双胚胎移植后发生双胎妊娠的影响因素分析

Factors related to occurrence of twin pregnancy after double-embryo transfer in vitro fertilization cycles

目的分析体外受精-胚胎移植（IVF—ET）治疗周期中，双胚胎移植后发生双胎妊娠的影响因素。方法选择2003年1月至2007年12月于上海交通大学医学院附属瑞金医院生殖医学中心接受IVF或卵母细胞胞质内单精子注射（ICSI）治疗、并获得临床妊娠的不孕患者275例，共280个周期，分为单胎妊娠组（198个周期）和双胎妊娠组（82个周期），比较两组患者的一般情况、临床特征及胚胎特征，并进行单因素和多因素回归分析。结果（1）两组患者年龄、继发不孕比例、不孕时间和不孕原因比较，差异均无统计学意义（P〉0．05）；（2）两组患者基础卵泡刺激素（FSH）水平、平均窦卵泡数、平均获卵数、卵巢反应性（以促性腺激素使用剂量与获卵数的比值表示）及注射人绒毛膜促性腺激素（hCG）日子宫内膜厚度比较，差异均无统计学意义（P〉0．05）；单胎妊娠组既往IVF治疗次数为（0．22±0．21）次，与双胎妊娠组[（0．18±0．16）次]比较，差异有统计学意义（P=0．03）；（3）两组患者的受精方式、平均可用胚胎数、平均移植胚胎评分，以及最优胚胎发育速度评分、形态评分和次优胚胎形态评分比较，差异均无统计学意义（P〉0．05）；单胎妊娠组的平均优质胚胎数及次优胚胎发育速度评分分别为（2．9±2．5）个和（3．4±0．2）分，分别与双胎妊娠组[（3．8±3．3）个和（3．7±0．2）分]比较，差异均有统计学意义（P〈0．05）；（4）多因素回归分析发现，首次IVF治疗周期（OR：1．82，P=0．02）、优质胚胎数（OR=1．35，P=0．01）、次优胚胎发育速度评分（OR=1．55，P=0．009）和卵巢反应性（OR=0．96，P=0．04）4个因素与双胎妊娠发生有独立相关性。结论首次进行IVF—ET、优质胚胎数多、所移植胚胎中次优胚胎发育速度评分高以及卵巢反应性好的患者发生双胎妊娠的风险较高，可尝试进行单胚胎移植。

Objective To analysis high risk factors of twin pregnancy after double-embryo transfer in fresh in vitro fertilization-embryo transfer （IVF-ET） cycles. Methods From Jan. 2003 to Dec. 2007, 275 infertile cases underwent IVF-ET or intracytoplasmatic sperm injection （ICSI） and obtained clinical pregnancy in Reproductive Medical Center, Ruijin Hospital affiliated to Shanghai Jiaotong University. A total of 280 cycles were performed, which were classified into single pregnancy group （ 198 cycles ） and twin pregnancy group （82 cycles）. The general information, patient and embryo characteristics were compared between those two groups, then univariate and multivariate regression were analyzed. Results （ 1 ） There was no statistical difference in the following clinical features between single and twin pregnancy groups, such as patients ages, the ratio of secondary infertility, period and possible causes of infertility （P 〉 0. 05）. （2） When comparing basal level of follicle stimulating hormone （FSH）, mean numbers of follicles, mean obtained ovum, ovarian responsibility （ratio of follicle stimulation hormone dose/number of oocyte retrieved） ,endometrial thickness given by human chorionic gonadotropin （hCG）, no significant difference were observed between two groups （ P 〉 0. 05 ）. Twin pregnant group had fewer cycles of in vitro fertilization treatment when compared with single pregnancy group （0. 18±0. 16 vs. 0. 22 ±0. 21, P =0. 03）. （3） No significant difference was observed in the following clinical index, including fertilization approaches, mean numbers of embryo, mean score of transferred embryo, developmental stage of top quality embryo, morphological score of embryo, morphological score of the second best embryo transferred （P 〉 0. 05 ）. The number of top-quality embryos and the development stage score of the second best embryo transferred were higher than those of single pregnant group （ 3.8 ±3.3 vs. 2. 9± 2. 5, P 〈 0. 05 and 3.7± 0. 2 vs. 3. d ± 0. 2, P 〈 0.05 ）. （4） Multivariate regression analysis showed that four variables was correlated independently with twin pregnancy including first treatment cycle of IVF-ET （ OR = 1.82, P = 0. 02 ）, number of good quality embryos（ OR = 1.35, P = 0. 01 ）, development stage score of the second best embryo （ OR = 1.55, P = 0. 009） and ovarian responsibility （ OR = 0. 96, P = 0. 04）. Conclusions It is advisable to perform single embryo transfer. If patients are at high risk factors of twin pregnancy including initial IV-F- ET treatment, good ovarian responsibility, more number of top-quality embryos and development stage score of the second best embryo transferred.