Endometrial Polyps and Fertility: A Complete Guide

Endometrial polyps are localised overgrowths of the endometrial lining -- the tissue that lines the inside of the uterus. They consist of endometrial glands, stroma, and blood vessels, and they project into the uterine cavity as soft, finger-like or round protrusions. Polyps can be sessile (broad-based, attached directly to the uterine wall) or pedunculated (attached by a narrow stalk).

Polyps range in size from a few millimetres to several centimetres. Some women have a single polyp; others may have multiple polyps scattered across the uterine cavity. Most polyps arise from the fundus (top) or cornual regions (where the fallopian tubes join the uterus) of the endometrial cavity, though they can develop anywhere along the uterine lining.

Unlike uterine fibroids, which grow from the muscular wall of the uterus, endometrial polyps are composed of endometrial tissue and originate from the lining itself. This distinction is important because it means polyps are typically softer, smaller, and easier to remove than submucosal fibroids.

Endometrial polyps are remarkably common. Prevalence estimates vary based on the population studied and the diagnostic method used:

• General population: 10-24% of all women, with prevalence increasing with age
• Women with abnormal uterine bleeding: 20-33% harbour endometrial polyps
• Infertile women: 16-32%, significantly higher than in fertile women
• Women with unexplained infertility: Up to 32% are found to have polyps when evaluated with hysteroscopy
• Women undergoing IVF: 6-32% have polyps detected during workup or monitoring

A large systematic review published in Human Reproduction Update found that the pooled prevalence of endometrial polyps among infertile women was approximately 25%, underscoring how frequently this condition is encountered in fertility practice.

In India specifically, studies from multiple centres have confirmed similar prevalence rates. A study from a tertiary care centre found endometrial polyps in 22% of women undergoing hysteroscopy for infertility evaluation. The condition is likely underdiagnosed in settings where routine hysteroscopy or saline sonohysterography is not performed as part of the standard fertility workup.

The prevalence of polyps increases with age, peaking between 40-49 years. However, they are common in women of all reproductive ages and should be considered in any woman undergoing fertility evaluation, regardless of age.

The precise cause of endometrial polyp formation is not fully understood, but several factors are associated with their development.

Hormonal Imbalance

Endometrial polyps are oestrogen-sensitive growths. They are thought to arise from an area of the endometrium that responds excessively to oestrogen stimulation, leading to localised overgrowth. This oestrogen dependence explains why polyps are more common during the reproductive years and why certain hormonal conditions increase risk.

The endometrial tissue within polyps shows overexpression of aromatase (the enzyme that produces oestrogen locally) and an imbalance between oestrogen and progesterone receptor expression. This creates a microenvironment where the polyp tissue grows independently of the normal hormonal cycling that governs the rest of the endometrium.

Tamoxifen Use

Tamoxifen, a selective oestrogen receptor modulator used in breast cancer treatment, is one of the strongest risk factors for endometrial polyps. Tamoxifen acts as an oestrogen agonist in the uterus, and women taking tamoxifen have a 30-60% incidence of endometrial polyps -- dramatically higher than the general population. These polyps tend to be larger and may have a higher rate of atypical or malignant changes.

Obesity

Higher body mass index (BMI) is associated with increased polyp prevalence. Adipose tissue produces oestrogen through peripheral aromatisation, and the resulting hyperestrogenic state promotes endometrial proliferation. This is particularly relevant in India, where rising obesity rates intersect with fertility challenges.

Age

Polyp prevalence increases with age through the reproductive years, peaking in the perimenopausal period. This is thought to relate to the cumulative effect of oestrogen exposure and the hormonal fluctuations that characterise the menopausal transition.

Other Risk Factors

• Hypertension: Several studies have found an independent association between hypertension and endometrial polyps, though the mechanism is unclear
• Hormone replacement therapy (HRT): Oestrogen-only HRT increases polyp risk; combined oestrogen-progestogen therapy carries lower risk
• Polycystic ovary syndrome (PCOS): The chronic anovulation and relative oestrogen excess in PCOS may promote polyp development
• Diabetes mellitus: Some studies suggest an association, though this may be confounded by obesity
• Prior polyps: Having had a polyp previously increases the likelihood of developing new ones

Abnormal Uterine Bleeding

The most common symptom of endometrial polyps is abnormal uterine bleeding. This can manifest as:

• Intermenstrual bleeding: Spotting or bleeding between periods -- the most characteristic symptom
• Menorrhagia: Heavy menstrual periods with increased flow or prolonged duration
• Postcoital bleeding: Spotting after sexual intercourse
• Postmenopausal bleeding: Any bleeding after menopause warrants investigation, and polyps are a common cause
• Irregular menstrual cycles: Unpredictable timing of periods

Infertility

For many women, infertility is the presenting complaint. The polyp is discovered during the fertility evaluation rather than because of symptoms. This is an important reason why thorough uterine cavity assessment is a critical part of the infertility workup.

Asymptomatic Polyps

A significant proportion of endometrial polyps -- estimated at 40-70% -- are completely asymptomatic. They cause no bleeding, no pain, and no noticeable symptoms. These "silent" polyps are typically discovered incidentally during:

• Transvaginal ultrasound performed for fertility evaluation
• Saline sonohysterography (SIS) or hysterosalpingography (HSG)
• Hysteroscopy performed for other indications
• IVF monitoring ultrasounds

The fact that so many polyps are asymptomatic reinforces the importance of imaging the uterine cavity in all women undergoing fertility evaluation, not just those with bleeding symptoms.

The relationship between endometrial polyps and infertility is well-established, though the exact mechanisms are still being elucidated. Research has identified several pathways through which polyps impair fertility.

Mechanical Interference with Implantation

Polyps physically occupy space within the uterine cavity. A polyp located near the site where an embryo would normally implant can act as a physical barrier, preventing the embryo from making contact with healthy endometrium. Large polyps or multiple polyps can distort the cavity geometry, reducing the available surface area for implantation.

Polyps near the tubal ostia (the openings of the fallopian tubes into the uterus) can interfere with sperm transport by blocking access to the tubes, or can impede the passage of a fertilised embryo from the tube into the uterine cavity.

Inflammatory Mediators

Endometrial polyps create a pro-inflammatory microenvironment within the uterine cavity. Studies have demonstrated that polyps are associated with:

• Elevated glycodelin levels: Glycodelin is a glycoprotein that inhibits natural killer (NK) cell function and may impair implantation at the polyp site
• Increased inflammatory cytokines: Polyps are associated with elevated levels of interleukins (IL-6, IL-10) and tumour necrosis factor (TNF-alpha) in uterine fluid, creating a hostile environment for embryo implantation
• Altered endometrial receptivity markers: The endometrium surrounding a polyp shows changes in integrin expression and other implantation markers that may reduce receptivity

Disruption of Endometrial Receptivity

Research using gene expression profiling has shown that the presence of endometrial polyps alters the molecular landscape of the surrounding endometrium, not just the polyp tissue itself. This means that a polyp can affect implantation potential even at sites distant from the polyp itself.

Key findings include altered expression of HOXA10 and HOXA11 (transcription factors critical for implantation), reduced expression of leukaemia inhibitory factor (LIF), and changes in progesterone receptor expression. These molecular changes may narrow or shift the implantation window.

Abnormal Uterine Bleeding

In polyps that cause abnormal bleeding, the resulting disruption to the endometrial cycling can create an unfavourable environment for embryo implantation. Irregular bleeding may also interfere with the timing of intercourse or insemination.

Evidence from IUI Studies

Some of the strongest evidence linking polyps to infertility comes from studies comparing IUI outcomes before and after polypectomy. A landmark randomised controlled trial (the REMOVE Trial) and its subsequent systematic review demonstrated that women who underwent hysteroscopic polypectomy before IUI had significantly higher pregnancy rates (51-63%) compared to those who underwent a diagnostic hysteroscopy only (25-28%). This near-doubling of pregnancy rates after a simple outpatient procedure represents some of the most compelling evidence in reproductive medicine.

Transvaginal Ultrasound (TVS)

Transvaginal ultrasound is the first-line investigation. On ultrasound, endometrial polyps typically appear as focal, echogenic (bright) thickenings within the endometrial stripe, sometimes with a feeding blood vessel visible on colour Doppler imaging (the "pedicle artery sign"). TVS is widely available, inexpensive, and non-invasive.

However, standard TVS has limited sensitivity for detecting small polyps. Polyps can be missed if the endometrium is thick (as in the secretory phase), or they may be confused with submucosal fibroids, endometrial hyperplasia, or normal endometrial folds. The sensitivity of TVS for polyps ranges from 50-90%, depending on the timing in the menstrual cycle and the operator's experience.

Optimal timing: TVS is most accurate for polyp detection in the early proliferative phase (days 4-6 of the menstrual cycle), when the thin endometrium provides better contrast against the polyp.

Saline Infusion Sonohysterography (SIS/SHG)

SIS is the most important non-invasive test for diagnosing endometrial polyps in the fertility context. A small volume of sterile saline is infused into the uterine cavity through a thin catheter during transvaginal ultrasound. The saline distends the cavity and outlines intracavitary lesions with excellent clarity.

SIS has a sensitivity of 90-98% and specificity of 85-95% for endometrial polyps, making it significantly more accurate than standard TVS. It clearly distinguishes polyps from submucosal fibroids and endometrial hyperplasia, and provides information about polyp size, number, and location relative to the tubal ostia.

In India, SIS is readily available at most fertility centres and costs approximately Rs 2,000-5,000, making it an excellent screening test. Many fertility specialists include SIS as part of the standard workup for all infertile women.

Hysteroscopy

Hysteroscopy is the gold standard for diagnosis and treatment of endometrial polyps. A thin hysteroscope (2.5-5mm diameter) is passed through the cervix into the uterine cavity, providing direct visualisation of the endometrial surface. Polyps are seen as smooth, glistening, pale pink or reddish protrusions.

The key advantage of hysteroscopy is that it is both diagnostic and therapeutic -- a polyp can be identified, assessed, and removed in the same procedure (see-and-treat approach). Hysteroscopy has a sensitivity of 95-100% for endometrial polyps.

Diagnostic hysteroscopy can be performed as an office procedure without anaesthesia (using a miniature hysteroscope), though operative hysteroscopy for polypectomy is usually performed under short general anaesthesia or sedation.

Other Diagnostic Methods

• Hysterosalpingography (HSG): May show filling defects suggestive of polyps, but cannot reliably distinguish polyps from other intracavitary lesions. HSG has low sensitivity for polyps and should not be relied upon for polyp diagnosis
• Endometrial biopsy (Pipelle sampling): Blind biopsy may miss a polyp entirely or sample only normal tissue adjacent to the polyp. It is not a reliable method for polyp diagnosis, though it may detect polyp tissue incidentally
• 3D ultrasound: Can provide better delineation of polyps compared to 2D ultrasound, but is less widely available

Standard Diagnostic Tests in India

• Transvaginal Ultrasound (TVS) — First-line imaging — best performed in early proliferative phase (days 4-6). Sensitivity 50-90%; may miss small polyps.
• Saline Sonohysterography (SIS/SHG) — Gold standard non-invasive test — saline distends the cavity, outlining polyps with 90-98% sensitivity. Cost: Rs 2,000-5,000.
• Hysteroscopy — Definitive diagnostic and therapeutic tool — direct visualisation with 95-100% sensitivity. Allows same-session removal (see-and-treat).
• 3D Ultrasound — Better polyp delineation than 2D ultrasound. Useful when SIS is not available or to plan hysteroscopic approach.
• Histopathology — All removed polyps are examined microscopically to confirm benign nature and exclude malignancy (risk 0.5-3%).

The Gold Standard

Hysteroscopic polypectomy is the definitive treatment for endometrial polyps -- and it is one of the most straightforward and effective procedures in fertility medicine. The procedure involves removing the polyp under direct hysteroscopic vision, ensuring complete excision of the polyp along with its base to minimise recurrence.

How the Procedure Works

1. Anaesthesia: Short general anaesthesia or conscious sedation. Some small polyps can be removed under local anaesthesia in an office setting
2. Cervical dilation: The cervix is gently dilated to allow passage of the hysteroscope (usually 5-9mm)
3. Uterine distension: The cavity is distended with fluid (normal saline or glycine, depending on the energy source used)
4. Visualisation: The hysteroscope provides a magnified view of the entire uterine cavity
5. Removal: The polyp is removed using one of several techniques:

• Grasping forceps: For small, pedunculated polyps
• Hysteroscopic scissors: For pedunculated polyps
• Bipolar resectoscope: For larger or sessile polyps -- shaves the polyp from its base
• Hysteroscopic morcellator (e.g., TruClear, MyoSure): Mechanical devices that cut and simultaneously aspirate polyp tissue -- increasingly popular for their speed and completeness of removal

1. Base cauterisation: The base of the polyp is lightly cauterised to reduce recurrence
2. Specimen retrieval: Removed tissue is sent for histological examination to confirm benign nature

Procedure Duration and Recovery

• Duration: 15-30 minutes
• Hospital stay: Day-case procedure -- most women go home within 2-4 hours
• Recovery: 1-2 days of mild cramping and light spotting. Most women return to normal activities the next day
• Intercourse and conception: Most specialists advise waiting 1-2 weeks for cavity healing. Many recommend attempting conception from the next menstrual cycle itself
• Follow-up: A follow-up ultrasound or SIS at 4-6 weeks may be performed to confirm complete removal

Complications

Hysteroscopic polypectomy is a very safe procedure with a complication rate of less than 1%. Possible complications include:

• Uterine perforation (rare, less than 0.5%)
• Infection (very rare with prophylactic antibiotics)
• Bleeding (usually self-limiting)
• Fluid overload (very rare with modern technique and monitoring)
• Intrauterine adhesion formation (Asherman syndrome) -- extremely rare after polypectomy alone

Costs in India

Hysteroscopic polypectomy costs in India typically range from Rs 15,000 to Rs 50,000, depending on:

• The hospital or fertility centre
• Whether the procedure is combined with diagnostic laparoscopy
• The type of equipment used
• The city (metros tend to be more expensive)
• Anaesthesia costs

This makes it one of the most cost-effective fertility interventions available. Given its relatively low cost and high fertility benefit, polypectomy offers an excellent return on investment for women with infertility and endometrial polyps.

Natural Conception After Polypectomy

Multiple studies have demonstrated improved pregnancy rates following hysteroscopic polypectomy. Key evidence includes:

• Spontaneous pregnancy rate after polypectomy: 43-65% within 12 months, depending on the study and patient characteristics
• Improvement over no treatment: Studies comparing polypectomy with observation have consistently shown higher pregnancy rates in the polypectomy group
• Time to pregnancy: Many women conceive within 3-6 months of polyp removal, suggesting that the polyp was a significant contributing factor to their infertility

IUI Outcomes After Polypectomy

The evidence for polypectomy before IUI is particularly strong:

• The REMOVE trial (a multicentre RCT) demonstrated that hysteroscopic polypectomy before IUI resulted in a clinical pregnancy rate of 51% compared to 25% in the diagnostic-hysteroscopy-only group -- a relative improvement of over 100%
• A systematic review and meta-analysis confirmed these findings, showing that polypectomy approximately doubled the clinical pregnancy rate per IUI cycle
• The benefit was observed for polyps of all sizes, including those smaller than 1 cm

These results have led most fertility societies to recommend polypectomy before IUI for any polyp identified during the workup, regardless of size.

IVF Outcomes After Polypectomy

The evidence for polypectomy before IVF is also supportive, though the data are somewhat less definitive than for IUI:

• A systematic review published in Fertility and Sterility found that polypectomy before IVF was associated with improved clinical pregnancy rates (OR 1.58) and implantation rates
• Studies have shown that women who had polyps removed before IVF had comparable outcomes to women who never had polyps, suggesting that polypectomy effectively neutralises the negative impact
• Some studies report that polyps found incidentally during IVF monitoring -- even those as small as 5-10mm -- are associated with reduced implantation and pregnancy rates if not removed before embryo transfer

Should All Polyps Be Removed Before IVF?

This is an area of active debate, but the emerging consensus favours removal:

Arguments for removing all polyps before IVF:

• The procedure is quick, safe, and inexpensive relative to the cost of an IVF cycle
• Even small polyps may impair implantation through inflammatory mechanisms
• Removing a polyp eliminates uncertainty about its contribution to implantation failure
• The cost of a failed IVF cycle (Rs 1.5-3 lakh) far exceeds the cost of polypectomy (Rs 15,000-50,000)
• Most guidelines (ESHRE, ASRM) recommend removal of polyps discovered during fertility evaluation

Arguments for leaving very small polyps:

• Some very small polyps (<5mm) may resolve spontaneously
• Delaying IVF for polypectomy adds time, which matters for older patients
• The evidence for removal of polyps under 1 cm is less robust

The pragmatic approach most Indian fertility specialists follow: Remove all polyps identified before starting IVF, regardless of size. The procedure adds only 2-4 weeks to the timeline, the cost is minimal relative to IVF, and the potential benefit to implantation is well-supported by evidence. For patients where time is extremely critical (e.g., age over 40, rapidly declining AMH), a freeze-all strategy with concurrent polypectomy before frozen embryo transfer is an efficient approach.

Recurrence Rates

Endometrial polyps can recur after removal. Published recurrence rates vary:

• Overall recurrence: 15-43% depending on the study, follow-up duration, and definition of recurrence
• Time to recurrence: Most recurrences develop within 6-24 months of polypectomy
• Risk factors for recurrence: Multiple polyps at initial polypectomy, larger polyps, incomplete removal of the polyp base, and obesity

Can Recurrence Be Prevented?

Several strategies have been studied:

• Complete base excision: Thorough removal of the polyp base with cauterisation is the most important technical factor in reducing recurrence. The hysteroscopic morcellator may offer a lower recurrence rate compared to blind polyp avulsion (twisting or blind curettage)
• Levonorgestrel-releasing intrauterine device (LNG-IUD/Mirena): Studies have shown that the LNG-IUD significantly reduces polyp recurrence. However, this is only an option after completing fertility treatment, as the IUD is a contraceptive device
• Progestins: Oral progestins after polypectomy may reduce recurrence in some cases, though the evidence is mixed
• Weight management: Addressing obesity and the associated hyperestrogenic state may help reduce recurrence risk
• Timely conception: The best "prevention" of recurrence in the fertility context is conceiving before polyps have a chance to recur. This is one reason fertility specialists recommend attempting conception or starting IVF within 2-3 months of polypectomy

It is helpful to understand how endometrial polyps differ from other conditions that can affect the uterine cavity:

Polyps vs Submucosal Fibroids

• Tissue origin: Polyps arise from the endometrial lining; fibroids arise from the muscular uterine wall
• Consistency: Polyps are soft; fibroids are firm and solid
• Removal: Polyps are easier and quicker to remove; large fibroids may require more complex surgery
• Recurrence: Both can recur; fibroids generally have lower recurrence rates after complete removal
• Distinction on imaging: SIS and hysteroscopy can usually distinguish between the two. MRI is definitive when needed

Polyps vs Endometrial Hyperplasia

• Focal vs diffuse: Polyps are localised; hyperplasia is diffuse thickening of the entire endometrium
• Cancer risk: Simple hyperplasia without atypia has a low cancer risk; polyps have an even lower malignancy rate (0.5-3%)
• Treatment: Polypectomy for polyps; progestins or other hormonal management for hyperplasia

Polyps vs Adhesions (Asherman Syndrome)

• Nature: Polyps are overgrowths; adhesions are scar tissue bands
• Appearance on hysteroscopy: Very distinct -- polyps are rounded, glistening protrusions; adhesions are pale, fibrous bands crossing the cavity
• Treatment: Both treated hysteroscopically, but adhesion lysis carries higher recurrence risk

Understanding the costs involved helps with planning and decision-making:

Cost comparison with fertility treatment:

• One IUI cycle: Rs 10,000-25,000
• One IVF cycle: Rs 1,50,000-3,00,000
• Cost of polypectomy: Rs 15,000-50,000

The cost of polypectomy represents a fraction of the cost of a single IVF cycle. Given that removing a polyp can approximately double IUI success rates and improve IVF implantation rates, it represents one of the best value-for-money interventions in fertility medicine.