The best options at this stage would be to either continue with a PI (such as darunavir) or switch to efavirenz. The British HIV Association still advocates one of these two options even in early pregnancy. I suspect Raltegravir or even Dolutegravir would be good options but there is not much information at the moment to promote their use in pregnancy.

I would personally try boosted darunavir and see how she goes.

I am attaching link to the British guidance on HIV treatment in pregnancy (2014 update):

http://www.bhiva.org/documents/Guidelines/Pregnancy/2012/BHIVA-Pregnancy-guidelines-update-2014.pdf