瑞典科学家证实：产前超声波检查不会影响儿童的智力

瑞典一项大型流行病学研究发现：在常规超声波扫描与智力损害之间没有直接关系。

瑞典Karolinska研究院研究员Helle Kieler解释说：“对超声检查可能会降低智力水平的担忧引起大家的关注。”Uppsala大学也参与了此次研究。

较早期的流行病学调查已经证实，曾经暴露于子宫超声扫描的年轻男性，比其它男性更加容易出现左撇子；在左撇子倾向与难产儿童智力下降之间有相关性。

这项研究发表在2005年5月的《流行病学》期刊，是根据20世纪70年代（常规超声扫描胎儿发育在瑞典开始应用的年代）出生的180000例儿童的资料进行的研究。在20年之后，对年轻的男性报名参加军队服役的时候进行智力测验。当科学家比较接受过超声扫描的男性与那些没有接受过超声扫描检查的男性的时候，结果发现曾经在分娩时候暴露于超声检查的男性智力水平较低。但是差异非常小，而且其它影响结果的因子不能够被排除。

为了阐明这些研究结果，研究人员开展了较小规模对他们兄弟的研究。这就允许他们证实，曾经暴露于胎儿超声扫描的兄弟，在智力上并不次于他们没有接受过超声扫描的兄弟，

Kieler女士说：“这些结果再次证实常规胎儿超声检查对胎儿最终发育具有持久性的影响。但是十分重要必须记住的是，这项研究反应的是在20实际70年代使用的超声波检查的作用。从那个年代以来，扫描方案已经发生了改变，现如今出生的儿童暴露于超声检查的机会比这项研究中涉及的儿童要大出许多。”
 
Prenatal Ultrasound Does Not Effect Children’s Intellect
 
A major Swedish epidemiologic study found no clear correlation between routine ultrasound scans and intellectual impairment.

“Fears have been expressed that sonography can lead to diminished intellectual capacity,” explained Helle Kieler, a researcher at the Karolinska Institute (Stockholm, Sweden); Uppsala University (Sweden) also took part in the study.

Earlier epidemiologic research had demonstrated that young men who had been exposed to in utero ultrasonic scans are more apt than other young men to be left-handed; there is a correlation between left-handedness and reduced intellectual capacity in children born after a difficult pregnancy.

The study, which was published in the May 2005 issue of the journal Epidemiology, is based on data from about 180,000 boys born in the 1970s, when routine ultrasound exams of fetal development were first introduced in Sweden. Nearly 20 years later, the young men were given intelligence examinations when signing up for their military service. When scientists compared the boys who underwent ultrasound scanning with those who had not, it became apparent that intellectually capacity was lower in those who were exposed to ultrasound during gestation. However, the differences were small and other factors in the results could not be excluded.

To understand these findings, the researchers then performed a smaller-scaled study of brothers. This enabled them to validate that there was nothing to suggest that the brother who had been exposed to fetal ultrasonic radiation was intellectually inferior to that of his brother, who did not have the ultrasound scan.

“The results are reassuring in terms of the risk that routine prenatal sonography has lasting effects on the development of the fetal brain,” said Ms. Kieler. “It is important to remember, however, that the study reflects the effects of how ultrasound was used in the 1970s. Scanning procedures have changed since then, and children born today have generally been exposed to more ultrasonic radiation that those included in the study.”