The impact of a lot of things on fertility and pregnancy are unknown. Because the only way to make it known is to have a test group - essentially hundreds of women of child bearing age with no known fertility issues would have to have the vaccine, try to get pregnant over the next year, and if a higher proportion than normal didn't fall pregnant, then it can be said to have an impact of x%.
Given there's no current plans to roll the vaccine out to this age group, why on earth would a) tests be carried out and b) the fact tests haven't been carried out be newsworthy?
By the same token, the vaccine hasn't been licensed for under 16s. Not because it's dangerous but because it hasn't been tested.