Research findings shed light on predictive value of PdG testing for pregnancy outcomes

By MDLinx staff
Published October 4, 2022

Key Takeaways

  • Research links positive PdG cycles with increased pregnancy rates and reduced chances of first-trimester pregnancy loss.

  • The study also discussed the benefits of progesterone or ovulation induction for women with negative PdG cycles at the luteal phase of a woman’s cycle, as well as using luteinizing hormone and PdG testing as preconception screening tools.

  • These findings come at a time when the accuracy of some ovulation tests is being called into question via lawsuits. Clinicians recommending these tests to patients who are trying to get pregnant should be mindful of research findings on the tests’ accuracy.

A study published in the September 2022 issue of Obstetrics & Gynecology Research shows an association between positive PdG cycles and increased pregnancy rates, along with reduced chances of first-trimester pregnancy loss.[]

The study was sponsored by Proov, the manufacturer of the first and only FDA-approved PdG-test and the first full-cycle tracking kit.

These findings could be helpful to clinicians in their efforts to advise and care for patients who are trying to get pregnant, before initiating IVF therapy. PdG testing also gives couples more data and understanding of the cycle.

Study results

Researchers were able to correlate positive cycles of the major progesterone (P4) metabolite pregnanediol-3-glucuronide (PdG), which is used to confirm ovulation, with a 75% increase in pregnancy rates as well as a decrease in first-trimester pregnancy losses related to low progesterone. While testing for PdG may provide useful feedback about the quality of the cycle, it should be noted that the test itself doesn’t affect the outcome of a pregnancy.

The goal of the study, which had 185 participants, was to "give a complete picture of progesterone production across the luteal phase required for pregnancy," according to the authors.

This research focused on the benefits of luteal phase support with progesterone or ovulation induction for women with negative PdG cycles.

The luteal phase occurs after ovulation, continues through the next menstruation or through pregnancy, and is responsible for progesterone secretion. The luteal phase is triggered by luteinizing hormone (LH.) After the dominant follicle ruptures, releasing an oocyte, the dominant follicle becomes the corpus luteum, which secretes progesterone in preparation for pregnancy.

If fertilization occurs, the corpus luteum continues to secrete progesterone until the first 6–8 weeks of pregnancy; then the placenta takes over. If fertilization does not occur or if enough progesterone is not secreted, the corpus luteum breaks down, resulting in menstruation. Therefore, progesterone is crucial for pregnancy to occur, and PdG testing can help determine if a woman has low progesterone during pre-conception.[]

This study suggests the use of LH and PdG testing as preconception screening tools to help identify subfertility in women and the probability of first-trimester loss of pregnancies due to low progesterone. If a woman who is trying to conceive has a negative PdG cycle, she can potentially use medications that help to induce LH and progesterone secretion at the preconception stage, which can potentially decrease the need for IVF treatments.

"At-home urinary PdG testing over four days offers a noninvasive method of monitoring mid-luteal activity and can be used as a marker of luteal health."

Beckley, et al.

"It is a more patient-friendly way to assess for progesterone deficiency and provides a more complete picture of luteal function when compared to a brief snapshot of one serum progesterone level," the study authors continued.

Ovulation test scrutiny

Ovulation tests are the focus of a lawsuit against major manufacturers (including Clearblue, First Response, Up&Up, and CVS Health) contending that their tests are unreliable and misleading to consumers, impacting their conception chances by providing incomplete information.

Clinicians should be mindful of this type of legal action concerning ovulation tests, as it may be indicative that some are giving unreliable results, possibly impacting patients’ chances of having successful pregnancies.

What this means for you

These findings indicate that positive PdG cycles, in addition to LH levels, are the benchmark for preconception testing. A positive PdG cycle is a sign of increased chances of having a full-term pregnancy, while a negative PgG cycle can potentially guide subfertility treatment by administering medications that increase progesterone levels before discussing potentially unnecessary IVF treatments. Clinicians should stay current on research concerning ovulation tests to ensure that these patients are using ones with verified high accuracy.

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