Congratulations on your pregnancy! Folic acid is indeed an essential nutrient during pregnancy, and it's great that you're looking into it. Folic acid helps prevent neural tube defects, which are serious birth defects of the brain and spine, such as spina bifida and anencephaly.
Ideally, folic acid should be taken before conception and continued through at least the first trimester. The neural tube develops during the first month of pregnancy, often before a woman knows she's pregnant, so having adequate levels from the start is crucial. Most healthcare providers recommend that women of childbearing age who are planning or capable of becoming pregnant take 400 to 800 micrograms (mcg) of folic acid daily. Once pregnancy is confirmed, you should continue taking folic acid during the first 12 weeks.
As for taking folic acid throughout the entire pregnancy, some prenatal vitamins contain it, so you might continue the recommended dosage provided by your healthcare provider. It's generally fine to take folic acid with or without food, but some prefer taking it with meals to minimize any mild side effects like nausea.
If you have a history of neural tube defects in your family or other health factors, your healthcare provider might recommend a higher dosage. Always best to confirm your specific needs with them.
Having these discussions early on and staying informed will certainly benefit you and your baby. Have you already talked to your healthcare provider about a prenatal vitamin plan? They can offer personalized advice based on your health history.