Whether progesterone 16.25 ng/ml is normal or not cannot be determined by the value alone, but also depends on the period of time. If it is in a woman’s first trimester it is usually normal, while in the fourth to sixth months it may be abnormal.
Progesterone acts mainly on the corpus luteum during pregnancy and maintains the corpus luteum during early pregnancy. Progesterone’s main role is to promote the thickening of the endometrium, causing the blood vessels and glands therein to proliferate, and converting the endometrium from a proliferative phase to a secretory phase, so as to facilitate the attachment of a fertilized egg. So progesterone is important in both pregnancy and non-pregnancy.
The normal value of progesterone in women is 4.73 to 50.74 ng/ml in the first trimester of pregnancy and 19.41 to 45.3 ng/ml in the fourth to sixth months.
Non-pregnant follicles are 0.31 to 1.52 ng/ml in the middle of the follicle, 5.16 to 18.5 ng/ml in the middle of the corpus luteum, and <0.08 to 0.78 ng/ml in the postmenopausal period (chemiluminescence).
Therefore, progesterone 16.25ng/ml is normal in the first trimester of a woman's pregnancy, the mid-luteal phase of the non-pregnant state, and abnormal in other periods. High or low levels require prompt medical attention to identify the cause and related treatment.