From the Guidelines
A 1.9 cm follicle on the right ovary is considered a normal physiological finding and does not require immediate intervention, as indicated by the O-RADS US risk stratification and management system 1.
Management Approach
The management of a 1.9 cm follicle on the right ovary depends on the patient's symptoms, medical history, and reproductive goals.
- For women trying to conceive, this follicle size suggests approaching ovulation, and timed intercourse every 1-2 days is recommended.
- If this is part of a fertility treatment cycle, continue following the specific protocol prescribed by your fertility specialist, which may include triggering ovulation with human chorionic gonadotropin (hCG) injection (typically 5,000-10,000 IU) when the follicle reaches 18-22 mm.
- For women not trying to conceive who have this finding incidentally, no specific management is needed as follicles naturally develop and regress during menstrual cycles.
Follow-up Evaluation
However, if the follicle persists beyond one menstrual cycle or grows larger than 3 cm, follow-up ultrasound evaluation is warranted to rule out a functional ovarian cyst or other pathology, as suggested by the American College of Radiology's O-RADS US risk stratification and management system 1.
Rationale
This approach is based on the understanding that follicular development is a normal part of ovarian function, with dominant follicles typically reaching 18-25 mm before ovulation occurs. The risk of malignancy in simple cysts, such as this follicle, is extremely low, especially in premenopausal women, with a risk of approximately 0.5% 1.
From the Research
Management of a 1.9 cm Follicle on the Right Ovary
The management of a 1.9 cm follicle on the right ovary depends on various factors, including the patient's symptoms, medical history, and reproductive goals.
- Follicle Size and Maturity: According to 2, there is no ideal size when it can be assumed that a follicle is mature, but estimation of follicle size is of value and is a good guide to the timing of hCG administration. A follicle size of 1.9 cm is relatively small, and its maturity cannot be determined solely based on size.
- Monitoring Follicular Development: Studies such as 3 and 4 suggest that ultrasound is a useful technique for monitoring ovarian follicular development. Real-time ultrasound can measure follicular growth during the periovulatory period, and the results can be used to assess the progress of the ovarian cycle.
- Treatment Options: If the follicle is functional and causing symptoms, treatment options may include watchful waiting, as most functional ovarian cysts resolve without treatment within a few cycles 5. However, if the cyst persists or is pathological, surgical management may be indicated.
- Hormonal Treatment: The use of hormonal contraceptives, such as norethisterone, can affect ovarian folliculogenesis and may lead to the formation of follicular cysts 6. However, the effectiveness of hormonal treatment for a 1.9 cm follicle on the right ovary is not well established and would depend on individual patient factors.