正常双绒毛膜双胎孕期估重差异性及其影响因素

Discordance and impact factors of estimated fetal weight of twins in normal dichorionic pregnancy

目的探讨正常双绒毛膜双胎孕期超声估重(EFW)差异率及其影响因素。方法回顾性分析550名正常双绒毛膜双胎(1 100胎)孕妇的产前孕期超声生物测量指标,并根据胎儿双顶径、头围、腹围、股骨长计算双胎EFW差异率,分析其与孕周的关系,观察性别、受孕方式(试管组与非试管组)是否影响EFW差异率。结果正常双绒毛膜双胎EFW差异率总体呈偏态分布,中位数为6.56%,四分位间距为8.92%,第95百分位数为20.81%,与孕周无明显相关。性别相同组与性别不同组、不同受孕方式组间双胎EFW差异率差异均无统计学意义(P均>0.05)。结论产前超声对双绒毛膜双胎估重有重要参考价值,EFW差异率可作为双绒毛膜双胎孕期生长评估相对恒定的指标。

Objective To investigate the difference of intertwin estimated fetal weight(EFW)in normal dichorionic pregnancy and the impact factors.Methods Prenatal ultrasonic parameters of 550 normal dichorionic twins(1 100 fetuses)were retrospectively analyzed.Fetal weight was estimated based on head circumference,abdominal circumference,biparietal diameter and femur length.The growth discordance ratio of EFW was calculated between the two fetuses.The correlation between the gestational weeks and the discordance ratios was assessed.In addition,whether the gender difference and different fertilization way could be impact factors of EFW discordance was evaluated.Results No obvious correlation was observed between EFW discordance ratio and gestation age.EFW discordance ratio was skew distribution,with median of 6.65%,interquartile range of 8.92%and the 95th percentiles of 20.81%.There was no statistical significant difference of EFW discordance ratio between gender-identical group and gender-specific group,nor between two groups with different fertilization way(both P>0.05).Conclusion Ultrasound is valuable to obtain EFW in dichorionic twins.EFW discordance ratio can be used as a relatively date-independent index in evaluation of the growth of dichorionic twins.