Tracking your basal body temperature (BBT) is a great way to confirm ovulation through the identification of temperature rises in your body due to increased progesterone production after ovulation.
Historically, the only ways to gauge adequate progesterone levels were by tracking BBT or getting a blood test. Doctors often measure progesterone around day 21 of the cycle–typically about seven days after ovulation–hoping to catch the post-ovulation rise. This process required a drive to the doctor’s office, an uncomfortable needle-stick, and the chance of missing ovulation.
Ovulation tracking can be tricky, and there are a few common challenges you might run into:
- Your BBT doesn’t show a clear spike
- You miss a few days of tracking and can’t see your coverline
- You struggle to track your temperature consistently every morning
- You suffer from a thyroid imbalance that may affect your basal body temperature
You could visit a reproductive endocrinologist, who uses ultrasounds to track follicle growth and ovulation—but this is expensive and requires frequent clinic visits throughout your cycle.
Fortunately, advancements in at-home hormone testing offer a more convenient way to gain insight into your cycle and suggest that ovulation may have occurred–including progesterone testing or PdG testing.
What is PdG?
PdG (Pregnanediol Glucuronide) is a urine metabolite of progesterone, the hormone that plays a crucial role in the menstrual cycle and pregnancy. After ovulation, your body breaks down progesterone, and PdG is what remains. Measuring PdG levels in urine may indicate that ovulation has occurred, providing valuable information if you are trying to conceive.
PdG tests are at-home urine tests that come with easy-to-use test strips. They are very similar to ovulation tests that measure luteinizing hormone (LH) and pregnancy test strips that measure human gonadotropin hormone (hCG)—dip a test strip in urine and read the results a few minutes later. All three types of fertility tests can be read, stored, and charted in the free Premom Ovulation Tracker app. Talk about a convenient way to track your hormone levels!
Measuring Progesterone To Identify Ovulation
Measuring progesterone may indicate ovulation has occurred. After ovulation, progesterone reduces cervical mucus production, raises body temperature by 04.-1.0ºF, helps the uterus get ready for a fertilized egg, reduces muscle movements in the uterus, and supports early pregnancy.
Traditionally, progesterone was measured through blood tests. However, with PdG tests, you can measure pregnanediol (PdG), the metabolite of progesterone, using at-home progesterone urine test strips or PdG tests. Tracking progesterone levels this way helps you better understand your cycle and improves your chances of timing intercourse for the best chance of getting pregnant.
Research shows that PdG typically begins to rise 24-36 hours after ovulation and reaches a detectable high level (5μg/mL) five days after ovulation [3].
Since this timing is after the LH surge that occurs before ovulation day, a progesterone test is ideal to indicate if ovulation may have occurred.
PdG tests have also been studied in association with cervical mucus tracking [5]. You can use PdG test strips 5-7 days after the disappearance of highly fertile-type mucus to see if ovulation may have occurred.
The Luteal Phase and Progesterone
The luteal phase–the second half of the menstrual cycle–is dominated by progesterone, the hormone released with successful ovulation. Without ovulation, the presence of progesterone is highly unlikely. (This may be due to other medical conditions.)
The luteal phase consists of three phases that are similar in length for most women. Progesterone levels increase during the first two phases:
- Luteinization Process (early stage): Progesterone starts rising
- Progestation Process (middle stage): Peak progesterone levels support implantation
- Luteolysis Process (late stage): Progesterone drops if pregnancy doesn’t occur
Again, with PdG testing, progesterone levels that are at least 5μg/mL can be detected and used to indicate that ovulation may have occurred.
- PdG can be detected as early as 3 days after ovulation.
- PdG levels are typically highest seven days after an LH peak.
When To Use Progesterone (PdG) Testing
Adding PdG testing to your fertility tracking can give you more confidence when trying to conceive.
It’s especially helpful if you:
- Haven’t seen a positive ovulation test after multiple cycles
- Have LH surges that are inconsistent or last longer than 7 days
- Have positive ovulation tests all cycle long
- Have an irregular ovulation cycle and menstrual cycle
- Have PCOS (Polycystic Ovary Syndrome) or other fertility concerns
Here’s how PdG testing works in three different scenarios:
1. You See No LH Surge But See a PdG Spike
If you don’t see an LH surge, but you got a positive PdG result, ovulation likely happened. Possible reasons you missed your LH peak:
- Your LH surge level was too low to detect
- Your LH surge is rapid and was simply missed
- Your LH surge does not typically follow the usual low-high-peak-low trend, but you have ovulated
2. You See No LH Surge and No PdG Spike
If you didn’t see an LH surge and you didn’t get a positive PdG test, consider tracking your basal body temperature (BBT) and using your BBT chart to confirm ovulation. If your BBT chart doesn’t show a spike, it’s a good idea to visit your doctor to rule out an ovulation dysfunction issue. When an LH peak and PdG are both missing, it indicates ovulation likely didn’t happen—an anovulatory cycle.
3. You See an LH Surge and a PdG Spike
This is the ideal scenario! Most fertile women usually find both their LH peak and PdG spike. Seeing both provides reassurance that your body is ready for pregnancy. If you track with the Premom app, it can even help predict both your next ovulation day and period start date.
References
- Blackwell LF, Vigil P, Gross B, d’Arcangues C, Cooke DG, Brown JB. Monitoring of ovarian activity by measurement of urinary excretion rates of estrone glucuronide and pregnanediol glucuronide using the Ovarian Monitor, Part II: reliability of home testing. Hum Reprod. 2012;27(2):550-557. doi:10.1093/humrep/der409
- Blackwell LF, Vigil P, Cooke DG, d’Arcangues C, Brown JB. Monitoring of ovarian activity by daily measurement of urinary excretion rates of oestrone glucuronide and pregnanediol glucuronide using the Ovarian Monitor, Part III: variability of normal menstrual cycle profiles. Hum Reprod. 2013;28(12):3306-3315. doi:10.1093/humrep/det389
- Bouchard TP, Fehring RJ, Schneider M. Pilot Evaluation of a New Urine Progesterone Test to Confirm Ovulation in Women Using a Fertility Monitor. Front Public Health. 2019;7:184. Published 2019 Jul 2. doi:10.3389/fpubh.2019.00184
- Ecochard R, Bouchard T, Leiva R, et al. Characterization of hormonal profiles during the luteal phase in regularly menstruating women. Fertil Steril. 2017;108(1):175-182.e1. doi:10.1016/j.fertnstert.2017.05.012
- Ecochard R, Boehringer H, Rabilloud M, Marret H. Chronological aspects of ultrasonic, hormonal, and other indirect indices of ovulation. BJOG an International Journal of Obstetrics & Gynaecology. 2001;108(8):822-829. doi:10.1111/j.1471-0528.2001.00194.x
- Leiva R, McNamara-Kilian M, Niezgoda H, Ecochard R, Bouchard T. Pilot observational prospective cohort study on the use of a novel home-based urinary pregnanediol 3-glucuronide (PDG) test to confirm ovulation when used as adjunct to fertility awareness methods (FAMs) stage 1. BMJ Open. 2019;9(5):e028496. Published 2019 May 27. doi:10.1136/bmjopen-2018-028496
- Wegrzynowicz AK, Beckley A, Eyvazzadeh A, Levy G, Park J, Klein J. Complete Cycle Mapping Using a Quantitative At-Home Hormone Monitoring System in Prediction of Fertile Days, Confirmation of Ovulation, and Screening for Ovulation Issues Preventing Conception. Medicina (Kaunas). 2022;58(12):1853. Published 2022 Dec 15. doi:10.3390/medicina58121853
