Is High-Intensity Focused Ultrasound (HIFU) safe for women of childbearing age with concerns about fertility?

HIFU and Fertility: Safety Considerations for Women of Childbearing Age

High-Intensity Focused Ultrasound (HIFU) for benign prostatic hyperplasia was described as "moderately promising" but investigational in 2003, and there is no established evidence supporting its safety or efficacy for fertility preservation or treatment in women of childbearing age. 1

Current Evidence Status

The available evidence on HIFU relates primarily to:

• Benign prostatic hyperplasia treatment in men, where HIFU remains investigational with insufficient long-term data beyond 2 years 1
• Cosmetic dermatology applications for skin laxity, wrinkles, and submental fat reduction, which target superficial tissues at depths of 4.5-6.0 mm 2, 3, 4, 5
• Adenomyosis treatment in women desiring pregnancy, showing a pooled pregnancy rate of 53.4% and live birth rate of 35.2%, but with very weak evidence quality and substantial heterogeneity 6

Critical Fertility Preservation Context

When counseling women of childbearing age about fertility preservation, established guidelines emphasize:

• Oocyte or embryo cryopreservation are the preferred fertility preservation options for women facing gonadotoxic treatments, as these techniques are proven and facilitate preimplantation genetic diagnosis when needed 1
• Fertility preservation strategies should preferably be used at the time of diagnosis before treatment initiation 1
• Ovarian tissue cryopreservation is currently the only fertility preservation option in pediatric patients and those with hormone-dependent diseases 1

Adenomyosis-Specific HIFU Data

The only reproductive outcome data for HIFU involves adenomyosis treatment:

• A 2024 meta-analysis of 557 patients showed pregnancy rates of 53.4% and live birth rates of 35.2% after HIFU treatment for adenomyosis 6
• The evidence quality is very weak with substantial heterogeneity between studies 6
• Comparative studies with higher methodological rigor, preferably randomized clinical trials, are badly needed to establish whether HIFU truly improves fertility outcomes 6

Mechanism and Safety Concerns

HIFU works by:

• Focusing ultrasound waves at frequencies of 1-7 MHz (or up to 20 MHz for dermatologic applications) to create a focal point several millimeters below the tissue surface 2, 3
• Raising tissue temperature to more than 60°C at the focal point, causing coagulative necrosis or thermal ablation 1, 2
• Leaving tissue above and below the focal point theoretically unaffected 2

The thermal effects of HIFU on ovarian reserve, oocyte quality, or reproductive organs have not been systematically studied in women of childbearing age.

Critical Pitfalls to Avoid

• Never assume HIFU is fertility-sparing without specific evidence for the indication and anatomic location being treated - thermal injury to reproductive organs could be irreversible
• Do not delay established fertility preservation methods (oocyte/embryo cryopreservation) in favor of unproven HIFU applications 1
• Recognize that "non-invasive" does not equal "safe for fertility" - thermal tissue destruction at 60°C+ could damage ovarian reserve or uterine function depending on proximity 2
• For adenomyosis patients desiring pregnancy, acknowledge the weak evidence base and consider HIFU only after thorough counseling about alternative treatments and the lack of high-quality comparative data 6

Recommendation for Clinical Practice

Women of childbearing age considering any HIFU treatment should receive explicit counseling that:

1. HIFU's effects on fertility are largely unknown for most applications
2. For adenomyosis specifically, pregnancy outcomes after HIFU show promise but lack rigorous evidence 6
3. Established fertility preservation methods (oocyte/embryo cryopreservation) should be prioritized when fertility preservation is the primary goal 1
4. Any HIFU treatment near reproductive organs requires careful assessment of potential thermal injury risk to ovaries, fallopian tubes, or uterus

If HIFU is being considered for adenomyosis in a woman desiring pregnancy, she should understand that while pregnancy rates of 53.4% have been reported, the evidence quality is very weak and randomized trials are needed to confirm benefit. 6