What is the significance of a progesterone level of 1.55 nmol/L on day 21?

There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.

The FDA Drug Labels for progesterone (PO) do not address this question.

From the Research

Progesterone Level Significance

• A progesterone level of 1.55 nmol/L on day 21 is significantly lower than the median progesterone level associated with viability, which is around 59 nmol/L 1.
• According to a study, a single serum progesterone level of ≥5ng/ml (approximately 15.9 nmol/L) is highly specific for confirming ovulation 2.
• Another study found that a progesterone level of <6.3 ng/mL (approximately 20.034 nmol/L) is associated with a high likelihood of non-viable pregnancy, while a level of ≥20-25 ng/mL (approximately 63.6-79.5 nmol/L) is associated with a high likelihood of viable pregnancy 3.
• The physiological role of progesterone is crucial in the menstrual cycle and pregnancy, and it has various clinical implications, including contraception, treatment of dysfunctional uterine bleeding, and prevention of cancer 4.
• In the context of assisted reproductive technology, elevated progesterone levels during the ART cycle may lead to cycle cancellations or further progesterone supplementation, but the practice varies, and the optimal progesterone level is still a topic of debate 5.

Clinical Implications

• The progesterone level of 1.55 nmol/L on day 21 may indicate a lower likelihood of pregnancy viability, but it is essential to consider other factors and biomarkers, such as β human chorionic gonadotropin (βhCG) levels, to determine the viability of the pregnancy 1, 3.
• The progesterone level may also be influenced by various factors, including the timing of the measurement, the individual's menstrual cycle, and the presence of any underlying medical conditions 2, 4.
• Further research is needed to determine the optimal progesterone level for confirming ovulation and predicting pregnancy viability, as well as to establish standardized guidelines for the use of progesterone in clinical practice 2, 3, 5.