低氧培養箱(5-6% O2) vs一般氧氣培養箱(19% O2)是否提高懷孕率活產率仍具爭議(0~5% improvement??)

Fertil Steril. 2016 Mar 21. pii: S0015-0282(16)30010-3. doi: 10.1016/j.fertnstert.2016.02.037. [Epub ahead of print]

Low versus atmospheric oxygen tension for embryo culture in assisted reproduction: a systematic review and meta-analysis.

Nastri CO1, Nóbrega BN1, Teixeira DM1, Amorim J1, Diniz LM1, Barbosa MW1, Giorgi VS1, Pileggi VN1, Martins WP2.

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Abstract

OBJECTIVE:

To appraise the available evidence comparing low oxygen (LowO2) and atmospheric oxygen tension (AtmO2) for embryo culture.

DESIGN:

Systematic review and meta-analysis.

SETTING:

Not applicable.

PATIENT(S):

Women undergoing assisted reproduction using embryo culture.

INTERVENTION(S):

Embryo culture using LowO2 versus AtmO2.

MAIN OUTCOME MEASURE(S):

Reproductive, laboratory, and pregnancy outcomes.

RESULT(S):

A total of 21 studies were included in this review. All used O2 concentration between 5% and 6% in the LowO2 group. Considering the studies that randomized women/couples, we observed very low quality evidence that LowO2 is better for live birth/ongoing pregnancy (relative risk [RR] = 1.1, 95% confidence interval [CI] 1.0-1.3) and clinical pregnancy (RR = 1.1, 95% CI 1.0-1.2). Considering the studies that randomized oocytes/embryos, we observed low quality evidence of no difference of fertilization (RR = 1.0, 95% CI 1.0-1.0) and cleavage rate (RR = 1.0, 95% CI 1.0-1.1), and low quality evidence that LowO2 is better for high/top morphology at the cleavage stage (RR = 1.2, 95% CI 1.1-1.3). No studies comparing pregnancy outcomes were identified. Several studies used different incubators in the groups-a new model for the LowO2 group and an old model for the AtmO2 group. The risk of detection bias for the laboratory outcomes was high as embryologists were not blinded.

CONCLUSION(S):

Although we observed a small improvement (∼5%) in live birth/ongoing pregnancy and clinical pregnancy rates (PRs), the evidence is of very low quality and the best interpretation is that we are still very uncertain about differences in this comparison. The clinical equipoise remains and more large well-conducted randomized controlled trials are needed. They should use the same incubators in both groups and the embryologists should be blinded at least when evaluating laboratory outcomes.