Pelvic Ultrasound (USG)

Real-time sonographic imaging is the most common and most useful imaging technique employed in obstetrics and gynecology patients. However, it is a user-dependent imaging modality and multiple factors affect the images obtained, thereby directly affecting patient diagnosis and management. Operator experience and ability are probably the most important factors in making diagnoses that directly affect patient care. Other factors, such as the patient’s body habitus, history of prior abdominal surgery, and, in obstetrics, fetal position, can all affect image quality and diagnostic performance.

Transabdominal ultrasound is a superficial examination through the abdominal wall.
The procedure is as follows:

  • the woman removes clothing from the lower part of the abdomen and lies on her back;
  • the doctor applies a gel to enhance the quality of the device’s signal;
  • the probe moves over the area being studied, and an image appears on the monitor screen;
  • depending on the tasks, the procedure can take from 10 to 30 minutes.

Transvaginal ultrasound involves inserting a special probe into the vagina. This allows for a better study of the urinary and reproductive systems.
The procedure is as follows:

  • the woman undresses below the waist and lies on her back;
  • the ultrasound doctor puts a special condom on the probe;
  • the device is inserted a few centimetres inside the vagina.
  • the probe moves over the area being studied, and an image appears on the monitor screen;
  • depending on the tasks, the procedure can take from 10 to 30 minutes.

Advantages of Ultrasound (USG):
✅ Accessibility, simplicity, and lack of contraindications;
✅ Does not impose radiation exposure on the human body and is considered safe;
✅ Effective for early-stage disease detection;
✅ Has wide applications in various medical fields;
✅ Enables detection of pathologies in internal organs, glands, and vessels at early stages;
✅ Used for pregnant women with the aim of detecting early fetal pathologies.

Potential gynecologic indications for ultrasound examination:

  • Evaluation of abnormal uterine bleeding in pre- and postmenopausal women
  • Assessment and follow-up of a pelvic mass
  • Evaluation for signs, symptoms, or sequelae of pelvic infection (eg, tubo-ovarian abscess, hydrosalpinx)
  • Evaluation of congenital uterine, gonadal, or lower genital tract anomalies
  • Evaluation of pelvic pain or dysmenorrhea
  • Localization of an intrauterine device
  • Evaluation of endocrine abnormalities (eg, polycystic ovary syndrome)
  • Evaluation of the pelvic floor in the work-up of women with pelvic organ prolapse and urinary or anal incontinence, as well as evaluation of urethral diverticula, rectal intussusception, mesh location, and residual urine volume
  • Evaluation of the menstrual cycle (endometrial thickness, follicular development)
  • Evaluation, monitoring, and/or treatment of patients with infertility
  • Screening for pelvic malignancy
  • Evaluation when there is limited clinical examination of the pelvis
  • Evaluation of complications after pelvic surgery, delivery, or pregnancy loss or termination
  • Guidance for interventional or surgical procedures
  • Pre- and postoperative evaluation of pelvic structures
  • Follow-up or further characterization of previously detected abnormality

Patient preparation:

  • Reason for the examination – The sonographer should know the indication for the ultrasound examination and results of other evaluations related to the patient’s problem. The last menstrual period (or estimated delivery date in obstetric examinations) should be documented. All of this information is critical for targeting specific structures, choosing whether to use a transvaginal and/or transabdominal technique, and deciding whether additional studies may be helpful (eg, saline infusion sonohysterography, Doppler velocimetry).

● Patient position – In obstetrics and gynecology, most examinations are performed with the woman in a semi-recumbent position. A padded table and pillows provide reasonable comfort. It is desirable to be able to elevate the head of the bed because many pregnant women are unable to lie flat, especially later in pregnancy. Others will require pillows under their knees or behind their back to achieve a comfortable position.

Transvaginal ultrasound examinations are done with the woman in a lithotomy position. Alternatively, a cushion can be placed under the buttocks to raise the pelvis, while the lower extremities are separated and/or frog-legged (soles of feet together and knees apart).

● Modifications for patients with obesity – Abdominal obesity limits the technical quality of the ultrasound examination. Imaging may be improved by having the patient lie on her side and placing the transducer at the side of the maternal abdomen rather than in the midline where the thickness of abdominal adipose tissue is often greater, and/or by use of transvaginal ultrasound.

Although fetal anatomic surveys for malformations are typically performed transabdominally at 18 to 20 weeks, performing the examination later in gestation (20 to 22 weeks) in the obese gravida may improve visualization of anatomy. Transvaginal ultrasound in the late first or early second trimester may also help with fetal evaluation in these patients.

● Bladder filling – In transabdominal obstetric examinations, there is little benefit to the patient having a full bladder, and it has drawbacks (eg, false diagnosis of placenta previa or falsely elongated cervix). Urine in the bladder is useful when the area of the lower uterine segment is of interest as it can provide a helpful window for the evaluation. In transabdominal gynecologic examinations, the bladder does not have to be full; however, if the uterus and ovaries cannot be seen well, it may be necessary to have the patient fill her bladder to a comfortable capacity.

Transvaginal sonography is usually performed with an empty bladder.

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