Researchers define an LH surge as when your LH levels reach 2.5X your baseline concentration of LH (AKA the average LH concentration early in your cycle.)
For most people with ovaries, low, high, and peak LH levels correspond with the following concentrations (in milli-international units per milliliter, or mIU/mL):
- Low (<20 mIU/mL): Your LH concentration is at or near its baseline level. Test again the next day.
- High (20-40 mIU/mL): Your LH concentration is nearing a surge or already surging. Most people at this concentration will ovulate within 24-48 hours. During this time, there’s a higher chance of getting pregnant.
- Peak (>40 mIU/mL): Your LH concentration is nearing its highest levels. You can use your highest concentration to determine your surge level for future cycles.
That said, it's really important to note LH levels and LH patterns across the cycle are far from being one-size-fits-all. You can read more about this on our blog.
You can use the Modern Fertility App to scan your strips and get predictions about your most fertile days based on your unique LH pattern.