How do I get folic acid? What if we add too much?

It is almost well known that folic acid supplementation is required during pregnancy preparation and pregnancy through years of popularizing science. 

As a medical worker, I am also worried about: some businesses through excessive promotion of the role of folic acid, to achieve hidden commercial interests, is not conducive to the public’s correct understanding of folic acid. 

In order to uncover the mysteries of this “magic medicine for pregnancy,” today we are going to explore the folic acid.

How do I get folic acid? What if we add too much?

What is folic acid? 

Folic acid (folic acid), also known as vitamin B9, is a water-soluble vitamin, the body can not be synthesized, only from food intake, it can participate in the synthesis and metabolism of DNA. It plays an important role in cell division and growth, synthesis of nucleic acid, amino acid and protein. 

Lack of folic acid in pregnant women can lead to low birth weight, cleft lip and palate, heart defects, neural tube defects and other malformations. 

It is recommended that women of childbearing age should be given 400 micrograms of folic acid per day (equivalent to one folic acid tablet) from the first three months of pregnancy and for the entire duration of pregnancy [1]. 

In fact, natural folic acid is widely found in plant and animal foods, especially in yeast, liver and green leafy vegetables. If folic acid is so common, why supplement it?

Why extra folic acid?

The reason for this is that the natural folic acid is extremely unstable and is easily oxidized by sunlight and heat, so the human body does not really get much folic acid from food, coupled with the fact that the first trimester of pregnancy (3-6 weeks) is a critical period for the differentiation of the fetal organ system. Cell growth, division is very strong, so pregnant women’s demand for folic acid is much higher than normal people.

So as early as 1990, the United States Centers for Public Health and Disease Control and Prevention recommended that all pregnant women take a daily supplement containing 0.4 to 0.8 milligrams of folic acid to prevent neural tube defects in the fetus. [2].

It did not take long, however, to raise questions about the safety of long-term folic acid use: in the mid-1990s, three studies showed that long-term folic acid use increased the natural abortion rate in pregnant women. [2].

As a result, the debate over whether folic acid is harmful has attracted dozens of scientists to research.

Ultimately, a study of 23806 pregnant women in China found that women who took folic acid daily did not have an increased risk of spontaneous abortion.

The Brazilian multicenter trial report also showed no difference in spontaneous abortion rates between the high folic acid (4 mg/ d) group and the low folic acid group (0.4 mg/d). [3-4].

More interestingly, a 2018 study by the American Academy of Reproductive Medicine even found that women who took folic acid before or during pregnancy had a lower risk of spontaneous abortion. [2].

Thus, based on the available evidence, we can almost conclude that folic acid supplementation before and during pregnancy does not increase the risk of miscarriage, but rather increases a woman’s chances of pregnancy and maintenance of pregnancy.

Is folic acid the more the better? 

Studies have confirmed that large doses of folic acid will produce toxic side effects, interfere with the absorption of zinc, intrauterine growth retardation, neonatal birth weight is too low. 

An overdose of folic acid supplements may also mask early symptoms of vitamin B12 deficiency, causing irreversible neurological damage in megaloblastic anemia patients with folic acid and vitamin B12 deficiency. 

In addition, excess folic acid may interfere with the action of anticonvulsant drugs and induce convulsions. [5]. 

For the health of the baby, mothers must listen to the doctor’s advice, but can not be lazy and ignore the folic acid supplement, of course, do not take too much folic acid, according to the doctor’s recommended dose.

The health of the pregnant woman and the fetus requires the joint efforts of the pregnant woman, her family and the doctor. In addition to regular birth checks and advice from doctors, pregnant women also need to pay attention to a balanced diet, moderate exercise and a reasonable schedule, in order to give birth to a healthy baby.


1.文兰. 准妈妈如何科学补充叶酸[J]. 江苏卫生保健, 2017(2):34-35.

2.Chiu, Y.H.; Chavarro, J.F.; Souter, I. Diet and female fertility: Doctor, what should I eat? Fertil. Steril. 2018,110, 560–569.

3.Gindler J, Li Z, Berry RJ, Zheng J, Correa A, Sun X, et al. Folic acid supplements during pregnancy and risk of miscarriage. Lancet 2001;358:796–800.

4.Vila-Nova C, Wehby GL, Queiros FC, Chakraborty H, Felix TM, Goco N,et al. Periconceptional use of folic acid and risk of miscarriage—?ndings of the Oral Cleft Prevention Program in Brazil. J Perinat Med 2013;41:461–6.

5、佘远红, 汪之顼. 孕期营养对孕妇和胎儿近期健康的意义[C]// 江苏省营养学会学术会议. 2014.

Leave a Reply

Your email address will not be published. Required fields are marked *