辅助生殖技术治疗后单卵双胎妊娠的临床分析

Outcome analysis of monozygotic twin pregnancy conceived by assisted reproductive techniques

目的探讨经辅助生殖技术（ART）治疗后单卵双胎（MZT）的发生、处理及妊娠结局。方法回顾性分析2010年1月-2015年6月在南方医科大学南方医院生殖医学中心行体外受精-胚胎移植（IVF-ET）、单精子卵胞浆内显微注射-胚胎移植（ICSI-ET）治疗后临床妊娠患者的基本资料,统计MZT的发生情况,按单纯性MZT、伴MZT多胎妊娠及异位妊娠分类分析94例MZT的处理及妊娠结局,同时分别对比单纯MZT与同期非MZT双胎妊娠、伴MZT三胎妊娠减灭单胎和减灭双胎后、以及伴MZT三胎妊娠与非MZT三胎妊娠减为双胎后的流产率、活产率、早产率和足月产率等指标。结果获得临床妊娠的6257个胚胎移植周期中,94例为MZT妊娠（1.5%,94/6257）,其发生率在IVF（1.8%,47/2649）与ICSI（1.2%,10/822）间比较无统计学差异（P=0.272）;在新鲜胚胎移植周期（1.6%,57/3471）与冻融胚胎移植周期（1.3%,37/2786）间比较也无统计学差异（P=0.310）。94例MZT中,45例为单纯MZT,43例为伴MZT的三胎妊娠,3例为伴MZT的四胎妊娠,3例为异位妊娠（含复合妊娠）。与同期非MZT双胎妊娠相比,单纯MZT妊娠的足月产率、活产率较低,流产率及新生儿畸形发生率较前者高,且差异均具有统计学意义（P〈0.05）;比较减灭单胎和减灭双胎的伴MZT三胎妊娠,减灭双胎妊娠组的足月产率、活产率均高于减灭单胎妊娠组,且流产率和早产率也低于后者,但经统计学处理,显示无统计学意义（P〉0.05）;与同期减为双胎的非MZT三胎妊娠者相比,伴MZT三胎妊娠减为双胎后的足月产率、早产率、活产率均低于前者,流产率较前者高,但均无统计学意义（P〉0.05）。结论经ART治疗后MZT妊娠的发生率显著高于自然妊娠;单纯MZT的妊娠结局较异卵双胎差;对于伴MZT的多胎妊娠,减灭MZT孕囊者可能获得较好的妊娠结局。

Objective To analyze the incidence, management, and outcomes of monozygotic twin（MZT） pregnancy conceived by assisted reproductive techniques（ART）. Methods A retrospective analysis was performed of clinical pregnancies after in vitro fertilization and embryo transfer（IVF-ET） and introcytoplasmic sperm injection and embryo transfer（ICSI-ET） from January, 2010 to June 2015 at our center. We investigated the incidence, managements and outcomes of 94 MZT pregnancies.Comparison of the pregnancy outcomes was made between the expectantly managed MZT pregnancies, dizygotic twin（DZT）pregnancies, monozygotic（MZ）-triplet pregnancies with selective embryo reduction（SER） to 2 fetuses and 1 fetus, and nonMZ triplet pregnancies with SER to 2 fetuses. Results Ninety-four MZT pregnancies occurred in the total of 6257 clinical pregnancy cycles with an incidence of 1.5%. No significant difference was found in the incidence of MZT pregnancies between IVF and ICSI cycles or between fresh and thawed cycles（P〉0.05）. Of the 94 MZT pregnancies, 45 were MZT pregnancy cycles,43 were MZ-triplet pregnancy cycles, 3 were MZ-quadruplet pregnancy cycles and 3 were ectopic pregnancies. The expectantly managed MZT was associated with a significantly greater rate of miscarriage and malformation and a lower rate of live birth and term birth（P〈0.05） in comparison with DZT pregnancy cycles that did not undergo SER. Similar outcomes were found between MZ-triplet pregnancies with SER to 2 fetuses and MZ-triplet pregnancies with SER to 1 fetus（P〉0.05）, and between MZ-triplets with SER to 2 fetuses and non-MZ triplet pregnancies with SER to 2 fetuses（P〈0.05）. Conclusion ART is associated with a much higher incidence of MZT pregnancies than spontaneous conception. MZT pregnancies are at high risk of adverse outcomes, and reduction of MZT in multiple pregnancies may help to improve the outcomes.