I used glyphosate wearing a pair of gloves when I was pregnant. I also weeded on my hands and knees right up to 8 months - I found it a really comfy position to be in actually, and good for getting the baby to lie the right way and avoid a back to back labour - try it!
Yes, please, please be careful when using glyphosate whilst you are pregnant - there is all sorts of nasty 'inert' byproducts mixed in with the herbicide, many of which are proven to cause various health problems. I'm excited for weedingtech (foamstream)to bring out their garden sized product. My council use the big amenities one and it's so nice to know there are no herbicide toxins floating around the park!!