Transvaginal ultrasonography assessment of ovarian volumes in postmenopausal women

OBSTETRICS & GYNECOLOGY

ORIGINAL ARTICLE

Transvaginal ultrasonography assessment of ovarian volumes in postmenopausal women

Salim Wehba; César Eduardo Fernandes; José Arnaldo Souza Ferreira; Lúcia Helena Azevedo; Rogério Bonassi Machado; Jacqueline Leme Lunardelli; Sonia Rolim Rosa Lima; Valdemar Iwamoto

Clinic of Endocrine Gynecology and Climacterium at the College of Medical Sciences of the Santa Casa of São Paulo - São Paulo, Brazil

^{Address for correspondence}

ABSTRACT

The authors evaluated ovarian volumes by transvaginal ultrasonography at different periods after menopause. Ninety-eight postmenopausal women with an average age of 51.9 years and a one- to eight-year postmenopausal period were studied. The control group consisted of 40 women during menacme with an average age of 31.8 years, who were also submitted to transvaginal ultrasonography to evaluate ovarian volume.There was no significant difference between right and left ovarian volumes in the study groups.There was a significant decrease in measure and standard deviations of the volumes after the first year of menopause (mean volume - 2.2 ± 0.9 cm³) when compared to the control group (mean volume - 6.3 ± 2.0 cm³ ), followed by a slow and gradual shrinking after this phase. Decrease in ovarian volume became significant after the fourth postmenopausal year. Transvaginal ultrasonography demonstrated great importance as an investigative method of ovarian diseases in postmenopausal women.

Uniterms: Ovary. Ultrasonography. Menopause.

RESUMO

Os autores avaliaram através da ultra-sonografia transvaginal as medidas dos volumes ovarianos em diferentes períodos de tempo de pós-menopausa. Foram estudadas 98 mulheres menopausadas, com idade média de 51,9 anos e tempo de pós-menopausa variando de 1 a 8 anos. Como grupo controle foram consideradas 40 mulheres no menacme, com idade média de 31,8 anos também submetidas à ultra-sonografia transvaginal para aferição do volume ovariano. Não houve diferença significativa entre os volumes ovarianos direito e esquerdo nos grupos estudados. Encontraram decréscimo significativo entre as médias e desvios padrão dos volumes ovarianos a partir do primeiro ano de pós-menopausa (volume médio de 2,2 ± 0,9 cm³), quando comparadas com grupo controle de pacientes no menacme (volume médio de 6,3 ± 2,0 cm³), seguindo-se de diminuição lenta e gradual a partir desta fase. Especificamente na pós-menopausa, a diminuição do volume ovariano tornou-se significativa a partir do quarto ano. Salientam a importância da ultra-sonografia transvaginal na pós-menopausa, como método propedêutico na detecção das patologias ovarianos nessa faixa etária.

INTRODUCTION

Ovarian cancer is an important cause of death due to difficult detection and diagnosis of its initial lesions. The prognosis for women who are in an advanced stage of the disease remains poor, with a survival rate of 15 percent after a period of 5 years; while women in stage I of the disease have a much better prognosis, with a survival rate of 95 percent in 5 years.¹

The difficulty in initially diagnosising ovarian cancer has been attributed to its poor clinical presentation in stages I and II, and to the almost impossible detection of ovarian enlargements in postmenopausal women by bimanual pelvic examination. Therefore, it is imperative to develop adequate detection methods, which would unarguably have a great impact on survival rates, especially in postmenopausal women, in whom the incidence of ovarian cancer is higher.²

Ultrasonography has been used in postmenopausal women for detection of ovarian enlargements and neoplasic lesions.³ Transvaginal assessment, a recently developed ultrasonography technique, allows for better visualization of the ovary than conventional abdominal ultrasonography, and seems more efficient in detecting ovarian tumors.

It is a know fact that ovarian size decreases progressively throughout menopause. This shrinking is most evident in the ovarican cortical, as a consequence of the acentuated decrease in the growth and maturation of follicles.⁴ Obliterate arteriolar sclerosis and cortical fibrosis also contribute to the decrease in ovarian size.⁵ As a consequence, ovarian weight decreases 30 percent, according to Block.⁶ Iwamoto et al. assessed ovarian volume by abdominal ultrasonography and observed a regressive curve that appears after menopause.⁷

Since transvaginal ultrasonography is more accurate in evaluating the ovarian volume, in this study we evaluated the ovarian volume of women at different periods after menopause, in order to establish normal parameters of ovarian volume in the postmenopausal period.

PATIENTS AND METHODS

We studied 98 women during menopause with an average age of 51.9 years, and a 1- to 8-year period of menopause.

Women over 40 years old, with an amenorrhea period of at least one year and high FSH levels, were considered postmenopausal.^8,9 Race and number of gestations were not considered. All patients presented normal clinical and laboratorial conditions. Patients with previous gynecological surgeries, and those with pelvic masses (detected either clinically or ecographically) were excluded. No patient was undergoing hormonal replacement therapy.

Control groups consisted of transvaginal ultrasonograms of 40 clinically normal women during menacme (age 20-40 years, mean: 31.8 years) treated as outpatients at the Department of Obstetrics and Gynecology of the College of Medical Sciences of the Santa Casa of São Paulo.

Ultrasonography was performed with a Toshiba SAL-38D and a mechanical endovaginal sector transducer of 5.0 MHz. Ovaries were assessed in three planes and their size calculated with the simplified elliptic formula: length x height x depth x 0.523.¹⁰ The ovaries and vessels were identified in all cases and did not show any texture or surface alterations. Statistical analysis was done by the t test with coupled samples; the Kruskall-Wallis test for independent samples; and a regression analysis of variance.

RESULTS

The average volumes of right and left ovaries for control and studied groups are listed in Table 1. There was no significant difference between right and left ovarian volumes. Therefore, we used randomly, the average right ovarian volume of both study groups for analysis.

After comparing the right ovarian volume of both groups, a significant difference could be noted in relation to the average and standard deviation of both groups (Table 2). This difference was present in the first year after menopause and is shown in Chart 1.

Ovarian volume in relation to postmenopausal period is shown in Chart 2 and Table 3. After a sharp decrease in the first year, the difference in ovarian volume once again became significant after the fourth year, as demonstrated by the variance analysis and indicated by a straight line.

DISCUSSION

Ultrasonographic study of the female pelvis is an invaluable method of genital assessment after menopause. Abdominal pelvic ultrasonography was first used in early detection of ovarian cancer¹¹ and endometrial thickness.¹²

The recently introduced transvaginal ultrasonography has improved image resolution through higher frequency transducers and proximity to the pelvic organs, without the limitations of the abdominal technique.¹³ High frequency (5-7.5 MHz) endovaginal transducers produce clear images that are easier to interpret, and may effectiveley complement the routine bimanual pelvic exam.¹⁴

Establishing the limits of measurement of ovarian volume for each period after menopause is of great importance. With such, increases in ovarian volumes or the appearance of anomalous images would require other methods offering a better investigation.^11,15

In our study, there was no significant difference between right and left ovaries. However, we noted a significant decrease in ovarian volumes between the studied groups that began in the first year after menopause. These findings coincide with the morphorologic studys of postmenapausal ovaries.^4.16 We would also highlight that, after the initial decrease in ovarian size, the shrinking slows down until the fourth year, when it becomes significant, as demonstrated by the regressive analysis of ovarian volume and postmenopausal period.

Malignant tumors of the ovary have a significantly elevated frequency amongst postmenopausal women over 50 years old.² Small tumors (diameter < 5.0 cm) are rarely detected palpably during a bimanual pelvic examination. BJORKHOEM & SILLFVESWAR report that 31 percent of Stage I ovarian carcinomas presented a diameter below 5.0 cm, and that survival rates for granulosa tumors of this size was 100 percent;¹⁷ while in those with diameters between 5-15cm it was 57 percent.¹⁸

In the past few years, much has been discussed about the role of ultrasonography in ovarian cancer detection. According to VAN NAGELL et al.,^19,20 ovaries may be visualized transvaginally in 95 percent of the cases during menacme and in more than 85 percent of the postmenopausal cases. The same authors, in a study of 1300 asymptomatic postmenopausal women, detected 33 abnormal ovaries, of which 2 were cancers in an early stage.

Our results show that the ovarian volume before menopause can be predicted. Therefore, the routine use of transvaginal ultrasonography in climacteric women assumes an important role in finding volume and structure modifications, and could reduce in mortality through early diagnosis.

• 1 . Karlan BY, Raffel LJ, Crvenkovic G, et al. A multidisciplinary approach to the early detection of ovarian carcinoma: rationale, protocol design, and early results. Am J Obstet Gynecol 1993;169(3):494.
• 2. Gambrell RD Jr. Use of progestogen therapy. Am J Obst Gynecol 1987;156:1304.
• 3. Wolf SI, Gosink BB, Feldesman MR. Prevalence of simple adnexal cysts in postmenopausal women. Radiology 1991;180:65.
• 4. Nicosia SV. Morphological changes of the human ovary throughout life. In: Sorra CB, ed. The Ovary. New York: Raven Press, 1983.
• 5. Lang WR, Apont GE. Gross and microscopic anatomy of the aged female reproductive organs. Clin Obst Gynecol 1978;10:454.
• 6. Block E. Quantitative morphological investigations of the follicular system in women. Acta Anatom 1952;14:108.
• 7. Iwamoto VM, Wehba S, Ferreira JAS, et al. Comportamento do volume ovariano pela ultra-sonografia em mulheres na pos-menopausa. Reprodução 1989;4(2):75.
• 8. Chakravarti S, Collins WP, Forecast JD, Newton JR, Oram DH, Studd JWW. Hormonal profiles after the menopausal. Br Med J 1976;2:784.
• 9. Wehba, S. Teste de progesterona no rastreamento de lesões hiperplásicas de mulheres na pós-menopausa. Tese de Doutorado em Ginecologia. Escola Paulista de Medicina, 1988.
• 10. Ivarsson SA, Nilsson KO, Persso PH. Ultrasonography of the pelvic organs in prepubertal and postpubertal girls. Arch Dis Child, 1983;58:352.
• 11. Campbell S, Goessons L, Goswamy RK, Whitehead M. Real time ultrasonography for determination of ovarian morphologycal and volume: a possible early screening lest for ovarian cancer? Lancet 1982;I:425.
• 12. Nasri MN, Coast GJ. Correlation of ultrasound findings and endometrial histopathology in postmenopausal women. Br J Obstet Gynaecol 1989;96:1333.
• 13. Nasri N, Shepherd, JH, Setchell ME, Lowe DG, Chard T. Role of vaginal scan in measurement of endometrial thickness in postmenopausal women. Br J Obstet Gynaecol 1991;98:470.
• 14. Timor-Tritsch IE. Is office use of vaginal ultrasonography feasible? Am J Obstet Gynecol 1990;162(4):983.
• 15. Andolf E, Svalenius ES, Asted B. Ultrasonography for early detection of ovarian carcinoma. Br J Obst Gynecol 1986;93:1286.
• 16. Chang JR, Judd HL. The ovary after menopause. Clin Obst Gynecol 1981;24:191.
• 17. Bjorkhol E, Silfverswar C. Prognostic factors in granulosa cell tumors. Gynecol Oncol 1971;11: 261.
• 18. Fox H, Agrawet K, Langley FA. A clinicopathologic study of 92 cases of granulosa cell tumor of the ovary with special reference to the factor influencing prognosis. Cancer 1975;35:231.
• 19. van Nagell JR, DePriest PD, Puls LE, et al. Ovarian cancer screening in asymptomatic postmenopausal women by transvaginal sonography. Cancer 1991;68:458.
• 20. van Nagell JR, Higgins RV, Donaldson ES, et al. Transvaginal sonography as a screening method for ovarian cancer. Cancer 1991;65:573.

Address for correspondence:

Salim Wehba

Rua Canário, 1135 - lndianópolis

São Paulo/SP - Brasil - CEP 04521-005

Publication Dates

• Publication in this collection
  12 Nov 2008
• Date of issue
  June 1996