Transvaginal Scan During Menstruation
Yes, it is absolutely safe and appropriate to perform a transvaginal scan (TVS) while menstruating—menstruation is not a contraindication to transvaginal ultrasound. 1
Primary Recommendation
The American College of Emergency Physicians explicitly states that transvaginal ultrasound can be performed safely during any phase of the menstrual cycle, including active menstruation. 1
Transvaginal ultrasound remains the first-line imaging approach for evaluating pelvic structures in reproductive-aged women regardless of menstrual status, due to its superior resolution and diagnostic accuracy compared to other modalities. 1
The American College of Radiology guidelines for obstetrical and gynecological imaging do not list menstruation as a contraindication or limitation for transvaginal scanning. 2, 3
Technical Considerations During Menstruation
While TVS can be performed during menstruation, the presence of menstrual blood may slightly affect visualization quality in some cases, but this does not preclude the examination. 4
The endometrial thickness interpretation varies with menstrual cycle phase in premenopausal women, so the radiologist should be informed of the patient's menstrual status for appropriate interpretation. 4
For specific procedures like hysterosalpingo-contrast sonography (HyCoSy), timing after menstruation matters more for technical reasons—performing the study 7-10 days after menstruation or when endometrial thickness exceeds 5.45 mm reduces complications like venous intravasation. 5 However, this is specific to contrast studies, not routine diagnostic TVS.
Important Distinction: TVS vs. Pap Testing
Do not confuse transvaginal ultrasound with Pap testing—these are different procedures with different requirements. 6
Conventional cytology Pap testing should be postponed if the patient is menstruating and rescheduled at the earliest opportunity, as menstrual blood can interfere with cytological interpretation. 6
However, this Pap testing restriction does not apply to transvaginal ultrasound, which uses sound waves rather than cellular sampling. 1
Common Clinical Pitfalls to Avoid
Never default to transrectal ultrasound simply because the patient is menstruating—this is an inappropriate substitution as menstruation is not a contraindication to TVS. 1
Transrectal ultrasound should only be used when transvaginal ultrasound is either declined by the patient or deemed not feasible for other reasons (such as vaginal stenosis or patient preference). 2, 1
Transabdominal ultrasound alone provides insufficient resolution for comprehensive pelvic evaluation and should not be used as a substitute when TVS is indicated, regardless of menstrual status. 1
Patient Counseling
Proper patient counseling should include explaining that menstruation does not prevent the examination and that the procedure can proceed safely. 1
The presence of a chaperone is essential throughout the transvaginal examination procedure, as recommended for all TVS examinations. 1
The patient should empty her bladder before transvaginal scanning to optimize image quality and comfort, which is standard practice regardless of menstrual status. 1