Table 2

Surgical characteristics and findings at pathology of women who underwent unilateral or bilateral oophorectomy

Characteristic	Unilateral oophorectomy (n=570)		Bilateral oophorectomy (n=1653)
Characteristic	n	%	n	%
Prior gynaecological conditions
Ovarian cysts
No	199	34.9	922	55.8
Yes	371	65.1	731	44.2
Fallopian tube cysts
No	522	91.6	1527	92.4
Yes	48	8.4	126	7.6
Uterine fibroids
No	420	73.7	674	40.8
Yes	150	26.3	979	59.2
Prior gynaecological procedures
Prior tubal ligation or resection
No	408	71.6	1027	62.1
Yes	162	28.4	626	37.9
Prior ovarian resection
No	525	92.1	1558	94.3
Yes	45	7.9	95	5.7
Prior unilateral oophorectomy
No	570	100.0	1503	90.9
Yes	–	–	150	9.1
Oophorectomy
Laterality*
Right	280	49.1	84	5.1
Left	290	50.9	66	4.0
Both	–	–	1503	90.9
Indication for oophorectomy†
Benign condition	509	89.3	675	40.8
Benign tumour	339	59.5	382	23.1
Cyst or endometriosis	146	25.6	285	17.2
Other‡	24	4.2	8	0.5
No ovarian indication	61	10.7	978	59.2
Pathology of the removed ovaries§
Ovarian cancer	11	1.9	25	1.5
Benign condition	415	72.8	779	47.1
Benign tumour	158	27.7	164	9.9
Cyst or endometriosis¶	219	38.4	575	34.8
Other**	38	6.7	40	2.4
Normal	144	25.3	847	51.2
Pathology unavailable	0	0.0	2	0.1
Hysterectomy
Hysterectomy status
None	305	53.5	24	1.5
Before	42	7.4	157	9.5
Concurrent	223	39.1	1472	89.1
Indication for concurrent hysterectomy††
Cancer	3	0.5	11	0.7
Suspicion of cancer‡‡	86	15.1	311	18.8
Bleeding	124	21.8	834	50.5
Pain	107	18.8	590	35.7
Fibroids or polyps	51	8.9	418	25.3
Prolapse	38	6.7	337	20.4
Endometriosis	23	4.0	201	12.2
Anaemia	9	1.6	63	3.8
Family history of cancer	0	0.0	35	2.1
Menstrual migraine	1	0.2	29	1.8
Premenstrual syndrome	0	0.0	27	1.6
Other§§	9	1.6	83	5.0
Pathology of the removed uterus¶¶
Cancer	4	0.7	40	2.4
Fibroids or polyps	125	21.9	938	56.7
Endometriosis	17	3.0	220	13.3
Adenomyosis	24	4.2	223	13.5
Other***	17	3.0	94	5.7
Normal	67	11.8	330	20.0

*For bilateral oophorectomy, laterality refers to the second unilateral oophorectomy in the 150 women who had a prior unilateral oophorectomy.
†The indication was listed by the gynaecologist in the medical record at the time of oophorectomy. For women with different indications in the two ovaries, we reported the most severe indication (only one indication for each woman, in the order shown).
‡Torsion, tubo-ovarian abscess, ectopic pregnancy, placenta previa, pelvic congestion, pelvic inflammatory disease, chronic abdominal pain, post-hysterectomy vaginal bleeding and other rare indications.
§The pathology results were determined by a pathologist following the surgery. For women with different pathology in the two ovaries, we reported the most severe pathology (only one pathology for each woman, in the order shown). Women with cancer as the indication for oophorectomy were excluded; however, some women with benign ovarian indication or no ovarian indication had ovarian cancer or metastasis to the ovaries discovered at pathology.
¶Among the 219 women with unilateral oophorectomy, 139 had only cysts, 25 had only endometriosis and 55 had both cysts and endometriosis. Among the 575 women with bilateral oophorectomy, 321 had only cysts, 120 had only endometriosis and 134 had both cysts and endometriosis.
**Torsion, ectopic pregnancy, haemorrhage, infarction, fistula, ovarian fibrosis, hyperthecosis, giant cell reaction and other rare pathologies.
††The indication was listed by the gynaecologist in the medical record at the time of hysterectomy. Each woman may have more than one hysterectomy indication recorded.
‡‡Adnexal, pelvic and uterine masses not specified as benign or cancer.
§§Infection or inflammation, uterine cyst, benign tumour, adenomyosis, cervical neoplasia, myohypertrophy, placenta accreta or percreta and other rare indications.
¶¶The pathology results were determined by a pathologist following the surgery. Each woman may have more than one pathology.
***Infection or inflammation, uterine cyst, benign tumour, bicornuate uterus, cervical neoplasia, myohypertrophy, placenta accreta or percreta and other rare pathologies.