Expected Luteinizing Hormone Levels on Days 8-9 of the Menstrual Cycle
The expected level of luteinizing hormone (LH) on days 8-9 of a normal menstrual cycle is approximately 7.14 IU/L, with a reference range of 4.78-13.2 IU/L, representing the follicular phase levels before the mid-cycle surge. 1
Understanding LH in the Menstrual Cycle
LH levels vary significantly throughout the menstrual cycle, following a characteristic pattern:
Early to Mid-Follicular Phase (Days 8-9):
- LH levels remain relatively stable during this phase
- Median value: 7.14 IU/L
- Reference range: 4.78-13.2 IU/L 1
Late Follicular Phase (Days -5 to -1 before LH surge):
- LH begins to gradually increase in preparation for ovulation
Mid-Cycle/Ovulation (LH surge):
- Median peak value: 22.6 IU/L
- Reference range: 8.11-72.7 IU/L 1
- This surge typically occurs around day 14 in a 28-day cycle
Luteal Phase:
- LH levels decline after ovulation
- Median value: 6.24 IU/L
- Reference range: 2.73-13.1 IU/L 1
Variability Factors to Consider
It's important to note that LH levels can vary based on several factors:
- Cycle Length: Normal menstrual cycles can range from 21-35 days 2, affecting the timing of hormonal events
- Individual Variation: Significant differences exist between women and between cycles in the same woman 3
- Age: Hormonal patterns change throughout reproductive years
- Assay Method: Different laboratory methods may produce different reference ranges 1
Clinical Implications
- Proper interpretation of LH levels requires knowledge of the cycle day and phase
- Days 8-9 represent the mid-follicular phase in a typical 28-day cycle
- At this point, LH levels should be stable before the dramatic mid-cycle surge
- For accurate assessment of ovarian reserve, FSH (not LH) should be measured between days 2-4 of the cycle 4
Measurement Considerations
- For proper characterization of LH levels, the timing of blood sampling is crucial
- The pulsatile nature of LH release means that single measurements may not fully represent the hormonal status 2
- For research purposes, multiple samples (at least 3x/hour) may be needed for complete characterization 2
Days 8-9 of the menstrual cycle typically represent the mid-follicular phase before the LH surge, with expected values around 7.14 IU/L (4.78-13.2 IU/L), though individual variation is common.