Progesterone is one of the most important hormones that regulates the female reproductive system. It plays many different roles, both during your menstrual cycle and during pregnancies.
As a result, it’s no surprise that abnormal progesterone levels can lead to a wide range of imbalances and health problems.
But do you know what healthy progesterone levels should be?
Healthy progesterone levels
Normal progesterone levels vary depending on your age, which stage of your menstrual cycle you’re on, and whether you’re pregnant or not. Reference values can vary slightly depending on the laboratory.
According to the University of Rochester Medical Center, normal progesterone levels range between:
- Prepubescent girls: 0.1 to 0.3 ng/mL
- Stage of the menstrual cycle:
- Follicular stage: 0.1 to 0.7 ng/mL
- Ovulation: < or = 12 ng/mL
- Luteal stage: 2 to 25 ng/mL
- Trimester of pregnancy:
- First trimester: 10 to 44 ng/mL
- Second trimester: 19.5 to 82.5 ng/mL
- Third trimester: 65 to 290 ng/mL
- Post-menopausal women: < or = 0.20 ng/mL
Very low levels of progesterone can also be found in men, although a progesterone test isn’t typically carried out in males unless a condition called adrenal gland dysfunction is suspected. Normal progesterone levels in men should be <0.20 ng/mL.
What are the functions of progesterone?
Progesterone is a hormone that is mainly secreted by your ovaries. When you’re not pregnant, it’s specifically produced by the corpus luteum, which is a temporary structure that forms in your ovary each month to aid in the case of possible fertilization.
During early pregnancy, the placenta takes over the secretion of progesterone. Progesterone’s most important function is to prepare your uterus each month and make sure it’s ready to receive the implantation of a fertilized egg or embryo.
Once an embryo has implanted, progesterone continues to help maintain the pregnancy. If a woman doesn’t get pregnant during a cycle, progesterone levels drop, which is one of the mechanisms that leads to menstruation.
According to the Hormone Health Network, progesterone also inhibits uterine contractions during early pregnancy in order to protect the pregnancy. It also increases blood flow to the blood vessels in the endometrium (the innermost lining of the uterus) to provide nutrients to the growing embryo.
Throughout pregnancy, progesterone remains elevated to prevent more eggs from being released by your ovaries. At the same time, it helps prepare your breasts so they produce milk for breastfeeding.
Progesterone plays other roles in the human body. According to the Cleveland Clinic, progesterone is also involved in the regulation of our blood pressure, mood, and sleep patterns.
Progesterone can also be used as a medical treatment. According to the NHS, hormone replacement therapy (HRT) typically contains both estrogen and progesterone, although some patients only require estrogen. HRT can be used to decrease symptoms caused by menopause and reduce its associated health risks.
Synthetic progesterone can also be found in many different types of hormonal contraceptives. The most common type of contraceptive pill is the combined pill, which contains both a synthetic estrogen and progesterone.
There are also different progesterone-only contraceptives, which can be used by women who can’t take estrogen for some reason. According to NPS MedicineWise, these include:
- “Mini-pill” or progesterone-only pills
- Contraceptive injections, which are administered as an intramuscular injection every 3 months.
- Contraceptive implants, which are inserted under the skin and can last anywhere between 3 to 5 years, depending on the brand.
- Vaginal rings, which are placed inside the vagina and release progesterone into the vaginal mucosa. Vaginal rings are typically left inside the vagina for 21 days, and then removed for 7 days.
- Hormonal intrauterine devices (IUDs), which are placed inside the uterus where they release progesterone to prevent conception. These devices can last 3 to 7 years, depending on the brand.
What happens if my progesterone levels aren’t normal?
Different conditions can cause abnormal progesterone levels, leading to a wide range of manifestations. It’s important to seek guidance from your physician if you suspect a hormonal imbalance, since they’ll be able to order the necessary tests to reach an accurate diagnosis and prescribe the right course of treatment.
High progesterone
Increased levels of progesterone during pregnancy could point to a twin pregnancy, but it could also be a sign of an abnormal type of pregnancy called molar pregnancy. High progesterone when you’re not pregnant could be a sign of an ovarian tumor called a lipid ovarian tumor, also known as chorionepithelioma.
However, both of these conditions are extremely rare. According to the Society for Endocrinology, most cases of elevated progesterone have no serious medical consequences. Taking a high dosage of progesterone as a medical treatment can lead to a slightly increased risk of breast cancer.
Low progesterone
Low progesterone during pregnancy could increase your risk of sponteanous abortion or miscarriage. It can also increase the risk of preterm labor.
Low progesterone levels when you’re not pregnant could be a sign of a condition called hypogonadism, where your body doesn’t produce enough sexual hormones. This can also lead to irregular or heavy periods. Low progesterone levels can be found in patients with polycystic ovarian syndrome (PCOS).
Written by Dr. Andrea Pinto on July 9 2021
References
- Progesterone and Progestins - hormone.org
- Hormone Therapy for Menopause Symptoms - my.clevelandclinic.org
- Hormone Replacement Therapy (HRT) - nhs.uk
- Progesterone - urmc.rochester.edu
- Progesterone - yourhormones.info
