It is safe to use during pregnancy, especially if you have already gone through detox. I would suggest keeping your dosage down like you say ... 2 drops at a time, 3 times per day has worked for a lot of women. You really do want to keep it very gentle, allowing a slow and steady cleansing process.
If you wanted, I could try to put you in touch with other women who have used sodium chlorite during pregnancy. There have been quite a few.
Here is a prior post that I made on this same subject - it contains a couple of testimonials of women who used sodium chlorite during pregnancy: