Folic acid supplementation, things you should know when preparing for pregnancy

I have heard that you need to take folic acid during pregnancy, but do you know when to take it and how much to take? Today, let's talk about the big knowledge behind this trivial matter of taking folic acid.

1. What is folic acid?

Folic acid, also known as vitamin B9, is an essential B vitamin for the human body. It is particularly important for tissue growth. It cannot be synthesized in the human body and can only be taken in through diet or medication.

Foods rich in folic acid include animal liver, eggs, beans, yeast, green leafy vegetables, fruits and nuts. However, the folic acid in natural foods is easily decomposed after cooking or when exposed to heat, and the amount absorbed by the human body is relatively small; synthetic folic acid is more stable and is absorbed by the human body in larger quantities.

If pregnant women lack folic acid, the harm is not small. Folic acid deficiency in early pregnancy can cause stillbirth, miscarriage, brain and neural tube defects, and can also lead to malformations of the eyes, lips, palate, gastrointestinal tract, cardiovascular, kidneys, bones and other organs. Folic acid deficiency in the middle and late pregnancy affects hemoglobin synthesis and can cause megaloblastic anemia. Folic acid deficiency can also lead to homocystinemia and induce gestational hypertension, which is closely related to the occurrence of placental abruption, fetal growth restriction, premature birth, etc.

2. When should I start taking folic acid supplements?

You should start taking folic acid supplements only after you are sure you are pregnant, right?

NO NO NO, it is not enough to start taking folic acid after the pregnancy is known.

Why?

Because the neural tube is basically formed one month after the last menstrual period, that is, the process is completed before you know you are pregnant. If the mother's folic acid level is insufficient during this period, the closure of the fetal neural tube may be impaired, leading to neural tube defects, namely developmental malformations of the central nervous system including anencephaly and spina bifida.

Therefore, folic acid should be taken during the pregnancy preparation stage.

Studies have shown that taking one 0.4 mg folic acid tablet daily for at least three months is necessary for the red blood cell folate concentration to reach an effective level for preventing neural tube defects; taking 4 mg folic acid daily requires more than one month.

Therefore, most countries recommend daily folic acid supplementation starting three months before pregnancy to ensure that the embryo has better folic acid nutritional status in the early stages.

Folic acid supplementation can be appropriately combined with multivitamins. The vitamin B2, vitamin B6, and vitamin B12 contained in multivitamins play an important role in the folic acid pathway. However, excessive intake of vitamin A should be avoided because excessive intake can produce embryotoxicity.

3. How much folic acid should I take? Should I take it the same way as others?

The Guidelines for Peri-conception Folic Acid Supplementation to Prevent Neural Tube Defects (2017) recommends that pregnant women take 600 μg of folic acid daily. In order to prevent neural tube defects, in addition to the folic acid taken in the diet, different pregnant women need to take different amounts of folic acid daily according to their individual circumstances. The following describes how pregnant women should take folic acid to prevent neural tube defects in different circumstances.

⑴Women without high-risk factors:

For generally healthy women, it is recommended that they take a daily supplement of 0.4 mg or 0.8 mg of folic acid starting from the time they may become pregnant or at least 3 months before pregnancy until they are 3 months pregnant.

(2) Women whose spouse has a neural tube defect or whose spouse has a history of giving birth to a child with a neural tube defect:

It is recommended to supplement 4 mg of folic acid daily from the time of possible pregnancy or at least one month before pregnancy until the third month of pregnancy. Since there is no 4 mg but 5 mg folic acid dosage form in China, 5 mg of folic acid can be supplemented daily.

⑶ Women with congenital hydrocephalus, congenital heart disease, cleft lip and palate, limb defects, urinary system defects, or family history of the above defects, or first- or second-degree relatives with a history of neural tube defects:

It is recommended to supplement 0.8 to 1.0 mg of folic acid daily starting from the time of possible pregnancy or at least 3 months before pregnancy until the 3rd month of pregnancy.

⑷Women with diabetes, smoking, obesity or epilepsy:

It is recommended to supplement 0.8 to 1.0 mg of folic acid daily starting from the time of possible pregnancy or at least 3 months before pregnancy until the 3rd month of pregnancy.

⑸ Women who are taking medications that increase the risk of fetal neural tube defects:

Women who are taking anti-epileptic drugs (such as carbamazepine, valproic acid, phenytoin sodium, primidone, phenobarbital), hypoglycemic drugs (such as metformin), anticancer drugs (methotrexate), antibiotics (sulfasalazine, trimethoprim), diuretics (triamterene), and lipid-lowering drugs (cholestyramine) are advised to take a daily supplement of 0.8 to 1.0 mg of folic acid starting from the time of possible pregnancy or at least 3 months before pregnancy until the 3rd month of pregnancy.

⑹Women with gastrointestinal malabsorption diseases:

It is recommended to supplement 0.8 to 1.0 mg of folic acid daily starting from the time of possible pregnancy or at least 3 months before pregnancy until the 3rd month of pregnancy.

⑺Women with hyperhomocysteinemia:

It is recommended to supplement at least 5 mg of folic acid daily until the blood homocysteine ​​level drops to normal before considering conception, and continue to supplement 5 mg of folic acid daily until the pregnancy is 3 months.

⑻ Women with MTHFR gene mutation:

MTHFR, or methylenetetrahydrofolate reductase, is a key enzyme in the folate metabolic pathway. Its main function is to convert 5,10-methylenetetrahydrofolate into biologically functional 5-methyltetrahydrofolate in the folate metabolic pathway, so that it can provide a methyl group for homocysteine ​​to form methionine, thereby reducing the level of homocysteine.

When MTHFR gene mutation occurs, especially in women with MTHFR 677TT genotype and MTHFR 1298CC genotype, the activity of the enzyme is greatly reduced, and taking 0.4 mg daily is basically ineffective and cannot reduce homocysteine ​​to normal levels. Hyperhomocysteinemia increases the risk of neural tube defects and other adverse pregnancy outcomes.

So how to deal with it?

① You can take the third-generation folic acid, which is 5-methyltetrahydrofolate with biological functions;

② A larger dose of vitamin B12 can be used in combination, because vitamin B12 can work synergistically with 5-methyltetrahydrofolate;

③ Strengthen dietary supplements and eat foods high in folic acid, mainly animal liver, eggs, beans, yeast, green leafy vegetables, fruits and nuts.

In addition, it should be noted that for the prevention of neural tube defects, supplementation of folic acid until the third month of pregnancy is sufficient. However, due to the other benefits of folic acid for pregnant women or fetuses, some academic groups in China and abroad recommend that women without high-risk factors can supplement 0.4 mg of folic acid daily until the end of pregnancy, or even throughout the lactation period; for women with high-risk factors, they can supplement folic acid according to the above requirements until the third month of pregnancy, and then supplement 0.8-1.0 mg of folic acid daily until the end of pregnancy. Recent studies have shown that women who continue to supplement 400 μg of folic acid daily in the middle and late stages of pregnancy can reduce the physiological increase in homocysteine ​​levels in the late pregnancy, which is particularly important for women with a short interval between pregnancies.

If you have multiple high-risk factors and the situation is complicated, you need to follow the guidance of your doctor or pharmacist based on your specific situation and receive folic acid supplementation recommendations that are suitable for you.

If you are planning to have a baby, you should first adjust your body to the best condition.

Either reading or traveling, one of your body and soul is always on the road.

References:

[1] China Maternal and Child Health Association Birth Defect Prevention and Molecular Genetics Branch, Peri-conceptional Folic Acid Supplementation for Prevention of Neural Tube Defects Guidelines Working Group. Peri-conceptional Folic Acid Supplementation for Prevention of Neural Tube Defects Guidelines (2017) [J]. Chinese Journal of Reproductive Health. 2017, 28(5): 401-410.

[2] Chinese Nutrition Society, Dietary Guidelines Revision Expert Committee, Dietary Guidelines Revision Expert Working Group for Women and Children. Dietary Guidelines for Pregnant Women[J]. Chinese Journal of Perinatal Medicine, 2016, 19(09): 641-648.

[3] American College of Obstetricians and Gynecologists(ACOG). ACOG practice bulletin. Neural tube defects[J]. Int J Gynaecol Obstet. 2003,83(1):123-33.

[4] Schaefer, Christof Schaefer, Paul WJ Peters, Richard K Miller. (2015,Third edition). Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment[M]. Pittsburgh: Academic Press.

[5] Wang Chen, Sun Yiying, Zhu Yuchun. Nutritional recommendations of the International Federation of Gynecology and Obstetrics on adolescents, pre-pregnancy and pregnancy (III)[J]. Chinese Journal of Perinatal Medicine, 2017, 20(02): 153-158.