aetiology

Last reviewed 10/2022

Aetiolgy is unknown. Many genetic and environmental factors have been shown to influence fibroid formation.

Recognised risk factors for the development of uterine fibroids include:

• race
• higher incidence is seen in black and Asian women than in white women
• genetic
• a considerable genetic influence has been reported especially for early onset disease
• first degree relatives have a 2.5 fold increased risk while the risk increase six fold in early onset cases
• age
• rare before menarche
• risk increases with age during reproductive years
• seldom develop or enlarge after the menopause unless stimulated by exogenous oestrogens
• early menarche – before 11 years
• pregnancy
• lower rates of fibroid is seen in full term pregnancy
• more common in nulliparous women, and in those who have not been pregnant for some time
• hormonal contraception
• reduced risk seen with progestin only injectable contraceptives and oral contraceptives
• obesity
• 2-3 times more common
• dietary
• excessive consumption of beef and ham is associated with an increased risk
• diet consisting of green vegetables has been shown to decrease the risk
• clinical conditions
• hypertension
• diabetes
• occur with increased frequency in conjunction with endometrial hyperplasia and granulosa cell tumours of the ovary
• smoking
• appears to decrease the risk of fibroid formation and growth (1,2,3)

Note:

• pre-existing fibroids may increase in size if the woman uses the oral contraceptive pill and during pregnancy (because of stimulation by oestrogen)
• there is no evidence to confirm that dietary changes after presentation and diagnosis of fibroid will influence patient’s symptoms

Reference:

• (1) Lumsden MA et al. Fibroids: diagnosis and management. BMJ. 2015;351:h4887
• (2) Alexander-Sefre F. Clinical Review: Uterine fibroids. GPonlline 2012  
• (3) Vilos GA et al.The management of uterine leiomyomas. J Obstet Gynaecol Can. 2015;37(2):157-81.