From my experience, Visbiome is not a placebo. There is a survey I posted here about effectiveness of VSL/Visbiome, you can search and see what the community experience is. Sure everyone has a different problem, and they might not help everyone. I think you should give it a try before antibiotics, because you are pregnant. Many medications are “believed” to be safe without empirical support. Especially the first trimester is very very important. Trying a strong probiotics in order to avoid antibiotics during pregnancy is a good idea. Many disease have environmental links during pregnancy but the causes are not well known. Self-medicating or experimenting with drugs during pregnancy is a very very bad idea.