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The Problem with OPKs and PCOS

If you are trying to get pregnant, or trying not to get pregnant, knowing when you ovulate is very important. But figuring out when you ovulate can be a challenge. And for people with PCOS, it can be especially challenging. It is natural to seek help from an Ovulation Predictor Kit (OPK), but this isn't always helpful for people with PCOS.

Here’s why. Ovulation Predictor Kits tend to work by measuring the amount of Luteinizing Hormone (LH) in the urine. In a normal menstrual cycle, there is a big LH surge just before ovulation. The urine test strip detects the high level of LH and indicates that ovulation is about to happen.

This method of prediction can be problematic for people who have PCOS. The issue is that with PCOS, LH can be elevated at different points in the cycle, or just chronically elevated. This can create either a false positive result, or the test will not detect ovulation since the baseline of LH is chronically high. For people with PCOS, traditional OPKs based on LH levels are not an ideal tool.

According to Kate Davies, a Registered Nurse and Nurse Fertility Consultant, the best method for ovulation prediction is to be properly trained in natural family planning, which consists primarily of tracking body temperature and cervical mucus.

Before ovulation, not only is there a surge in LH, but there is a rise in body temperature which correlates to a rise in progesterone levels. Progesterone levels can also be used to predict ovulation. For people with PCOS, body temperature will be a better predictor of ovulation than measuring LH. Additionally, body temperature tracking is a method that will show if one has not ovulated, which is very important for people with PCOS.

Basal body temperature refers to the temperature of the body when at rest and is the most accurate type of temperature reading to predict ovulation. The natural family planning method usually involves use of a basal body thermometer, and tracking oral temperature every morning before getting out of bed. Basal body thermometers differ from regular thermometers by having more detailed calibration, measuring 1/10th or even 1/100th of a degree. This is important because the change in temperature being tracked is very small.

Looking at different OPKs available on the market, many of them claim to work for PCOS. However, these claims are not always substantiated. Kate Davies’ article, How to Choose the Right Fertility App and Monitor, describes how a large selection of OPKs work, and explains why most of them will not be accurate with PCOS. She recommends a device to track temperature changes that has clinical research behind it to validate its accuracy in predicting ovulation. It is called OvuCore and made by OvuSense.

This device is a vaginal insert that measures core body temperature overnight, takes a temperature reading every 5 minutes, and uses a predictive algorithm to achieve a high degree of reliability in determining ovulation. Is this product necessary for everyone trying to track their ovulation? Definitely not. But for people with PCOS who are feeling confused, and not getting the information they need about their cycle, this device may be very useful.

When using the natural family planning method, tracking ovulatory mucus is also a key part of the process. People with PCOS are likely to have cycles that behave differently in this regard too. For example, people with PCOS may find that they produce mucus, but then it disappears. And this can happen several times during the same cycle. These “false starts” will correlate with rises and declines in body temperature as the body attempts to ovulate. The body may finally achieve ovulation late in the cycle, or the cycle may remain anovulatory.

Once one is properly trained in how to track cervical mucus changes and basal body temperature, the natural family planning method has been shown to be up to 99% effective. For anyone using the method, it is highly recommended to work with a fertility specialist for proper training, and one can expect it to take 3 months to effectively learn the method.

For people with PCOS who are not ovulating, herbal support and nutritional changes can make a big difference. Consider reaching out to a Registered Herbalist or a Licensed Nutritionist for help.


  1. Davies, K. (2020). How to choose the right fertility app and monitor. PCOS Diva.

  2. Medling, A. (2021). OvuSense: Fertility monitor for women with PCOS (updated). PCOS Diva.

  3. Medling, A. (2016). The best ovulation predictor kit & fertility monitoring for PCOS. PCOS Diva Podcast.

  4. OvuSense.

  5. S. Papaioannou, M. Aslam, B. H. Al Wattar, R. C. Milnes & T. G. Knowles (2013) User's acceptability of OvuSense: A novel vaginal temperature sensor for prediction of the fertile period. Journal of Obstetrics and Gynaecology, 33:7, 705-709, DOI: 10.3109/01443615.2013.817984

  6. Papaioannou S, Delkos D, Pardey J, Milnes R.C., Knowles T.G. (2014). Vaginal core body temperature assessment identifies pre-ovulatory body temperature rise and detects ovulation in advance of ultrasound folliculometry. Retrieved from

  7. Steward K, Raja A. (2022). Physiology, ovulation and basal body temperature. StatPearls Publishing, LLC. Retrieved from

  8. Your Fertility Journey.

Having trouble with your own PCOS?

About me:

My name is Jillian Bar-av and I am a Registered Herbalist and Licensed Nutritionist who works with busy women to help them have the energy to do what they love. I specialize in conditions that affect the reproductive system and urinary tract, such as PCOS and Interstitial Cystitis. I believe that it takes healthy people to create a healthy planet, and I want to make a difference for both.

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