Fibroids (Uterine Leiomyomas) — Definition, Types, Symptoms & Fertility Impact

It depends on the fibroid's location. Submucosal fibroids (inside the uterine cavity) significantly reduce fertility and IVF success rates by 50–70% — they must be removed before any treatment. Intramural fibroids (within the uterine wall) affect fertility if large (>3–4cm) or if they distort the cavity. Subserosal fibroids (on the outer uterine surface) have minimal impact on fertility. Many women with fibroids conceive naturally — the fibroid's location, not its size, determines its fertility impact.

It depends on the fibroid type: Submucosal fibroids (inside cavity) → yes, must be removed hysteroscopically before IVF or IUI — they significantly reduce implantation rates. Intramural fibroids >4cm or distorting the cavity → myomectomy generally recommended before IVF. Intramural fibroids <3cm, not distorting the cavity → evidence for removal is weak; most clinics proceed with IVF without myomectomy. Subserosal fibroids → no surgery needed for fertility. Always have an SIS (saline sonogram) or hysteroscopy to assess whether the cavity is affected before deciding.

Submucosal fibroids are associated with increased miscarriage rates — they alter endometrial blood flow and receptivity in the cavity where the embryo implants. Large intramural fibroids may also increase miscarriage risk by distorting the uterine cavity or compromising endometrial blood supply. Subserosal fibroids are not associated with increased miscarriage. Hysteroscopic removal of submucosal fibroids has been shown to normalise miscarriage rates to the background population rate.

Yes — fibroids are oestrogen-sensitive and can enlarge during the high-oestrogen environment of IVF stimulation (where peak E2 levels reach 2,000–5,000 pg/mL). This is typically temporary and fibroids return to pre-stimulation size after the cycle. For most women with small-moderate fibroids, this does not cause problems. Rarely, rapid expansion of a large fibroid can cause "red degeneration" — sudden painful necrosis of the fibroid — requiring hospital admission. Women with large fibroids (>5cm) being stimulated for IVF should be monitored for this complication.

Myomectomy is surgical removal of fibroids while preserving the uterus. Types: hysteroscopic myomectomy (for submucosal fibroids — day procedure, recovery 1–2 weeks, IVF from next cycle); laparoscopic myomectomy (keyhole for medium fibroids — recovery 2–3 weeks, wait 3–6 months before IVF); open (abdominal) myomectomy (large or multiple fibroids — recovery 4–6 weeks, wait 3–6 months before IVF). The healing time before IVF is required to allow the uterine muscle to scar and strengthen — particularly important for intramural myomectomy where the uterine wall was opened and sutured.