LH Surge Before Your Period – Why Does This Happen?
If you are trying to conceive, you probably already know that testing for luteinizing hormone (LH) is helpful for predicting your fertile window and ovulation. And because ovulation typically occurs midway through your cycle, you’ve probably only ever tested for LH during the first half of your cycle – i.e the follicular phase.
But what happens if you continue to test for LH after ovulation? You may assume that LH simply returns back to its baseline level. However, you may be surprised to learn that it’s actually common for some women to experience additional peaks in LH after their initial surge and before their upcoming period.
In this article, we’ll explore how common it is to have an LH surge before your period, the potential causes of this phenomenon, and what “normal” LH levels look like throughout your cycle. We’ll follow this up by answering some of your most frequently asked questions about LH. Let’s get started!
How common is an LH surge before your period?
Experiencing a surge in LH before your period is more common than you may think. In fact, one research study from the American Society of Reproductive Medicine found that over the course of 281 cycles among 107 women, 33% of cycles had a double peak of LH, another 8% of cycles had multiple peaks of LH, and 11% of cycles had LH levels that plateaued, meaning that LH levels continued to stay elevated after the initial surge.
Although nearly half of cycles (48%) only had a single peak, this study is a good reminder that LH surge patterns vary greatly among women.
What causes an LH surge before your period?
There are a few explanations for why LH may remain elevated or peak again before your period. For example, when progesterone drops dramatically at the end of your luteal phase, it is possible for this drop to trigger a slight increase in LH. It’s also possible to see a rise in LH if implantation occurs, as implantation can cause your overall hormone levels to fluctuate.
Additionally, if your baseline LH levels are naturally higher than average, it is possible for any slight fluctuation to cause an LH test to yield a positive or higher than average result – leading you to believe that your LH levels are surging a second time.
Can you have an LH surge before your period and still be pregnant?
Yes. It is still possible to be pregnant even if tests show that your LH levels are surging. Again, LH can sometimes be affected by implantation, so try not to worry if your LH levels appear to be surging or higher than their baseline levels.
What are LH levels throughout your cycle?
Individual LH levels can vary dramatically among women. However, there are general LH thresholds that are considered “normal”. Here’s a brief look at what you can expect your LH levels to be when they are at their lowest, highest, and baseline level.
For the purposes of this article, LH ranges from the Mayo Clinic Laboratories were used. However, please note that ranges may vary among individual laboratories.
Baseline LH levels typically range between 0.7 to 14.6 IU/L. To break that down even further, it is common to see LH measure between 1.9 IU/L to 14.6 IU/L during the first half of the cycle (the follicular phase) and 0.7 to 12.9 IU/L during the second half of your cycle (the luteal phase).
However, it is generally accepted that any LH measurement between 5-25 IU/L is normal.
In women with a regular menstrual cycle, LH levels tend to be at their lowest during the luteal phase, typically measuring between 0.7 to 12.9 IU/L. However, in women who are pregnant, LH levels are generally much lower and can be as low as <1.5 IU/L.
LH levels are at their highest when they are surging, which occurs approximately 24-36 hours before ovulation. During this time, they can measure as low as 12.2 IU/L to as high as 118.0 IU/L.
LH is also higher than the baseline in women who are experiencing menopause, ranging anywhere from 5.3 to 65.4 IU/L in menopausal women.
LH surge FAQs
Are there any symptoms of an LH surge?
Although rare, it is still possible to experience some physical symptoms related to your LH surge prior to ovulation. For example, some women may experience any of the following:
- Slight twinge or pain in the ovaries, also called “mittleschmerz”
- Breast pain or tenderness
- Slight bleeding or spotting
- Increase in cervical mucus that may be more slippery than normal
- Increase in basal body temperature
How long does LH surge last?
The average LH surge typically lasts between 24-36 hours. However, this can vary depending on each individual, and it can even vary from cycle to cycle.
What are the best ways to test an LH surge?
There are several different ways that you can track and test for your LH surge. This includes:
- Keeping track of your individual cycle and physical symptoms.
- Using ovulation predictor kits (OPK’s) – such as Clearblue Digital Ovulation Test or First Response Easy Read Ovulation Test
- Using a digital hormone monitoring system – such as Mira
- Having your blood tested at your doctor’s office
The “best” testing method will depend on your individual situation and your pregnancy goals. For example, simply keeping track of your cycle and physical symptoms may not be the most efficient method if you are tracking LH in order to conceive as quickly as possible. Instead, OPK’s or full hormone tracking systems, like Mira, will make it much easier for you to monitor your LH levels and accurately predict your LH surge.
For those struggling to become pregnant, or those experiencing symptoms of hormonal conditions like polycystic ovarian syndrome (PCOS) or endometriosis, it’s a good idea to have your hormones tested at your doctor’s office with a blood test. Your doctor can then help you explore potential solutions that work for you and your body.
Utilizing a mix of methods – such as monitoring hormone levels with Mira while also keeping a journal of your physical symptoms – is the most thorough way to not only keep track of your hormones, but to also stay in tune with your body as well.
How often should you test for your LH surge?
In order to test for your LH surge, you should aim to test for LH daily starting around 5-7 days before your estimated date of ovulation. If you’re unsure about when you may ovulate, it’s a good idea to start testing early on in your cycle, such as the day after your period ends and not later than the 6th day of your cycle. This will ensure that you will not miss your LH surge.
Once a rise in LH has been detected, this signals that ovulation is likely to occur within the next 24-36 hours. If you are trying to conceive, you should aim to have sex with your partner during this window of time. After ovulation is complete, it is no longer necessary to continue testing for LH during your current cycle.
After consistent testing and tracking, you should be able to accurately predict not only the length of your cycle, but also your fertile window.