Ultrasonography in infertility

Ultrasonography is an essential tool not only in investigating the cause for infertility but also useful to monitor the course of treatment.

The two route of ultrasonography commonly performed for infertile women are transvaginal and Transabdominal.

The transvaginal sonography is commonly done to study the ovaries and uterus, in which a probe covered with a sterile cover is introduced into the vagina. This gives a clearer image than a transabdominal scan and does not require the patient to have a full bladder.

A transabdominal scan however requires the patient to have a full bladder in order to visualize the organs of interest, wherein the sonography transducer is placed externally on the lower abdomen.

Uses of ultrasound:
• Diagnostic:

Ultrasonography can be used to diagnose a multitude of diseases of the uterus and ovaries, such as uterine fibroids, uterine septa, ovarian cysts etc. This modality offers a relatively inexpensive, accurate and least invasive way to diagnose these. The introduction of the ‘3D’ ultrasound has improved the diagnostic accuracy of ultrasound for these diseases.

Every infertile woman must undergo a ‘baseline’ scan at the onset of her treatment. This scan is performed at the beginning of her menstrual period (it can be performed while she is still bleeding). This scan is done when the hormone levels are at their lowest and the ovaries are at ‘rest’, before the development of new ovarian follicles. The number of small follicles seen at this stage on the scan gives us an idea of the reserve of the ovaries which can help in deciding how well the ovaries will respond to the medications given for stimulation.

During this baseline scan, the endometrial cavity is also examined for presence of any polyp, septum or any other abnormality. Use of Doppler can help in assessing the blood flow to the uterus.

A saline contrast ultrasound (also known as a saline infused sonogram (SIS) and sonohystogram (SHG)) is a specialized ultrasound that helps us visualize the internal cavity of the uterus.

For a saline contrast ultrasound a little catheter is placed in the uterine cavity, through which saline is infused. This causes the uterine cavity to open up. Once the uterine cavity is open (distended) one can visualize any growth form the endometrium as mentioned previously.

• Therapeutic:
Ultrasound is used to monitor the treatment cycles of women who are receiving medications to stimulate follicular growth. Serial sonographies are done the monitor the rate at which the follicles are growing and their response to the medications, which helps the specialist to decide further doses.

Ultrasound can help in predicting ovulation in these women and thus enable them to maximize the fertility potential.

For those women who have undergone higher treatment options such as ovarian stimulation for in-vitro fertilization, the retrieval of the eggs once mature are done under the guidance of a transvaginal ultrasound probe. In this procedure, a needle is guided through the transvaginal probe and each of the follicles is aspirated under visualization.

Patients who are being prepared for transfer of embryos require to have a good endometrial lining for the embryos to implant. This can be assessed with the help of transvaginal ultrasound.

Once these patients are ready for embryo transfer, this too is done under ultrasound guidance with the help of a transabdominal probe. This helps the specialist to deposit the embryos through a catheter at the optimum position.