uterine fibroids (leiomyomas)

see also:

• gynaecology

• uterine fibroids are common in women (present in 2-10% of pregnant women although this is likely an under-estimate due to difficulty in Dx, incidence of 40% - 60% by age 35 and 70% - 80% by age 50)
  • during pregnancy:
    • the ability of ultrasound to detect fibroids is even more limited (1.4%–2.7%) primarily due to the difficulty of differentiating fibroids from physiologic thickening of the myometrium
    • increase in size is mainly in the 1st 10 weeks but most do not significantly increase in size during pregnancy
    • a minority will decrease in size during the puerperium
    • 10-30% of women with fibroids will develop complications during pregnancy
  • rare familial cause:
    • hereditary leiomyomatosis and renal cell cancer (HLRCC)

• usually asymptomatic but can cause symptoms due to either:
  • mass effect if very large
    • constipation
    • urinary issues
    • venous compression and risk of DVT
    • childbirth issues
      • premature births - ~ double the risk
      • placental abruption
      • placenta praevia
      • fetal malpresentations eg. breech
      • obstructed labour
      • increased likelihood of LUSCS
      • post partum haemorrhage
      • retained placenta if fibroid was located in the lower uterine segment
  • increased menorrhagia
  • dysmenorrhoea
    • only cause dysmenorrhoea if submucosal or protrude into uterine cavity
  • pain from red degeneration (infarction from insufficient blood supply)
    • particularly likely during 2nd and 3rd TM of pregnancy when fibroids are > 5cm
    • Mx is analgesia - non-steroidal anti-inflammatory drugs (NSAIDs) may be used for a short duration between 20 and 30 weeks but are generally avoided after 30 weeks due to risks to the fetus
  • uterine rupture after myomectomy
• they are also associated with increased risk of:
  • spontaneous miscarriage
  • bleeding in early pregnancy esp. if the placenta implants close to the fibroid
  • cardiovascular events
    • a 2025 study suggests that women with uterine fibroids have an almost doubled risk of cardiovascular events over 10 year study period (risk of developing cardiovascular disease was 81% higher among those women with fibroids compared to those without; 5.4% of women with fibroids had experienced a cardiovascular event compared to 3% of women without fibroids). The risk was much higher in women who had fibroids under age 40yrs - the risk for cardiovascular disease was 251% higher (or more than 3.5 times more likely) in those with fibroids compared to those without fibroids. ¹⁾
• may cause false positive rise in serum CA-125 levels

• simple analgesia
• Mx of menorrhagia such as tranexamic acid, hormonal Rx, etc
• large symptomatic fibroids:
  • uterine artery embolization
  • goserelin
    • generally results in a halving of size over several months
  • myomectomy
    • this should be avoided at LUSCS due to high risk of severe haemorrhage requiring blood transfusion, uterine artery ligation, and/or puerperal hysterectomy
  • hysterectomy