腦下垂體拮抗劑GnRH antagonist使用要點

誘導排卵(COH)期間，不穩定&過高的LH將對卵子胚胎品質及懷孕率產生不良影響
過晚施打腦下垂體拮抗劑GnRH antagonist造成LH過高，對卵子胚胎品質及懷孕率產生不良影響‧
單純施打GnRHantagonist應考慮前一周期服用避孕藥，適度壓制自體產生之FHS, LH, 亦減低卵泡生長速度不一之缺點

http://humrep.oxfordjournals.org/content/22/11/2805.full





Figure 2:

(a) Synchronized follicular development after FSH administration in a long GnRH agonist regimen and (b) Follicular development in a fixed day 6 GnRH antagonist regimen without OC pretreatment

The long GnRH agonist protocol suppresses endogenous FSH levels, leading to a follicular cohort of all small follicles at the initiation of FSH administration without leading larger follicles. After exogenous FSH administration, FSH levels remain above the threshold, resulting in a synchronized follicular development. As soon as one or two follicles meet the hCG administration criteria, most follicles will be of more or less similar size and sensitive for hCG. In the fixed GnRH antagonist protocol, endogenous FSH levels are not suppressed during the early follicular phase. The luteo-follicular transition induces FSH levels above the threshold for a short period until hormonal feedback occurs, leading to the initiation of follicular growth of a few leading follicles. After exogenous FSH administration, FSH levels arise above threshold again and will initiate several additional follicles to grow. As soon as the leading follicles meet the hCG criteria, several other follicles will be of smaller sizes and may not be sensitive for hCG yet. Such an asynchronized cohort may therefore result in less oocytes retrieved, compared to the long agonist protocol

Figure 3:

Schematic overview of expected FSH and LH concentrations in various GnRH analogue regimens

a and b are regimens without oral contraceptive pill (OCP) pretreatment: (a) long GnRH agonist protocol and (b) fixed day 6 GnRH antagonist protocol. (c) FSH is started 2 days after the last OCP and (d) FSH is started 5 days after the last OCP in a fixed day 6 GnRH antagonist regimen