Introduction

Uterine Fibroid (called leiomyomas) are non-cancerous growths made of muscle and tissue, which form in and out of the wall of the uterus. Fibroids are formed by uterine smooth muscle cells (myometrium), and their proliferation is predominantly determined by circulating estrogen levels. The benign tumour can vary in size, number and location. The pathophysiology of fibroids is still poorly understood. Fibroids can appear as an asymptomatic incidental observation on imaging or symptomatically.¹

Prevalence in individuals of reproductive age

The estimated prevalence rates vary from 4.5% to 68.6%, depending on the study population and diagnostic approach.²

Risk factors of uterine fibroids include:

• Gender
• Race 
• Gender 
• Genetics
• Time since last birth 
• Premenopausal status 
• Hypertension 
• Nutrition^2,3
  

Ultrasound imaging shows that black people assigned female at birth have a much greater cumulative incidence of fibroids (>80%) than white people AFAB (∼70%), amongst people AFAB under 50.⁴

Overview of infertility challenges

Fibroids are present in 5-10% of infertile patients, and may be the sole cause of infertility in 1-2.4% of patients.⁵ Fibroids may cause infertility by obstructing the fallopian tubes and impairing gamete - define gamete for readers - transport. 

Many hypotheses have been proposed to elucidate the negative impact of fibroids on fertility. These include:

• Decreased gamete transport 
• Embryo implantation 
• Persistent endometrial inflammation 
• Anatomical distortion of the endometrial cavity 
• Dysfunction in the endometrial blood supply 
• Increased uterine contractility  
• Aberrant local hormonal environment⁵

Understanding fibroids

Fibroids can range in size from very small to as large as a melon. It could occur as a single or multiple fibroids.

Fibroids are classified into several categories based on where they grow in the uterus:

• Subserous or subserosal fibroids grow on the muscle layer's outer wall
• Intramural fibroids develop within the muscle wall of the uterus
• Submucosal fibroids develop on the inner wall
• Pedunculated fibroids are fibroids that grow on stalks⁶

Symptoms and complications

Nearly 25% to 50% of individuals with uterine fibroids have symptoms such as:

• Heavy menstrual bleeding 
• Reproductive problems 
• Pain
• Increased urine frequency 
• Anaemia⁷ 

Complication includes anaemia, infertility and recurrent pregnancy loss.

Impact of fibroid on fertility and pregnancy outcomes

Preterm labour and delivery, placental abruption, malpresentation and breech positioning, and bleeding after childbirth are the most commonly reported consequences of fibroids in pregnancy.

A study of people assigned female at birth with infertility found that those with fibroids in any site had considerably lower rates of clinical pregnancy, implantation, continued pregnancy, and live birth rates compared to controls.⁸

Diagnosis

The first-line diagnostic imaging approach for detecting fibroids is ultrasonography, preferably transvaginally. It is a widely available, inexpensive, non-invasive, and painless method of examining the uterine cavity. Ultrasound is noted for its great sensitivity and specificity in finding fibroids.⁸

Magnetic resonance imaging (MRI) gives extra information in cases of unclear ultrasound findings, large fibroids, or when the shadow prevents evaluation (specificity 100%, accuracy 97%, and sensitivity 86-92%).⁸

A hysteroscopy should be performed for a more in-depth investigation or to confirm uterine cavity involvement.⁸

ART overview

Assisted Reproductive Technology (ART) procedures involve surgically removing eggs from a person AFAB ovaries, combining them with sperm in the laboratory, and returning them to a person AFAB patient or a gestational carrier. ART also includes egg and embryo cryopreservation (freezing) and egg and embryo donation.⁹

Types of ART

According to the CDC, "they do not include treatments in which only sperm are handled (i.e., intrauterine—or artificial—insemination) or procedures in which a person assigned female at birth- takes medicine only to stimulate egg production with no intention of having eggs retrieved.⁹

• IVF : This is when egg are fertilised outside the body and implanted into the uterus
• IUI:This is when sperm is placed directly into the uterus around the time of ovulation
• ICSI: A single sperm is injected directly into an egg, often used in cases of male infertility
• Egg/sperm donation: This approach is used when individuals can not donate their own egg

When is ART indicated?

In vitro fertilization is recommended for couples who are unable to conceive for:

• Congenital or acquired tubal illness
• Moderate male infertility occurs when medical-surgical treatment or prior intrauterine inseminations have failed or were deemed inappropriate.
• Severe male-factor infertility
• Endometriosis
• Idiopathic infertility occurs when the preceding intrauterine insemination procedure did not produce results or was not deemed appropriate for the couple
• Repeated miscarriages
• Genetic diseases
• Intrauterine insemination is commonly utilised in couples who have had donor sperm treatment
• Unexplained infertility
• Endometriosis-related infertility
• Mild male factor infertility
• Cervical factor infertility
• Ovulatory factor infertility¹⁰

Impact of fibroids on ART outcomes

According to the available research, non cavity-distorting intramural fibroids would greatly reduce the implantation rate, pregnancy rate, and live birth rate following IVF therapy, as well as significantly raise the miscarriage rate, but not the ectopic pregnancy rate.¹¹

Pre-ART evaluation and management of fibroids

A well-detailed evaluation of uterine fibroid, including size, number, locatio,n is important to determine the right management before ART.¹²

Surgical removal of fibroid is recommended for intramural and submucosal fibroids that larger than 4cm especially when uterine cavity is distorted.¹³

Myomectomy such as laparoscopy and hysteroscopy are surgical removal of uterine fibroid that helps improve fertility outcomes. Studies has proved that myomectomy prior to ART increases pregnancy and delivery rates.¹³

Medical therapies such as GnRH Agonist and antagonist:

• These medications help to shrink fibroid by causing a “medical menopause” leading to reduction in estrogen¹⁴
• Studies prove this may be effective immediately before ART or before surgery to minimise fibroid growth¹⁴

ART Strategies in Women with Fibroids

Individualised protocols are required for managing fibroids following ART. Submucosal fibroids that deform the uterine wall are frequently removed prior to ART because they have a negative influence on implantation and pregnancy rates. 

Intramural fibroids larger than 3-4 cm are removed, particularly if they deform the uterine cavity. On the other hand, subserosal fibroids, which do not impact the uterine cavity, often do not need surgical intervention before ART.

When to proceed with ART without surgery 

In cases where fibroids are asymptomatic, small and do not distort the uterine cavity, proceeding with ART without prior surgical intervention may be appropriate. The approach minimises surgical risk and reduces treatment delays.

Monitoring during ovarian stimulation:

During ovarian stimulation for ART, close monitoring is necessary in women with fibroids because fibroids influence ovarian response, and may complicate follicular monitoring. Transvaginal ultrasound is commonly used to assess fibroid size and location throughout the stimulation phase.

Embryo transfer considerations: 

Fibroids that distort the uterine cavity can impact embryo transfer success, thus surgical removal of those fibroids is recommended prior to embryo transfer, to enhance implantation rates.

Outcome of ART in patients with fibroids

The presence of fibroids, such as submucosal and large intramural types, are shown to be associated with reduced implantation, pregnancy and live birth rate in ART cycles.

Summary

Fibroid management in patients undergoing ART requires a multidisciplinary approach that prioritises individual patient’s needs and challenges. A tailored treatment strategy, informed by current evidence and advanced technology, can improve ART outcomes. Early intervention is key to optimising fertility prospects for women with fibroids.