What is a PdG Test — and Should You Get One?

In the world of TTC, what is a PdG test? Turns out, it’s one of your best tools for helping you suss if you’re ovulating succesfully. We’re diving into the details here.
If you’re trying to conceive (TTC), chances are, you’ve already come across lots of different acronyms — DPO, BBT, IVF, and, of course, TTC itself.

And then there’s the PdG test.

Still not fully clued in on what this little urine-based hormone test is exactly?

Let’s just say, it’s an essential piece of your TTC toolkit, especially if you’re a PCOS or endometriosis warrior.

Timing is everything when trying to conceive and we’re not about to waste a moment of yours.

So, read on as we reveal how PdG tests work, what they tell you, and how they can help your chances of conceiving.

We’ve also thrown in some progesterone questions that might be on your mind, too with answers approved by embryologist expert Navya Muralidhar.

In this article: 📝

What is PdG?

The PdG here stands for pregnanediol-3a-glucuronide.

Catchy right?

But what exactly is it?

PdG appears in your urine when your body is breaking down the hormone progesterone.

As the main urine marker of progesterone, the amount of it in your pee indicates how much is in your body.

That’s important, because progesterone is closely linked to ovulation – more specifically to the moment an egg leaves one of your ovaries.

When an egg is released, the follicle that released the egg forms the corpus luteum – a temporary hormone-secreting structure – which starts to produce progesterone to help prepare for pregnancy.

So far so good.

Once ovulation takes place, your progesterone levels increase.

One of Progesterone’s important jobs is to prepare the lining of the uterus for pregnancy, making it sticky enough for your embryo to make itself a home – what you know as implantation.

It goes without saying, you want your progesterone levels high to ensure this implantation window is wide open.

What is a PdG Test?

So, where does the PdG test come in?

Higher PdG levels mean higher progesterone levels, which mean ovulation has taken place.

In the past, you’d have to go to the doctor to test to see if ovulation had happened.

To do that, they’d give you an ultrasound or blood test.

But things have changed.

Now, you can carry out a PdG test yourself at home by, you guessed it, peeing on a stick.

And because it’s so easy to do, the tests can be repeated over many days.

That way, you can get a more complete picture of your progesterone levels than you’d get from a single blood test.

Is PdG test same as ovulation test?

Not exactly, the key difference being ovulation tests help you predict when you can expect to ovulate while PdG tests confirm you have.

Ovulation tests work by measuring a surge in luteinizing hormone (LH) whose whole bit is telling your ovaries that it’s time to release that egg baby!

A PdG test is what swoops in to tell you if implantation has indeed been made possible.

Both are equally important for your TTC journey.

What makes PdG tests particularly important is the supportive role it plays in helping women who are struggling to conceive.

PCOS is one of the leading causes of infertility in women, thanks in no small part to the hormonal imbalances it creates – one of which is progesterone imbalances.

If you have PCOS, a PdG test can be an invaluable tool for helping you gain insight into whether you are ovulating normally – especially when used with an ovulation test.

It’s all about setting you up for success and taking intolerable guestwork out of the equation.

Is a PdG test a pregnancy test?

A PdG test doesn’t actually tell you whether you’re pregnant – no more than an ovulation test can.

But it can help you find out whether you’ve ovulated and the length of what’s known as your “luteal phase”.

That’s the time between ovulation and the start of your next period.

Having this information when you’re TTC can help you better understand where you’re at in your cycle and see if anything is getting in the way of ovulation.

When is the best time to test PdG?

For PdG, you can expect to get the most accurate results if you test first thing in the morning (that’s FMU in TTC lingo).

Most tests recommend that you test about a week after you expected to ovulate, every morning, for a period of about four days.

How long after ovulation does PdG rise?

According to this study, progesterone rises between 24 to 36 hours after ovulation

Which means you can expect pregnanediol 3-glucuronide to reach peak levels as little as five days after ovulation – though it’s not uncommon to for PdG to spike even nine days after.

Does PdG drop during implantation?

Quite the opposite.

If progesterone has worked its magic and prepared the endometrial lining needed for implantation, you can expect PdG levels to remain elevated.

The reason being that once an embryo successfully implants, that corpus luteum we talked about earlier will continue to produce progesterone.

It’s more the case that PdG will drop if implantation doesn’t occur.

Does PdG drop if pregnant?

Progesterone is super important for a healthy pregnancy – there’s a reason it’s considered the pregnancy hormone. 🦸‍♀️

It’s what helps your uterus support and keep your growing baby comfortable throughout your pregnancy.

It even helps your immune system handle the new DNA forming within your incredibly smart body.

In the first seven to nine weeks of pregnancy, the corpus luteum will continue producing progesterone before the placenta takes over.

Progesterone levels will continue to rise throughout your first, second, and third trimester – we’re talking up to 10 times higher – before falling back to their normal pre-pregnancy levels.

Can you get pregnant with low PdG levels?

Knowing how big a role progesterone plays in pregnancy, you may be wondering how low is too low.

The reality is, progesterone holds so much responsibility it needs to be working as high a capacity as possible.

All of this makes sense when we consider how it works to prepare your body for pregnancy and helps you support your baby’s growth and development throughout.

Chances are, if your PdG levels are too low for implantation, you may have already noticed signs of low progesterone such as:

• Irregular or missed periods
  
• Abnormal bleeding or spotting
  
• Depression
  
• Trouble sleeping
  
• Reproductive challenges
  
• Pregnancy loss

As for the reason why your progesterone levels are low, this a little more complicated and unique to each individual.

Causes can include an underactive thyroid, PCOS, chronically high cortisol levels, and menopause.

But this is also why a PdG test can be so beneficial – it gives your doctor a starting point to find the right direction for your TTC journey.

Because the good news is, there are plenty of treatments available to help you get closer to being a mama.

A PdG test may just help you get there faster (and with a little less frustration).

How does PdG confirm ovulation?

Before we answer this, let’s confirm what successful ovulation looks like.

Basically it means an egg has been released and your progesterone remained high enough for conception to happen.

If your PdG is registering a spike in pregnanediol 3-glucuronide, you can be confident you’ve achieved peak healthy ovulation.

Nice.

What should PdG be to confirm ovulation?

If you’re wondering how to read PdG test results, the answer will depend on the type of test.

Some tests will simply display the result as “positive” or “negative”.

A positive result means you have at least 5 µg/mg – and that you’ve likely ovulated.

Other tests will show you a specific number.

That also means you’ll be able to see how your PdG levels change over time if you take multiple tests.

Does positive PdG test mean you ovulated?

100%

Most PdG tests are designed to turn positive when there’s at least 5 µg/mg present in your pee.

That being said, it is recommended to test your PdG levels over multiple days for a clearer picture of your ovulation.

Still, that first positive test is worth celebrating. 🎉

How accurate are PdG tests?

Hmm the big question.

And a fair one too!

Studies show that urinary pregnanediol 3-glucuronide testing can confirm ovulation with 100% specificity.

It’s even been shown that PdG testing is more accurate than blood tests as progesterone tends to be released in the bloodstream in pulsations.

With such big fluctuations, a single blood test is not enough to give a reliable result.

That would require blood tests several days in a row.

Since your FMU show your average progesterone levels for the previous day – fluctuations included – PdG tests can give you the most accurate results.

And if we’re going to take multiple tests, we’d take peeing on a stick over a blood test any day.

What does PdG mean in fertility?

Your PdG test meaning may be only part of the picture when it comes to your fertility.

But, if you’re TTC, every piece of information can bring you closer to celebrating a positive result.

If tests show your PdG levels are low, don’t panic.

Talk to your doctor and identify your next steps. Various treatments are available.

You have options.

And if you need some support along the way, join us on Peanut.

The TTC journey can be tough.

You don’t have to go through it alone. 👭🏽