Serum progesterone trend after day of transfer predicts live birth in fresh IVF cycles

Our objective was to determine if a change in serum P4 from day of transfer (defined as day 19) to day 28 could predict live birth outcome in patients undergoing IVF.

This study was a retrospective analysis of fresh IVF cycles from 2010 to 2013 at a single center. Primary outcomes include raw and percent change in serum P4, live birth rate, missed abortion, and biochemical pregnancies.

Our results showed an association between live birth rate and percent change in P4. Patients with a 10% or greater drop in serum P4 from day 19 to day 28 had a lower live birth rate, at 26 versus 63%. Interestingly, both groups had "normal" serum P4 levels on day 19, but patients with a 10% or greater drop had lower P4 levels than their counterparts. There was no association between percent P4 change and spontaneous abortion or biochemical pregnancy.

This is the first study to show that percent drop in serum P4 from day of transfer to day 28 is associated with decreased rates of live birth and ongoing pregnancy in fresh IVF cycles, even despite "high or normal" P4 levels on day of transfer.