Adenomyosis and Fertility: Does It Stop You Getting Pregnant?

Adenomyosis and Fertility: What the Evidence Shows

Adenomyosis occurs when tissue similar to the endometrium (uterine lining) grows into the muscular wall of the uterus (myometrium). It is estimated to affect 20–35% of women of reproductive age — though it is significantly underdiagnosed because it was historically only confirmed at hysterectomy. It is now increasingly diagnosed by transvaginal ultrasound and MRI.

How Adenomyosis Impairs Fertility

Adenomyosis affects fertility through multiple mechanisms:

1. Impaired uterine contractility: Adenomyotic foci within the myometrium disrupt the normal coordinated uterine contractions that are essential for sperm transport and embryo implantation.

2. Endometrial dysfunction: Adenomyosis causes generalised progesterone resistance in the endometrium — the uterine lining does not respond normally to progesterone during the luteal phase. This impairs the transition from proliferative to secretory endometrium that is required for implantation.

3. Altered immunological environment: The inflammatory cytokines, altered NK cell populations, and aberrant gene expression found in adenomyotic uteri create an environment that is less receptive to embryo implantation.

4. Structural disruption: Severe or diffuse adenomyosis distorts the uterine cavity, further impairing implantation.

How Common Is Adenomyosis in Infertile Women?

Studies using modern ultrasound criteria find adenomyosis in 15–20% of infertile women — significantly higher than the general population. Among women with recurrent implantation failure, prevalence reaches 30–40%.

Diagnosing Adenomyosis

Transvaginal ultrasound (TVUS): First-line investigation. Features:

• Asymmetric myometrial thickening
• Heterogeneous myometrial echotexture
• Fan-shaped shadowing (myometrial cysts)
• Subendometrial echogenic lines and buds
• Poorly defined endometrial-myometrial junction

TVUS sensitivity for adenomyosis: approximately 72–82% (operator-dependent).

MRI: Gold standard non-invasive investigation. Criteria: junctional zone (JZ) thickness ≥12mm on T2-weighted imaging is the most validated criterion. MRI is particularly valuable for extensive or deep adenomyosis and pre-surgical planning.

Histology: Definitive diagnosis requires tissue — either from biopsy or hysterectomy specimen. Endometrial biopsy has low sensitivity for adenomyosis (not recommended for diagnosis).

Focal vs Diffuse Adenomyosis

Focal adenomyosis (adenomyoma): A localised nodule of adenomyosis within the myometrium. Similar to a fibroid in appearance. Can be excised surgically (adenomyomectomy) — though with greater technical difficulty and uterine scar risk than standard myomectomy.

Diffuse adenomyosis: Widespread throughout the myometrium. Much more difficult to treat surgically. Medical suppression (GnRH agonist, dienogest, Mirena IUD) can reduce bulk and symptoms. No surgical cure short of hysterectomy.

Adenomyosis and IVF: Does It Reduce Success?

Yes — adenomyosis reduces IVF outcomes. Multiple meta-analyses show:

• Clinical pregnancy rate approximately 28% lower in women with adenomyosis vs controls
• Live birth rate approximately 30% lower
• Miscarriage rate approximately 2× higher

These effects are more pronounced in diffuse adenomyosis than focal.

Should Adenomyosis Be Treated Before IVF?

No definitive RCT evidence supports specific pre-IVF treatment for adenomyosis — this is an active area of research. Current evidence-based options:

GnRH agonist pre-treatment (most common approach): A GnRH agonist (leuprorelin, goserelin) for 2–3 months before IVF suppresses adenomyotic lesions, reduces uterine volume, and may improve endometrial receptivity. Several retrospective studies show improved IVF outcomes after GnRH agonist pre-treatment in adenomyosis. This delays starting IVF but is widely used in specialist centres.

Dienogest (progestin suppression): Long-term progestin treatment reduces adenomyosis bulk and inflammation. Not used immediately before IVF (suppresses ovarian function) but may be used between cycles.

Levonorgestrel IUD (Mirena): Highly effective for adenomyosis-related bleeding and pain — reduces lesion size over 12–24 months. Removed before IVF. Some retrospective data suggests improved outcomes after Mirena pre-treatment.

Adenomyomectomy: Excision of focal adenomyoma where possible. Limited by the diffuse nature of most adenomyosis and the risk of uterine scar. Not recommended as routine pre-IVF treatment.

Getting Pregnant With Adenomyosis

Many women with adenomyosis do conceive — naturally and with IVF. Key practical points:

• Seek evaluation if you have symptoms (severe dysmenorrhoea, heavy periods, pelvic pressure) and are trying to conceive — adenomyosis diagnosis changes management
• If diagnosed with adenomyosis before IVF, discuss GnRH agonist pre-treatment with your specialist
• FET (frozen embryo transfer) in a natural cycle may have modestly better outcomes than fresh transfer in adenomyosis — the uterus is not under the additional hormonal stress of stimulation
• After successful treatment, pregnancy monitoring for complications (preterm birth rate and caesarean section rate are elevated in adenomyosis pregnancies)

Reference: ESHRE Working Group — Adenomyosis and Reproduction, 2023. ASRM — Adenomyosis: Impact on Fertility and ART Outcomes, 2022.