Progesterone is a natural steroid hormone important for the female reproductive system. It primarily prepares the body for potential pregnancy, acting as a chemical messenger that influences processes necessary for successful reproduction.
Progesterone’s Essential Role in Reproduction
Progesterone is fundamental to the female reproductive cycle, especially after ovulation. After an egg’s release, the follicle’s remnants form the corpus luteum, which produces progesterone. This hormone transforms the uterine lining (endometrium), making it thicker and receptive for a fertilized egg to implant.
If conception occurs, progesterone levels continue to rise, supporting early pregnancy. It maintains the uterine environment, supplying nutrients to the developing embryo and preventing contractions that could dislodge it. Around 10 to 12 weeks, the placenta takes over progesterone production, ensuring continued pregnancy support.
How Elevated Progesterone Can Affect Fertility
While progesterone is important for reproduction, unusually high levels, especially at the wrong time in the menstrual cycle, can interfere with fertility. High progesterone can disrupt ovulation by signaling the body that it has already occurred, preventing egg release.
Elevated progesterone can also negatively impact the uterine lining’s receptivity to an embryo. Prematurely high levels can cause the endometrium to mature too quickly, leading to embryo-endometrial asynchrony. This means the uterine lining may not be prepared to receive the embryo when it arrives, potentially leading to implantation failure. High progesterone can alter the gene expression profile of the endometrium, making it unsuitable for successful implantation.
Progesterone influences cervical mucus, making it thicker and less permeable to sperm. While this is a normal function after ovulation to prevent further sperm entry, sustained high levels at other times can hinder sperm transport. In some cases, conditions causing persistently high progesterone, such as nonclassic congenital adrenal hyperplasia (CAH), have been linked to impaired folliculogenesis and recurrent implantation failure.
Common Causes of High Progesterone Levels
Various factors can lead to elevated progesterone levels. Pregnancy is the most common and normal reason, as levels naturally increase to support the developing fetus and maintain the uterine lining. Outside of pregnancy, other conditions can cause these elevations.
Ovarian cysts, particularly corpus luteum cysts, can produce progesterone, leading to higher-than-normal levels. These cysts form from the follicle after ovulation and may continue to secrete hormones instead of dissolving. Adrenal gland disorders, which also produce some progesterone, can contribute to elevated levels.
Congenital adrenal hyperplasia (CAH) is an inherited genetic condition affecting adrenal gland hormone production, often resulting in consistently elevated progesterone. Certain medications, like hormonal therapies or fertility treatments, can also temporarily increase progesterone levels. Rarely, ovarian or adrenal tumors can cause high progesterone production.
Identifying and Addressing High Progesterone
Identifying elevated progesterone levels typically involves a blood test. This test is often performed around day 21 of a standard 28-day menstrual cycle, or about seven days before an expected period. This timing aims to capture progesterone levels when they are expected to peak after ovulation.
Symptoms of high progesterone can be vague, including fatigue, bloating, breast tenderness, and mood changes. Medical testing is often necessary for a definitive diagnosis. If high progesterone levels are detected and are a concern for fertility, consulting a healthcare provider is important. They can assess the situation and determine the underlying cause.
Addressing high progesterone levels usually focuses on managing the root cause. This might involve treating underlying conditions like ovarian cysts or adrenal gland disorders. If medication, such as hormonal therapies or fertility treatments, is the cause, dosage or treatment type adjustments may be considered under medical supervision. The approach aims to normalize hormone levels to support reproductive health.