延後取卵時機可增加取卵數但可能著床率下降

延後取卵時機(>17mm x3 oocytes), 可能可增加取卵數，
但缺點可能導致子宮內膜黃體化，進而導致著床率下降，
若該週期打算冷凍胚胎不考慮植入，可考慮延後1-2天至卵子更大(>18mm x5)取卵

http://humrep.oxfordjournals.org/content/20/9/2453.full

Prolongation of follicular phase by delaying hCG administration results in a higher incidence of endometrial advancement on the day of oocyte retrieval in GnRH antagonist cycles

1. Efstratios M. Kolibianakis1, 
2. Claire Bourgain, 
3. Evangelos G. Papanikolaou,
4. Michel Camus, 
5. Herman Tournaye, 
6. André C. Van Steirteghem and
7. Paul Devroey

+Author Affiliations

1. Centre for Reproductive Medicine, Dutch-speaking Brussels Free University, Laarbeeklaan 101, 1090 Brussels, Belgium

1. 1To whom correspondence should be addressed. Email: stratis.kolibianakis@otenet.gr

• Received December 20, 2004.
• Revision received February 14, 2005.
• Accepted April 7, 2005.

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Abstract

BACKGROUND: Prolongation of follicular phase by delaying hCG administration has been reported to result in a significantly lower ongoing pregnancy rate that did not seem to be due to an embryonic factor. The aim of this prospective randomized study was to assess the effect of delaying hCG administration on endometrial histology. METHODS: Ten oocyte donors underwent endometrial biopsy on the day of oocyte retrieval and endometrial histology was assessed by Noyes’ criteria. Ovarian stimulation was performed with recombinant (r)FSH and daily GnRH antagonist starting on day 6 of stimulation. Patients were randomized by a computer-generated list to receive 10 000 IU of hCG either as soon as ≥3 follicles ≥17 mm were present on ultrasound (early-hCG group, n=5) or 2 days after this criterion was met (late-hCG group,n=5). RESULTS: When hCG was delayed, endometrial advancement was present in all samples examined (median advancement 3 days, range 2–3 days). On the contrary, no secretory changes were observed when the follicular phase was not prolonged (difference in the proportion of patients with advancement between the early-hCG and the late-hCG group: 100%, 95% CI: 38–100). CONCLUSIONS: Prolongation of follicular phase by delaying hCG administration results in a higher incidence of endometrial advancement on the day of oocyte retrieval in GnRH antagonist cycles.