High Prolactin: Does It Prevent Pregnancy, and Why Is It Retested?

Short Answer

High prolactin can make it harder to get pregnant by suppressing ovulation; however, the cause is usually found, and with treatment the hormone axis generally recovers. According to the TEMD (Society of Endocrinology and Metabolism of Turkey) 2022 Pituitary guideline, the upper limit in women is 25 ng/mL; even so, your laboratory's range is what counts. With a mild elevation, pregnancy, medicines, thyroid and kidney disease, and macroprolactin are ruled out first. According to the Pituitary Society 2023, values less than 5 times the upper limit are measured again.

How does it appear on your report?

• Name: It is listed as "Prolactin" or "PRL".
• Unit: In the national unit list, prolactin is reported in µg/L; this is the same number as ng/mL. Some laboratories use mIU/L. According to TEMD, 1 ng/mL equals 21.2 mIU/L. On this basis, 25 ng/mL is approximately 530 mIU/L.
• Macroprolactin: This is a separate test. The blood is treated with polyethylene glycol (PEG) and the percentage drop in prolactin is reported.
• Sex-specific range: Separate ranges are given for women and men. There may also be a separate range for pregnancy.

The "My Test Results" (Tahlillerim) screen in e-Nabız (Türkiye's national health record app) lists results with their reference values and highlights out-of-range values in color. Comparing your previous prolactin results on a graph makes it easier to interpret a repeat measurement.

Normal value and reference range

Group	Example value (ng/mL)	Source
General normal range	5–20	TEMD Pituitary 2022
Women, upper limit	Below 25	TEMD Pituitary 2022
Women (not pregnant)	4.8–23.3	University of Iowa
Men	4.0–15.2	University of Iowa
Pregnancy, 3rd trimester	95–473	University of Iowa

The reference range covers 95% of healthy people; about 1 in 20 healthy people may fall slightly outside the range.

According to TEMD, hyperprolactinemia is a value above 25 ng/mL in women and above 20 ng/mL in men, in blood drawn at least 2 hours after waking. According to the Total Testing Process Guide, prolactin can rise up to tenfold during pregnancy.

Does high prolactin prevent pregnancy?

It can, but usually not permanently.

• How does it affect fertility? According to TEMD 2025, high prolactin suppresses kisspeptin secretion in the brain. This slows down the hormone axis that stimulates the ovaries.
• Effect by level: According to TEMD 2022, a mild elevation of 20–50 ng/mL can shorten the luteal phase. Values of 50–100 ng/mL can lead to infrequent periods or to periods stopping.
• It improves with treatment: According to the Pituitary Society 2023, once prolactin returns to normal, the hormonal suppression generally resolves. According to TEMD, the first-line treatment for prolactinoma is dopamine agonist medicines, and the success rate is high.
• Fertility can return quickly: The Pituitary Society recommends barrier contraception for women who do not want to become pregnant when starting treatment, because pregnancy can occur before periods return.
• Macroprolactin is a separate condition: This large-molecule prolactin is biologically inactive. According to TEMD, if macroprolactin is detected in a person without symptoms, no further testing is needed.

Prolactin is not checked in everyone trying to conceive. NICE NG257 (March 2026) recommends the test for people with an ovulation disorder, milk discharge from the nipple (galactorrhea) or a pituitary tumor. ASRM 2021 also recommends ordering it when periods are infrequent or absent and when there is milk discharge.

What does a high value mean?

From common and harmless causes to serious ones:

• Blood draw conditions: According to the Pituitary Society, needle stress can increase prolactin 2–4 fold, and this effect lasts less than 1 hour. Sleep, exercise, sexual intercourse, breast stimulation, a protein-rich meal and alcohol can also raise the value.
• Pregnancy and breastfeeding: Prolactin rises naturally during these periods.
• Medicines: Antipsychotics, some antidepressants, stomach medicines such as metoclopramide and domperidone, estrogen, opiates and some blood pressure medicines can raise prolactin.
• Hypothyroidism: Thyroid hormone deficiency can raise prolactin. According to the Pituitary Society, this elevation reverses with thyroid treatment.
• Kidney and liver failure: These are among the known causes of mild elevation.
• Macroprolactin: According to the Pituitary Society, large-molecule forms can be detected in 10–25% of people with high prolactin.
• PCOS: TEMD lists this among the causes. The Pituitary Society, however, states that PCOS alone rarely causes high prolactin, and that further investigation is therefore required.
• Pituitary causes: According to TEMD, prolactinoma is the most common hormone-secreting pituitary adenoma. Other pituitary masses can also raise prolactin by compressing the pituitary stalk.

The size of the value gives a clue but does not make the diagnosis. According to TEMD, values above 250 ng/mL usually suggest prolactinoma. With antipsychotic medicines, estrogen and elevations of unknown cause, the value is mostly between 25 and 100 ng/mL. According to the Pituitary Society, in antipsychotic-related elevation a value exceeding 10 times the upper limit is rare.

When read together

• High prolactin + high TSH: Hypothyroidism is suspected; the thyroid is evaluated first. See the Thyroid Tests Guide.
• High prolactin + positive pregnancy test: This may be a physiological elevation due to pregnancy. TEMD asks that evaluation in women begin by ruling out pregnancy.
• High prolactin + no symptoms: Checking macroprolactin is recommended.
• High prolactin + low FSH, LH and estradiol + no periods: This indicates that the hormone axis is suppressed. See FSH and LH Values.
• Large pituitary adenoma + only mildly high prolactin: According to TEMD and the Pituitary Society, the sample is diluted 1/100 and measured again to check for a measurement error (the "hook effect").
• High prolactin + high creatinine: Kidney failure may be the cause of a mild elevation.

Preparing for the test

• Time: According to TEMD, blood should be drawn at least 2 hours after waking.
• Food: Give blood preferably 4 hours after a protein-rich meal.
• Stress and exercise: Rest before the blood draw. The Total Testing Process Guide states that stress and strenuous exercise in the previous 12 hours can affect prolactin.
• Breast stimulation: Try not to give blood immediately after a breast examination or breastfeeding.
• Biotin: According to the University of Iowa laboratory, more than 5 mg of biotin in the last 12 hours can make prolactin read falsely low. Tell the laboratory about the supplement.
• Medicines: Mention all the medicines you take. Do not stop a medicine on your own; if necessary, the decision to pause or change it is made by the physician who prescribed it.
• If stress is suspected: According to TEMD, a cannula can be placed in an arm vein and 2–3 samples taken 15–20 minutes apart. The average value gives a more accurate result.

Which doctor, which test?

• Endocrinology: The main specialty that investigates the cause of high prolactin.
• Obstetrics and Gynecology: Co-manages complaints of irregular periods and inability to conceive.
• Psychiatry: In people taking antipsychotics, changes to treatment are planned together with the psychiatrist.
• Tests that may be ordered: Repeat prolactin, macroprolactin, TSH and free T4, creatinine, liver tests and a pregnancy test.
• Imaging: The Pituitary Society recommends a pituitary MRI for a confirmed elevation if there is no other cause. According to TEMD, a visual field examination is ordered for a large adenoma close to the optic nerves.
• Unnecessary tests: According to TEMD, dynamic tests that stimulate prolactin release are no longer recommended.

In Türkiye

• National guideline: According to the TEMD 2022 Pituitary guideline, a single prolactin measurement is sufficient for diagnosis if there was no blood draw stress. The guideline gives the normal range as 5–20 ng/mL.
• Macroprolactin thresholds: According to TEMD, if the drop after PEG is below 40%, there is no macroprolactinemia. 40–60% is a gray zone, and above 60% favors macroprolactinemia. Some laboratories use a different threshold; for example, the University of Iowa uses 50%.
• Treatment options: According to TEMD, cabergoline and bromocriptine are used in Türkiye; cabergoline is the first choice. The guideline reports success rates of 80–90% with cabergoline and 70–80% with bromocriptine.
• Monitoring in pregnancy: According to TEMD, routine prolactin measurement is not performed during pregnancy in pregnant women with prolactinoma. Headache and visual complaints are important during follow-up.
• Unit standard: In the Ministry's national list, prolactin is reported in µg/L.

When should I seek emergency care?

• If you have a very severe headache of sudden onset together with loss of vision, call 112 (the emergency number in Türkiye). TEMD defines this picture as an emergency.
• If you have a prolactinoma, have become pregnant, and have developed a severe headache or visual disturbance, seek care the same day.
• If clear, watery fluid starts to drip from your nose during prolactinoma treatment, contact your physician the same day.
• If you notice your field of vision narrowing, for example if you are bumping into objects at your sides, get examined within a few days.
• If the laboratory or your physician has called you about your result, call back the same day.

Related tests

• Lab Test Guide: all tests
• FSH and LH Values
• Estradiol (E2) Values
• Beta HCG Values
• Ovulation Test and LH
• Thyroid Tests Guide

What changed? (October 2026)

• New page: based on the Pituitary Society 2023 international consensus statement and the TEMD 2022 Pituitary guideline.
• Who should have prolactin checked is consistent with NICE NG257 (March 2026). The Endocrine Society 2011 guideline also covers investigating the cause, medicine-related elevation and the management of prolactinoma in pregnancy.

Sources

• Türkiye Endokrinoloji ve Metabolizma Derneği (TEMD). Hipofiz Hastalıkları Tanı, Tedavi ve İzlem Kılavuzu. 2022. https://file.temd.org.tr/Uploads/publications/guides/documents/Hipofiz-hastaliklari-tani-ve-tedavi-kilavuzu-2022yeni.pdf (accessed October 2, 2026)
• TEMD. Adrenal ve Gonadal Hastalıklar Kılavuzu. 2025. https://file.temd.org.tr/Uploads/publications/guides/documents/AdrenalKilavuz2025.pdf (accessed October 2, 2026)
• T.C. Sağlık Bakanlığı SHGM. Tıbbi Biyokimya Toplam Test Süreci Rehberi. May 2024, Publication No. 1287. https://dosyamerkez.saglik.gov.tr/Eklenti/48692/0/tibbi-biyokimya-toplam-test-sureci-rehberipdf.pdf (accessed October 2, 2026)
• T.C. Sağlık Bakanlığı SHGM. Test Ölçüm Birimleri, Versiyon 2. 15.09.2021. https://dosyamerkez.saglik.gov.tr/Eklenti/41467/0/test-olcum-birimleri-versiyon-2-pdfpdf.pdf (accessed October 2, 2026)
• T.C. Sağlık Bakanlığı. e-Nabız Kullanım Kılavuzu V2.1. 2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)
• Petersenn S, Fleseriu M, Casanueva FF et al. Diagnosis and management of prolactin-secreting pituitary adenomas: a Pituitary Society international Consensus Statement. Nat Rev Endocrinol 2023;19:722-740. https://doi.org/10.1038/s41574-023-00886-5 (accessed October 2, 2026)
• Melmed S, Casanueva FF, Hoffman AR et al. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2011;96:273-288. https://doi.org/10.1210/jc.2010-1692 (accessed October 2, 2026)
• NICE. Fertility problems: assessment and treatment (NG257). March 31, 2026. https://www.nice.org.uk/guidance/ng257 (accessed October 2, 2026)
• Practice Committee of the American Society for Reproductive Medicine. Fertility evaluation of infertile women: a committee opinion. Fertil Steril 2021;116:1255-1265. https://doi.org/10.1016/j.fertnstert.2021.08.038 (accessed October 2, 2026)
• University of Iowa Health Care. Pathology Laboratory Handbook: Prolactin; Macroprolactin Check. Current version. https://www.healthcare.uiowa.edu/path_handbook/handbook/test1560.html and https://www.healthcare.uiowa.edu/path_handbook/handbook/test2960.html (accessed October 2, 2026)