Mateizel I, Santos-Ribeiro S, Done E, Van Landuyt L, Van de Velde H, Tournaye H, Verheyen G
Centre for Reproductive Medicine, UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium
Centre for Reproductive Medicine, UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
Hum Reprod. 2016 Nov;31(11):2435-2441. doi: 10.1093/humrep/dew216. Epub 2016 Sep 22.
Does the manipulation of gametes or embryos during ARTs increase the risk for monozygotic twinning (MZT)?
Frozen embryo transfer (ET) is associated with a lower MZT rate, while blastocyst culture is associated with an increased risk of monozygotic pregnancy.
Monozygotic twins have a higher risk for perinatal complications. Although an increased incidence of monozygotic pregnancies after ART has been previously reported, data regarding the possible impact of different laboratory procedures are conflicting.
STUDY DESIGN, SIZE, DURATION: All clinical pregnancies after single ET carried out in our centre between 2004 and 2013 (n = 6096) were retrospectively analysed for the incidence of MZT. The effect of different laboratory procedures on the incidence of MZT was evaluated.
PARTICIPANTS/MATERIALS, SETTING, METHODS: The following ART risk factors were assessed: maternal age, type of ET (fresh versus frozen), zona pellucida (ZP) manipulation (specifically, ICSI, embryo biopsy and assisted hatching), use of donor oocytes, embryo stage at time of ET (cleavage, compaction, early or advanced blastocyst) and culture media.
The overall MZT rate was 2.2% (136/6096). Frozen ET was associated with a significant reduction in MZT incidence (adjusted odds ratio (aOR) 0.48, 95% CI 0.29-0.80), while blastocyst transfer (early or advanced blastocyst) was associated with a significant increase in MZT risk (aOR 2.70, 95% CI 1.36-5.34; aOR 2.05, 95% CI 1.29-3.26, respectively). No significant differences were found between the MZT and singleton (non-MZT) groups regarding maternal age, the use of different ZP manipulation techniques, not type of culture media used.
LIMITATION, REASONS FOR CAUTION: This study is limited by its retrospective nature and the fact that monozygosity was not confirmed by genetic testing. Furthermore, since monozygotic pregnancy is a rare event, other ART parameters that may influence its incidence could not be assessed during our analysis.
Our findings warrant future studies designed to investigate the association between specific ART procedures and MZT, namely the potential risk of blastocyst transfer to increase MZT.
STUDY FUNDING/COMPETING INTERESTS: No external funding was used for this study. There are no conflicts of interest.
辅助生殖技术（ARTs）过程中对配子或胚胎的操作是否会增加单卵双胎（MZT）的风险？
冷冻胚胎移植（ET）与较低的MZT发生率相关，而囊胚培养与单卵妊娠风险增加相关。
单卵双胞胎围产期并发症风险更高。尽管此前已有报道称ART后单卵妊娠的发生率有所增加，但关于不同实验室操作可能产生的影响的数据存在冲突。
研究设计、规模、持续时间：对2004年至2013年期间在我们中心进行的单胚胎移植后的所有临床妊娠（n = 6096）进行回顾性分析，以确定MZT的发生率。评估了不同实验室操作对MZT发生率的影响。
参与者/材料、设置、方法：评估了以下ART风险因素：产妇年龄、ET类型（新鲜胚胎移植与冷冻胚胎移植）、透明带（ZP）操作（具体而言，卵胞浆内单精子注射、胚胎活检和辅助孵化）、供体卵母细胞的使用、ET时的胚胎阶段（卵裂期、致密化期、早期或晚期囊胚）以及培养基。
总体MZT发生率为2.2%（136/6096）。冷冻ET与MZT发生率的显著降低相关（调整后的优势比（aOR）为0.48，95%置信区间为（CI）0.29 - 0.80），而囊胚移植（早期或晚期囊胚）与MZT风险的显著增加相关（aOR分别为2.70，95% CI 1.36 - 5.34；aOR为2.05，95% CI 1.29 - 3.26）。在产妇年龄、不同ZP操作技术的使用以及所用培养基类型方面，MZT组和单胎（非MZT）组之间未发现显著差异。
局限性、谨慎原因：本研究受其回顾性性质的限制，且单合子性未通过基因检测确认。此外，由于单卵妊娠是罕见事件，在我们的分析过程中无法评估可能影响其发生率的其他ART参数。
我们的研究结果为未来旨在研究特定ART程序与MZT之间关联的研究提供了依据，即囊胚移植增加MZT的潜在风险。
研究资金/利益冲突：本研究未使用外部资金。不存在利益冲突。
