Excessive folic acid during pregnancy can increase risk of autism

O Estado de S.Paulo | 09/04/2017
Fonte: Ludimila Honorato
The substance in only one of the several factors that can contribute to the disorder, but correct dosage is essential to baby’s neurodevelopment.

The consumption of folate - or folic acid synthetically - before and during pregnancy is essential to help closing the neural tube of babies, which will form central nervous system. The substance also prevents morphological issues, such as anencephaly, cleft lip and cleft palate, but excessive vitamin (B9) can increase the risk of autism in children twice.
The conclusion is from a study conducted by researchers of Johns Hopkins Bloomberg School of Public Health, in the United States, which analyzed 1,391 mothers and respective children between 1998 and 2013. Folate level in mothers’ blood was measured right after delivery, and children were followed during this period.

The results, showed in 2016, indicated that mothers of autist children had levels of folate four times higher than adequate levels. The excess was found in one every ten participants.

“The excessive folate acts in a very specific condition, in DNA hypermethylation mechanism of the fetus, which may prejudice neurodevelopment. The excess may prejudice the genes which make encephalon maturation and cause any malformation, being able to develop autism or partial autism”, explains Antonio Cabral, Doctor of obstetrics from Universidade Federal de São Paulo (Unifesp) and full professor of obstetrics from Medicine College of Universidade Federal de Minas Gerais (UFMG).

However, Cabral clarifies that autism is caused by several others reasons than only this isolated factor. “There must be genetic predisposition and other factors. The excessive folate can have a different consequence to other person”, he says.
Autism. The psychiatrist Andreas Stravogiannis, technical director at Associação de Amigos do Autista (AMA), explains that autism is a neurodevelopment disorder and has multiple causes. “There is a genetic factor and environmental factors which, along with hereditary factors, can cause this condition”, he says.

Among the potential environmental causes, the specialist mentions neonate infections, problems during delivery, malnutrition of the mother, which may interfere with fetus formation, and exposure to chemical or toxic substances during pregnancy or after baby is born during the first days of life and premature delivery.

Stravogiannis says that physicians and science still wonder why so distinct factors lead to an autism condition - or other neurological change.  Nevertheless, he highlights that not every mother who goes through these situations will have a child with autism.

“When autism diagnosis is provided, we have to investigate the possible causes, but in most cases, the patients do not have enough evidences to justify the autism”, explains the psychiatrist.

Continued recommendation. At the time of the study disclosure, some physician questioned the results. According to reviews, the researchers would be ‘irresponsible’ and ‘generating risks’ to mothers who should actually keep taking vitamin. In addition, a study published in 2013 at The Journal of the American Medical Association showed that ingestion of folic acid by pregnant women reduced autism risk.

Antonio Cabral explained that, at that moment, it was warned that women were already taking folic acid in their nutrition. The substance can be naturally found in fruits and vegetables and is used to enrich flours. “It just should not be consumed under high doses”, he emphasizes. The ingestion of folic acid by pregnant women is still important.

As women already consume the vitamin in food, even without knowing it, pregnant women or those who are planning to get pregnant should pay attention to correct dosage when using supplementation. Ingesting 0.4 to 0.8 milligrams per day before pregnancy and in the first months of gestation is the ideal, according to Cabral, following the recommendations of World Health Organization (WHO) and Brazilian entities such as Federal Medical Council (CFM) and Brazilian Federation of Gynecology and Obstetrics Associations (Febrasgo).

However, this dose can vary from woman to woman. “If she has any activity or habit that may reduce folic acid [in organism], such as smoking or intense physical activity, she can use this dosage or a higher one. She has to talk to the doctor to see if it is excessive”, says Cabral. A blood test measuring folate quantity can also help to correctly prescribe the vitamin.

Absence or incorrect ingestion. In Brazil, 55.4% of women get pregnant without planning to, according to a research conducted by National School of Public Health of Fundação Oswaldo Cruz (ENSP/Fiocruz). In other words, they do not benefit from positive actions of folic acid before conception. In addition to helping in neurodevelopment and morphology, the vitamin helps to form the heart, and if taken under lower dosages during pregnancy, it avoids premature delivery, affirms Cabral.

The risk of excessive folate in blood is not that difficult. Because it is a common vitamin, the substance is sold in drugstores with no medical prescription required and freely distributed by Brazilian Single Health System (SUS). In this last case, it is acquired for several purposes, such as against anemia, and can be available under a dosage higher than that indicated for pregnant women.

More studies. “Adequate supplementation is protective - it still applies to folic acid”, says Daniele Fallin, one of the authors of the study from Johns Hopkins Bloomberg. However, researchers say that more studies are required to determine how much folic acid a woman should consume during pregnancy.

“Folic acid acts in the first quarter, mainly in neural tube. It had to be seen if in this initial period the mothers showed high values”, considers Stravogiannis, highlighting the fact the study measured post-delivery folate levels. Among important benefits and potential risks of excessive folate in pregnant women, physicians and women are warned to pay attention to the adequate dosage of the substance.
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