Pelvic Ultrasound

Pelvic ultrasound is one of the main tools used to assess the female reproductive system, including the uterus, endometrium, ovaries, cervix, parametrium, and bladder. It can also provide indirect information about the fallopian tubes.

It can help:

• confirm or rule out structural abnormalities, including fibroids, cysts, polyps, developmental abnormalities, and hydrosalpinx, as well as signs suggestive of endometriosis
• assess the thickness and structure of the endometrium at different stages of the menstrual cycle
• monitor follicular development and confirm ovulation
• assess blood flow within abnormal growths using Doppler ultrasound and 3D imaging, which can help distinguish benign findings from potentially suspicious ones
• monitor the effectiveness of treatment, including hormone therapy, ovarian stimulation, and preparation for IVF

The examination can be performed in two ways, which are often used together:

Transabdominal ultrasound is performed through the abdominal wall. It provides a general view of the pelvic organs and is useful for detecting large growths and assessing the pelvic cavity, but it provides less detail of smaller structures.

Transvaginal ultrasound is the primary approach used in gynecology. It provides clearer images of the endometrium, ovaries, and cervix, allows follicles to be measured accurately, and helps assess blood flow.

Patients who are not sexually active are generally offered a transabdominal ultrasound with a full bladder. If necessary and with the patient’s consent, a transrectal ultrasound may be performed.

When should the examination be performed?

The phase of the menstrual cycle is important.

Routine preventive ultrasound

A routine pelvic ultrasound is usually performed during the early follicular phase, between days 5 and 9 of a 28-day cycle.

At this stage:

• the endometrium is thin, usually measuring 3–5 mm, which makes polyps and other localized changes easier to detect
• the ovaries contain antral follicles, but a dominant follicle has not yet developed, allowing their structure to be assessed without interference from functional changes
• cysts detected during the first phase of the cycle are more likely to represent structural abnormalities, while findings during the second phase may be functional, such as the corpus luteum or a corpus luteum cyst

To confirm ovulation or monitor follicular development, ultrasound may be performed on days 10, 12, 14, and 16, depending on the purpose of the examination.

During a fertility assessment or before IVF, the timing is determined individually. The examination may be scheduled for the middle of the luteal phase, usually between days 21 and 23, to assess secretory changes in the endometrium.

How is the examination performed?

Before a transvaginal ultrasound, the patient empties her bladder. A full bladder is required for a transabdominal ultrasound.

The procedure takes approximately 10–15 minutes and usually causes minimal discomfort when performed carefully. The patient lies on her back with her knees bent. For a transvaginal ultrasound, the probe is covered with a protective sheath and ultrasound gel to ensure hygiene and safety.

If you have acute pain or bleeding, or if a complication such as ovarian torsion, ovarian rupture, or an ectopic pregnancy is suspected, the ultrasound is performed urgently on any day of the menstrual cycle. In these situations, symptoms and clinical findings are more important than the phase of the cycle.

Preventive ultrasound: when and for whom?

According to clinical guidelines and evidence-based medical practice, preventive pelvic ultrasound may be recommended for women without symptoms:

• once a year if risk factors are present, such as a family history of ovarian or uterine cancer, long-term use of combined oral contraceptives or hormone replacement therapy, obesity, diabetes, early onset of menstruation, or late menopause
• once every three to five years for women aged 30–50 without symptoms or known risk factors, to detect fibroids, adenomyosis, or ovarian cysts that may cause symptoms later
• once every one to three years after menopause, as ovarian enlargement or an endometrial thickness greater than 4–5 mm may require further evaluation

Pelvic ultrasound does not replace cervical cancer screening with liquid-based cytology or HPV testing. These examinations serve different purposes.

2026 © Elena Konovalova