Comparison of pregnancy outcomes following transferring one or two embryos in a selected group of infertility patients.

辅助生殖技术（ART）处理的问题对涉及的个人和整个社会都具有根本的重要性。尽管取得了重大进展，但抗逆转录病毒治疗在许多方面仍然非常昂贵。造成这种情况的一个主要原因是怀孕率相对较低，平均每次手术的怀孕率为25%。对低妊娠率问题的常见反应是将几个胚胎返回子宫。与这种策略相关的一个困境是多胎妊娠的高风险，这与母亲和胎儿的不良后果有关。与独生子女相比；双胞胎的胎儿、新生儿和围产期死亡率高3-6倍，多胞胎的死亡率高5-15倍。脑瘫幸存者中双胞胎的发病率是双胞胎的6倍，三胞胎的发病率是三胞胎的20倍。在抗逆转录病毒治疗中，与多胎妊娠相关的不良后果发生率的增加已得到充分证实。我们提出一项随机对照研究来评估单胚胎移植（SET）与双胚胎移植（DET）的比较。多胎妊娠风险高的不孕妇女将被随机分配接受一个或两个胚胎，这是目前常用的治疗方法。然后，我们将检查单胎和多胎妊娠的比率，以及这组患者的妊娠成功率。这个项目对社区的潜在好处是非常巨大的，因为它有能力大大减少多胞胎的数量。患者也将受益于获得更准确的信息，从而在治疗期间做出明智的选择。

Assisted reproductive technology (ART) deals with issues of fundamental importance to individuals involved, and society as a whole. Despite major advances, ART continues to be very costly in many regards. A major reason for this is the relatively low rate of pregnancy, which averages 25% per procedure. The common response to the problem of low pregnancy rates is to return several embryos to uterus. A dilemma associated with this strategy is the high risk of multiple pregnancy, which is associated with adverse consequences for mother and fetus(es). Compared to singleton births; fetal, neonatal, and perinatal mortality rates are 3-6 times higher in twins, and 5-15 times higher in multiple births of a higher order. Cerebral palsy rates among survivors are six times higher in twins and twenty times higher in triplets. The increase in the incidence of adverse outcomes related to multiple pregnancy has been well documented in ART. We propose a randomised controlled study to assess single embryo transfer (SET) compared to double embryo transfer (DET). Infertility women with a high risk of multiple pregnancy will be randomly allocated to receive one or two embryos, which is the usual treatment at present. We shall then examine the rates of single and multiple pregnancies, and the success of those pregnancies in this group of patients. Potential benefits to the community from this project are very substantial, as it has the capacity to substantially reduce the number of multiple births. Patients will also benefit by having more accurate information with which to make an informed choice during treatment.