Martins W P, Nastri C O, Rienzi L, van der Poel S Z, Gracia C R, Racowsky C
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900 - Monte Alegre, Ribeirao Preto - SP, 14049-900, Brazil.
SMEAR fertilidade, Reproductive Medicine, Av. Aurea Aparecida Bragheto Machado, 220 - City Ribeirao, Ribeirao Preto - SP, 14021-570, Brazil.
Hum Reprod. 2016 Nov;31(11):2561-2569. doi: 10.1093/humrep/dew244. Epub 2016 Oct 7.
Is blastocyst transfer safe when compared to cleavage stage embryo transfer regarding obstetric and perinatal outcomes?
The clinical equipoise between blastocyst and cleavage stage embryo transfer remains as the evidence associating blastocyst transfer with some adverse perinatal outcomes is of low/very low quality.
Extended embryo culture to the blastocyst stage provides some theoretical advantages and disadvantages. While it permits embryo self-selection, it also exposes those embryos to possible harm due to the in vitro environment. Both effectiveness and safety should be weighed to permit evidence-based decisions in clinical practice.
STUDY DESIGN, SIZE, DURATION: This is a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies reporting perinatal outcomes for singletons comparing the deliveries resulting from blastocyst and cleavage stage embryo transfer. Observational studies were included because the primary outcomes, perinatal mortality and birth defects, are rare and require a large number of participants (>50 000) to be properly assessed. The last electronic searches were last run on 11 March 2016.
PARTICIPANTS/MATERIALS, SETTING, METHOD: There were 12 observational studies encompassing 195 325 singleton pregnancies included in the study. No RCT reported the studied outcomes. The quality of the included studies was evaluated according to the Newcastle-Ottawa Scale and the quality of the evidence was evaluated according to GRADE criteria.
Blastocyst stage transfer was associated with increased risks of preterm birth (<37 weeks), very preterm birth (<32 weeks), large for gestational age and perinatal mortality, although the latter was only identified from one study. Conversely, blastocyst stage transfer was associated with a decrease in the risks of small for gestational age and vanishing twins, although the latter was reported by only one study.
LIMITATIONS, REASONS FOR CAUTION: The observational nature of the included studies and some inconsistency and imprecision in the analysis contributed to decreasing our confidence in the estimates.
Due to the overall low quality of available evidence, the clinical equipoise between cleavage stage and blastocyst transfer remains. More large well-conducted studies are needed to clarify the potential risks and benefits of blastocyst transfer. As this review was initiated to support global recommendations on best practice, and in light of the challenges in lower resource settings to offer extended culture to blastocyst stage, it is critical to take into consideration these obstetric and neonatal outcomes in order to ensure any recommendation will not result in the overburdening of existing maternal and child health care systems and services.
STUDY FUNDING/COMPETING INTERESTS: No external funding was either sought or obtained for this study. The authors have no competing interests to declare.
CRD42015023910.
与卵裂期胚胎移植相比，囊胚移植在产科和围产期结局方面是否安全？
由于将囊胚移植与某些不良围产期结局相关联的证据质量低/极低，囊胚移植与卵裂期胚胎移植之间的临床平衡仍然存在。
将胚胎培养延长至囊胚期有一些理论上的优缺点。虽然它允许胚胎自我选择，但也使这些胚胎暴露于因体外环境可能造成的伤害。在临床实践中，应权衡有效性和安全性以做出基于证据的决策。
研究设计、规模、持续时间：这是一项对随机对照试验（RCT）和观察性研究的系统评价和荟萃分析，这些研究报告了单胎妊娠的围产期结局，比较了囊胚移植和卵裂期胚胎移植后的分娩情况。纳入观察性研究是因为主要结局，即围产期死亡率和出生缺陷很少见，需要大量参与者（>50000）才能进行适当评估。最后一次电子检索于2016年3月11日进行。
参与者/材料、设置、方法：该研究纳入了12项观察性研究，涉及195325例单胎妊娠。没有RCT报告所研究的结局。根据纽卡斯尔-渥太华量表评估纳入研究的质量，并根据GRADE标准评估证据质量。
囊胚期移植与早产（<37周）、极早产（<32周）、大于胎龄和围产期死亡率增加相关，尽管后者仅在一项研究中得到确认。相反，囊胚期移植与小于胎龄和消失双胎的风险降低相关，尽管后者仅在一项研究中有所报告。
局限性、谨慎理由：纳入研究的观察性性质以及分析中的一些不一致性和不精确性降低了我们对估计值的信心。
由于现有证据的总体质量较低，卵裂期和囊胚期移植之间的临床平衡仍然存在。需要更多大型的高质量研究来阐明囊胚移植的潜在风险和益处。由于启动这项综述是为了支持关于最佳实践的全球建议，并且鉴于在资源较少的环境中提供延长培养至囊胚期存在挑战，考虑这些产科和新生儿结局至关重要，以确保任何建议都不会导致现有母婴保健系统和服务负担过重。
研究资金/利益冲突：本研究未寻求或获得外部资金。作者声明无利益冲突。
PROSPERO注册号：CRD42015023910。
