Fibroids and fertility – Dr. Jessica Farren


Fibroids is another common conditions that may influence fertility – it can affect 1 in 3 women. Often they don’t cause any problems at all – but we explain a little more what impact fibroids could have, and how they can be managed, below.

What are fibroids?

Fibroids are knots of muscle that grow from within the wall of the womb. They are not cancerous. Unless treated, they grow over time. Most stay only a few centimetres big, and may only be noticed on ultrasound – but some can be as big as a watermelon! They’re sometimes known as uterine myomas or leiomyomas.

Fibroids develop more frequently in women of African-Caribbean origin, and often run in families. They also occur more often in overweight or obese women because of the increased level of the hormone oestrogen in the body. Women who have had children have a lower risk of developing fibroids, and the risk decreases further the more children you have

Fibroids can sit in very different positions depending on where they start, and how big they grow. For convenience’s sake, they are often divided into three types – 1) submucous (on the inner surface of the womb), 2) intramural (sitting within the wall of the womb) or 3) subserous (on the outside of the womb). Sometimes they are divided into seven types depending on how much of them is protruding into the inside or outside the womb. It is not always possible on an ultrasound scan to be 100% sure where a fibroid sits – and sometimes MRI scans or hysteroscopy (a look inside the womb with a camera) is necessary.

Most women are unaware they have fibroids because they don’t have any symptoms. Symptoms, if present, depend on the size and location of the fibroid(s). Fibroids that sit close to the lining of the womb may increase the surface area of the lining of the womb, and in doing so make your periods very heavy. Some fibroids may be well away from the lining of the womb, but be noticeable because of their size – causing you lower abdominal or back pain because of their weight, or can even be noticeable to others (who may wrongly think you’ve just put on weight)..

Fibroids and fertility

It is important to remember that the majority of women with fibroids get pregnant and have babies without any problems at all. A lot of these women don’t even know that have fibroids until their first scan – and, if they’re not causing problems, then there’s no real reason to look for them before trying to conceive.

Occasionally they may contribute to subfertility. This again depends on both their size and location. Some fibroids may obstruct the passage of eggs through the fallopian tubes. It is also theorised that fibroids distorting the lining of the womb may negatively impact implantation.

There is some evidence that fibroids slightly reduce the success rates of IVF. Some fibroids may physically make access to the womb or ovaries during IVF more difficult – and removal may be suggested to facilitate treatment. If you do see a fertility specialist they will advise you whether the fibroids would be best removed surgically, or (more often) left well alone. Surgery to remove fibroids from the womb is called a ‘myomectomy’; this can occasionally be performed by keyhole procedure, but may need a larger cut. Sometimes if the fibroids sit very much in the lining of the womb, the best approach is through the cervix (known as transcervical resection – which doesn’t involve any cuts to the tummy at all). Surgery does have risks – and it is important to weigh these up against any possible fertility benefit.

Fibroids and pregnancy

The jury is out as to whether fibroids may be associated with an increased risk of miscarriage. Again, it is likely to depend a lot on where they are in the womb. It seems likely that if a pregnancy is unluckily finds itself trying to implant on a fibroids within the lining of the womb, it might be more likely to miscarry in the early days. Large fibroids, by their weight putting pressure on the cervix, may increase the risk of later miscarriage or premature birth – but overall this remains uncommon.

Fibroids will often grow during pregnancy. Sometimes they outgrow their blood supply. When they are starved of a blood supply, they can degenerate, and this can be very painful, sometimes requiring hospital admission.

Occasionally, fibroids sitting low in the womb may obstruct the birth canal and mean a Caesarean section is necessary. If significant fibroids are detected at your routine 20 week scan, you will often be referred for further scans to monitor their size and position (and also to measure the size of your baby, as measuring your bump with a tape measure – as is routine practice – may be inaccurate when large fibroids make your bump bigger).

Finally, if before the pregnancy you had surgery to remove a fibroid, and, in doing so, a large area of the womb needed to be repaired, then you may be recommended to deliver by Caesarean section.

Other implications of fibroids

As mentioned above, fibroids can be troublesome by making your periods heavier, or just by being big and heavy – which may cause lower abdominal or back pain, or press on the bladder and cause a you to need to go to the loo more often.

Other than surgery mentioned above, there are lots of other methods to treat fibroids – though these are generally not recommended in women wishing to conceive. They involve using heat treatment, or cutting off the blood supply to them, in order to persuade the fibroids to shrink. Sometimes women may opt for a hysterectomy (to have the womb removed) once they have completed their families. If you want to investigate these options further, you should ask your GP to refer you to a specialist centre.