瑞典一項大型流行病學研究發現：在常規超聲波掃描與智力損害之間沒有直接關系。

瑞典Karolinska研究院研究員Helle Kieler解釋說：“對超聲檢查可能會降低智力水平的擔憂引起大家的關注。”Uppsala大學也參與了此次研究。

較早期的流行病學調查已經證實，曾經暴露于子宮超聲掃描的年輕男性，比其它男性更加容易出現左撇子；在左撇子傾向與難產兒童智力下降之間有相關性。

這項研究發表在2005年5月的《流行病學》期刊，是根據20世紀70年代（常規超聲掃描胎兒發育在瑞典開始應用的年代）出生的180000例兒童的資料進行的研究。在20年之后，對年輕的男性報名參加軍隊服役的時候進行智力測驗。當科學家比較接受過超聲掃描的男性與那些沒有接受過超聲掃描檢查的男性的時候，結果發現曾經在分娩時候暴露于超聲檢查的男性智力水平較低。但是差異非常小，而且其它影響結果的因子不能夠被排除。

為了闡明這些研究結果，研究人員開展了較小規模對他們兄弟的研究。這就允許他們證實，曾經暴露于胎兒超聲掃描的兄弟，在智力上并不次于他們沒有接受過超聲掃描的兄弟，

Kieler女士說：“這些結果再次證實常規胎兒超聲檢查對胎兒最終發育具有持久性的影響。但是十分重要必須記住的是，這項研究反應的是在20實際70年代使用的超聲波檢查的作用。從那個年代以來，掃描方案已經發生了改變，現如今出生的兒童暴露于超聲檢查的機會比這項研究中涉及的兒童要大出許多。”
 
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.”