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How to accurately time a Progesterone test

Your doctor may have suggested that you have a progesterone test to confirm ovulation or to assess your progesterone levels in the luteal phase.

 The main test to determine whether a woman is ovulating is by a blood test, which assesses the level of the hormone Progesterone. Progesterone increases in the blood stream following ovulation and reaches it’s peak at 7 days before the next menstrual period. This test is termed a 21-day Progesterone test and is performed on day 21 of a 28 day cycle.

 However, the majority of women don’t have regular 28-day cycles and this can cause confusion on when is best to test and worst still, inaccurate test timing leading to a woman being told that she’s not ovulating. Incorrect timing of Progesterone testing is common and to get the best result, it’s important to be as accurate as possible in timing the test.


Regular cycles

If you have a regular cycle, once OvuSense has confirmed that you have ovulated then it is reasonable to organise your progesterone test for 7 days post ovulation.

Irregular cycles

If you have lengthy irregular cycles, timing your progesterone test is a little more complex.  Whilst the time to ovulation can vary, the time from ovulation to your next period is always consistent. After ovulation your next period will occur 10-16 days later. It is recommended for lengthy irregular cycles that the initial test is performed later (for example day 28 of a 35 day cycle) and then repeated weekly until the next menstrual period starts (NICE Guidelines April 2018).

Progesterone results 

When considering your result, it’s important to remember that the most common reason for an inadequate result is poor timing. If you think this might be the case, ask your Doctor for a repeat test next cycle.

·         A Progesterone level of 30nmol/l* or above is indicative of ovulation in that cycle

·         A result between 16-30nmol/l* indicates that ovulation is likely to have occurred, however may have been mis-timed and a repeat in the next cycle is recommended.

·         A level that is less than 16nmol/l* may mean that ovulation has not occurred, and the test should be repeated in the next cycle.

·         A consistently low result over subsequent cycles may show lack of ovulation and possible progesterone deficiencies. Ask your doctor for a referral to a specialist to discuss what this may mean for you and possible treatment.


NICE (2018) Assessing and managing ovulation disorders https://pathways.nice.org.uk/.../assessing-and-managing-ovulation-disorders.pdf (Accessed 12/06/18)

*UK reference ranges



This blog was written by:  Kate DaviesFertility Nurse and Coach at Your Fertility Journey.

Book your FREE consultation with the OvuSense Fertility Nurse, Kate -  to assess your fertility potential, answer your burning fertility questions, get recommendations on how to optimize your fertility and have your charts analysed.

If you are an OvuSense customer you are entitled to a FREE 1 hour consult, if you are not currently using OvuSense you can book a FREE 15 minute consultation. Consultations are held by Skype or Telephone. Don't see a time that suits you? Email Kate on kate.davies@fertility-focus.com

About our regular contributor, Kate Davies:

Kate Davies (RN, BSc (Hons), FP Cert) is a registered Fertility Nurse Consultant and IVF coach with over 25 years of experience in fertility and women's health. She worked in the UK's National Health Service as a specialist nurse in Gynecology, Sexual and Contraceptive Health and Fertility for 20 years before founding Your Fertility Journey consultancy company. A member of the British Fertility Society and registered with the Nursing and Midwifery Council, she is a practitioner with Fertility UK where she receives regular training and clinical supervision. She has a special interest in both natural contraception and PCOS and has taken specialist training in the latter to enhance her knowledge and practice. She carries out consultations either using online video or at her Harley Street Clinic in London, providing both emotional support and clinical advice to her patients.  In 2017, Your Fertility Journey was awarded Best Fertility Consultancy UK by Lux Health, Beauty and Wellness Awards, and in 2019 were given the title of Best Fertility Consultancy and Best Fertility Nurse by GHP's Alternative Medicine and Holistic Health Awards. Find her on LinkedIn, follow her on Instagram at @your_fertility_journey, and listen to her on The Fertility Podcast.

Kate Davies - Independent Fertility Nurse
Your Fertility Journey

Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition.