Fact Check: Are VQ scans safe in pregnancy?

Are VQ Scans Safe in Pregnancy?

Introduction

The safety of ventilation-perfusion (VQ) scans during pregnancy has become a topic of interest, particularly in the context of diagnosing pulmonary embolism (PE). The claim in question is whether VQ scans are safe for pregnant women and their fetuses. This claim is significant as it pertains to the health and safety of both the mother and the developing fetus during a critical time.

What We Know

1. Radiation Exposure: VQ scans expose the fetus to approximately 1-2 mSv of radiation, which is comparable to the radiation exposure from computed tomography pulmonary angiography (CTPA) scans 28. According to the American College of Obstetricians and Gynecologists (ACOG), the radiation doses from various imaging modalities, including VQ scans, are generally considered low 5.

2. Comparative Safety: A study published in the Journal of the American Medical Association (JAMA) assessed the safety of VQ scans by examining adverse pregnancy outcomes such as preterm labor and congenital anomalies. The findings suggested that VQ scans do not significantly increase the risk of these outcomes compared to other imaging methods 6.

3. Guidelines and Recommendations: Various medical guidelines, including those from ACOG, recommend that imaging studies, including VQ scans, should be performed when the benefits outweigh the risks, particularly in cases of suspected PE 54.

4. Alternative Imaging Options: VQ scans are often considered a safer alternative to CTPA in pregnant patients, especially for those who may have contraindications to contrast agents used in CT scans 79.

5. Indeterminate Results: Concerns have been raised regarding the accuracy of VQ scans, as a significant percentage of scans can yield indeterminate results. However, in pregnant patients, the rate of indeterminate results is reportedly lower than in the general population 9.

Analysis

The evidence surrounding the safety of VQ scans during pregnancy is derived from a mixture of clinical studies, expert guidelines, and patient information resources.

• Source Credibility: The studies cited, particularly those from peer-reviewed journals like JAMA 6 and PMC articles 12, provide a level of credibility due to their scientific rigor and the peer-review process. However, it is important to note the potential for publication bias, as studies with positive findings may be more likely to be published.

• Potential Conflicts of Interest: Some sources, such as patient information documents from hospitals 37, may have an inherent bias towards reassuring patients about the safety of procedures they offer. This could affect the objectivity of the information presented.

• Methodological Concerns: While the studies generally report low risks associated with VQ scans, the methodologies used to assess safety—such as the evaluation of adverse outcomes—may not account for all variables, including the timing of the scan in relation to pregnancy stages or the health status of the mother.

• Expert Opinions: Articles from medical professionals and organizations 54 provide guidelines based on consensus and expert opinion, which can be valuable but also reflect the prevailing attitudes and practices that may not always align with emerging evidence.

• Lack of Comprehensive Data: There is a need for more extensive longitudinal studies that track the long-term effects of VQ scans on both mothers and children. Current data primarily focus on immediate outcomes, which may not capture delayed effects.

Conclusion

Verdict: True

The evidence suggests that VQ scans are generally safe for use during pregnancy, particularly when the benefits of diagnosing conditions like pulmonary embolism outweigh the associated risks. Key evidence supporting this conclusion includes the relatively low radiation exposure to the fetus, findings from peer-reviewed studies indicating no significant increase in adverse pregnancy outcomes, and guidelines from reputable medical organizations recommending their use under specific circumstances.

However, it is essential to acknowledge the limitations of the available evidence. While current studies indicate safety, they often focus on immediate outcomes and may not fully account for long-term effects or variations in individual health circumstances. Additionally, the potential for publication bias and conflicts of interest in some sources underscores the need for cautious interpretation of the findings.

Readers are encouraged to critically evaluate the information presented and consult healthcare professionals when considering imaging options during pregnancy. The decision to proceed with a VQ scan should be made collaboratively, weighing the potential benefits against the risks in the context of each individual case.

Sources

1. Computed tomography pulmonary angiography versus ... PMC6312023
2. V/Q scans and computerized tomography pulmonary ... PMC4214031
3. Nuclear medicine lung (VQ) scans Information for patients during pregnancy Yale Medicine
4. CT and MR Pregnancy Guidelines UCSF Radiology
5. Guidelines for Diagnostic Imaging During Pregnancy and Lactation ACOG
6. Suspected Pulmonary Embolism in Pregnancy - JAMA Network JAMA Network
7. Nuclear Medicine Lung (V/Q) Scan in Pregnancy - York and Scarborough York Hospitals
8. Vq Scan Safety During Pregnancy: Any Risks? | ShunChild ShunChild
9. V/Q or CTPA in suspected PE in pregnancy Resus
10. Investigation of Suspected Pulmonary Embolism (PE) in Pregnancy - Risks Hey NHS