Overview
Prolactin is a hormone secreted by the pituitary gland that plays a key role in breast milk production. It is also crucial for fertility, menstrual cycles, ovulation, sexual health and overall hormone balance in both women and men. Abnormally high or low prolactin levels can affect fertility, sometimes causing subtle symptoms such as changes in menstrual cycles or mood swings. Understanding how prolactin functions, what influences its levels and how it is measured can help you better understand your body. This guide covers what is prolactin, its role, normal levels, causes of imbalance, warning signs, testing methods and its impact on fertility and overall health
Understanding Prolactin and Its Function
Prolactin is best known for its role in breast milk production after childbirth, but it also quietly affects many other aspects of your health. Beyond supporting breast development during pregnancy, prolactin influences fertility, menstrual cycles, ovulation, sexual health, metabolism, fluid balance and even mood and behaviour.
In your body, prolactin is mainly produced by lactotroph cells in the pituitary gland, but smaller amounts are also made in the uterus, breasts, brain, immune cells, prostate, skin and fat tissue.
Its production is carefully regulated. Dopamine, a hormone from the hypothalamus, acts like a brake: the more dopamine, the less prolactin is released. Prolactin even stimulates dopamine in return, creating a balance that keeps your body functioning smoothly.
Oestrogen and other hormones; like thyrotropin-releasing hormone, oxytocin and antidiuretic hormone, also influence prolactin levels. This means your hormone levels naturally shift during your menstrual cycle and rise significantly during pregnancy to prepare your body for breastfeeding.
Understanding prolactin is not just about milk production; it helps you make sense of fertility changes, menstrual irregularities, mood shifts and overall hormone health, giving you insight into what is happening in your body and when to seek help.
What Does Prolactin Do in Women and Men?
Prolactin is a hormone that influences reproductive health and overall hormonal balance, but its role differs between women and men.
In Women
- Breast Growth and Milk Production: Prolactin helps the breasts develop during pregnancy and triggers milk production after childbirth.
- Ovulation and Menstrual Cycle: It works alongside oestrogen and progesterone to regulate ovulation.
- Impact of High Prolactin: Levels that are too high outside of pregnancy or breastfeeding can disrupt ovulation, leading to irregular periods and reduced fertility. Understanding prolactin can help explain changes in cycles or difficulties conceiving.
In Men
- Testosterone and Sperm Production: Prolactin supports healthy testosterone levels, which are essential for sperm production, libido and overall reproductive health.
- Impact of High Prolactin: Excess prolactin can lower testosterone, reduce sex drive, cause erectile difficulties and affect sperm count, potentially impacting fertility.
By understanding how prolactin functions in both sexes, you can better interpret symptoms like irregular cycles, reduced libido or fertility challenges and know when to seek medical advice.
What Are Normal Prolactin Levels?
Normal prolactin levels vary by sex and laboratory standards.
| Group | Normal range (nanograms per milliliter (ng/mL) |
|---|---|
| Women (non-pregnant) | 4-23 |
| Men | 3-15 |
| Pregnant women | Significantly higher (may reach up to 200) |
How Are Prolactin Levels Tested?
Prolactin levels are measured through a simple blood test, usually done in the morning since prolactin naturally rises during sleep. Fasting overnight may be requested to ensure accurate results.
Levels can be temporarily influenced by stress, exercise or nipple stimulation, so borderline results are often rechecked to confirm accuracy.
Reference ranges (ng/mL):
Men: under 20 Women (non-pregnant): under 25 Pregnant women: 80-400Elevated fasting levels are called hyperprolactinemia.
In some cases, doctors may recommend an MRI scan to examine the pituitary gland for tumours or inflammation that could be causing high prolactin levels.
Understanding how prolactin is tested helps you interpret results and know when further investigation may be necessary.
What Causes High Prolactin Levels?
High prolactin levels, also known as hyperprolactinemia, can result from a variety of medical, hormonal or lifestyle factors.
Common causes include:
- Prolactinoma: A benign tumour of the pituitary gland that produces excess prolactin.
- Medications: Certain antidepressants, antipsychotics and other drugs can raise prolactin levels.
- Hypothyroidism: Low thyroid hormone can indirectly increase prolactin production.
- Polycystic Ovary Syndrome (PCOS): Hormonal imbalances in PCOS may elevate prolactin.
- Chronic stress or illness: Physical or emotional stress can temporarily increase prolactin.
Understanding the cause of high prolactin is important, as treatment depends on addressing the underlying factor.
What Symptoms Can High or Low Prolactin Cause?
Changes in prolactin levels can affect reproductive health, sexual function and overall well-being.
High prolactin (hyperprolactinemia) may cause:
- Irregular or missed periods in women
- Milk production unrelated to pregnancy or breastfeeding (galactorrhea)
- Vaginal dryness in women or erectile difficulties in men
- Reduced sexual desire or libido
- Headaches or vision changes
Some people may have no noticeable symptoms and only discover high prolactin during routine blood tests or fertility evaluations.
Low prolactin is uncommon but can lead to:
- Reduced milk production after childbirth
- Usually no other noticeable effects
Treatment is rarely needed unless low prolactin is linked to a pituitary or hormonal disorder.
How Are Abnormal Prolactin Levels Treated and When Should You See a Doctor?
Treatment for abnormal prolactin levels depends on the underlying cause:
- Medication to Lower Prolactin: Doctors often prescribe dopamine agonists to reduce prolactin and restore hormonal balance.
- Treating Thyroid Disorders: If hypothyroidism is causing high prolactin, correcting thyroid levels can normalise prolactin.
- Adjusting Medications: Certain drugs may raise prolactin; changing or stopping these medications under medical supervision can help.
- Monitoring Pituitary Tumours: Small, symptom-free pituitary tumours may be observed rather than treated immediately.
When to see a doctor:
- Irregular or suddenly changing menstrual cycles
- Unexpected milk discharge outside of pregnancy or breastfeeding
- Difficulty conceiving or other fertility concerns
- Symptoms accompanied by abnormal hormone test results
Early evaluation can help identify the cause, prevent complications and improve reproductive and hormonal health.
Conclusion
Prolactin is a hormone that affects more than milk production. It plays a role in fertility, menstrual cycles and overall hormone balance. Knowing what is prolactin helps explain why changes in this hormone can affect the body in different ways.
Many people only hear about prolactin when a test result comes back abnormal or when fertility is being checked. Understanding how prolactin works makes these results easier to interpret. It also helps you recognise when symptoms may need medical attention. With the right
Table of Contents
- Understanding Prolactin and Its Function
- What Does Prolactin Do in Women and Men?
- What Are Normal Prolactin Levels?
- How Are Prolactin Levels Tested?
- What Causes High Prolactin Levels?
- What Symptoms Can High or Low Prolactin Cause?
- How Are Abnormal Prolactin Levels Treated and When Should You See a Doctor?
- Conclusion
Common Questions Asked
Can lifestyle changes help manage prolactin levels?
Yes. Maintaining a healthy weight, managing stress, avoiding excessive alcohol and reviewing medications with your doctor can support normal prolactin levels and overall hormone balance.
How does prolactin affect fertility treatments like IVF?
High prolactin can disrupt ovulation, which may affect IVF outcomes. Doctors often check and manage prolactin before starting fertility treatments to improve chances of success.
Can men be affected by high prolactin without obvious symptoms?
Yes. Some men may have elevated prolactin without noticeable changes in libido or sexual function, but it can still impact testosterone levels and sperm quality, which may only be detected through testing.
Does prolactin fluctuate naturally during the menstrual cycle?
Yes. Prolactin levels can rise slightly at certain points in the cycle, particularly around ovulation and menstruation. These natural fluctuations are usually not a cause for concern.
Can prolactin issues indicate other underlying health conditions?
Sometimes. Persistent high prolactin may point to thyroid disorders, pituitary tumours or PCOS. Identifying the cause is important for effective treatment and long-term health.