COH時間越長,可能造成子宮內膜老化, 進而降低懷孕率

COH時間越長, 延長濾泡期, 植入時間往後延後之結果，可能造成子宮內膜受E2刺激時間延長,造成子宮內膜老化,  進而降低懷孕率

http://humrep.oxfordjournals.org/content/21/4/1012.full

Table IV.

Ongoing pregnancy per embryo transfer in groups of patients defined by percentile analysis (thirdile) of the duration of menstruation, duration of stimulation and duration of the menstruation-free interval

	Ongoing pregnancy n (%)	Pa
Menstruation duration		0.32
3–4 days	5/28 (10.7)
5 days	8/35 (22.9)
≥6 days	4/19 (21.1)
Duration of stimulation		0.12
7–10 days	12/48 (25.0)
11 days	1/16 (6.3)
12–18 days	2/18 (11.1)
Menstruation-free interval		0.02
1–5 days	12/44 (27.3)
6 days	2/15(13.3)
≥7 days	1/23 (4.3)