Hyperprolactinaemia or hyperprolactinemia (HP) is the presence of abnormally high levels of prolactin in the blood. Normal levels are less than 500 mIU/L [20 ng/mL or µg/L] for women, and less than 450 mIU/L for men.
1. pregnancy-related
a) during pregnancyb: 10–400 ng/ml
b) postpartum: PRL decreases ≈ 50% (to ≈ 100 ng/ml) in the first week postpartum, and is usually back to normal in 3 weeks
c) in the lactating female: suckling increases PRL, which is critical for lactogenesis (once initiated, nonpregnant PRL levels can maintain lactation).
First 2–3 months postpartum: basal PRL = 40–50 ng/ml, suckling → increases × 10–20. 3–6 months postpartum: basal PRL levels become normal or slightly elevated, and double with suckling. PRL should normalize by 6 months after weaning
2. pituitary neuroendocrine tumor
a) prolactinoma: larger prolactin microadenomas and macroadenomas usually produce PRL > 100 ng/ml
b) stalk effect (p. 753): rule of thumb, the percent chance of an elevated PRL being due to a prolactinoma is equal to one half the PRL level
c) some tumors secrete both PRL and GH
3. drugs: dopamine receptor antagonists (e.g. phenothiazines, metoclopramide), oral contraceptives (estrogens), tricyclic antidepressants, verapamil, H2 antagonists (e.g. ranitidine), some SSRIs, in particular paroxetine (Paxil®)
4. primary hypothyroidism: TRH, a prolactin releasing factor (PRF) (p. 165), will be elevated
5. empty sella syndrome
6. transient elevations in human serum prolactin (HSP) levels occur following 80% of generalized motor, 45% of complex partial, and only 15% of simple partial seizures.16 Peak levels are reached in 15–20 minutes, and gradually return to baseline over the subsequent hour.
7. breast or chest-wall trauma/surgery: usually ≤ 50 ng/ml
8. excessive exercise: usually ≤ 50 ng/ml
9. stress: in some cases the stress of having the blood test is enough to elevate PRL, anorexia nervosa
10. ectopic secretion: reported in renal cell or hepatocellular tumors, uterine fibroids, lymphomas
11. infiltrating hypothalamic tumors
12. renal failure
13. cirrhosis
14. macroprolactinemia:
Hyperprolactinemia (HPRL) and polycystic ovary syndrome (PCOS) are common causes of infertility in women of reproductive age.