10–15%
of reproductive-age women have endometriosis
50%
of women with infertility have endometriosis
ERA
testing may personalise implantation window timing
NAC
N-acetylcysteine reduces endometrioma size in studies
How Endometriosis Affects Fertility
How Endometriosis Affects Fertility
- →Endometriosis is the presence of endometrial-like tissue outside the uterus — most commonly on the ovaries, fallopian tubes, peritoneum, and bowel. It affects 10–15% of women of reproductive age and is present in up to 50% of women with infertility.
- →The primary fertility mechanisms include: distorted pelvic anatomy (adhesions blocking fallopian tubes), impaired folliculogenesis (reduced egg quality in affected ovaries), elevated peritoneal inflammatory cytokines (toxic to sperm and embryos), and altered endometrial receptivity (impaired implantation window).
- →Endometriomas (ovarian cysts filled with old blood, also called 'chocolate cysts') directly damage the ovarian cortex and reduce ovarian reserve. Surgical removal of endometriomas must be weighed carefully — it can further reduce ovarian reserve. Discuss with your specialist before proceeding.
Inflammation & Oocyte Quality
- →Endometriosis is fundamentally an inflammatory condition. Peritoneal fluid in women with endometriosis contains elevated levels of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and reactive oxygen species (ROS) — all of which are directly toxic to oocytes and sperm.
- →Oxidative stress within the follicular microenvironment impairs mitochondrial function in the developing oocyte, increasing the risk of chromosomal errors (aneuploidy) and reducing fertilisation rates. This is why antioxidant supplementation is particularly important in endometriosis.
- →Anti-inflammatory dietary strategies — reducing arachidonic acid (from red meat and processed foods), increasing omega-3 fatty acids, and eliminating refined sugars — measurably reduce peritoneal inflammatory markers and may improve oocyte quality in women with endometriosis.
Endometrial Receptivity in Endometriosis
- →Women with endometriosis show altered expression of implantation-related genes in the endometrium, including reduced integrin αvβ3 (a key adhesion molecule for embryo attachment) and altered HOXA10 expression during the implantation window.
- →The implantation window may be shifted in women with endometriosis — some research suggests the window opens earlier or later than expected. Endometrial receptivity analysis (ERA) testing may be recommended for women with endometriosis undergoing IVF to personalise transfer timing.
- →Progesterone resistance — where endometrial cells fail to respond normally to progesterone — is a hallmark of endometriosis. This impairs decidualisation (the transformation of the endometrium to support implantation) and increases the risk of early pregnancy loss.
Anti-Inflammatory Nutrition Protocol
Anti-inflammatory Priority Foods
- •Oily fish 3×/week (salmon, sardines, mackerel)
- •Colourful vegetables at every meal
- •Berries daily (anthocyanins reduce NF-κB activation)
- •Turmeric with black pepper (curcumin reduces TNF-α)
- •Extra virgin olive oil as primary fat
- •Flaxseeds (lignans support oestrogen metabolism)
Foods to Reduce
- •Red and processed meat (arachidonic acid precursor)
- •Refined sugars and ultra-processed foods
- •Alcohol (worsens oestrogen excess)
- •Trans fats (margarine, fried foods)
- •Conventional dairy if inflammatory symptoms worsen
- •Gluten (some evidence for benefit in endometriosis — trial elimination for 3 months if symptomatic)
Supplement Protocol
Discuss all supplements with your practitioner before starting.
N-Acetylcysteine (NAC)
600 mg 3×/day
Reduces endometrioma size in some studies; potent antioxidant that replenishes glutathione in follicular fluid
Omega-3 (DHA/EPA)
2–3 g/day
Reduces peritoneal prostaglandin E2 and inflammatory cytokines; improves oocyte quality
Vitamin D3
Target 100–150 nmol/L
Vitamin D deficiency is significantly more common in women with endometriosis; reduces NF-κB inflammatory signalling
Curcumin
500–1000 mg with piperine
Inhibits NF-κB and reduces TNF-α; some evidence for reducing endometriosis lesion growth in animal models
CoQ10 (ubiquinol)
400–600 mg/day
Supports mitochondrial function in oocytes; particularly important given oxidative stress burden in endometriosis
Resveratrol
500 mg/day
Inhibits aromatase activity; reduces oestrogen production in endometriotic lesions; antioxidant
Your Action Plan
Endometriosis Checklist
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Medical Management
Discuss surgical vs medical management with your gynaecologist before fertility treatment
Ask about endometrial receptivity analysis (ERA) testing if planning IVF
Request anti-Müllerian hormone (AMH) and antral follicle count (AFC) to assess ovarian reserve
Discuss progesterone support protocol with your IVF team — progesterone resistance is common in endometriosis
If endometrioma >4 cm, discuss surgical options carefully — weigh reserve impact vs inflammatory burden
Nutrition Protocol
Adopt an anti-inflammatory Mediterranean-style diet
Increase oily fish to 3× per week
Add berries and colourful vegetables daily
Reduce red meat to maximum 2× per week
Eliminate alcohol during fertility treatment
Consider 3-month gluten elimination trial if symptomatic — reintroduce to assess impact
Supplements (discuss with practitioner)
N-Acetylcysteine 600 mg 3×/day
Omega-3 DHA/EPA 2–3 g/day
Vitamin D3 — check levels, target 100–150 nmol/L
CoQ10 (ubiquinol) 400–600 mg/day
Curcumin 500–1000 mg with piperine