Can I use LH instead of BBT to avoid pregnancy?

Whether you’re new to Fertility-awareness Based Methods (FABM) or an old hand, it’s natural to be curious about the various kinds of FABMs. For example, if you’re monitoring your cervical mucus (CM) and basal body temperature (BBT) daily, you may also wonder whether can use  luteinizing hormone (LH) instead of BBT for preventing pregnancy. You may have heard this called the LH method.

While we don’t recommend nixing CM observations, it may be worth exploring combining CM with LH. Research shows this method is highly effective for trying to avoid (TTA) pregnancy (1). Couples have used it for years. 

So we dug up the 21-page manual on the LH method. Here’s a rundown of what you need to know before you try it for yourself.

What is the LH Method?

The LH Method is a type of FABM developed by practitioners at Marquette University in Milwaukee, Wisconsin, in the late ‘90s (2). You may have heard it called the Marquette Method. 

In the simplest terms, the method relies on:

  • Observing changes in your cervical mucus (read here to brush up on CM)
  • Using a fertility monitor to test for LH and estrogen in urine (more on this below)

Together, these fertility cues help you pinpoint your fertile window — which the Marquette folks define as the 5 days before ovulation and ovulation day — so you can avoid sex during your fertile window.

Let’s take a minute to explain the vital role of LH in the ovulation phase of your menstrual cycle. Ovulation happens when LH signals the ovary to release an egg. Over an average 28-day cycle, LH remains pretty flat, then peaks a day or two before day 14 of your cycle (3). Tracking that surge is a crucial step in the LH method. (But identifying the surge can be tricky sometimes, which we’ll get to.)

The manual outlining the LH method advises you to use the rather pricey Clearblue® Fertility Monitor, which measures urinary LH and estrogen (3). You pee on test strips about 10 days a month, and the monitor uses the test strip data and an algorithm to tell you the low, high, and peak days in your cycle (4).

The Clearblue Monitor stores up to 6 cycles of data, which you can review on a handy touchscreen (4). A paper in Human Reproduction found the monitor correctly detected ovulation in 91.1% of cycles (5), while a separate study showed the monitor was effective in identifying the complete fertile window ahead of time (5). 

Now, for a series of important caveats. First, we all know that a 28-day cycle isn’t the norm, and the fertile window may vary from one month to the next, even among women with an “average” cycle (8). The Marquette folks aren’t oblivious to the issue of variability. In fact, their manual includes an example drawn from tracking one woman over 3 cycles that showed her fertile window was days 10-15 in the first cycle, days 6-11 in the second, and days 17-22 in the third cycle (3). 

But the idea with the LH method is that the combination LH and CM observations can accurately identify your peak days — even when they vary month to month (3). 

By now you may be thinking — this sounds good, but how well does it work in reality?

How accurate is the LH method to avoid pregnancy?

The method is very effective when followed to the letter, per a study in the Journal of Obstetric, Gynecologic, and Neonatal Nursing (1). 

A research team taught 195 couples to observe CM and use the ClearBlue electronic monitor to prevent pregnancy, then followed the couples for 12 months. With perfect use, the method was 98% effective in avoiding unintended pregnancy, but effectiveness slipped to around 86% with less-than-perfect use (1).

Meanwhile, a separate study by a research team at Marquette University found that couples who used the electronic monitor, observations of CM, and BBT (7) prevented pregnancies 99.4% of the time.

What are the cons of using the LH method?

Cost may be a factor in the LH method. A Clearblue Fertility Monitor retails for around $150, which doesn’t include the price of test strips and is unlikely to be covered by insurance. 

Another issue: your test kit may not catch the LH surge. As the Marquette manual notes, the “Clearblue monitor misses the LH surge in about 1 out of 10 cycles (3).” (Urine tests kits, in general, have problems detecting the LH surge. Read up on that here.)

Also, don’t use this method for at least two cycles if you were recently (3):

  • Pregnant 
  • On hormonal contraception
  • Breastfeeding

One final note: this method isn’t recommended for those with polycystic ovarian syndrome (PCOS), and taking tetracycline antibiotics also may affect the accuracy of this method (3).

So should I use the LH method or not?

Consider using LH if you’re having a hard time getting the hang of taking your BBT, or if your schedule or lifestyle make it nearly impossible to record your BBT at the same time daily to get an accurate reading (check out our BBT 101 for more on how to get an accurate reading). 

The bottom line is the LH method, if followed correctly, may be highly effective to avoid pregnancy. Like other FABMs, the method puts you in charge of your fertility and gives you insights into your incredible body. And, that’s a concept we can all get behind.



Photo by Priscilla Du Preez on Unsplash

References:

  1. https://www.factsaboutfertility.org/marquette-featured-research/
  2. https://nfp.marquette.edu
  3. https://nfp.marquette.edu/pdf/nfp_user_manual.pdf
  4. https://www.clearblue.com/ovulation-tests/fertility-monitor-with-touch-screen
  5. https://www.researchgate.net/publication/12229933_Prediction_of_ovulation_by_urinary_hormone_measurements_with_the_home_use_ClearPlanR_Fertility_Monitor_Comparison_with_transvaginal_ultrasound_scans_and_serum_hormone_measurements
  6. http://npr.pl/badania/timing_intercourse.pdf
  7. https://www.ncbi.nlm.nih.gov/pubmed/18997569
  8. https://www.researchgate.net/publication/7080221_Variability_in_the_Phases_of_the_Menstrual_Cycle

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