Page 118 - PRECONGRESS COURSE 06

Luteal phase physiology after COS
• The luteal phase of all stimulated cycles is disrupted (Edwards et al. 1980)
• Supraphysiological steroid level (E2 and P4) in early-mid luteal phase exert a negative feed-back on the hypothalamic-pituitary axis reducing LH secretion in early luteal phase
(Tavaniotou and Devroey, 2006; Tavaniotou et al., 2001)
LH/LH like activity in natural cycle versus GnRHa Kisspeptin and hCG trigger
GnRHa
4h
14h
Kisspeptin
0
hCG Natural
20h
48h
Hoff et al., 1983; Gonen et al., 1990; Itskovitz et al., 1991; Jayasena et al., 2014
12 h
14h
28-32 h
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