Pregnancy Biomarker
Collection Type: Blood
Related System: Pregnancy
Prolactin is a hormone produced by the anterior pituitary that primarily stimulates breast development and milk production (lactation). A prolactin blood test measures the circulating concentration of this hormone. It is used to evaluate causes of menstrual irregularities, infertility, unexplained milk production (galactorrhea), low libido in men, and symptoms suggesting a pituitary tumor (headache, visual field defects). Prolactin levels vary widely with physiological states: they rise markedly in pregnancy and breastfeeding, are higher in women than men at baseline, show pulsatile and sleep-related variation, and can be affected by age, stress, and certain medications.
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Symptom CheckerNon-pregnant adult female: 4.8-23.3 ng/mL OR 102-494 mIU/L Pregnancy 1st trimester: 34-386 ng/mL OR 721-8,183 mIU/L Pregnancy 2nd trimester: 71-566 ng/mL OR 1,505-12,000 mIU/L Pregnancy 3rd trimester: 80-653 ng/mL OR 1,696-13,844 mIU/L
Q: What happens if prolactin level is high?
A: High prolactin (hyperprolactinemia) causes menstrual irregularities or absent periods, infertility and galactorrhea in women; in men it causes low libido, erectile dysfunction, reduced sperm production and sometimes gynecomastia. Both sexes may have reduced bone density (osteopenia/osteoporosis), headaches and visual disturbances if a pituitary tumor is present. Treatment depends on the cause and can often restore hormones and fertility.
Q: What does prolactin do to females?
A: Prolactin in females primarily stimulates breast development and milk production (lactation) after childbirth. During pregnancy it supports mammary gland growth and helps establish milk secretion postpartum. Elevated prolactin suppresses gonadotropin-releasing hormone, reducing ovulation and menstrual function, which can cause infertility or amenorrhea. It also influences maternal behavior, immune responses, and fluid balance.
Q: What is the fastest way to reduce prolactin?
A: The fastest way to lower high prolactin is medical treatment with a dopamine agonist—cabergoline (preferred) or bromocriptine—which often reduces levels within days to weeks. Also address reversible causes (stop offending drugs, replace thyroid hormone for hypothyroidism), reduce stress, and avoid nipple/chest stimulation. See an endocrinologist promptly, especially with headaches or visual changes, for tailored care and monitoring.
Q: What is a normal prolactin level?
A: Normal prolactin levels vary by sex, pregnancy status and lab method. Typical ranges: non‑pregnant women about 2–29 ng/mL (≈40–615 mIU/L) and men about 2–18 ng/mL (≈40–380 mIU/L). Pregnant women have much higher levels. Labs differ—use your lab’s reference range and discuss abnormal results with your clinician, since medications, stress and pituitary conditions can raise prolactin.
Q: Can prolactin cause weight gain?
A: Yes chronically high prolactin (hyperprolactinemia) can contribute to weight gain. Elevated prolactin may change appetite, metabolism, and sex-hormone levels, promoting fat accumulation; prolactinomas and some medications that raise prolactin are linked with weight gain. Treating the cause (medication change or prolactinoma therapy) often helps. If you suspect high prolactin, see a doctor for blood tests and management.
Q: Can PCOS cause high prolactin?
A: PCOS does not usually cause elevated prolactin. Mild prolactin increases can coexist with PCOS, and both conditions share symptoms (irregular periods, infertility). If prolactin is high, clinicians check for other causes—pituitary adenoma, hypothyroidism, certain medications or stress—because treatment differs. Testing prolactin, thyroid function and pituitary imaging is advised when levels are persistently raised.