OVO Clinic, 8000 Boulevard Decarie #100, Montreal, Quebec, Canada.
Reprod Biomed Online. 2012 Nov;25(5):460-5. doi: 10.1016/j.rbmo.2012.06.019. Epub 2012 Jul 8.
Monozygotic multiple pregnancies are three times more common after assisted reproduction (with or without IVF) than after spontaneous conception (1.2% versus 0.4%). These pregnancies are associated with multiple maternal and fetal risks. This article is a description of nine cases of monozygotic pregnancies following IVF at the OVO Clinic (Montreal) between January 2007 and August 2011 and a scientific review of the literature on monozygotic multiple pregnancies after assisted reproductive treatment found in the MEDLINE and Cochrane Databases. In this retrospective series, 3522 embryos were transferred and 1033 pregnancies were obtained, of which there were nine monozygotics (0.87%). The exact mechanism behind this increased frequency remains uncertain. Possible explanations associated with fertility treatments include alterations of the zona pellucida, transfers at the blastocyst stage, prolonged culture, preimplantation genetic diagnosis, ovarian stimulation and maternal age. Assisted reproduction treatment appears to increase monozygotic pregnancies; however, the rate is still low and therefore it is difficult to exactly conclude the real mechanism. There are two types of multiple pregnancy: the dizygotic (two different embryos) and the monozygotic (one embryo which splits to make two identical genetic embryos). We know the risk factors for dizygotic pregnancies, but the mechanism of monozygotic pregnancies remains unclear. Assisted reproduction treatment seems to increase the multiple monozygotic pregnancy rate to 3-times more than that in nature. Several possibilities could be suspected as responsible for these monozygotic multiple pregnancies - advanced maternal age, alterations of the zona pellucida, transfers at the blastocyst stage, prolonged culture and ovarian stimulation - but a absolute explanation is not yet defined. This article is a scientific review of the literature on monozygotic multiple pregnancies after IVF treatment and a description of nine cases following IVF treatment at the OVO Clinic in Montreal between January 2007 and August 2011. The bibliographic references were found in the Medline and Cochrane Database.
同卵多胎妊娠在辅助生殖（无论是否进行 IVF）后比自然受孕后常见三倍（1.2%对 0.4%）。这些妊娠与多种母婴风险相关。本文描述了 2007 年 1 月至 2011 年 8 月期间在 OVO 诊所（蒙特利尔）进行 IVF 后发生的 9 例同卵妊娠，并对 MEDLINE 和 Cochrane 数据库中关于辅助生殖治疗后同卵多胎妊娠的文献进行了科学综述。在这个回顾性系列中，共移植了 3522 个胚胎，获得了 1033 例妊娠，其中有 9 例是同卵妊娠（0.87%）。这种频率增加的确切机制仍不确定。与生育治疗相关的可能解释包括透明带改变、囊胚期转移、延长培养、植入前遗传学诊断、卵巢刺激和母亲年龄。辅助生殖治疗似乎增加了同卵妊娠的发生；然而，这种发生率仍然很低，因此很难准确推断出真正的机制。多胎妊娠有两种类型：双卵（两个不同的胚胎）和单卵（一个胚胎分裂成两个相同遗传的胚胎）。我们知道双卵妊娠的危险因素，但单卵妊娠的机制仍不清楚。辅助生殖治疗似乎将多胎同卵妊娠的发生率提高到自然妊娠的 3 倍以上。有几种可能性被怀疑是导致这些单卵多胎妊娠的原因，如高龄产妇、透明带改变、囊胚期转移、延长培养和卵巢刺激，但还没有明确的解释。本文是对 IVF 治疗后同卵多胎妊娠文献的科学综述，并描述了 2007 年 1 月至 2011 年 8 月期间在 OVO 诊所进行 IVF 治疗后的 9 例同卵多胎妊娠。参考文献在 Medline 和 Cochrane 数据库中找到。
