Endometriosis and fertility

Of all the questions endometriosis raises, fertility is among the most charged. For many women, the fear of not being able to have children arrives with the diagnosis itself, sometimes before a doctor has said a word about it. The reality is gentler, and more nuanced, than the fear. A diagnosis of endometriosis is not a verdict on motherhood. Many women with the disease conceive, naturally or with help, and carry healthy pregnancies.

This article explains how endometriosis can affect fertility, what can be done, and what is known about pregnancy itself. It is written to inform, and it does not replace a consultation with a physician.

A common difficulty, but not a universal one

Not every woman with endometriosis has trouble conceiving. A substantial share do: estimates commonly fall between a third and a half. Seen from the other direction, endometriosis is found in something like a quarter to a half of women investigated for infertility, which is one reason the disease is so often discovered during a fertility workup. For some women, difficulty conceiving is the first and only sign, with no pain to announce it.

It is worth holding both halves of this picture at once. The disease can weigh on fertility, and most women who have it will still become mothers if they wish to.

Why endometriosis can affect fertility

There is no single reason. Endometriosis can interfere at almost every stage of reproduction, and which mechanisms are at work differs from one woman to the next.

The inflammation the disease produces in the pelvis alters the fluid that bathes the ovaries and tubes, and this environment can disturb the meeting of egg and sperm and affect the quality of the eggs and the early embryo.

Anatomy plays its part. Adhesions can bind and distort the fallopian tubes and ovaries; cysts on the ovary, called endometriomas, can lower the ovarian reserve, the stock of eggs a woman carries, an effect more pronounced in severe or bilateral disease.

Ovulation can be disturbed, and the lining of the uterus can become less receptive, making implantation harder. Indirectly, pain during sex can reduce the frequency of intercourse, and with it the chances of conceiving. In most cases several of these factors act together rather than one alone.

What can be done

A great deal can be done, and the right path depends on the woman, her age, the form of her disease, and her wishes.

Many women conceive without any assistance. When conception does not come on its own, assisted reproduction offers a well-established route: stimulation of ovulation, intrauterine insemination, and in vitro fertilisation. The evidence here is reassuring. Recent analyses find that women with endometriosis who undergo IVF achieve live-birth and pregnancy rates comparable to women with other causes of infertility, even if the rate of implantation can be somewhat lower.

Surgery has a role in selected cases, weighed with care, since operating on the ovaries can itself reduce the egg reserve. Partly for this reason, and where ovarian reserve is a concern or surgery is planned, freezing eggs ahead of time, known as fertility preservation, is sometimes proposed, so that the possibility of a later pregnancy is protected.

Because the disease can progress over time, and because ovarian reserve declines with age in every woman, some specialists suggest not putting off the question of pregnancy for too long where motherhood is wanted. This is information to weigh with a doctor, in one's own time, rather than a reason for haste.

Pregnancy itself: what the research shows

Conceiving is one chapter; the pregnancy that follows is another, and here too endometriosis leaves a mark, though a more modest one than is sometimes feared.

A growing body of research links the disease to a somewhat higher risk of certain complications: early miscarriage, premature birth, raised blood pressure and pre-eclampsia, a placenta lying low in the uterus (placenta previa), and delivery by caesarean. The miscarriage link, long debated, was put on firmer ground by a French study at the Cochin hospital in Paris, which found miscarriage in around 29 percent of pregnancies among women with endometriosis, against roughly 19 percent in women without it. Several later analyses have pointed the same way.

Two things temper this. The increased risks are concentrated in the severe and deep forms of the disease, and in the cases where adenomyosis is present as well; women with superficial or ovarian disease appear to carry much less additional risk. And these are relative increases on what remains, in absolute terms, a modest base. The great majority of women with endometriosis who become pregnant go on to have healthy pregnancies and healthy babies. What matters most is being followed by a team that knows the diagnosis and can watch for the few complications that deserve attention.

Pregnancy is not a cure

It is sometimes said that pregnancy heals endometriosis. It often quiets the symptoms, as the lesions are put to rest by the hormonal changes of those months, but it does not cure the disease, and symptoms commonly return afterwards.

What to take from this

A diagnosis of endometriosis asks a woman to hold two truths together: that the disease can make conceiving harder and a pregnancy more closely watched, and that motherhood remains well within reach for most. Knowing early is what tilts the odds in her favour. It opens the way to monitoring, to preserving fertility where that makes sense, and to planning a pregnancy with the right support in place.

Geneviève is a diagnosis program for endometriosis and complex gynaecological conditions, built around a single belief: that every woman deserves a precise, thorough answer, delivered with care.

This article is for information and does not replace a consultation with a physician.