Leucovorin and autism have been in the news since September 2025. If you’re pregnant or planning a pregnancy, or you have a child with developmental delays, it helps to know what the FDA approved and what it didn’t.

The short version

  • Leucovorin is a form of folate. It’s also called folinic acid. It has long been an FDA-approved medicine, including to reduce side effects of some cancer treatments.
  • What the FDA approved in March 2026: Wellcovorin (leucovorin) tablets as the first treatment for cerebral folate transport deficiency in adults and children with a confirmed change in the FOLR1 gene, according to the FDA.
  • What it didn’t approve: leucovorin for autism. Autism spectrum disorder isn’t part of the approved use.
  • Cerebral folate deficiency is rare. It’s a neurological condition in which folate can’t get into the brain properly, and it can cause developmental delays with features that resemble autism, seizures, and movement problems.
  • For pregnancy, nothing has changed. Folic acid, 400 mcg a day before and during early pregnancy, is still the recommendation to prevent neural tube defects.

What leucovorin is

Leucovorin is a form of folate that the body can use directly. It isn’t the same as the folic acid in prenatal vitamins and fortified foods. Doctors have used it for decades, mostly alongside certain chemotherapy drugs.

What the FDA decided

On September 22, 2025, the FDA announced that it was starting the process to update the label of leucovorin tablets for cerebral folate deficiency, a condition in which folate transport into the brain is impaired. The FDA said people with the condition have been observed to have developmental delays with autistic features, seizures, and problems with movement and coordination. It based the move on its review of published case reports and other literature from 2009 to 2024.

On March 10, 2026, the FDA approved the updated use. The approval covers adults and children with cerebral folate transport deficiency who have a confirmed variant in the folate receptor 1 (FOLR1) gene. The FDA’s approval was based on a systematic review of the published literature, including case reports and data on how the drug works, rather than a clinical trial.

The approval is narrow. It applies to people who have this rare genetic condition and a confirmed gene variant. It doesn’t extend to autism in general.

What the research says about folate and autism

Folic acid in pregnancy and autism. Some observational studies have found a lower risk of autism in children whose mothers took folic acid around pregnancy, and others haven’t. The NIH says it’s unclear, according to its folate fact sheet. Observational studies show a link, not proof of cause. Folic acid’s proven benefit is lowering the risk of neural tube defects.

Leucovorin and autism. The FDA’s March 2026 approval is for cerebral folate transport deficiency with a confirmed FOLR1 variant. It doesn’t say that leucovorin treats autism. The approval rests on published case reports and a review of how the drug works, and the question of whether leucovorin helps children with autism who don’t have this condition wasn’t part of it.

Safety. According to the label for Wellcovorin, serious allergic reactions, including anaphylaxis, have been reported with leucovorin, and the drug shouldn’t be used by anyone with a history of allergic reaction to leucovorin, folic acid, or an ingredient in the tablets. It also can interact with other medicines. It needs a prescription and a doctor’s supervision.

If you’re pregnant or planning a pregnancy

  • Keep taking folic acid: 400 mcg a day, starting at least a month before pregnancy, as the CDC and the U.S. Preventive Services Task Force recommend. See Why Folic Acid Matters in Pregnancy.
  • Don’t take leucovorin on your own. It isn’t a prenatal supplement, and there’s no approved use for preventing autism.
  • Don’t go above the upper limit of 1,000 mcg a day of folic acid unless your doctor recommends it. Very large amounts can hide a B12 deficiency.
  • Ask your provider if you have questions about folate and your baby’s development.

If you have a child with developmental delays

  • Talk with your child’s pediatrician or a specialist about an evaluation. Developmental delays have many causes.
  • Cerebral folate deficiency with a FOLR1 variant is rare, and the approval requires a confirmed variant, which means a specialist’s diagnosis and genetic testing.
  • Don’t start leucovorin or another folate product for your child without a prescription and a doctor’s guidance.

What to do now

  • If you could become pregnant, take 400 mcg of folic acid every day.
  • Bring questions about leucovorin or folate to your child’s doctor or your own provider, not to a supplement shelf.
  • Check the date and source on anything you read about autism treatments, and look for the FDA, NIH, or CDC.

Related reading

Sources

Updated November 2026. This article is for general information and is not a substitute for advice from your health care provider.