|SydPath Information Sheet||
Dr Graham Jones
|PhysiologyProgesterone is a steroid hormone secreted by
the corpus luteum in response to LH secreted by the pituitary and also in larger amounts
by the placenta during pregnancy. During reproductive years there is a pronounced change
in concentration throughout the menstrual cycle with low concentrations in the follicular
phase and a marked rise in the luteal phase to a peak approximately 7 days prior to the
next menstrual period. It should be noted that there is a variation of over +-/ 20%
in progesterone concentrations during any single day and between days in the same patient.
During pregnancy progesterone concentrations rise continually from the mid-luteal peak of
the cycle in which conception occurs until full term is reached.
Indications for testing
The main purpose for measuring serum progesterone is assessment of ovulation. A raised "mid-luteal" progesterone is a good marker of ovulation in that menstrual cycle. The timing of the mid-luteal sample is best calculated as 7 days prior to the next expected menstrual period. If the cycle is irregular two samples one week apart in the second half of the cycle may be a suitable strategy.
Progesterone may have other indications in specific clinical circumstances.
A riased mid-luteal progesterone is
taken as good evidence of ovulation. There is some variation in the literature concerning
the exact values on which to base this assessment. Some of this uncertainty may relates to
variation within individual patients.
Some authors have suggested the
following interpretation (Williams 2003):
General Reference intervals are as follows:
Serum progesterone is measured in routine venous serum or heparin plasma collections with results available the same day as collection. SydPath uses the Roche Modular system for measurements.C, T, EA. Best Practice No 170 : Investigation of infertility with the emphasis on laboratory testing and with reference to radiological imaging. J. Clin Pathol 2003;56:261-267
|Further information available for SydPath clients from Dr Graham Jones: 8382-9160|
Pathology Service of St Vincent's Hospital, Sydney
|Last updated 5/9/2011|