Adnexal and ovarian masses

The incidence of adnexal masses in pregnancy appears to be increasing with the expanding use of antenatal ultrasound:¹

• The majority of such masses do not cause problems and most are probably cysts of the corpus luteum that have not undergone full involution. They usually resolve by the second trimester of pregnancy.
• Persisting adnexal masses are at risk of complications and may rarely require emergency or elective surgical resection (the optimal surgical window being around 16 to 20 weeks of gestation).

Type of tumour

Benign

• Functional ovarian cysts, e.g. corpus luteum cyst.
• Benign cystic teratomas.
• Serous or mucinous cystadenomas.
• Fibromas.

Malignant

All rare and usually low-stage/low-grade:²

• Germ cell tumours.
• Borderline ovarian tumours.
• Epithelial tumours.
• Sex-cord stromal tumours.

Uterine fibroids (leiomyomata)

Evidence suggests that there is an increased risk of pregnancy loss associated with the presence of uterine fibroids in early pregnancy, especially with multiple fibroids.³One review suggests that fibroids are probably more common than thought in pregnancy, but cause fewer problems than expected:⁴

• One longitudinal study found a complication rate of 4 in 72 affected pregnancies.⁵
• There is a generally held belief that fibroids grow during pregnancy but longitudinal studies have shown that this happens rarely.⁵
• If they do enlarge, it is usually during early pregnancy.⁴

Epidemiology

• The incidence of either fibroids or ovarian masses/tumours during pregnancy is difficult to estimate, as there have been no rigorous population-based studies with agreed criteria.
• Fibroids appear to be relatively common but their exact prevalence is not defined and probably largely dependent on the type of population surveyed.
• Clinically detectable ovarian masses are thought to affect about 1 in 1,500 pregnancies.
• Ultrasound scanning probably detects prevalence of adnexal masses in early pregnancy of about 1 in 200.
• The vast majority of these adnexal masses do not persist beyond the second trimester.
• Ovarian malignancy is very rare at approximately 7 cases per 10,000 pregnancies in one series.⁶

Presentation

• Most adnexal masses and fibroids are detected coincidentally during routine antenatal ultrasound.
• A small proportion of both pathologies may be large enough to detect clinically during bimanual palpation of the uterus.
• The mass may also cause complications (see list under 'Complications', below) and the patient then presents with symptoms caused by this.

Differential diagnosis

• For ovarian tumours, the main question is whether the tumour is benign or malignant.
• Uterine fibroids (once visualised by ultrasound scanning) are unlikely to be confused with other pathologies.

Investigations

The investigation of choice for uterine or ovarian masses in pregnancy is detailed ultrasound scanning including Doppler:⁷

• This indicates the size, location, appearance and likelihood of any problems, to assist decisions on management. Morphological criteria can identify benign ovarian cysts compared with malignant masses relatively accurately.
• Ovarian tumour markers are used mainly to monitor disease status during treatment, rather than as a diagnostic test, due to a lack of specificity. Several markers can be elevated due to pregnancy itself, e.g. CA-125, beta human chorionic gonadotrophin (beta-hCG).^8,9
• In confirmed malignancy, investigations to stage the tumour (such as CT/MRI scanning of the pelvis) may be used, as the risk to the mother is considered to outweigh that to the fetus.¹

Management

Ovarian masses

• If the mass is thought to be benign and unlikely to cause complications, expectant management and follow-up scans are recommended.
• There is little evidence to support the routine laparoscopic excision of presumed benign ovarian tumours.¹⁰
• Surgery after 15 weeks of gestation is indicated for large (greater than 5-10 cm in diameter) and/or symptomatic tumours and those that appear highly suspicious for malignancy (solid or mixed solid and cystic) on ultrasound.¹¹
• The extent of surgery is decided by the intraoperative findings showing whether the tumour is benign/malignant:
  • Conservative surgery is indicated for benign masses/borderline ovarian tumours.
  • More extensive surgery (including staging biopsies) for confirmed higher-grade malignancies.
• Rarely, chemotherapy may be given after delivery or at least after 20 weeks in order to minimise the potential fetal toxicity. The short- to medium-term fetal outcome appears to be relatively good.¹²

Uterine fibroids

• Most fibroids cause no problems during pregnancy and are usually observed.⁴
• Diffuse uterine fibroids can be successfully treated conservatively to achieve a successful pregnancy outcome.¹³
• Intractable fibroid pain unresponsive to medical treatments is an indication for myomectomy, as is a large fibroid (≥ 5 cm) located in the lower uterine segment.
• Fibroids are normally operated upon in the first or second trimester unless there is emergency indication.
• Myomectomy should not be carried out at the time of Caesarean section except in emergency, as there is a high morbidity due to haemorrhage.
• Bilateral uterine artery embolisation (UAE) immediately after Caesarean delivery may be effective in decreasing postpartum blood loss and minimising the risk of myomectomy or hysterectomy.¹⁴

Complications

Ovarian tumours¹

• Torsion presenting as acute abdomen.¹⁵
• Rupture presenting as acute abdomen.
• Obstruction of labour.
• Preterm labour.
• Malignant transformation causing peritoneal spread (may lead to ascites and peripheral oedema).

Uterine fibroids

Most women with fibroids have uneventful pregnancies; however, evidence does suggest an association with:¹⁶

• Red degeneration due to hypoperfusion - acute abdominal pain.¹⁷
• Otherwise unexplained vaginal bleeding.
• Placental abruption.
• Intrauterine growth restriction.
• Preterm labour.
• Postpartum haemorrhage.
• Malpresentation (rare).
• Obstructed labour (rare).

Large submucosal and retroplacental fibroids have greatest risk of complications⁴

Prognosis

The outcome is very good for the majority of patients with fibroids and ovarian masses during pregnancy.

• Where intervention for fibroids is needed, outlook is usually good, especially for elective surgery.¹⁸
• Prognosis in cases of ovarian malignancy is related to tumour grade and stage, but one series shows 70% maternal survival and relatively good fetal outcomes:⁶
  • Earlier diagnosis gave a better prognosis.
  • A worse prognosis was associated with presence of ascites.

Document references

1. Giuntoli RL 2nd, Vang RS, Bristow RE; Evaluation and management of adnexal masses during pregnancy. Clin Obstet Gynecol. 2006 Sep;49(3):492-505. [abstract]
2. Leiserowitz GS, Xing G, Cress R, et al; Adnexal masses in pregnancy: how often are they malignant? Gynecol Oncol. 2006 May;101(2):315-21. Epub 2005 Nov 28. [abstract]
3. Benson CB, Chow JS, Chang-Lee W, et al; Outcome of pregnancies in women with uterine leiomyomas identified by sonography in the first trimester. J Clin Ultrasound. 2001 Jun;29(5):261-4. [abstract]
4. Ouyang DW, Economy KE, Norwitz ER; Obstetric complications of fibroids. Obstet Gynecol Clin North Am. 2006 Mar;33(1):153-69. [abstract]
5. Neiger R, Sonek JD, Croom CS, et al; Pregnancy-related changes in the size of uterine leiomyomas. J Reprod Med. 2006 Sep;51(9):671-4. [abstract]
6. Zhao XY, Huang HF, Lian LJ, et al; Ovarian cancer in pregnancy: a clinicopathologic analysis of 22 cases and review of the literature. Int J Gynecol Cancer. 2006 Jan-Feb;16(1):8-15. [abstract]
7. Glanc P, Salem S, Farine D; Adnexal masses in the pregnant patient: a diagnostic and management challenge. Ultrasound Q. 2008 Dec;24(4):225-40. [abstract]
8. Leiserowitz GS; Managing ovarian masses during pregnancy. Obstet Gynecol Surv. 2006 Jul;61(7):463-70. [abstract]
9. Sayin NC, Inal HA, Varol FG; Pregnancies complicated by adnexal masses: a case series. Arch Gynecol Obstet. 2008 Dec;278(6):573-7. Epub 2008 Apr 1. [abstract]
10. Bunyavejchevin S, Phupong V; Laparoscopic surgery for presumed benign ovarian tumor during pregnancy. Cochrane Database Syst Rev. 2006 Oct 18;(4):CD005459. [abstract]
11. Marret H, Lhomme C, Lecuru F, et al; Guidelines for the management of ovarian cancer during pregnancy. Eur J Obstet Gynecol Reprod Biol. 2010 Mar;149(1):18-21. Epub 2009 Dec 29. [abstract]
12. Ghaemmaghami F, Hasanzadeh M; Good fetal outcome of pregnancies with gynecologic cancer conditions: cases and literature review. Int J Gynecol Cancer. 2006 Jan-Feb;16 Suppl 1:225-30. [abstract]
13. Purohit R, Sharma JG, Singh S; A case of diffuse uterine leiomyomatosis who had two successful pregnancies after Fertil Steril. 2011 Jun;95(7):2434.e5-6. Epub 2011 May 5. [abstract]
14. Liu WM, Wang PH, Tang WL, et al; Uterine artery ligation for treatment of pregnant women with uterine leiomyomas Fertil Steril. 2006 Aug;86(2):423-8. Epub 2006 Jun 8. [abstract]
15. Schraga ED et al; Ovarian Torsion, Medscape, Feb 2010
16. Lee HJ, Norwitz ER, Shaw J; Contemporary management of fibroids in pregnancy. Rev Obstet Gynecol. 2010 Winter;3(1):20-7. [abstract]
17. King R, Overton C; Management of fibroids should be tailored to the patient. Practitioner. 2011 Mar;255(1738):19-23, 2-3. [abstract]
18. Goldberg J, Pereira L; Pregnancy outcomes following treatment for fibroids: uterine fibroid embolization versus laparoscopic myomectomy. Curr Opin Obstet Gynecol. 2006 Aug;18(4):402-6. [abstract]

Internet and further reading

• Hennessy BT, Coleman RL, Markman M; Ovarian cancer. Lancet. 2009 Oct 17;374(9698):1371-82. Epub 2009 Sep 28. [abstract]
• Taylor D et al; Acute Abdomen and Pregnancy, Medscape, Oct 2009
• Helm CW; Ovarian Cysts, Medscape, Apr 2011

Acknowledgements