Ideally, pregnancy planning and preparation should be taken three months prior to conception, but it's permissible to start taking folic acid after you learn about the pregnancy. It's a water-soluble vitamin, and an overdose is practically impossible.
Folic acid is involved in DNA and RNA (custodians of genetic material) synthesis, which is especially important during fetal development. A folic acid deficiency can lead to defects in the neural tube (from which the brain and the spinal cord is formed) and other congenital malformations.
The recommended dose of folic acid before pregnancy is 0.4 mg per day.
My husband and I decided that we would start our family this year, so I got off the contraceptive. I began to exercise and checked in with my gynecologist. This is key, more so for late starters like me. I also went on folic acid tabs upon the recommendation of my doctor. I downloaded the Flo app and began to further educate myself on ovulation, knowing my most likely days of conception and planning around those days. Flo has been very useful in this regard. I'm now 16 weeks pregnant and loving every moment of it.