High Prolactin and Infertility: Myths, Causes & Treatments
Patient: Dr Malpani, I’ve heard that prolactin can affect fertility. What exactly is prolactin?
Dr Malpani: Prolactin is a hormone produced by the pituitary gland, a small gland below the brain. Its main role is to stimulate milk production in women during and after pregnancy. But both men and women have prolactin, and when the levels rise too high — a condition called hyperprolactinemia — it can interfere with ovulation and fertility.
Patient: So high prolactin levels can stop me from ovulating?
Dr Malpani: Yes. Prolactin blocks two key hormones needed for ovulation — FSH and GnRH. That’s why breastfeeding women usually don’t get pregnant. When levels are high, women may notice irregular cycles or even a milky breast discharge called galactorrhea.
Patient: What’s considered a normal prolactin level?
Dr Malpani:
- Men: 2 – 18 ng/ml
- Non-pregnant women: 2 – 29 ng/ml
- Pregnant women: 10 – 209 ng/ml
Some labs use different units, which causes confusion. If the result is in mIU/L, the normal value is less than 700 mIU/L.
A slight elevation is usually not important. Stress — even the stress of a blood draw — can cause a temporary rise. That’s why levels should always be rechecked before making a diagnosis.
Patient: What can cause high prolactin levels?
Dr Malpani: There are several possibilities:
- Prolactinoma (a small benign pituitary tumour that secretes prolactin)
- Medications (such as antidepressants, painkillers, or opiates that block dopamine)
- Hypothyroidism
- PCOS (polycystic ovarian syndrome)
- And in some cases, we never find a clear cause.
In men, high prolactin can cause low sperm counts, erectile dysfunction, and loss of libido.
Patient: If I do have high prolactin, how is it treated?
Dr Malpani: The good news is that this is one of the most treatable causes of infertility.
- If it’s due to hypothyroidism or a drug you’re taking, correcting that fixes the problem.
- If it’s due to a prolactinoma, medications work extremely well.
The two most effective drugs are:
- Bromocriptine (2.5 mg tablets, usually taken at bedtime). The dose is increased gradually until prolactin levels normalise. Some women need 4–6 tablets a day. Once levels are normal, periods become regular and ovulation resumes. Downside: It can cause nausea and dizziness, especially at the start.
- Cabergoline (0.5 mg tablet, once or twice a week). This is better tolerated, with fewer side effects, and is often used when bromocriptine doesn’t work.
Remember: these drugs don’t “cure” the condition. They control it while you take them. Once you get pregnant, they are stopped.
Patient: Should I be worried if my levels are just slightly high?
Dr Malpani: Not at all. Mild elevations are often meaningless. Sadly, some doctors make the mistake of blaming infertility entirely on marginally raised prolactin and stop the rest of the evaluation. That’s not sensible. Your full infertility workup should continue, because prolactin may just be one small piece of the puzzle.
Patient: So prolactin can cause infertility, but it’s also one of the easiest problems to fix?
Dr Malpani: Exactly. Unlike poor egg quality or advanced age, hyperprolactinemia is highly treatable. With proper diagnosis and the right medication, fertility can be restored very effectively.