Progesterone Test vs. PdG Test: What’s the difference?
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 1/18/21
Progesterone tests and PdG tests are two different ways to measure progesterone and confirm ovulation. But what is the difference and which is better?
What is progesterone and why is it important?
During a woman’s cycle, there are two primary hormones at work: estrogen and progesterone. In the first half of your cycle, the follicular phase, estrogen is elevated and progesterone is low.
Progesterone’s time to shine is during the luteal phase. After ovulation occurs, the follicle from which the egg was released (now known as the corpus luteum) starts producing progesterone.
Progesterone stabilizes the uterine lining and makes it “sticky” enough for an embryo to implant. Progesterone also creates a healthy uterine environment in which an embryo can thrive. Without enough progesterone during the luteal phase, it can be more difficult to get pregnant.
If conception has not occurred following ovulation, progesterone drops, menstruation occurs, and the entire cycle repeats.
Even if you’re not trying to conceive, progesterone plays a vital role in your quality of life. Progesterone acts as a natural antidepressant to lower anxiety, help with mood changes, and can even help in relieving postpartum depression. It also can improve your sleep quality and energy levels by stimulating the thyroid.
Additionally, progesterone can help relieve menopause symptoms and support bone health. Many menopause symptoms are caused by an imbalance of estrogen and progesterone as hormones change over time.
Even if you’re not trying to conceive, progesterone plays a vital role in your quality of life.
When does progesterone rise?
As we mentioned, progesterone rises after ovulation occurs and should stay elevated for several days during the luteal phase.
If you successfully conceive, progesterone will remain high throughout the implantation window and early pregnancy. Once the placenta develops — around weeks 8-12 of pregnancy — it takes over the production of progesterone from the corpus luteum and maintains elevated production throughout the pregnancy.
How do progesterone tests work?
A blood, or serum, progesterone measurement is taken through a one-time blood test from your doctor or a mail away kit. A progesterone blood draw can give you a specific numeric value of progesterone in blood. Usually, doctors order a blood test on day 21 of your cycle, approximately 7 days after ovulation, when progesterone should be the highest.
Progesterone blood tests only show levels at one point in time. This can be problematic as studies show serum progesterone levels fluctuate day by day, even hour by hour. So if you were to get a blood test in the morning, you could get very different results than if you were to get a test in the afternoon. This could lead to inaccurate assumptions about your levels.
Additionally, progesterone needs to remain elevated for several days during the luteal phase to allow for conception to occur. A single progesterone blood test will not show your levels over time.
Why would I get a progesterone test?
While a progesterone blood test likely won’t give complete information surrounding your luteal phase health, it can tell you whether or not you have ovulated that cycle. If you did not ovulate, there would be no corpus luteum present to produce progesterone and therefore you would have low levels on a blood test.
Progesterone blood tests can tell you whether or not you ovulated that cycle.
What is PdG?
PdG (Pregnanediol Glucuronide)is the urine metabolite of progesterone – the hormone released by the ovary after ovulation. After progesterone circulates through your bloodstream, it is metabolized by the kidneys and excreted from the body as PdG. PdG levels in urine correlate to progesterone levels in blood.
How do PdG tests work?
PdG tests are hormone test strips that measure PdG levels in first morning urine samples. Simply collect a first morning urine sample, dip the PdG test in the sample, lay the test strip flat for processing, and read the results.
Since PdG tests are non-invasive, they allow for easy tracking over several days to confirm that ovulation was “successful.” Successful ovulation refers to an ovulatory event in which an egg was released and PdG levels remained elevated for long enough to allow for the best possible chance at conception.
PdG tests are threshold based, meaning they turn positive when PdG reaches a certain level in urine. While a physical PdG test does not provide exact numerical measurements, the Proov app can read your Proov PdG test and provide this measurement.
Why would I get a PdG test?
Unlike a progesterone blood test, PdG testing allows for at home monitoring, meaning you can confirm successful ovulation from the comfort of your own bathroom. You can also track PdG levels over several days for a more complete picture of ovulation, compared to results from a one-time blood test, leading you to actionable next-steps.
Measure your PdG levels with Proov!
Proov PdG tests are the first and only FDA cleared PdG test kit to confirm successful ovulation at home. Proov tests are easy to use and non-invasive, allowing you to track PdG levels throughout the critical window of your luteal phase.
Proov is the first and only FDA cleared PdG test kit to confirm successful ovulation at home.
Testing with Proov on days 7, 8, 9, and 10 after peak fertility confirms that successful ovulation did in fact occur. We like to see four positive Proov PdG tests on these days to confirm successful ovulation and adequate PdG levels.
If you get anything less than three or four positive Proov tests during the testing window, this could be a sign of suboptimal ovulation which could be making it more difficult to get pregnant. You can improve ovulation quality with natural methods such as seed cycling or herbals, or with help from your doctor. If you never get a positive Proov PdG test, we recommend consulting your doctor as this could be a sign of anovulation.
Progesterone and PdG tests are both valuable tools during your trying to conceive journey. Understanding the pros and cons of each will help you make informed decisions to reach your fertility goals faster.