FSH and LH Levels: How to Read Them by Cycle Day

Short Answer

FSH and LH are pituitary hormones that control the ovaries; because they change with the cycle phase, the phase-specific range on your report is what applies. A single high FSH value alone does not establish a diagnosis of early menopause or menopause. According to the ESHRE 2024 guideline, a diagnosis under age 40 requires both at least 4 months of menstrual irregularity and an FSH above 25 IU/L. The LH-to-FSH ratio, meanwhile, is not among the diagnostic criteria for polycystic ovary syndrome (PCOS).

How does it appear on your report?

• FSH: The report says "Follicle-stimulating hormone (FSH)" or just "FSH".
• LH: It appears under the name "Luteinizing hormone (LH)".
• Unit: In the national unit list of the Turkish Ministry of Health, the unit for both hormones is IU/L. Some reports write mIU/mL; the number is the same.
• Phase-specific range: Many laboratories give separate ranges for the follicular phase, ovulation, the luteal phase and after menopause.

The "Tahlillerim" (My Tests) screen in e-Nabız (Türkiye's national health record app) lists results together with reference values. Results outside the range are colored. This color is based on the range given by the laboratory. Knowing which day of the cycle you gave blood changes the interpretation. For example, a high LH on the day of ovulation is an expected finding.

Normal value and reference range

Cycle phase	FSH (IU/L)	LH (IU/L)
Follicular phase (first days of the period)	3.5–12.5	2.4–12.6
Ovulation period	4.7–21.5	14.0–95.6
Luteal phase (after ovulation)	1.7–7.7	1.0–11.4
After menopause	25.8–134.8	7.7–58.5
Male	1.5–12.4	1.7–8.6

Example ranges: University of Iowa Health Care laboratory, current immunoassay method. Your own laboratory's range may differ.

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

The situation is different in pregnancy. According to the Total Testing Process Guide, the high estrogen of pregnancy suppresses FSH and LH secretion. These hormones fall below the measurement limit.

On which day should it be checked?

• If your periods are regular: According to the 2021 opinion of the American Society for Reproductive Medicine (ASRM), basal FSH and estradiol are measured together between days 2 and 4 of the period.
• If your periods are irregular or absent: According to the ESHRE 2024 guideline, when investigating premature ovarian insufficiency, FSH does not need to be timed to a specific cycle day.
• To catch ovulation: The LH surge occurs 1–2 days before ovulation. It is more practical to track this with a home urine test.

Is high FSH a sign of early menopause?

Not always. FSH fluctuates around ovulation and during the transition to menopause. That is why the diagnosis is not made from a single number.

• Under 40 (premature ovarian insufficiency, POI): The 2024 guideline of ESHRE, ASRM and partner organizations requires at least 4 months of irregular or absent periods plus an FSH above 25 IU/L for diagnosis. If the diagnosis is uncertain, FSH is repeated after 4–6 weeks. The previous 2015/2016 guideline required two separate measurements.
• NICE takes a different view: The NICE NG23 menopause guideline (last updated April 2026) requires two high FSH values 4–6 weeks apart for POI. It recommends not making the diagnosis from a single blood test.
• Ages 40–45: According to TEMD 2025, cessation of ovarian function at this age is early menopause. NICE considers FSH at this age only in those with symptoms and changes in their periods.
• Over 45: According to TEMD 2025 and NICE NG23, if there are irregular periods and menopausal symptoms, FSH measurement is not needed for diagnosis. Menopause is a clinical diagnosis made after 12 consecutive months without a period.
• TEMD 2025 note: An FSH above 30 IU/L may point to menopause. However, because FSH is variable, it is not sufficient on its own.

According to ESHRE, in women diagnosed with POI for non-surgical reasons, the ovaries may work from time to time. Therefore the chance of spontaneous pregnancy is not zero. If you do not want to become pregnant, it is recommended that you continue to use contraception.

What does it mean if it is high?

• Ovulation period: LH and FSH rise naturally in the middle of the cycle.
• Menopausal transition and menopause: FSH rises as ovarian reserve decreases.
• Premature ovarian insufficiency: TEMD 2025 lists Turner syndrome, autoimmune diseases, chemotherapy, radiotherapy and surgery among the causes. In some cases no cause is found.
• PCOS: According to TEMD 2025, the average LH level may be increased in PCOS. However, this finding does not establish the diagnosis.
• In men: According to TEMD 2025, high LH and FSH together with low testosterone suggest that the problem is in the testes.

What does it mean if it is low?

• Luteal phase: After ovulation, both hormones are in the low range.
• Pregnancy: FSH and LH are suppressed.
• Hormonal medications: According to ESHRE, birth control pills, injections and long-acting methods can lower FSH. NICE recommends not diagnosing menopause with FSH in people using these medications.
• Hypothalamic amenorrhea: According to TEMD 2025, inadequate nutrition, excessive exercise and prolonged stress suppress hormone secretion. In this picture FSH and LH are low or normal and estrogen is low.
• High prolactin and pituitary diseases: TEMD 2025 lists these among the causes of low gonadotropins.

Read together

• High FSH + low estradiol + no period for months: According to ASRM, this picture suggests ovarian insufficiency. Under age 40, the ESHRE criteria apply.
• Low or normal FSH + low estradiol: ASRM considers this picture consistent with hypothalamic amenorrhea. Prolactin and, if needed, pituitary evaluation are required.
• LH high, FSH normal ("high LH/FSH ratio"): It can be seen in PCOS but is not a diagnostic criterion. The 2023 International PCOS Guideline makes the diagnosis with two of these three findings: ovulatory dysfunction, androgen excess, polycystic ovaries on ultrasound. In adults, AMH can also be used instead of ultrasound. The guideline recommends FSH and LH only to rule out other causes.
• FSH + AMH: NICE NG257 (March 2026) recommends using AMH or antral follicle count, not FSH, to predict ovarian response in IVF. According to NICE, AMH does not predict the chance of spontaneous pregnancy either.
• FSH + hCG + prolactin + TSH: For menstrual irregularity, TEMD 2025 requires pregnancy to be ruled out first. If needed, prolactin and thyroid tests are added. Details are in the article Elevated Prolactin.

Preparation before the test

• Cycle day: If your periods are regular, your doctor will most likely ask for blood between days 2 and 4 of your period.
• Hormonal medications: If you use a contraceptive method, tell your doctor. Do not stop the medication on your own; if needed, a plan is made with your doctor.
• Biotin: According to the University of Iowa laboratory, more than 5 mg of biotin taken in the last 12 hours can make LH appear falsely low. If you take supplements, tell the laboratory.
• Possibility of pregnancy: If your period is late, a pregnancy test is done first.
• Fasting: Ask your laboratory whether separate fasting is required for FSH and LH. If other tests are ordered in the same tube, their rule applies.

Which doctor, which test?

• Obstetrics and Gynecology: The first place to go for menstrual irregularity, inability to conceive and menopausal symptoms.
• Endocrinology: Needed for suspected pituitary problems with low FSH/LH, and for follow-up of PCOS and premature ovarian insufficiency.
• In men: Urology or Endocrinology evaluates.
• Tests that may be ordered: Pregnancy test, estradiol, prolactin, TSH and, if needed, AMH. According to ESHRE, AMH can be used to support the diagnosis if the FSH result is uncertain.
• After a POI diagnosis: TEMD 2025 recommends karyotype analysis, FMR1 gene screening, TSH and thyroid antibodies.

In Türkiye

• National guideline: The 2025 Adrenal and Gonadal Diseases Guideline of TEMD (Society of Endocrinology and Metabolism of Türkiye) recommends calling the condition under age 40 "primary ovarian insufficiency (POI)".
• Age at menopause: According to the same guideline, the age at menopause in Türkiye is reported as 47–49. However, there is no large epidemiological study on this.
• PCOS prevalence: In the Turkish study cited by TEMD, PCOS prevalence was 6.1% by NIH criteria, 15.3% by AE-PCOS criteria and 19.9% by Rotterdam criteria.
• Unit standard: In the Ministry's national list, FSH and LH are reported in IU/L.
• e-Nabız: You can see your previous FSH results on the same screen and compare them with a chart.

When should you seek urgent care?

• If you have a sudden, very severe headache with loss of vision, call 112 (the emergency number in Türkiye). This picture may be due to bleeding in the pituitary and is an emergency.
• If your period is late, your pregnancy test is positive and you have abdominal pain or bleeding, go to the emergency department.
• If the laboratory or your doctor has called you about your result, call back the same day.
• If you are under 40 and have not had a period for more than 3 months, it is not an emergency, but make a scheduled appointment within a few weeks.
• If you have chest pain, shortness of breath or fainting, call 112 whatever your hormone result.

Related tests

• Lab Test Guide: all tests
• Estradiol (E2) Levels
• Elevated Prolactin
• Ovulation Test and LH
• Beta hCG Levels
• Early Menopause: When Should It Be Taken Seriously?
• Early Menopause / POI Guide
• Thyroid Tests Guide

What has changed? (October 2026)

• The ESHRE/ASRM/CRE WHiRL/IMS 2024 POI guideline was used as the basis: a single high FSH, with an appropriate clinical picture, is considered sufficient for diagnosis. The NICE NG23 approach requiring two measurements is also noted.
• Consistent with NICE NG257 (March 2026) and the TEMD 2025 Adrenal and Gonadal Diseases Guideline.

Sources

• Türkiye Endokrinoloji ve Metabolizma Derneği (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. 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 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. e-Nabız Kullanım Kılavuzu V2.1. 2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)
• Panay N, Anderson RA, Bennie A et al. ESHRE, ASRM, CRE WHiRL and IMS Guideline Group on POI. Evidence-based guideline: premature ovarian insufficiency. Hum Reprod Open 2024;2024(4):hoae065. https://doi.org/10.1093/hropen/hoae065 (accessed October 2, 2026)
• NICE. Menopause: identification and management (NG23). 2015, last updated April 15, 2026. https://www.nice.org.uk/guidance/ng23 (accessed October 2, 2026)
• Teede HJ et al. Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab 2023;108(10):2447-2469. https://doi.org/10.1210/clinem/dgad463 (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: Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). Current version. https://www.healthcare.uiowa.edu/path_handbook/handbook/test828.html and https://www.healthcare.uiowa.edu/path_handbook/handbook/test1256.html (accessed October 2, 2026)