One thing is, if soy is not organic then it is grown with a boatload of pesticides. So only organic and (IMO) non-GMO soy should be consumed. You probably already know that.
One of the concerns with soy I remember reading is that it mimics estrogenic qualities, and large amounts of it are feared to have negative effects on the proper development of male children, both in utero and during childhood (if they consume soy formula and/or lots of soy milk). Whether there is any scientific proof or it's just supposition, I have no idea.
I remember reading that although we have this idea that people in Asia eat lots of soy - and look how healthy they are - that's not accurate. I think the average daily consumption across Asia was like one ounce or less.
If you want to read opinions against
the safety of soy, you'll find a lot of articles at: http://www.mercola.com/article/soy/index.htm#
Do you consume dairy products? One approach you might consider would be to rotate through various protein sources so you aren't overloading on soy. Suggestions would be organic goat and cow milk, yogurt, &/or milk powder; almond, walnut, or hazelnut meal; nut butters; ground flax seeds; etc. You can also boost up baked goods with these items to increase your protein.
One last thing, long-time vegetarians actually seem to process protein better than meat eaters and therefore many people believe they don't need as many grams of protein per day during pregnancy. I can't find the info offhand, but I seem to recall Ina May Gaskin writing that 60-75 grams was appropriate for a long-time vegetarian (whereas I think the range is around 75-100 for non-vegetarians).