Progesterone–a hormone produced mainly in the ovaries by the corpus luteum (what the follicle turns into after it releases the egg)– helps prepare the uterus for the implantation of a fertilized egg. If a fertilized egg implants, progesterone then helps the uterine lining (endometrium) to maintain the pregnancy. During pregnancy, the placenta also produces progesterone to support a healthy pregnancy.
Progesterone Test and Fertility: When and Why
A progesterone blood test checks for the amount of progesterone in your blood on the day of the test.
If you’re having trouble conceiving, or undergoing a fertility treatment cycle, your doctor will monitor your progesterone levels to confirm whether ovulation has occurred.
If you’ve suffered a miscarriage, stillbirth, or unusual bleeding, your doctor may also check your progesterone, as it’s also known to support a healthy pregnancy.
Women with low progesterone and a history of miscarriages may be prescribed progesterone supplements as soon as a pregnancy is confirmed. Progesterone supplementation may help reduce the chances of another miscarriage by improving the uterine environment to help sustain a pregnancy.
Progesterone levels rise after ovulation and peak five to nine days after your luteal phase–which occurs during the second half of the menstrual cycle, after ovulation occurs–so progesterone level is usually checked six to eight days after you ovulate (about day 21 of a day 28 cycle). After the midluteal period, your blood progesterone levels will begin to fall if the egg is not fertilized.
- If your progesterone level is elevated within a certain range during the luteal phase, it likely means you are ovulating.
- If your progesterone level is not elevated, it can mean that you’re not ovulating.
- If your menstrual cycle is irregular, you may be asked to come in for several blood tests until your period begins. This can pinpoint when ovulation occurs and ensure an accurate test result.
Contributors to low progesterone levels are:
- Obesity
- Insulin resistance
- High stress levels
- Poor diet
- Lack of exercise
Higher levels of progesterone than normal can be caused by:
- Adrenal cancer
- Ovarian cancer
- Congenital adrenal hyperplasia
During pregnancy, progesterone levels are consistently elevated (beyond just the luteal phase of your cycle).
Dr. Alan Copperman is a board-certified reproductive endocrinologist and infertility specialist with a long history of success in treating infertility and applying fertility preservation technologies. He serves as Medical Director of Progyny, a leading fertility benefits management company, and co-founded and serves as Medical Director of RMA of New York, one of the largest and most prestigious IVF centers in the country. Dr. Copperman is also the Vice Chairman and Director of Infertility for the Icahn School of Medicine at Mount Sinai, and Chief Medical Officer of Sema4, a health information company. Dr. Copperman has been named to New York magazine’s list of Best Doctors 17 years in a row. He has been recognized by his peers and patient advocacy organizations for his commitment to patient-focused and data-driven care. He has published more than 100 original manuscripts and book chapters on reproductive medicine and has co-authored over 300 scientific abstracts on infertility, in vitro fertilization, egg freezing, ovum donation, and reproductive genetics.