Estrogen | Timing of transfer | Progesterone | |
---|---|---|---|
Ovulatory Cycles | |||
Natural cycles | Follicular development | LH surge | Corpus luteum |
Modified natural cycles | Follicular development | hCG trigger | Corpus luteum with or without supplemental progesterone |
Stimulated cycles | Follicular development | hCG trigger or LH surge | Corpus luteum with or without supplemental progesterone |
Programmed Cycles | |||
Programmed cycles | Exogenous estrogen (oral, vaginal, transdermal) | Initiation of progesterone | Intramuscular and/or vaginal progesterone |