Hormone Management in IVF Cycles

Introduction to Hormone Dynamics

Estrogen and progesterone levels are typically maintained at supraphysiological levels in stimulated IVF cycles, while in hormone replacement frozen embryo transfer (HRT-FET) cycles, exogenous hormones replace endogenous production to achieve target therapeutic levels, according to the American Society for Reproductive Medicine 1

In programmed FET cycles with exogenous estrogen and progesterone supplementation, achieving appropriate exogenous hormone levels is key, not the source (endogenous vs. exogenous), as recommended by the American College of Obstetricians and Gynecologists 2
Estrogen priming phase should continue for 12-14 days minimum with estradiol valerate 6mg daily, as suggested by the Society for Assisted Reproductive Technology 2
Endometrial assessment should confirm thickness ≥7-8mm with trilaminar pattern before progesterone initiation, according to the American Society for Reproductive Medicine 2
Progesterone supplementation should be initiated at 800mg vaginal daily once adequate endometrial development is confirmed, as recommended by the European Society of Human Reproduction and Embryology 2
Transfer timing should be calculated precisely from the first progesterone dose (117-120 hours for blastocyst transfer), as suggested by the American College of Obstetricians and Gynecologists 2