Dunno... I use to use an electric comb.

But more than anything i kept a nit comb in the shower and every time I conditioned my hair I would do a quick section and comb. Did this with DD too... works the best, cause it only takes a couple of minutes and it is done routinely...

You have to make sure to get the comb right to the roots on all sections. You may wish to do it every day to begin with, then every 2nd day.

If you still wish to use chemicals just ask your chemist, they will know which ones are safe for use during pregnancy

Good luck