Should Hysteroscopy be a Routine Component of the Infertility Workup?

Keith Isaacson, M.D.
Director, Division of Reproductive Endocrinology and Infertility Massachusetts General Hospital Boston, Massachusetts Associate Professor of Obstetrics and Gynecology Harvard Medical School Boston, Massachusetts

Introduction

Hysteroscopy is a procedure involving the placement of a scope (hysteroscope) through the cervix and into the uterine cavity. It allows for direct visualization of the inside of the uterus. In many cases the uterus is distended with fluid or gas to open up the uterus for a better view. Hysteroscopy may be done in the office or in an outpatient surgery setting. For a test to be useful for the general infertility evaluation, it should meet the following criteria: a) it should identify abnormal lesions that could impact a patients fertility b) the likelihood of these lesions should be high enough so that the correction of this abnormality will enhance fertility c) the test should be easy to perform by the general gynecologist and fertility expert and d) the test should be cost effective and not too expensive.

Uterine Abnormalities Related to Infertility

Any intrauterine abnormality that can affect embryo implantation can, in theory, affect the ability of a woman to conceive. Examples of lesions visible to the naked eye include fibroids, polyps and scar tissue in the uterine cavity as well abnormal cavity shapes that are present at birth. Other uterine abnormalities such as fibroids in the wall of the uterus are not clearly related to infertility nor or they often detected by evaluation of the uterine cavity. Chronic low-grade inflammation of the uterus is not a condition detected by gross observation.

Fibroids in the Cavity of the Uterus (submucosal fibroids)

Submucosal fibroids often present with heavy periods (menorrhagia). However they can also present with infertility and recurrent miscarriages. It has been postulated that submucosal fibroids block or decrease the normal blood supply to the placental tissue. The true prevalence of submucous myomata in the infertile population is not known but one study suggested that it was 7.8%. Numerous studies have shown that office hysteroscopy can not only detect the presence or absence of submucous fibroids but it can give other valuable information such as intrauterine location (cornual or cervical), its vascularity, and the percentage of the fibroid accessible for hysteroscopic resection. Knowledge of this data is invaluable for appropriate presurgical planning.

Endometrial Polyps

Endometrial polyps often present with midcycle spotting or bleeding after intercourse. The data on their impact on implantation is non-existent and therefore speculative. Intuitively one would assume that if an embryo attempts to implant on an endometrial polyp, that normal embryo growth would be difficult in that polyps have been shown to look quite different under the microscope than normal endometrium. Therefore, if a polyp occupies a significant portion of the uterine cavity, one could imply that it can adversely affect embryo implantation. In the same study noted above, 24% of the infertile population had documented endometrial polyps. Much like submucous myomas, office hysteroscopy can easily detect even very small endometrial polyps.

Scar Tissue in the Uterine Cavity (Asherman's syndrome)

The universal incidence of Asherman's syndrome is increasing. (Schenker JG, Etiology of and therapeutic approach to synechia uteri. European J Obstet Gynecol & Repr Endocrinol 1996:65:109-113). The main offender is trauma to the uterus after D&C after a delivery or after a miscarriage. However, intrauterine scarring from infections such as tuberculosis are also increasing in poorly developed countries and in immunocompromised patients. The clinical implications of intrauterine scar tissue vary with the degree of pathology. The European Society of Hysteroscopy recently introduced a 7 point evaluation system to score the degree of scarring. This system accounts for the density of the adhesions, the occlusion of the endometrial cavity and the scarring of the cavity wall. When more scarring is present, the treatment is usually less successful. Direct hysteroscopic view of the endometrial cavity is the only way to determine the degree of intrauterine scarring and can easily be performed in the office.

Congenital Abnormalities

The prevalence of congenital uterine abnormalities in the general population ranges from 0.2% to 10%. The prevalence is nearly 13% in infertile patients with uterine septum being the most common abnormality.

It is likely that the double uterus (bicornuate and didelphys uterus) do not play a significant role in infertility. It is theorized that the vasuclarity to the uterine septum is inadequate to support embryo implantation and therefore results in repeated early pregnancy loss.

The office hysteroscope will easily detect a congenitally abnormal uterine cavity. It is very useful in evaluating changes due to in utero DES exposure which are often mistaken for uterine fibroids. The hysteroscope can not determine if a "Y" shaped cavity is due to a septum or a bicornuate uterus. This must be determined by a MRI exam or by a direct surgical view.

Prevalence of Uterine Abnormalities in Asymptomatic Patients Undergoing in vitro Fertilization

The range intrauterine pathology found in infertile patients undergoing assisted reproductive technologies ranges from 11-42%. A summary of the data are presented below.

IVF population with no additional symptoms

• Shamma et al (1992) - 12/28 (42%)
• Giovanni et al (1998) - 18/100 (18%) all had a normal HSG and 2 failed cycles
• Kim et al (1999) - 8/72 (11%)
• Ayida et al (1997) - 16/47 (34%)

As a result of these data, most IVF units across the country are performing some technique for evaluating the uterine cavity. The question arises as to whether or not an asymptomatic polyp has any impact on fertility or implantation. The only evidence we have is from one small retrospective study by Shamma who found a 37.5% clinical pregnancy rate in patients undergoing IVF without intrauterine lesions and a 8.3% clinical pregnancy rate in patients with lesions.

SUMMARY

In conclusion, hysteroscopy fulfilled the criteria we felt was necessary to implement a diagnostic test for infertility. There is a significant prevalence of intrauterine pathology in the infertile population. Many uterine abnormalities found during hysteroscopy do impact on fertility and correcting them will enhance fertility. Office hysteroscopy is an excellent method for detecting uterine abnormalities during the evaluation of the infertile couple especially prior to embarking on assisted reproductive technologies such as IVF.