When Does the Brain Develop?
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Medically reviewed by
Baby Circle Medical Board
Reviewed on 18 July 2026
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It starts in the first weeks — folic acid is vitalEvidence-based & doctor-reviewed
The brain begins forming in the first few weeks — the neural tube closes by about week 6 — and continues developing throughout pregnancy and beyond. Folic acid before and in early pregnancy is vital for healthy neural-tube development.
The timeline
- The neural tube forms around weeks 3–4 and closes by about week 6.
- The brain grows rapidly through the second and third trimesters.
- Brain folds and connections develop strongly later in pregnancy and continue after birth.
Why folic acid matters
Taking folic acid before conception and in early pregnancy greatly lowers the risk of neural-tube defects like spina bifida.
Supporting brain development
- Take your prenatal supplements.
- Eat well, including omega-3 sources.
- Avoid alcohol and smoking.
Frequently asked questions
When does the brain start forming?
In the first few weeks; the neural tube closes by about week 6.
Why is folic acid important?
It sharply reduces the risk of neural-tube defects during early brain and spine development.
How can I support brain development?
Prenatal vitamins, good nutrition with omega-3s, and avoiding alcohol and smoking.
Follow your baby week by week 💜
See exactly how your baby grows in the complete 40-week guide.
40-Week GuideJoin The CircleReferences
- WHO. Antenatal care recommendations. who.int
- ACOG. Fetal development. acog.org
- NHS. You and your baby, week by week. nhs.uk
- Tommy's. Baby movements & development. tommys.org
- CDC. During Pregnancy. cdc.gov
Related reading
When Do the Lungs Develop?What Does My Baby Look Like This Week?Can My Baby Dream?📖 40-Week Pregnancy Guide
Medical disclaimer: This article is for general education only and is not a substitute for professional medical advice. Always consult your doctor about your pregnancy and your baby, and seek care immediately for any warning signs — including reduced or changed baby movements. Reviewed by the Baby Circle Medical Board.