Among the brands to remove ads were Mondelez, Lidl, Mars and other consumer products manufacturers.
A Reuters report said hundreds of paedophiles had posted comments below the videos, which appeared to have been uploaded by the children.
It quoted the report as saying that one clip, of a pre-teenage girl in a nightie, had attracted 6.5 million views.
Earlier this year, YouTube was found to be displaying advertisements from major manufacturers on videos that contained anti-Semitic, sexist, racist, and terrorist content.
A number of advertisers pulled their ads, but most have now gone back to the platform. AT&T is one company that has not returned to YouTube.
While Google does not provide a breakdown in its results of how much YouTube earns, Reuters said that the platform would provide about US$7.8 billion in worldwide ad revenue this year.
It quoted the chocolate maker Mars as saying: “We have taken the decision to immediately suspend all our online advertising on YouTube and Google globally.
“Until we have confidence that appropriate safeguards are in place, we will not advertise on YouTube and Google.”
Diageo, the maker of Smirnoff vodka and Johnnie Walker whisky, said it was investigating the matter and would suspend all YouTube advertising until safeguards were in place.
Germany discount retailer Lidl said it was “completely unacceptable that this content is available to view, and it is, therefore, clear that the strict policies which Google has assured us were in place to tackle offensive content are ineffective”.
HP was among the companies to suspend advertising globally.
A spokesman for the UK Department of Digital, Culture, Media and Sports said: “The government expects online platforms to have robust processes in place and to act promptly to remove content and user accounts that do not comply with their own policies.”