How do PdG tests work?
Written by: Dr. Amy Beckley, PhD, Founder and Inventor of the Proov test — the first and only FDA-cleared test to confirm successful ovulation at home.
Written on 2/22/21
PdG tests measure a urine metabolite of progesterone to confirm ovulation and help you get pregnant faster!
If you have been trying to conceive, you’ve probably peed on plenty of sticks. And we know there are many sticks to pee on!
But today we’re talking about a urine-based hormone test strip that provides you with powerful information: PdG tests! Keep reading to learn more about PdG tests and how they work.
What is progesterone?
Before talking about PdG, we should briefly chat about progesterone which is the precursor to PdG. As you probably know, women have two main sex hormones: estrogen and progesterone. The first phase of the cycle is the follicular phase. During this phase, your follicles are growing and putting out estrogen, while progesterone levels remain low.
The follicular phase ends with ovulation — and the release of an egg from a mature follicle. Then, the empty follicle starts producing progesterone and the luteal phase (the second half of your cycle) begins.
Progesterone is called “the pregnancy hormone” for its role in preparing the uterine lining for implantation in case fertilization occurs. Basically, progesterone makes the lining of your uterus “sticky” enough for an embryo to get cozy.
Progesterone levels rise gradually after the egg is released and should maintain an optimal level for several days after ovulation. Because of this, progesterone can be measured during the luteal phase to confirm ovulation occurred.
What is PdG?
PdG (or Pregnanediol Glucuronide) is a urine metabolite of progesterone. After progesterone circulates through your bloodstream, it is metabolized by the liver into PdG and is excreted from your body in urine. PdG levels in urine have been shown to correlate to progesterone levels in blood.
After progesterone circulated through your bloodstream, it is metabolized by the liver into PdG and is excreted from your body in urine.
What is a PdG test and what does it tell me?
A PdG test is a hormone test strip that measures the amount of PdG in your urine. A positive PdG test after ovulation confirms that ovulation occurred.
Right now you may be thinking, But doesn’t a progesterone blood test confirm ovulation? Why would I need a PdG test? And you’re right — serum progesterone tests do in fact confirm ovulation.
However, since PdG tests are non-invasive, you can more easily track your levels over time. This is critical because it turns out that serum progesterone levels can fluctuate drastically during short periods of time. Studies have shown that serum progesterone levels can fluctuate up to 8 times in just a 90-minute period. This means that a blood draw in the morning could give you a different assumption than a blood draw in the afternoon.
Additionally, progesterone blood tests only show levels at one point in time even though progesterone needs to stay elevated for several days during the luteal phase. Without taking multiple progesterone blood tests over several days, you won’t have a good idea of your levels over time.
This is where PdG testing comes in! PdG levels in first morning urine have been shown to take an average of progesterone levels from the day before, meaning PdG is not subject to the same drastic changes as serum progesterone. Plus, since PdG testing is non-invasive, you can easily test your levels over the most critical days of the luteal phase.
Above all, PdG tests give you a more complete picture of the quality of your ovulation that progesterone blood tests simply can’t offer. Understanding your PdG levels after ovulation and the quality of your ovulation can help you better gauge your chances at conception.
How do PdG tests work?
Proov PdG tests are the first and only FDA cleared PdG tests to confirm successful ovulation at home. Proov PdG tests are threshold based and turn positive when at least 5 μg/mL of PdG is present in urine. Published studies have shown this correlates to about 10 ng/mL of progesterone in blood.
This threshold level was decided based upon a study that evaluated urinary levels of PdG after an LH surge, concluding that ultrasound-confirmed ovulation could be identified retrospectively with 100% specificity when urinary PdG thresholds were more than 5μg/mL for three consecutive days following an LH surge.
Unlike traditional ovulation or LH tests, Proov PdG tests are considered positive when only the control line is present. If there are two lines on your PdG test (of any darkness), it is considered negative.
Do you feel better with numbers? We have created the Proov app, which can read your test for you and provide you with the numerical measurements.
Proov is the first and only FDA cleared PdG test kit to confirm successful ovulation at home.
When do I take a PdG test?
Proov PdG tests are taken after ovulation during your luteal phase confirm successful ovulation. We recommend taking a baseline PdG test the day after your period ends, around cycle day 5, 6, 7 or 8. This test will be negative but be sure to snap a picture as they’re helpful in determining if later tests are positive or negative, or if you’ve ovulated without a fully positive test.
After taking a baseline, you’ll want to use your preferred method to track peak fertility. Once you observe peak fertility (for example, a positive LH test or fertile cervical mucus), you’ll want to count 7 days. You’ll test with Proov PdG tests on days 7, 8, 9, and 10 after peak fertility.
While a single positive Proov test confirms that an egg was released, we like to see 3-4 positive Proov tests during this window to confirm that ovulation was successful and is not preventing you from conceiving. Anything less than that may be a sign of weak ovulation, which can make it harder to get pregnant.
If you want to read and store your tests in a convenient place, you can use the clinically validated Proov app. A recent study showed the Proov app to be accurate at detecting changes in Proov PdG tests and confirming ovulation.
How can I improve my PdG levels?
If your Proov results showed that your ovulation quality may be lacking, you may be wondering how you can improve your PdG levels and ovulation quality. Sometimes, simple lifestyle changes are enough to boost PdG levels and make sure you successfully ovulate.
- Diet plays an important role in your fertility. There are several fertility-friendly nutrients to focus on, such as folate, zinc, magnesium, and B vitamins. Some foods also can increase PdG production, such as spinach, kale, whole grains, pumpkin, and nuts.
- Stress reduction is always a good idea and can be especially helpful when TTC. Stress raises your cortisol levels, and high cortisol can cause hormone imbalances linked to infertility. Whether it’s meditation, yoga, a nice cup of herbal tea or a stroll in the forest, go for whatever helps you release some of the pressure.
- Seed cycling is supposed to help balance your hormones in a yummy way, by adding certain grains to your diet, at certain moments of your cycle.
- Prescription progesterone supplements are a great option for improving levels and ovulation quality. If you’re interested in prescription-strength supplements, we recommend consulting your doctor.
Now that you have a better idea of how PdG tests work, you are better equipped with more tools to help you along your fertility journey!