Serum Progesterone

Function

Progesterone is a steroid hormone primarily produced by the corpus luteum in the ovaries during the second half of the menstrual cycle and by the placenta during pregnancy. Its chief role is to prepare the endometrial lining of the uterus for the implantation of a fertilized egg and to maintain the pregnancy.

Why it is Ordered

• Ovulation Confirmation: A mid-luteal phase (Day 21) test is the gold standard for confirming that ovulation has occurred.
• Infertility Evaluation: To check if the corpus luteum is producing enough hormone to support a potential pregnancy.
• Early Pregnancy Monitoring: To assess the risk of miscarriage or ectopic pregnancy if a patient experiences spotting or pain.
• Abnormal Uterine Bleeding: To evaluate hormonal imbalances in non-pregnant women.

Associated Conditions

Low progesterone levels are associated with 'Luteal Phase Deficiency,' which can prevent implantation or lead to early pregnancy loss. It is also low in cases of ectopic pregnancy. High levels are seen during normal pregnancy, multiple gestations (twins), and occasionally in rare types of ovarian cysts or adrenal tumors.

Physiological Context

In men, progesterone is produced in small amounts by the adrenal glands and testes, serving as a precursor to testosterone and cortisol. In women, levels fluctuate wildly based on the phase of the menstrual cycle, necessitating precise timing for accurate interpretation.