The Progesterone Hormone

Progesterone is one of the two sex hormones. A woman’s ovaries produce this hormone during the Luteal Phase, or the last two weeks of a woman’s monthly cycle. This hormone thickens the nutrient-based endometrium in preparation to receive a fertilized egg. It also helps the breasts prepare for milk production. The main function of this hormone is that it causes the endometrium to secrete proteins during the second half of the menstrual cycle, preparing it for the arrival of an implanted fertilized egg.

Progesterone levels rise during the second half of the menstrual cycle, and following ovulation, the ovarian tissue that replaces the follicle continues to produce estrogen and progesterone. It is believed to be the culprit and the cause of PMS, or premenstrual syndrome, which is the cause of breast tenderness, mood swings and the bloated feeling.

Progesterone and Pregnancy

Progesterone also plays a crucial role in maintaining one’s pregnancy. This hormone is produced in the ovaries, the placenta (when a woman gets pregnant) and the adrenal glands. Progesterone also helps prepare your body for conception and pregnancy, plus it regulates a woman’s monthly menstrual cycle. It also plays a role in sexual desire. As mentioned, once pregnancy occurs, progesterone is produced in the placenta, and levels remain elevated throughout the term. The combination of high estrogen and progesterone levels prevent further ovulation during pregnancy.

During the early stages of pregnancy, progesterone levels double and triple compared to what they were before pregnancy. By the end of the first trimester, the placenta takes over progesterone production affecting the levels. The progesterone levels during pregnancy is also crucial for the survival of the fetus, as it keeps the uterus from contracting and promotes the growth of blood vessels, giving the needed nourishment to your baby. As the pregnancy continues, daily the progesterone levels rise, adding up to 15 times above average by the time the third trimester comes around.