negligible radiation risk. 3, 4

Documentation Requirements

• Document the clinical indication and risk-benefit assessment in the medical record. 3, 4
• Document pregnancy screening results before any imaging procedure. 3, 4
• The medical necessity of the examination must outweigh potential risks to the fetus. 3, 4