Fong C Y, Bongso A, Ng S C, Kumar J, Trounson A, Ratnam S
Department of Obstetrics and Gynaecology, National University Hospital, Kent Ridge, Singapore.
Hum Reprod. 1998 Oct;13(1O):2926-32. doi: 10.1093/humrep/13.10.2926.
It has been shown recently that delayed transfers improve implantation rates in assisted reproductive technology programmes. In a prospective study, the pregnancy rates and safety of outcome were evaluated in a group of patients after the transfer of day 5 blastocysts with enzymatic treatment of the zona pellucida. Nineteen women with a mean age of 32.6+/-5.2 years and mean 2.1+/-2.2 repeated attempts had blastocyst transfers with a mean number of 2.5+/-0.7 embryos replaced per patient. The clinical pregnancy rates per cycle/transfer and implantation rate were 53% and 33%, respectively. The multiple pregnancy rate was 40% (two pregnancies were triplets). The pregnancy and implantation rates were very much higher than observed for most assisted reproduction technology centres. The 'in-vitro implantation' rates of zona-free blastocysts on a variety of feeder monolayers was 92%, offering some thoughts as to the role of the zona and interaction of the inner cell mass and trophoectoderm with the endometrium in implantation. Based on the in-vitro studies and the high multiple pregnancy rates, it appears that zona-manipulated blastocysts implant relatively well and there would be a need to reduce the number of transferred embryos to one or two, thus reducing multiple pregnancies and having spare blastocysts available for cryopreservation. The results also suggest that using the embryo culture protocol and method of transfer in the present study offers encouraging improvements to assisted reproduction technology, and enzymatic treatment of the zona may allow better anchorage and dialogue of the embryo with the endometrium, helping us to improve and understand implantation.
最近研究表明，在辅助生殖技术项目中，延迟移植可提高着床率。在一项前瞻性研究中，对一组经酶处理透明带后移植第5天囊胚的患者的妊娠率和结局安全性进行了评估。19名平均年龄为32.6±5.2岁、平均经历2.1±2.2次反复尝试的女性接受了囊胚移植，每位患者平均移植2.5±0.7个胚胎。每个周期/移植的临床妊娠率和着床率分别为53%和33%。多胎妊娠率为40%（2例妊娠为三胞胎）。妊娠率和着床率远高于大多数辅助生殖技术中心的观察结果。无透明带囊胚在各种饲养层上的“体外着床”率为92%，这为透明带的作用以及内细胞团和滋养外胚层与子宫内膜在着床过程中的相互作用提供了一些思路。基于体外研究和高多胎妊娠率，似乎经透明带处理的囊胚着床相对良好，有必要将移植胚胎数量减少至一两个，从而减少多胎妊娠，并保留备用囊胚用于冷冻保存。结果还表明，采用本研究中的胚胎培养方案和移植方法可为辅助生殖技术带来令人鼓舞的改进，透明带的酶处理可能使胚胎与子宫内膜更好地锚定和相互作用，有助于我们改进和理解着床过程。
