Fibroids, Fertility and Pregnancy

What are uterine fibroids?

Fibroids are non-cancerous tumours of the uterus (womb). Fibroids grow out of the cells that make up your uterus. Uterine fibroids are also sometimes described as leiomyoma or myoma of the uterus.

Fibroids can be as small as a pea or as large as a football. Having uterine fibroids does not increase your risk of cancer. They are almost always benign, no matter how large they get.

Fibroids have different names depending on where they grow:

    The most common type of fibroids develop within the muscle wall of your uterus. These are called intramural fibroids. They can make your uterus appear bigger, and can cause heavy or painful periods and fertility problems.

    Fibroids that grow just under the inner lining of your uterus (endometrium) are called submucosal fibroids. They can alter the lining of your uterus and reduce your fertility. Submucosal fibroids can also cause heavy or painful periods.

    Fibroids that grow on the outside of your uterus are called subserosal fibroids. They may bulge or extend into your pelvis, putting pressure on your bladder or bowel.

    Cervical fibroids develop in the neck of your uterus (cervix).

Submucosal and subserosal fibroids may grow from a stalk (pedunculated). They may stick out into your uterus or into your pelvic area. If a fibroid or cluster of fibroids is particularly large or is growing on the outside of the uterine wall, it can push the uterus aside or force it to grow abnormally.

What causes uterine fibroids?

No one knows exactly what causes uterine fibroids. But the hormones that regulate your periods, particularly oestrogen, are known to play a part. Fibroids increase in size slowly over the years. But when oestrogen levels in your body rise, their rate of growth increases.

Can fibroids make it difficult to conceive?

It's rare for fibroids to seriously hamper your efforts to get pregnant, and much depends on what type of fibroid you have. Less than three per cent of women who seek help for infertility have fibroids without any other obvious cause for their fertility problem.

Submucosal fibroids are the most likely type to affect baby-making. These fibroids can distort the uterus, and interfere with embryo implantation, whether by natural conception or IVF. This could be caused by reduced blood flow, making the lining of the uterus unfriendly to a fertilised egg.

If you know you have a fibroid and you're having problems conceiving, see your doctor for referral to a fertility specialist. Your specialist will first find out whether there are any other possible causes of your fertility problem and treat them.

If no other cause can be found, your doctor may advise you to continue to try to conceive naturally for up to two years, unless you are over 34. In this case, you are better off seeking treatment sooner rather than later, because fertility declines with age.

Surgery to remove fibroids may improve your chances of pregnancy. Surgery is more helpful if you have submucosal fibroids than if you have intramural fibroids.

How common are fibroids?

Fibroids are very common in women of child-bearing age, particularly women of African or African-Caribbean descent. About 60 per cent of women of African or African-Caribbean descent have fibroids by the age of 35, compared with 40 per cent of caucasian women.

You are more likely to have fibroids if you are overweight, because your oestrogen levels increase as your body fat increases.

If you become pregnant, the levels of oestrogen in your body, especially in early pregnancy, can make existing fibroids grow faster. But pregnancy can also protect you from getting them in the first place, or from developing more. In fact, the more pregnancies you have, the less likely you are to have fibroids.

Taking the pill for many years or having a long-acting contraceptive injection also reduces your chance of developing fibroids.

How will I know if I have fibroids?

If you're under 30 you may not know, because you're unlikely to have symptoms. Only a third of women with fibroids get symptoms, which may include:

•  Painful periods.

• Prolonged and heavy menstrual bleeding, which may leave you low in iron (iron-deficiency anaemia). Try to eat foods that are rich in iron, such as lean red meat, chicken legs, pulses and green vegetables.

• Weeing more often, or pain on weeing, which is caused by pressure on your bladder.

• A feeling of fullness or pressure, which may cause constipation if the pressure is on your back passage.

• Pain in your back, belly or pelvis, depending on how big and where the fibroid is.

• Trouble conceiving.

Sadly, your chances of having a miscarriage are increased if you have fibroids.

How will my doctor test for fibroids?

Fibroids may be something your doctor looks for if you've arranged a check-up because you're not conceiving. She may pick up that you have a lumpy or irregularly shaped uterus. Or if you've gone to your GP with painful symptoms, she may arrange for you to have an ultrasound scan. A scan can tell fibroids from cysts, tumours and other growths.

Your GP may also refer you for a hysteroscopy. This is a procedure that allows a doctor to check the inside of your uterus through a viewing tube, inserted via your vagina. Submucosal fibroids can be seen during a hysteroscopy.

You may be offered a surgical investigation called a laparoscopy, to look for subserosal fibroids. You will have a general anaesthetic, so you will be asleep for the procedure. Your doctor will make a small cut just below your navel. Through the cut, she'll insert a tube carrying a tiny camera to view inside your pelvic area.

Can fibroids be treated?

Most fibroids don't need to be treated unless the symptoms are causing you problems. Even then, in many cases, your doctor may talk to you first about ways to ease your symptoms.

You shouldn't need to have surgery for fibroids before getting pregnant unless you are having troublesome symptoms, such as painful periods and heavy bleeding.

If you do need treatment, there are a number of options to consider. Some are more widely available than others and some are more successful than others. Your doctor will be able to tell you which treatments are best for you, and discuss how each procedure may affect your fertility.

Your doctor should also go through the risk and benefits of each procedure. Some may have higher risks of side-effects, such as bleeding, infection and scarring, than others. Treatments include:

Drugs that balance your hormones

Gonadotrophin-releasing hormone analogues (GnRHas) reduce the levels of oestrogen in your body. They shrink or temporarily halt fibroid growth. GnRHas may be taken as a nasal spray, a monthly injection or as an implant under your skin.

A course of treatment usually lasts only three months to six months. That's because the drugs often cause menopause-like symptoms, such as hot flushes, vaginal dryness and decreased bone density. As soon as the treatment stops, you can start trying for a baby.

Fibroids often continue growing once hormone therapy stops, so they can be useful for shrinking fibroids before surgery. Hormone replacement therapy (HRT) may be given alongside to ease the side-effects.

An operation to remove the fibroid This is carried out via a surgical operation called a myomectomy. For small fibroids, it may be carried out by keyhole surgery using a laparascope or hysteroscope. Which type of keyhole surgery is used will depend on whether the fibroid is on the outer or inner lining of the uterus. Open surgery is used for larger fibroids and involves a longer recovery time than keyhole surgery.

Myomectomy is not suitable for all women, as it depends on the size, number and location of the fibroids.

This operation is offered to women who still plan to have children, because it leaves the uterus intact. However, about one in four women find their fibroids grow back again after about three years.

Removing the lining of the uterus

This is a non-surgical procedure called endometrial resection or endometrial ablation. It is suitable for the treatment of submucosal fibroids, which have grown in the inner layer of the uterus. A surgeon will remove the endometrial tissue from the inner lining of the uterus, where the fibroid is growing. The endometrial tissue will grow back, and you can start trying for a baby once the treatment is completed.

Cutting off the fibroid's blood supply

A radiologist carries out this procedure, which is called uterine artery embolisation (UAE). It is best done using a magnetic resonance imaging (MRI) scan. This type of scan shows in detail where the fibroid is and the blood vessels that feed it.

The radiologist injects a plastic plug into the vessel to cut off the blood supply to the fibroid. The fibroid then shrinks, often to more than half its size, and may disappear altogether. One in 10 women need a repeat treatment at one year, rising to one in four within five years. If you want to have children afterwards, myomectomy may be a better option for you. That's because more research is needed to be sure that UAE is suitable for women wishing to protect their fertility .

Destroying tissues of the fibroid

This is a procedure called myolysis and can be carried out with keyhole surgery using a laparoscope or hysteroscope. Which method your surgeon uses depends on whether the fibroid is inside or outside the uterus.

Ultrasound or magnetic resonance imaging (MRI) scans are used during the procedure to locate the fibroid. A surgeon inserts needle probes or an electric current into the fibroid and cauterises both the fibroid and the blood vessels around it.

Can Fibroids Cause Fertility Problems?

Fibroids that change the shape of the uterine cavity (submucous) or are within the cavity (intracavitary) decrease fertility by about 70% and removal of these fibroids increases fertility by 70%. Other types of fibroids, those that are within the wall (intramural) but do not change the shape of the cavity, or those that bulge outside the wall (subserosal) do not decrease fertility, and removal of these types of fibroids does not increase fertility. Regular ultrasound is not the best way to determine exactly where fibroids are. For this information, MRI is best, but most expensive. Hysteroscopy (looking in the cavity with a small telescope) and saline-infusion sonography (ultrasound after sterile water is placed into the uterine cavity) are also very good.

Can Fibroids Cause Miscarriage?

Fibroids that bulge into the uterine cavity (submucous) or are within the cavity (intracavitary) may sometimes cause miscarriages. The fertilized egg comes down the fallopian tube and takes hold in the lining of the uterus. If a submucosal fibroid happens to be nearby, it can thin out the lining and decreases the blood supply to the developing embryo. The fibroid may also cause some inflammation in the lining directly above it. The fetus cannot develop properly, and miscarriage may result. However, with the next pregnancy, it is possible that the egg will settle in another location, and pregnancy may proceed without problems. However, if you do have a miscarriage and a fibroid is found bulging into the uterine cavity, it is advisable to have it removed.

 

Does Pregnancy Make Fibroids Grow?

Pregnancy has an unpredictable effect on fibroids, but most fibroids do not increase in size during pregnancy. The effect of pregnancy on fibroid growth probably depends on individual differences in the genetic changes in each fibroid and the type and amount of growth factors that are present in the blood. An ultrasound study of pregnant women with fibroids found that 69% of the women had no increase in the size of fibroids throughout the pregnancy. In the 31% of women who had an increase in size, it usually happened before the third month. Almost always, fibroids shrink after delivery.

Can Fibroids Cause Problems During Pregnancy?

Although many women will have fibroids during their lifetime, the fibroids most often occur in women in their late thirties and forties, a time in life many women have already completed their families. Only 2% of pregnant women are found to have fibroids when examined with ultrasound. Also, the vast majority of women who are pregnant and do have fibroids encounter no problems. They go on to have full-term, healthy babies without difficulty. Most studies show no differences in the risk of premature delivery, fetal growth problems, fetal abnormalities, placental problems, or heavy bleeding after delivery. The need for caesarean section, however, is more common among women who have fibroids (see below).

During pregnancy, the placenta makes large amounts of female hormones which may rarely cause fibroids already present to grow. Very rarely, if the fibroids grow too quickly the blood vessels supplying them may not be able to get enough oxygen to the tissue and degeneration of the fibroid cells can then occur. This process of degeneration can cause pain, but usually resolves in a short time without treatment and without harm to the baby. Some women may have mild contractions during this time, but it is extremely rare for premature labor to actually begin. However, it is crucial that a pregnant woman with fibroids see her physician if she experiences pain or contractions. Bed rest, heat, and pain medication will usually be prescribed, and medications to inhibit premature labor may sometimes be needed.

Can Fibroids Hurt the Developing Baby?

Fibroids almost never cause injury to a baby. Review of the entire world’s medical literature for the past 25 years discovered only four babies affected by a fibroid.

Do Fibroids Mean You Need a Caesarean Section?

Rarely, a fibroid may grow near the cervix during pregnancy. If it is large enough, it may prevent the baby from coming through the birth canal. This is not dangerous and can often be diagnosed by a sonogram before labor begins. Sometimes this problem is discovered during labor because the baby does not come down the birth canal. A caesarean section is then performed. However, most women with fibroids deliver their babies without any problems.