Uterine fibroids: impact on fertility and pregnancy

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Extract from the article: Les fibromes utérins sont des tumeurs bénignes (non cancéreuses) situées sur la paroi de l’utérus, de façon isolée ou en groupe. La majorité d’entre eux ne limitent pas les chances de tomber enceinte. Mais, dans certains cas, ces tumeurs bénignes peu

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Uterine fibroids are benign (non-cancerous) tumours located on the wall of the uterus, either singly or in groups. The majority of them do not limit the chances of becoming pregnant. But in some cases, these benign tumours can have an impact on fertility or even during pregnancy.

Benign tumours such as uterine fibroids do not systematically pose problems before or during pregnancy. But in some cases, depending on their location and sometimes their size, they can have an impact on fertility or on the progress of the pregnancy. To understand this, we need to distinguish between several types of fibroid depending on their position.

Intramural fibroids (types 3 and 4)

This is the most common type of fibroid. It develops in the central part of the uterine muscle, known as the myometrium. It is rarely a barrier to pregnancy. However, in rare cases, the fibroid is so large that it can cause problems during implantation of the egg in the uterus (by deforming the cavity of the uterus). Surgery may then be recommended. Studies have also shown that fibroids larger than 4 cm, even if they do not deform the uterine cavity, can prevent the onset of pregnancy by disrupting the contractility of the myometrium.

During pregnancy, due to the increase in oestrogen levels, the intramural fibroid tends to enlarge. If it grows large and rapidly, it can become necrotic and cause severe inflammation of the uterine muscle, with pain in the lower abdomen and possibly premature uterine contractions, which in extreme cases can lead to premature delivery.

Subserous fibroids (types 5 and 6)

This type of fibroid is located on the outer surface of the uterus and is rarely symptomatic. There are therefore few indications for treating it.Since the subserous fibroid has no impact on the uterine muscle or cavity, it has no influence on fertility.

The only possible problem during pregnancy is if the fibroid grows. In this case, it may cause necrosis and pain, with a possible premature uterine contraction during pregnancy. The most external fibroids, attached to the uterus by a tiny pedicle (pedunculated fibroids), can also twist on their axis as they grow and cause very painful necrosis (during and outside pregnancy).

Submucosal or endocavitary fibroids (type 0, 1 or 2)

These are the rarest fibroids, at least in isolated form. They form under the mucous membrane of the uterine cavity (wall lining the inside of the uterus). Whatever their size, they have a detrimental effect on fertility, as they prevent the egg from implanting in the uterine cavity.Fibroids also cause heavy periods, which can lead to anaemia.It is important to correct this anaemia before pregnancy, because once pregnant, the mother-to-be is more prone to iron deficiency.

For all these reasons, this type of fibroid is generally surgically removed in women who wish to become pregnant.

Abel OZIH

Article validated by Dr Dédé Bénédicta Améwoui, Obstetrician and Gynaecologist (Lomé)