As many practitioners know, the mid-luteal phase is the best time to assess progesterone, a very important hormone marker for overall cycle health.
Progesterone is only secreted in abundance after ovulation. Knowing whether a woman reaches healthy progesterone levels in the luteal phase is key to understanding her physical and emotional well-being, as well as her fertility.
Conventionally, serum progesterone is used to assess whether a woman has ovulated. The urine metabolites in the DUTCH test have been shown to correlate strongly to these measurements. However, in a study published in 1984, it was found that serum progesterone has dramatic fluctuations in the mid to late luteal phase throughout the day. The study evaluated serum progesterone and Luteinizing Hormone (LH) every 10 minutes for 24 hours in women throughout their luteal phase. This frequent sampling of the serum revealed more frequent low amplitude LH pulsations than had been previously characterised. These LH pulsations resulted in frequent fluctuations of progesterone secretion from the corpus luteum. These fluctuations were so dramatic that a woman could go from a high progesterone result to a relatively low result in a short period of time.
The following graph is from the published data:
“ in the mid- and late luteal phase, plasma progesterone concentrations rapidly fluctuated during the 24-h studies from levels as low as 2.3 to peaks of 40.1 ng/ml, often within the course of minutes.”
In fact, the researchers along with conventional medical professionals have concluded that when a single luteal phase serum progesterone is low, the result is considered inconclusive rather than diagnostic of a luteal phase defect or lack of ovulation. Since only low results would trigger therapy considerations, it is not ideal to base any therapy on a single serum result.
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- Filicori, M., J.P. Butler, and W.F. Crowley, Neuroendocrine regulation of the corpus luteum in the human. Evidence for pulsatile progesterone secretion. J Clin Invest, 1984. 73(6): p. 1638-47.