The first thing to say is that many women do not have any symptoms from uterine fibroids during their lives. This is because they are lucky in that the fibroids are small and usually within the wall of the uterus or extending from the surface. Equally, many women do get significant symptoms from uterine fibroids and this probably relates to the site and size of the fibroids which again relates to underlying genetic factors and the sensitivity of the fibroid to oestrogen which affects the oestrogen receptors within fibroids. If the fibroid involves the cavity of the uterus and therefore the lining of the womb, then this will result in heavy periods. These fibroids are called submucous or intracavity fibroids: they extend into the wall of the uterus to a varying degree (less than 50% they are called type I and more than 50% type II). As they get bigger, which they invariably do under the influence of oestrogen, the periods get worse and worse. This, of course, can result in anaemia, debilitation and may lead to the necessity of a blood transfusion. Fibroids which are near the womb lining, called interstitial or intramural fibroids, may also cause heavy periods by increasing the surface area of the cavity of the womb and particularly if their edge is adjacent to the womb lining.
Another constellation of symptoms comes under the heading of compression syndrome. In this condition, the fibroids grow large and cause the uterus to press on adjacent structures. Quite often, the uterus will impress the dome of the bladder and this causes frequency of urination. The fibroids may press on the bowel and give rise to constipation or can impinge on the vagina which can give discomfort during intercourse. If the fibroids press on posterior pelvic nerves, then this may result in sciatica and back pain. Many women with fibroids complain of bloating, whether this relates to the prostaglandins that fibroids secrete or simply the size of the fibroid is not clearly understood, but bloating is a very common problem in patients with enlarged fibroids.
Another problem is distension of the abdomen due to fibroid enlargement which produces a cosmetically unsightly lump simulating a pregnancy. Fibroids may grow to the size of a term pregnancy.
Another factor with fibroids which affects the symptoms is their rate of growth. This is extremely variable and fibroids may grow very rapidly or very slowly and are unpredictable in their behaviour.
During pregnancy the growth of fibroids due to oestrogen stimulation may cause them to outstrip their blood supply and they may die. This produces severe pain lasting weeks in the abdomen and can be a difficult diagnostic problem. Rarely fibroids may spontaneously die, not in the pregnancy situation, and again this is a cause of pelvic pain which can be severe. In the case of fibroids which spontaneously die, eventually the symptoms will regress spontaneously.