Ultrasonography in Female Infertility-PART 1: Ovarian Causes

Infertility is the inability to conceive despite frequent and unprotected intercourse between a man and his female partner for at least 1 year.

Female and male factors each account for about one-third of cases. In the remaining third of cases usually both female and male factors are involved. Included in the latter are also those in whom there is no identifiable causative factors (idiopathic).

In this article I focus on the various causes of female infertility and uses of sonography for its diagnosis.

Causes

Ovulation disorders

Ovulation disorders include polycystic ovarian disease (PCOD), luteal phase defect, and ovarian failure.

Sonography is an excellent tool in the diagnosis and management of PCOD, which will be the focus here.

PCOD. This condition is caused by both insulin resistance and hyperandrogenism in a woman. It results in the ovaries having multiple small follicles that fail to reach maturity (hence the name “polyfollicular syndrome”). Ultrasound imaging shows multiple small follicles (more than 12 in number) with increase in ovarian volume (on transvaginal ultrasound) of more than 10 cc with the size of each follicle being less than 10 mm. These remain the main criteria (the rule of 10) used to sonographically identify polycystic ovaries. In addition, the ovarian follicles are arranged around the rim, giving rise to the “necklace pattern” or “string of pearls” sign of the ovaries. These features are better appreciated on transvaginal ultrasound imaging. Another feature seen on sonography is increased echogenicity of the ovarian stroma, resulting in a brighter (hyperechoic) ovary.

The following ultrasound images show typical appearances of PCO.

CASE 1:

This right ovary shows typical features of PCO. The individual follicles are about 4 mm in diameter. Note also the hyperechoic ovarian stroma. (Ultrasound image courtesy of www.ultrasound-images.com.)

CASE 2:

 PCO: multiple small follicles arranged like a string of pearls or necklace around the ovarian rim.

(Image courtesy of Gunjan Puri, MD, India, and is reproduced from www.ultrasound-images.com.)

Ovarian cysts

Ovarian cysts like endometriomas also affect fertility. Endometriomas are blood-filled cysts of the ovaries, and are the result of bleeding into the ovaries due to endometriosis or ectopic endometrial tissues. Such cysts are known to seriously hamper fertility in the female. Endometriomas present as homogenous echogenic debris (blood) seen within the cyst. The densely homogenous appearance of the debris or particles is diagnostic of endometriomas, unlike hemorrhagic cysts, which are inhomogenous and have fine strands that pass within them.

This transvaginal ultrasound image shows a typical appearance of endometrioma of the left ovary. Note the highly echogenic nature of the debris within the cyst.

(Image courtesy of Shlomo Gobi, Israel, and is reproduced from www.ultrasound-images.com.)

Ovarian cysts that do not cause infertility

Functional cysts of the ovaries such as follicular cysts and corpus luteal cysts do not affect fertility in most cases. In fact, these cysts signify that the ovaries are functioning normally.

Cystadenomas and dermoid cysts also do not significantly affect female fertility.

References

Gallenberg M. Is there a link between ovarian cysts and fertility?  Mayo Clinic Web site.  April 26, 2011.

Mayo Clinic Staff. Infertility cause. Mayo Clinic Web site. April 26, 2011.

Puscheck EE. Infertility overview. Medscape Web site. April 26, 2011.