Does an estradiol level of 145 pmol/L and a luteinizing hormone level of 20 IU/L indicate that menstruation is imminent?

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Last updated: September 19, 2026 • View editorial policy

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Hormone Interpretation: Estradiol 145 pmol/L and LH 20 IU/L

These hormone levels suggest you are likely in the late follicular phase approaching ovulation, NOT that menstruation is imminent. Menstruation would be expected approximately 14 days after ovulation occurs, which has not yet happened with these values.

Understanding the Hormone Pattern

Your estradiol level of 145 pmol/L falls within the early-to-mid follicular phase range, while the LH of 20 IU/L is elevated and suggests either:

  • The beginning of the LH surge (which triggers ovulation)
  • Peak LH surge activity

According to established reference values, high FSH and LH levels with estradiol >150 pmol/L and progesterone <2 ng/mL indicate the midcycle gonadotropin surge 1. Your estradiol at 145 pmol/L is just below this threshold, but the elevated LH of 20 IU/L is consistent with surge activity.

What These Values Actually Mean

Follicular Phase vs. Ovulation

Research data shows that during the natural menstrual cycle 2:

  • Follicular phase: LH median 7.14 IU/L (range 4.78-13.2), estradiol median 198 pmol/L (114-332)
  • Ovulation phase: LH median 22.6 IU/L (range 8.11-72.7), estradiol median 757 pmol/L (222-1959)

Your LH of 20 IU/L places you at the lower end of the ovulation range, while your estradiol of 145 pmol/L is below typical ovulatory levels but within the follicular range.

Clinical Interpretation

The LH surge always occurs before ovulation 3, and ovulation typically happens 24-36 hours after the LH peak begins. Following ovulation, the luteal phase lasts approximately 14 days before menstruation begins. Therefore, with an LH of 20 IU/L, you are likely:

  • At the very beginning of your LH surge, or
  • In late follicular phase with rising LH

Menstruation would not be expected for approximately 14-16 days (accounting for time to ovulation plus the luteal phase).

Key Caveats

Pattern Matters More Than Absolute Values

The Endocrine Society guidelines emphasize that the pattern of hormone levels is more critical than absolute values 1. A single measurement cannot definitively determine cycle phase without:

  • Serial measurements to track hormone trends
  • Progesterone levels to confirm ovulation has occurred
  • Clinical context including cycle day and symptoms

What Would Indicate Imminent Menses

For menstruation to be truly imminent, you would expect:

  • Falling progesterone from luteal phase levels (>13 nmol/L) back to baseline
  • Low estradiol (<200 pmol/L)
  • Low LH (back to follicular baseline of 4-8 IU/L)
  • These changes occur in the late luteal phase, days +10 to +14 after ovulation 4

Your elevated LH indicates you are moving toward ovulation, not away from it toward menstruation.

References

1
Guideline

functional hypothalamic amenorrhea: an endocrine society clinical practice guideline.

The Journal of clinical endocrinology and metabolism, 2017

3
Research

Monitoring the menstrual cycle: Comparison of urinary and serum reproductive hormones referenced to true ovulation.

The European journal of contraception & reproductive health care : the official journal of the European Society of Contraception, 2015

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.