LH surge

What does lh surge mean?

LH surge: A sudden rise in luteinising hormone that triggers the ovary to release an egg, usually within about 36 hours.

How it is used in the Splash library

• Ovulation tests (often called OPKs) look for the LH surge – the hormone spike that tells your ovary “release the egg!”.

  From “How to use ovulation (LH) tests”

• Body signs such as LH tests, cervical mucus and basal body temperature add real information, which is why fertility awareness methods taught by trained practitioners combine several signs.

  From “How accurate are period tracker apps?”

LH surge explained

The LH surge is a sudden rise in luteinising hormone that triggers ovulation. When oestrogen from the growing follicle reaches a certain level, the brain releases a large burst of LH, and the follicle releases its egg about 24 to 36 hours later.

Ovulation predictor kits (LH tests) detect this surge in urine, which makes them useful for timing sex when trying to conceive.

What's typical

The surge itself often lasts a day or two. Some people have a short surge that is easy to miss with once-a-day testing, so testing twice a day around the expected time can help.

People with PCOS can have high LH levels, which can give positive LH tests on several days. Some fertility medicines also affect results.

A positive LH test shows the surge happened, but not that ovulation definitely followed. A temperature rise afterwards helps confirm it.

When to talk to a GP, nurse or pharmacist

• You never get a positive test across several cycles, or get positives on many days.
• You have been trying to conceive for a year (or 6 months if you are 36 or over).
• Your cycles are very irregular or longer than 35 days.

In the UK you can call NHS 111 for advice at any time. In an emergency call 999 (UK) or 911 (US). This is general information, not medical advice.