Progesterone

Function

Progesterone is a steroid hormone primarily produced by the corpus luteum in the ovaries following ovulation and by the placenta during pregnancy. Its chief function is to prepare the endometrium (lining of the uterus) for the implantation of a fertilized egg and to maintain the pregnancy by preventing uterine contractions.

Why it is Ordered

This test is a cornerstone of reproductive health assessments. It is ordered to:

• Confirm if ovulation has occurred during a menstrual cycle.
• Evaluate the health of an early pregnancy, especially if spotting or cramping occurs.
• Diagnose the cause of infertility or recurrent miscarriages.
• Monitor high-risk pregnancies or patients receiving progesterone supplementation.
• Help diagnose ectopic pregnancies (in conjunction with hCG levels).

Associated Conditions

Abnormal progesterone levels are associated with several conditions. Low levels during the luteal phase may indicate Luteal Phase Deficiency (LPD), which is a common cause of infertility. High levels outside of pregnancy may be seen in cases of congenital adrenal hyperplasia or certain ovarian tumors. During pregnancy, consistently low levels are a significant marker for potential miscarriage or ectopic pregnancy, while elevated levels are expected as the pregnancy progresses.