Day 21 Fertility Testing

There are two main reasons your fertility doctor may want to check your progesterone levels:

1. To confirm that you are ovulating
2. To confirm that you are producing enough progesterone.

Progesterone is a very important hormone, particularly for establishing and sustaining a healthy pregnancy. This hormone helps maintain an optimal uterine lining to ensure that it is a good environment for an embryo to implant.

Before you ovulate, high levels of estrogen cause your uterine lining to thicken. You should have very low levels of progesterone at this point in your cycle.

After you ovulate, progesterone starts to rise, reaching a peak about midway through your luteal phase. As progesterone levels increase, your uterine lining prepares to receive an embryo (if one is present).

Learn more about the Importance of Progesterone here.

Firstly, try not to worry! Progesterone suppositories can help increase low progesterone levels and reduce the chances of miscarriage by improving the uterine environment.

If you have a history of pregnancy losses, your doctor may prescribe progesterone supplementation  as soon as a pregnancy is confirmed in order to give you the best chance of a healthy, sustained pregnancy.

Some common contributors to low progesterone levels are: 

• High BMI 
• Insulin resistance 
• High stress levels 
• Poor diet 
• Lack of exercise

High levels of progesterone can be caused by: 

• Adrenal cancer 
• Ovarian cancer 
• Congenital adrenal hyperplasia 

However, if your Day 21 testing results come back with high progesterone levels, that does not mean that you need to worry about any of the above issues. Always talk to your doctor for insights on your personal situation.

It's important to know that when it comes to both hCG levels and progesterone levels, no single value can predict a healthy pregnancy outcome.

According to ACOG guidelines, a normal progesterone level in early pregnancy should be between 11.2 and 90 ng/mL (nanograms per milliliter), with levels above 25 ng/mL generally indicating a viable pregnancy, while levels below 5 ng/mL often associated with a nonviable pregnancy.

NOTE: It's always important to consult with your healthcare provider for interpretation based on your individual circumstances.