Route of administration of exogenous progesterone for luteal support does not significantly affect the serum concentration in assisted reproductive technology

The objective of this research is to study the guiding role of serum progesterone level on exogenous luteal support protocols. In the retrospective study, a total of 537 infertile women undergoing IVF/ICSI were recruited. Serum samples were obtained for serum progesterone measurements. The results demonstrated that the progesterone levels of all women gradually decreased over the course of 7 days after ET. The progesterone level of the pregnant women reached a nadir on day 7 after ET and subsequently began to rise, while the progesterone level of the non-pregnant women continued to decrease. Even with different routes of administration of exogenous progesterone, the progesterone levels followed the same patterns. The serum progesterone level does not represent the adequacy of exogenous progesterone supplementation. Therefore, there is no need to measure serum progesterone levels frequently after embryo transfer or adjust the dose according to serum progesterone levels.