Progesterone

The counter-hormone to oestrogen. It has a calming effect, supports sleep (via GABA-A) and takes part in regulating the lining of the womb. Low values in the second half of the cycle are looked at in premenstrual complaints, sleep problems and inner restlessness.

How progesterone acts in the body

After ovulation, the corpus luteum in the ovary produces progesterone; in pregnancy the placenta takes over. Progesterone transforms the built-up uterine lining into receptive tissue, raises body temperature slightly and counteracts the growth-promoting effects of oestradiol. Its breakdown product allopregnanolone enhances the effect of the calming messenger GABA in the brain. Without pregnancy the corpus luteum regresses; the drop in progesterone triggers menstruation.

Low progesterone – what happens in the body?

If there is little progesterone in the second half of the cycle – for example because ovulation did not occur or the corpus luteum fades early –, the effect of oestradiol predominates: the lining is remodelled less stably, spotting and a shorter second half of the cycle may follow, and the calming enhancement of GABA by allopregnanolone is weaker. In menopause, progesterone usually falls earlier than oestradiol.

High progesterone – what happens in the body?

High levels are physiological in pregnancy. Outside pregnancy they usually result from supplied progesterone; tiredness, drowsiness, breast tenderness and water retention may then occur.

The interpretation is given in your report.