Luteinizing hormone (LH) is the hormone that triggers ovulation to occur! It works closely together with follicle stimulating hormone (FSH) throughout your cycle to get your body to the point of ovulation.
FSH has been encouraging follicles in your ovaries to mature throughout the beginning of your cycle. LH has also been rising slowly during this time.
As one follicle (occasionally two) comes to maturity it has also developed receptors sensitive to LH. Just before ovulation your LH peaks sharply, which sends a signal to the mature follicle to burst and release your egg.
This little miracle means it’s time for you to play catch the egg – it will remain viable for only 12 to 18 hours.
Luteinizing hormone’s job isn’t quite done – when your egg liberates itself from your follicle LH signals to the empty nest to undergo conversion into the corpeus lutem (meaning “yellow body”). The corpeus lutem will secrete the hormone progesterone.
If you’re successful in getting pregnant this cycle the progesterone is vital to the early survival of your newly conceived baby.
Luteinizing hormone is also present in your man – it encourages the production of testosterone.
Now the Really Important Stuff
You’ve probably heard of the various fertility tests on the market. Luteinizing hormone is the key to these tests. Ovulation predictor kits detect the surge of LH, therefore letting you know that ovulation will soon occur (typically LH surges around 24-48 hours before ovulation). These tests work just like a pregnancy test – you pee on them.
Or, if you prefer using a test strip (I definitely prefer a test strip) you dip the strip into a clean container you’ve peed into.
You read the results of these tests a little differently than a pregnancy test. You’ll see a “control line.” If your line appears as dark or darker than the control line that indicates a lot of LH, and that you’ll probably ovulate soon. If it’s lighter (or non-existent) you need to hold out a bit longer for ovulation.
Generally you begin using an ovulation predictor kit several days before you expect ovulation to occur, then use one test or strip daily. Once LH is detected it’s time for you to grab your sweetie and baby dance.
Other fertility monitors (such as the Clearblue monitor) also use LH in addition to other hormones.
LH testing is a pretty simple way to enhance your understanding of your charts. Many testing choices are inexpensive, making this a good place to start if you’re a little unsure of what’s going on inside.