January 8, 2024
Adenomyosis is fairly common amongst reproductive-aged women, with estimates between 20-75% of women being affected by or diagnosed with the condition.
One of the major side effects of the condition is the impact it has on women's fertility. While it is recognised and accepted that more research is needed to definitively link adenomyosis and infertility, the current studies and analysis do show a relationship between the presence of the condition and difficulty conceiving a child.
What is Adenomyosis?
Adenomyosis is a condition where the lining of the womb extends abnormally deep into the uterus. The uterine tissue and cells grow deep in the muscular wall of the uterus and thickens it.
The displaced tissue will break down and bleed during a menstruation cycle, and this can cause discomfort and painful periods. It may also lead to abnormally heavy periods and bloating.
What Causes Adenomyosis?
We don’t know for sure. We know there is some link to endometriosis, a condition where cells from the lining of the womb are found outside the uterus. Adenomyosis often co-exists with fibroids, adenomyosis is routinely misdiagnosed as fibroids.
Despite this, some experts have developed a number of theories for what might cause adenomyosis:
- Tissue growth - some experts believe that endometrial cells, from the lining of the uterus, invade the muscle of the uterine walls.
- During development - some experts believe endometrial tissues ends up in the uterine muscle when the fetus is first formed.
- Childbirth - other experts believe a link exists between adenomyosis and childbirth, where inflammation of the uterine lining during postpartum periods can break the normal boundary of the cells that line the uterus.
- Stem cells - a recent theory proposes that bone marrow stem cells might invade the uterine muscle, causing adenomyosis.
How Does Adenomyosis Affect Fertility?
The link between adenomyosis and fertility is still unclear, and much more research is needed to definitively link the two. However, from the research available, it is clear that a link does exist, although the cause and reason have yet to be truly understood.
A 2017 meta-analysis of 11 articles evaluated the clinical outcomes of IVF treatments in women with (519 patients) and without (1,535 patients) an adenomyosis diagnosis.
The authors discovered that the presence of adenomyosis can negatively impact a woman’s chances of falling pregnant, both through planned and spontaneous methods. They also found the risk of miscarriage was higher in women with adenomyosis.
Unlike endometriosis, adenomyosis does not appear to affect the egg quality, which leads some experts to believe that the condition causes enough changes to the uterine environment to negatively influence fertility and pregnancy rates.
Some studies have shown that the presence of adenomyosis can impact the endometrium’s receptivity and uterotubal transport.
In layman’s terms, adenomyosis can cause issues with the endometrium’s ability to function properly (this is required for the embryo to successfully implant on the uterine wall) and may make it difficult for semen to travel due to structural changes to the uterine wall caused by the condition.
One of the real challenges in confirming a link between adenomyosis and infertility is the fact that adenomyosis is seldom diagnosed in isolation, and is often found alongside other conditions such as fibroids. It is also not unusual for adenomyosis and endometriosis to be misdiagnosed or to coexist, making it difficult for researchers to attribute infertility to a given condition properly.
Despite this, one study in Frontiers in Endocrinology looked at the success rate of IVF in two groups of women: one with adenomyosis (65 patients) and one with endometriosis (260) to see which condition had a greater impact on fertility.
The researchers found that, when controlled for age, adenomyosis had much worse outcomes on fertility compared to endometriosis:
- Declined implantation rate of 31.91% vs 46.74%
- Clinical pregnancy rate of 47.06% vs 64.42%
- Live birth rate of 31.37% vs 54.81%, and
- Significantly increased spontaneous abortion rate of 33.33% vs 13.43%
A 2018 study into the effects of adenomyosis on obstetric outcomes reported that "studies showed that the patients with adenomyosis have an increased risk of some poor obstetrical outcomes, such as miscarriage, preterm birth, premature rupture of membrane, small gestational age, hypertensive disorders and malpresentation."
So, what does this all mean? Despite a recognised lack of research and study, adenomyosis does negatively impact fertility and can lead to unsuccessful pregnancies, both in women trying to conceive naturally and those undergoing IVF.
How Can You Improve Your Fertility With Adenomyosis?
The authors of the previously mentioned meta-analysis concluded that treatment, either surgical (such as uterine artery embolisation) or medically with the use of Gonadotropin hormone-releasing hormone (also known as GnRH, which stimulates the production of estrogen and progesterone) improved fertility outcomes.
