探讨室间隔缺损最大直径（D_VSD）与主动脉根部内径（D_AO）比值对胎儿单纯室间隔缺损（i-VSD）预后评估的价值。

选取产前胎儿心脏超声诊断为i-VSD并于出生后3个月有随访记录的胎儿175例，其中膜周部i-VSD 83例，肌部i-VSD 82例，干下i-VSD 10例。依据D_VSD与D_AO的比值R（R=D_VSD/D_AO）将VSD分为大型（R>1/2）、中型（1/3<R≤1/2）、小型（R≤1/3），胎儿出生后3个月行超声心动图随访，观察不同部位、不同大小的i-VSD自然愈合情况。

（1）膜周部i-VSD 83例，出生后3个月自然愈合率为18.1%（15/83），肌部i-VSD 82例，出生后3个月自然愈合率为50.0%（41/82），干下型i-VSD10例，无自然愈合者，不同部位VSD自然愈合率比较，差异有统计学意义（χ²=24.3，P=0.000）。（2）83例膜周部i-VSD胎儿中，5例R≤1/3，出生后3个月自然愈合率为40.0%（2/5）；35例1/3<R≤1/2，出生后3个月自然愈合率为28.6%（10/35）；43例R>1/2，出生后3个月自然愈合率为7.0%（3/43）。不同R值的膜周部i-VSD胎儿出生后3个月自然愈合率比较，差异具有统计学意义（χ²=7.80，P=0.020）。^（3）82例肌部i-VSD胎儿中，21例R≤1/3，出生后3个月自然愈合率为66.7%（14/21）；39例1/3<R≤1/2，出生后3个月自然愈合率为53.8%（21/39）；22例R>1/2，出生后3个月自然愈合率为27.4%（6/22）。不同R值的肌部i-VSD胎儿出生后3个月自然愈合率比较，差异具有统计学意义（χ²=7.71，P=0.029）。（4）干下型i-VSD 10例，2例R≤1/3，4例1/3<R≤1/2，4例R>1/2，均未自然愈合。

不同部位的i-VSD其出生后自然愈合率有差别；D_VSD与D_AO的比值（R值）对胎儿期i-VSD的预后评估有重要价值。

To assess the value of the ratio of the ventricular septal defect diameter (D_VSD) to the aortic root dimension (D_AO) in prognosis evaluation of fetal isolated ventricular septal defects (i-VSD).

This study involved a total of 175 fetuses with i-VSD who were diagnosed by prenatal ultrasound imaging of the fetal heart and followed for 3 months after birth, including perimembranous i-VSD (n=83), muscular i-VSD (n=82), and subarterial i-VSD (n=10). Based on the ratio of D_VSD to D_AO (R=D_VSD/D_AO), VSD were divided into large (R>1/2), medium (1/3<R≤1/2), and small VSD (R≤1/3) VSD. Echocardiography follow-up was performed for 3 months after birth to observe the natural healing of i-VSD of different locations and sizes.

The natural healing rates were 18.1% (15/83) and 50.0% (41/82) in fetuses with perimembranous i-VSD and muscular i-VSD during the follow-up period, respectively. There was no natural healing for 10 fetuses with subarterial i-VSD. There was a statistically significant difference in the natural healing rates of VSD at different locations (χ²=24.3, P=0.000). Of 83 fetuses with perimembranous i-VSD, 5 had small, 35 had medium, and 43 had large i-VSD, whose natural healing rates were 40.0% (2/5), 28.6% (10/35), and 7.0% (3/43) during the follow-up period, respectively. There was a statistically significant difference in the natural healing rates of perimembranous i-VSD with different R values (χ²=7.80, P=0.020). Of 82 fetuses with muscular i-VSD, 21 had small, 39 had medium, and 22 had large i-VSD, whose natural healing rates were 66.7% (14/21), 53.8% (21/39), and 27.4% (6/22), respectively. There was a statistically significant difference in the natural healing rates of muscular i-VSD with different R values (χ²=7.71, P=0.029). Of 10 fetuses with subarterial i-VSD, 2 had small, 4 had medium, and 4 had large i-VSD, and no natural healing was observed.

There is a difference in the natural healing rate of i-VSD at different locations. The ratio of D_VSD to D_AO (R) is of significance in the prognosis evaluation of fetuses with i-VSD.