Long time lurker first time poster here. I had to chime in that the folic acid is so important, and it is most important before the woman could possibly find out, so she needs to start taking it ahead of time.
Also, with regard to the nitpicking on the OP for mentioning abortion, I don’t think the intention was to present it as an option. It IS relevant because a lot of frum people avoid certain prenatal tests due to the misconception that the purpose of these tests is to decide whether or not to continue the pregnancy. This could not be further from the truth! These tests provide useful information that could make a crucial difference during delivery and the hours following. Even knowing you would never consider terminating, there is still valuable information to be gleaned from these tests that could make a difference for other decisions down the line.