Prolactin Levels & Fertility: What High Prolactin Means

Learn how prolactin affects ovulation and fertility. Understand causes of high prolactin and treatment options.

Prolactin is a hormone primarily known for its role in breast milk production, but it also plays an important role in fertility. Elevated prolactin levels (hyperprolactinemia) can disrupt ovulation and cause irregular periods. Understanding your prolactin results is important if you're having difficulty conceiving.

What Does Prolactin Do?

Prolactin is produced by the pituitary gland and has over 300 known functions in the body. In reproduction, prolactin:

  • Stimulates breast development and milk production
  • Suppresses GnRH, which controls FSH and LH
  • Inhibits ovulation when levels are high (nature's birth control during breastfeeding)
  • Affects progesterone production and luteal phase
  • Plays a role in implantation

Understanding Prolactin Levels

Prolactin is measured in ng/mL or mIU/L. Normal ranges vary by lab, but general guidelines:

  • Normal (women): 2-29 ng/mL — no fertility impact expected
  • Mildly elevated: 30-50 ng/mL — may cause irregular cycles
  • Moderately elevated: 50-100 ng/mL — often causes anovulation
  • Significantly elevated: >100 ng/mL — requires investigation for prolactinoma
  • Normal (men): 2-18 ng/mL — elevated levels can affect sperm production

Prolactin should be tested fasting, in the morning, without breast stimulation beforehand, as levels fluctuate throughout the day.

Causes of High Prolactin

Elevated prolactin can have many causes:

  • Prolactinoma: A benign pituitary tumor (most common pathological cause)
  • Medications: Antipsychotics, antidepressants, anti-nausea drugs, opioids
  • Hypothyroidism: Low thyroid leads to high prolactin
  • PCOS: Sometimes associated with mildly elevated prolactin
  • Stress or recent breast exam: Can temporarily elevate levels
  • Pregnancy and breastfeeding: Naturally very high prolactin

Symptoms of High Prolactin

Hyperprolactinemia may cause:

  • Irregular or absent periods
  • Milky nipple discharge (galactorrhea)
  • Difficulty conceiving
  • Reduced libido
  • Headaches or vision changes (if prolactinoma present)

Treatment Options

High prolactin is usually very treatable:

  • Dopamine agonists (Cabergoline, Bromocriptine): First-line treatment, highly effective
  • Treating underlying cause: If medication-induced or due to hypothyroidism
  • Surgery: Rarely needed, only for large prolactinomas not responding to medication

Most women with prolactinoma-related infertility conceive successfully with medication treatment. Prolactin levels usually normalize within weeks of starting treatment.

Key takeaways

  • High prolactin suppresses ovulation by interfering with FSH and LH
  • Testing should be done fasting, in the morning, without prior breast stimulation
  • Medications are a common cause of elevated prolactin
  • Treatment with dopamine agonists is highly effective
  • Most women with hyperprolactinemia conceive successfully after treatment

Frequently asked questions

Can stress cause high prolactin?

Yes, acute stress can temporarily elevate prolactin. If your level is mildly elevated, your doctor may recommend retesting under less stressful conditions before starting treatment.

Is it safe to take prolactin medication during pregnancy?

Dopamine agonists are typically stopped once pregnancy is confirmed, as prolactin naturally rises during pregnancy. Most prolactinomas remain stable during pregnancy without medication.