The impact of endometrial preparation for frozen embryo transfer on maternal and neonatal outcomes: a review

Table 1 Cycle characteristics for frozen embryo transfer preparation

	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