体外受精-胚胎移植术后双胎妊娠自然减胎与初始单胎妊娠的分娩结局比较

目的比较体外受精-胚胎移植术后双胎之一孕早期自然减至单胎与初始单胎妊娠的产科结局。方法2010~2012年在广
州市妇女儿童医疗中心生殖医学中心行体外受精胚胎移植后获得单胎分娩患者409例，其中44例患者孕6周B超诊断为2个妊
娠囊，孕12周前其中一胎自然死亡；365例患者孕6周B超诊断为1个妊娠囊。比较两组患者分娩孕周、早产率、新生儿出生体
重、低体质量儿比例。结果在单胎分娩的患者中，10.8%（44/409）在孕6周B超时诊断为双胎，双胎自然减为单胎组与单胎组孕
妇平均分娩孕周为38.29±1.76和38.45±1.40周，两组比较差异无统计学意义（P=0.495）；早产率分别为15.9%（7/44）和10.13%
（37/365），两组比较差异无统计学意义（P=0.298）；新生儿出生体质量分别为3086.8±527.01和3261.8±437.85 g，双胎自然减为
单胎组新生儿出生体质量低于初始单胎组（P<0.05）。低体质量儿（<2500 g）比例双胎自然减为单胎组为6.82%（3/44），是初始
单胎组的2.74%（10/365）的2倍，但两组比较差异无统计学意义（P=0.316）。结论孕早期双胎自然减为单胎会导致剩余一胎新
生儿出生体质量低于单胎对照组。

Obstetric and neonatal outcomes of vanishing twin syndrome

Objective To compare the obstetric and neonatal outcomes of singleton pregnancies originating from vanishing twin
syndrome with those of singleton pregnancies originating from a single gestation following in vitro fertilization-embryo
transfer (IVF-ET). Methods This case-control study involved a total of 409 singleton deliveries after IVF-ET/freeze-thawed
embryo transfer, including 44 survivors of vanishing twin syndrome (study group) and 365 singletons (control group). The
duration of gestation, rate of preterm delivery, neonatal birth weight and proportion of low birth weight were compared
between the two groups. Results Of all the singletons born, 10.8% originated from a vanishing twin gestation. No differences
were found in the duration of gestation between the two groups. The mean gestational age was 38.29±1.76 vs 38.45±1.40 weeks
(P=0.495) in the study group and controls group, with the rate of preterm delivery of 15.9% vs 10.13% (P=0.298), respectively.
The mean birth weight was significantly higher in the control group (3261.8 ± 437.85 g vs 3086.8 ± 527.01 g, P<0.05), but the
proportion of low birth weight (<2500 g) showed no significant difference between the study and control groups (6.82% vs
2.74%, P=0.316). Conclusions The survivors of vanishing twin syndrome are at a higher risk of having lower birth weight than
singletons of single gestation following IVF-ET.