Day 21 Testing
Day 21 Testing refers to certain tests that are needed to be done on day 21 of your cycle. Your doctor or fertility specialist may want to check levels of certain hormones, such as progesterone, estradiol (E2), etc. The test also may include measuring the thickness of your uterine lining or endometrium.
What is tested in Day 21 Test?
Hormones function in unique and different ways for male bodies and female bodies. When a woman evaluate, a follicle in the ovary releases egg which goes into the fallopian tubes. From the fallopian tube the egg goes down to the uterus. After releasing the egg, the follicle left in the ovary and it releases a large amount of progesterone.
Day 21 is approximately 7 days after ovulation. Therefore, it is expected to see a spike in progesterone level. Therefore, the test particularly occurs on Day 21, so that the doctor can determine the level of progesterone in your body. A high Day 21 progesterone level is a sign of high pregnancy chances, whereas, low level of progesterone means that no egg has been produced and thus, pregnancy cannot be achieved.
Apart from progesterone, estradiol (E2) also released as the egg follicles grow in the ovary. That is why; a test of estradiol (E2) also is been included in the Day 21 test, as the amount of released estradiol (E2) peaks at ovulation.
Measuring serial estradiol (E2) levels for monitoring superovulation is an important part of Intrauterine Insemination (IUI) and In Vitro Fertilization (IVF). This is important because it indicates follicular growth. Superovulation refers to a controlled simulation of the ovaries as they are manipulated medically in a restricted condition. Superovulation is important as it help producing more than one egg in a month, whereas, normal ovulation produces only one egg a month.
In addition, an ultrasound exam is also used for measuring uterine lining, along with the testing of progesterone level and estradiol (E2) level. The doctor examines if the uterine lining is thick enough for a fertilize egg to implant or not.
Why the test takes place on Day 21?
Spike of progesterone is associated with the timing of ovulation, and also related to the subsequent menstrual period. It is important to note that the timing of ovulation and peak in progesterone is associated with a subsequent menstrual period, and not with a preceding one. Usually, the gap between ovulation and next period is about two week. Therefore, in a 28 days cycle progesterone is measured 7 days before the expected menstruation that is on day 21.
However, menstruation cycle is not same for everyone. Therefore, the testing day needs to be adjusted for longer or shorter cycle, but the gap between ovulation and Day 21 Test should be of 7 days. Note that the counting of days must start from day 1, which is the first day of flow.
What happens after Day 21 testing?
If the Day 21 test shows that the progesterone and estradiol (E2) level meet the minimum requirements then the doctor should process with further steps of pregnancy related medications and treatments. But if the Day 21 test result shows that you are not ovulating then there are certain medications including drugs. Your reproductive endocrinologist will discuss about these options in details with you.
