Is a transvaginal ultrasound (TVUS) for Polycystic Ovary Syndrome (PCOS) and endometriosis safe at 5 weeks of pregnancy?

Transvaginal Ultrasound Safety During Early Pregnancy

Transvaginal ultrasound (TVUS) is safe to perform at 5 weeks of pregnancy for evaluation of PCOS and endometriosis, with appropriate precautions. 1

Safety of TVUS in Early Pregnancy

• TVUS is routinely used in early pregnancy (around 5 weeks) to confirm pregnancy location, identify gestational sacs, and evaluate early development 1
• At 5 weeks gestation, TVUS can visualize the gestational sac, which typically appears as a round or oval fluid collection surrounded by hyperechoic trophoblastic tissue 1
• TVUS provides superior visualization compared to transabdominal ultrasound, especially in early pregnancy, due to the closer proximity of the transducer to the uterus 1
• The American College of Radiology (ACR) does not contraindicate TVUS in early pregnancy and recognizes it as an appropriate imaging modality during the first trimester 1

Specific Considerations for PCOS and Endometriosis Evaluation

• For patients with PCOS, TVUS can assess ovarian morphology even during early pregnancy, though hormonal changes of pregnancy may alter the typical appearance 2
• In patients with suspected endometriosis, TVUS during early pregnancy can still identify endometriotic lesions, though the primary focus should be on confirming viable intrauterine pregnancy 3, 4
• Women with PCOS and endometriosis have higher risks of early pregnancy complications, making early ultrasound assessment particularly valuable 5, 4

Procedural Safety Measures

• TVUS should be performed using real-time imaging as the probe is advanced to ensure safety 1
• The procedure should maintain an appropriate angle between the cervix and vaginal probe to prevent the probe from inadvertently slipping into the cervix 1
• The examination should use the lowest acoustic energy level compatible with accurate diagnosis (ALARA principle - As Low As Reasonably Achievable) 1
• The sonographer should focus on obtaining necessary diagnostic information while minimizing scan time 1

Important Clinical Considerations

• At 5 weeks, TVUS can confirm intrauterine pregnancy location and rule out ectopic pregnancy, which is crucial information for patients with PCOS and endometriosis who have higher risk of ectopic pregnancies 1
• The presence of a yolk sac within an intrauterine fluid collection on TVUS provides incontrovertible evidence of an intrauterine pregnancy 1
• If cardiac activity is not yet visible at 5 weeks (typically visible at 6 weeks), follow-up ultrasound may be recommended 1
• TVUS should be performed by experienced personnel familiar with early pregnancy imaging 1

Potential Pitfalls to Avoid

• Avoid excessive pressure during the examination to prevent discomfort and theoretical risk to the early pregnancy 1
• Be cautious with Doppler imaging in early pregnancy due to its higher energy levels; use only when clinically necessary 1
• Avoid misinterpreting intracavitary fluid with pointed or non-curved margins as a gestational sac 1
• Do not use terms like "pseudosac" or "pseudogestational sac" as these may lead to clinical errors in management 1

In conclusion, TVUS is a safe and appropriate imaging modality at 5 weeks of pregnancy for evaluation of PCOS and endometriosis when performed with proper technique and appropriate precautions.