Introduction

Prolactinoma is a non-terminal hormonal disorder resulting from the presence of a benign growth in the pituitary gland. The pituitary gland is a vital gland in the endocrine system because it produces hormones, which are chemicals that help control different functions in our body.¹ The pituitary gland produces the prolactin hormone, which is responsible for the production of breast milk after childbirth. However, if an individual has prolactinoma, an excessive production of prolactin would occur and this condition is popularly called hyperprolactinemia.¹ When there is an excess production of prolactin in the body, it compromises the reproductive system causing infertility leading to difficulties in conceiving a baby in women.² Prolactinoma also affects men leading to reduced sexual libido, erectile dysfunction and in rare cases spermatogenic disorders.³ Although prolactinoma has a direct impact on infertility, the condition is treatable with an effective treatment plan which results in full restoration of reproductive function in both males and females.³ Prolactinoma is not life-threatening but the relationship between prolactinoma and infertility emphasizes the need for an extensive knowledge of the disease state to enable early detection and medical treatment with integrative treatment.¹

Pathophysiology and epidemiology of prolactinoma

Dopamine is a neurotransmitter produced in the brain and plays an important role by inhibiting the secretion of prolactin from the pituitary gland. The decrease in the dopamine inhibition effects from the hypothalamus leads to the loss of regulation in prolactin production, when this occurs, there is a surge in prolactin levels affecting the release of (GnRH) gonadotropin-releasing hormone and inversely reducing the luteinizing hormone (LH) and follicle stimulating hormone (FSH).⁴ All of these aforementioned hormones are very important for a normal functioning reproductive system. Hence, a disruption of these hormones leads to fertility complications.⁴

Prolactinoma affects approximately 50 cases per 100,000 persons. Although the condition is rare, it has a greater incidence rate among individuals experiencing galactorrhea and amenorrhea.⁵ Furthermore, the condition is prevalent among women of reproductive age between (20 to 50 years) due to menstrual irregularities but it can occur to anyone at any age.⁵

Symptoms and clinical presentation of prolactinoma

Prolactinoma symptoms vary with prolactin levels, size, and location.⁶ In individuals assigned female at birth, symptoms include:⁶

• Menstrual changes
• Irregular periods
• Infertility
• Nipple discharge without pregnancy or breastfeeding
• Decreased libido
• Vaginal dryness causing discomfort during sex
• Headaches and vision issues due to the tumour's growth pressing on nearby nerves

For those assigned male at birth, symptoms encompass:

• Reduced sexual interest due to low testosterone
• Erectile dysfunction
• Infertility
• Breast tissue enlargement
• Nipple discharge
• Headaches and vision issues due to the tumour's growth pressing on nearby nerves

Diagnosis of prolactinoma

Prolactinoma diagnosis involves:

Blood tests to assess the level of prolactin in the body. For women, the normal range is about 4 to 23 ng/ml and 3 to 15 ng/ml for men. Values higher than the upper limit of the range indicate prolactinoma. In addition, a hormone panel consisting of thyroid-stimulating hormone (TSH) and growth hormone measures the pituitary gland's overall function.⁷

Imaging investigation: Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans are conducted to get a precise and detailed image of the pituitary gland, emphasising on size of the growth and specific location of growth in the gland. However, this diagnostic tool is less effective in detecting smaller growths in the gland.⁸

Differential Diagnosis: Distinguishing prolactinoma from other hyperprolactinemia causes, such as certain medications, pituitary disorders, hypothyroidism, and kidney disease is vital for proper treatment, requiring a review of medication history, additional hormone tests, and imaging scan analyses .^7,8

Prolactinoma and infertility

Prolactinoma has both direct and indirect effects on fertility through hormonal imbalance, the direct effects include increased levels of prolactin which interferes with the reproductive system.9 In women generally, the presence of high prolactin inhibits ovulation leading to difficulty in getting pregnant and also, causes irregular menstrual cycles.10 In men, high levels of prolactin cause low sperm production and reduced sexual libido.

Inversely, prolactinoma is linked with vision complications, hand eadaches and potentially affects other vital hormones responsible for fertility.⁹

Several research studies have indicated that the treatment of prolactinoma with dopamine agonists, have led to a significant improvement in fertility by reducing the levels of prolactin in the body and shrinking the size of the tumour.⁹

Treatment of prolactinoma

Treatment of prolactinoma involves; 

Medications such as dopamine agonists, such as Bromocriptine and Cabergoline, which lower prolactin levels by imitating dopamine's action in the brain. This treatment often results in tumour shrinkage and normalisation of menstrual cycles in women, enhancing fertility for both genders. Cabergoline is favoured for its less frequent dosage and milder side effects.¹¹

Surgery: If medications fail or if the tumour impacts the surrounding tissues, surgery may be considered. Transsphenoidal surgery, accessing the tumour through the nose or upper lip, is common, aiming to reduce prolactin levels and relieve compression symptoms with minimal brain tissue damage. However, surgery carries typical risks like infection or potential harm to normal pituitary function.⁷

Radiation therapy is reserved for cases not responding to medication and surgery, targeting tumour cells with high-energy rays. It is used with caution due to long-term side effects, including the risk of impairing other pituitary hormones.¹²

Managing prolactinoma treatments involves regular monitoring for side effects, such as nausea or dizziness with dopamine agonists, and potentially hormone replacement after surgery or radiation if other pituitary functions are compromised. Ongoing communication with healthcare providers is crucial for adjusting treatment and managing side effects efficiently.¹³

Managing fertility in patients with prolactinoma

Managing fertility for those with prolactinoma focuses on balancing treatments to lower prolactin levels, aiming to restore normal reproductive abilities. For couples who struggle to conceive naturally, even after achieving controlled prolactin levels, Assisted Reproductive Technologies (ART) like in vitro fertilisation (IVF) offer a solution. These approaches are particularly beneficial when other fertility-affecting factors are present.¹⁴

Prognosis and long-term management of prolactinoma

The prognosis for individuals diagnosed with prolactinoma is overwhelmingly positive. With timely and appropriate treatment, many of the symptoms, particularly those impacting fertility, can be effectively reversed, allowing those affected to enjoy a normal, healthy life. The key to successful outcomes often lies in early detection and diligent, ongoing management of the condition.¹¹

Long-term management

The management of prolactinoma is a multifaceted approach that typically extends over the long term to ensure the condition remains controlled and the quality of life is maintained. Here’s a more detailed look at the components of this management strategy:⁶

• Medication: Medications that reduce prolactin production, such as bromocriptine or cabergoline, stand as the cornerstone of prolactinoma treatment. For the majority of patients, these medications not only shrink the tumour but also normalize the prolactin levels, marking a significant step towards recovery and maintaining health
• Regular Check-ups: Consistent monitoring forms a critical part of managing prolactinoma. This includes routine blood tests to measure prolactin levels and regular MRI scans to monitor the tumour’s size and growth. Such regular check-ups are vital for evaluating the effectiveness of the treatment plan and making necessary adjustments to ensure the best possible outcomes
• Surgery: Surgery may be necessary for a minority of cases, particularly when medication proves to be ineffective or leads to severe side effects. The surgical intervention aims to remove the tumour, thereby alleviating symptoms and potentially restoring normal pituitary function
• Lifestyle Adjustments: Although lifestyle changes alone cannot resolve prolactinoma, adopting a healthy lifestyle plays a supportive role in managing symptoms and overall well-being. Regular physical activity, a nutritious diet, and avoiding certain medications known to elevate prolactin levels can complement medical treatments to enhance health outcomes

Through a combination of effective medical treatments, vigilant monitoring, possible surgical intervention, and supportive lifestyle adjustments, long-term management of prolactinoma is not only feasible but also highly successful, offering individuals a pathway to maintaining their health and well-being.

Summary

Prolactinoma, a benign tumour in the pituitary gland, causes excess production of prolactin, leading to a variety of symptoms that affect fertility in both men and women. Women might notice irregular menstrual cycles or lactation without pregnancy, while men could experience decreased libido or erection difficulties. Fortunately, prolactinoma is treatable, primarily through medications that reduce the prolactin levels and decrease the tumour size.

Early detection of prolactinoma is key for effective treatment and improving the likelihood of symptom reversal, including fertility restoration. The primary treatment method involves dopamine agonists like bromocriptine or cabergoline, which have shown success in managing prolactinoma and aiding fertility recovery. Delay in treatment can result in larger tumours and more complicated health issues possibly diminishing treatment efficacy.

The future holds promising prospects for advancing our comprehension and management of prolactinoma-induced infertility. Ongoing research is directed towards uncovering new medications with lesser side effects and higher efficacy, especially for patients unresponsive to existing therapies. There's also a keen interest in unravelling the underlying causes of prolactinoma to potentially develop preventive measures. Furthermore, the field of personalized medicine, which customizes treatment based on an individual's genetic profile, is seen as a hopeful avenue for enhancing patient outcomes.

With continuous research and development, the outlook for individuals facing infertility due to prolactinoma is increasingly optimistic, pointing towards more effective, individualized, and efficient treatment options in the future.