What is Progesterone?
A progesterone test is a blood test that measures its level in the blood. Progesterone plays an important role in pregnancy and fertility. Men also make progesterone but in much smaller amounts.
A progesterone test is used to find the cause of infertility in both men & women, monitor a high-risk pregnancy, find out the days of ovulation, and diagnose an ectopic pregnancy. The levels greater than normal can be indicative of ovarian cancer and cysts apart from pregnancy. If progesterone levels do not rise and fall on a monthly basis, a woman may not be ovulating nor having regular menstrual periods. This may be a cause of infertility.
The progesterone levels keep on fluctuating throughout your pregnancy and menstrual cycle, you may need to be retested several times.
Why is Progesterone done?
- To identify the cause of female infertility by helping track ovulation (release of egg from ovary)
- To help diagnose an ectopic pregnancy (a condition where the fertilized egg is implanted somewhere other than the uterus)
- To monitor the treatment with progesterone hormone
- To monitor the health of the fetus and placenta, especially in high risk pregnancy
- To determine the cause of abnormal bleeding from the uterus
What does Progesterone Measure?
The progesterone test measures the levels of progesterone in the blood. Progesterone is a hormone which helps to prepare the female body for pregnancy and maintain normal menstrual cycle and coordinate with other female hormones. Every month, the menstrual cycle begins with an increase in the level of estrogen hormone. This causes thickening of the inner lining of the uterus called endometrium. This coincides with an increase in levels of luteinizing hormone which induces the release of an egg from the ovary. Subsequently, a structure called corpus luteum forms on the ovary at the site where the egg was released. The corpus luteum produces progesterone hormone which arrests the endometrial growth and prepares the uterus for implantation of the fertilized egg.
At this juncture one of two things may happen. If the egg remains unfertilized, the corpus luteum slowly breaks down and progesterone levels fall. This induces breakdown of the endometrial lining and menstrual bleeding starts. However, if the egg is fertilized and attaches to the endometrium, the corpus luteum does not degenerate and continues progesterone secretion, thereby maintaining the thickened endometrial lining. After a few weeks of pregnancy, the placenta becomes fully formed and takes over the function of progesterone secretion till the completion of pregnancy. Therefore, increased progesterone levels are seen in pregnancy.
Levels of progesterone also fluctuates during normal menstrual cycle. Progesterone is secreted in much lower amounts in males, and is considered to play a small role in sperm development.
Few cancers can also result in abnormal progesterone levels in men and women.
Interpreting Progesterone results
If the result of a single progesterone test falls outside the normal range, it cannot be considered an abnormal result since progesterone levels change continuously. Abnormal results appear if the patient’s blood progesterone levels fall outside the normal range in multiple subsequent tests.
Apart from pregnancy, higher than normal progesterone levels can be seen in cases of:
· Ovarian cysts
· Ovarian cancer
· Molar pregnancy or non-viable pregnancy
· Congenital Adrenal Hyperplasia (CAH)
· Adrenal cancer
Lower than normal progesterone levels can be seen in cases of:
· Amenorrhea or no menstruation
· Ectopic pregnancy
· Miscarriage or death of fetus