Uterine Fibroids

Uterine fibroids are benign (non-cancerous) growths of muscle and fibrous tissue in or on the wall of the uterus. They are very common. A landmark ultrasound study estimated the cumulative occurrence by age 50 at more than 80% in Black women and about 70% in White women, so fibroids are among the most frequent gynaecological findings worldwide (Baird, 2003).

Most fibroids cause no symptoms and need no treatment. They matter for fertility mainly because of where they sit, not simply how big they are. Doctors group them into three types by location: submucosal (bulging into the uterine cavity), intramural (within the muscle wall), and subserosal (on the outer surface).

The exact cause of fibroids is not fully known, but their growth is driven by the hormones oestrogen and progesterone, which is why they tend to develop during the reproductive years and often shrink after menopause. Genetics also play a part: a family history of fibroids raises your own risk.

Other recognised risk factors include increasing age through the reproductive years, early onset of periods, obesity, and not having carried a pregnancy. Fibroids are more common and often diagnosed at a younger age in women of African ancestry. An Indian case series from urban Maharashtra found the highest occurrence between ages 31 and 40, which overlaps closely with the years many couples are trying to conceive (Ngorili, 2022).

Many women with fibroids have no symptoms at all, and the fibroids are found by chance on a scan. When symptoms do occur, the most common is heavy or prolonged menstrual bleeding, which can lead to iron-deficiency anaemia.

Other signs depend on the size and position of the fibroids. Large or numerous fibroids can cause pelvic pressure or a feeling of fullness, frequent urination, constipation, lower back pain, and pain during sex. Submucosal fibroids, which sit just under the lining inside the cavity, are the ones most likely to cause heavy bleeding and to interfere with conception, even when they are small.

Transvaginal ultrasound is the first-line test for fibroids. It is widely available, affordable, and gives a good picture of the number, size, and rough location of fibroids. For fertility, the key question is whether a fibroid touches or distorts the uterine cavity, and that needs a closer look.

Saline infusion sonography (SIS), where a little fluid is placed in the cavity during the scan, and hysteroscopy, where a thin camera looks directly inside the uterus, are the best ways to assess submucosal and cavity-distorting fibroids. NICE recommends outpatient hysteroscopy when submucosal fibroids or polyps are suspected (NICE NG88). MRI is reserved for mapping multiple or large fibroids before surgery.

Standard Diagnostic Tests in India

• Transvaginal ultrasound — First-line, low-cost test that shows the number, size, and approximate location of fibroids.
• Saline infusion sonography (SIS) — Fluid is placed in the cavity during a scan to reveal submucosal and cavity-distorting fibroids that a routine scan can miss.
• Hysteroscopy — A thin camera looks directly inside the uterus to confirm submucosal fibroids and assess the cavity, and can sometimes treat them in the same sitting.
• MRI — Reserved for mapping multiple or large fibroids, and for surgical planning before myomectomy.

Location decides the fertility impact, and submucosal fibroids are the most harmful. By bulging into the cavity, they distort the lining where an embryo would implant and are linked with significantly reduced implantation and pregnancy rates. The good news is that removing them helps: a systematic review found that resecting submucosal fibroids raised the clinical pregnancy rate, with a relative risk of 2.03 compared with leaving them in place (Pritts, 2009).

Subserosal fibroids, sitting on the outer surface, generally do not reduce fertility and usually need no treatment for conception. Intramural fibroids within the muscle wall are the grey area: when they do not distort the cavity, their effect is smaller and debated, which is why management is individualised.

• Submucosal: largest impact: Distorts the lining where the embryo implants and is linked with significantly reduced implantation and pregnancy rates.
• Intramural: variable: When the cavity is not distorted the effect is smaller and debated; large intramural fibroids may still matter.
• Subserosal: little to no impact: Fibroids on the outer surface generally do not reduce fertility and usually need no treatment for conception.
• Removal can help: Resecting submucosal fibroids raised the clinical pregnancy rate (relative risk 2.03) versus leaving them in place.
• Effect on IVF: Non-distorting intramural fibroids modestly lower IVF live birth (relative risk 0.79); subserosal fibroids do not.

Treatment depends on your symptoms, the fibroid type and location, and whether you are trying to conceive. If you want to preserve fertility, the goal is to remove fibroids that affect the cavity while protecting the uterus, so hysterectomy is avoided.

For submucosal fibroids, hysteroscopic resection (myomectomy through the cervix, with no abdominal cut) is the preferred treatment and the one with the clearest fertility benefit. Intramural and subserosal fibroids that genuinely need removal are taken out by myomectomy, done laparoscopically or by open surgery depending on size and number. ASRM advises that myomectomy for cavity-distorting fibroids can improve pregnancy rates and reduce early pregnancy loss (ASRM, 2017). Medical therapies mainly control bleeding and do not improve fertility, so they are used to manage symptoms rather than to help conception.

Before an IVF cycle, your doctor will check whether any fibroid involves the uterine cavity, because that is what matters most for an embryo to implant. Submucosal and cavity-distorting fibroids are usually removed first to give the transfer the best chance.

Subserosal fibroids do not appear to lower IVF success and are generally left alone. Intramural fibroids that do not distort the cavity are the nuanced case: a meta-analysis of more than 6,000 IVF cycles found a modest reduction in live birth (relative risk 0.79) and clinical pregnancy (relative risk 0.85) compared with women without fibroids (Sunkara, 2010). Whether to remove these before IVF is decided case by case, weighing the surgery against the expected gain.