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Adenomyosis explained and its impact on fertility

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Adenomyosis is a common disorder that affects roughly 20-35% of women. It causes severe menstrual pain and heavy periods, similar to endometriosis. In fact, adenomyosis is often referred to as the cousin of endometriosis.

Adenomyosis and endometriosis can both exist at the same time in a woman. Scientists have debated whether adenomyosis is just one special type of endometriosis. So far, the definition of adenomyosis is essentially “endometriosis inside the uterine muscle”.

What is adenomyosis?

Adenomyosis is a condition of the uterus, where the glands and supporting structures of the uterine lining (endometrium) grow within the thick muscular wall of the uterus.

Over time, these endometrium islands can grow in size and irritate the muscle fibres during the course of a menstrual cycle. In response, the muscle fibres also enlarge, ultimately leading to a larger than normal uterus. Occasionally, a benign tumour called an adenomyoma can form, which may require surgery.

The endometrium islands respond to a natural menstrual cycle in exactly the same way as the normal endometrium tissue that lines your uterus. Just before the period and in the early days of menstruation, the endometrium islands swell and contract more strongly than usual, which irritate surrounding muscle fibres and lead to bad pelvic pain.

What causes adenomyosis?

We still don’t know the exact cause of adenomyosis, but some risk factors have been associated with this condition. For example, past surgical procedures inside the uterus such as pregnancy termination or caesarean deliveries may have pushed the uterine lining cells into the muscular layer. Other risk factors include short menstrual cycles (< or = 24 days), obesity, and early time of first period.

How is adenomyosis diagnosed?

Traditionally, diagnosis was through invasive methods that involved taking some tissue for examination under the microscope. But today, we have high quality scans by ultrasound or MRI instead, which are non-invasive and yield diagnostic results that are 80-90% accurate. Comparing between these two methods, MRI generally has a greater specificity but the combination of MRI and transvaginal ultrasonography have the highest level of diagnostic accuracy.

If you experience heavy period bleeding and pain, consider making an appointment with a doctor. He/she will likely conduct both an internal examination and a pelvic scan.

Does adenomyosis affect fertility?

Earlier studies did not find an association between adenomyosis and infertility. But with better diagnostic tools, growing research now suggests that there is an impact on both spontaneous and assisted pregnancy when adenomyosis is present. A recent meta-analysis concluded that in women undergoing IVF, the rates of implantation, clinical pregnancy, live births were significantly lower in those with adenomyosis, whilst the risk of miscarriage was higher.

How does adenomyosis contribute to infertility is still an active area of research. Some possible events related to adenomyosis include lower endometrial receptivity for implantation, altered estrogen/progesterone receptor functions, and inflammatory responses that are toxic for an embryo.

In contrast to endometriosis, adenomyosis has not yet been shown to affect the egg quality or function itself. It is possible that adenomyosis contributes to infertility only through changing the uterine environment, but more research is needed.

What are treatment options for adenomyosis?

Treatment of adenomyosis can be medical or surgical depending on the severity of the condition and your wish for children. Your doctor may prescribe anti-inflammatory medications that help slow the blood flow and/or hormonal contraception that help with bleeding and pain.

Currently, the best studied medical treatment is insertion of a Mirena intrauterine device (IUD). It is reversible and reported to have 70% patient satisfaction rate.

However, if such medical methods fail or you do not wish to maintain fertility, surgical removal of the whole or part of the uterus is an alternative treatment. This eliminates the disease by removing the uterine musculature altogether, which offers freedom from bleeding and recurrence, but is usually incompatible with future pregnancies. Although it is not impossible to remove the adenomyosis while sparing fertility, a high degree of surgical skill is required.

If you have adenomyosis and would like to have a baby, it is best to seek advice from a fertility specialist. You may need treatment that can aid spontaneous pregnancy or be recommended assisted reproductive technologies such as IVF. Once pregnant, women with adenomyosis are more prone to premature delivery and placental problems, which need to be closely monitored throughout the pregnancy.

For more personalised information regarding adenomyosis, you can contact Melbourne-based fertility specialist and gynaecologist, Dr Alex Polyakov here.