A healthy 28-year-old woman attends before her first planned pregnancy. She has no medical problems, takes no medication and has a normal BMI. There is no family history of neural tube defects. She asks what she can do now to give her baby the best start. What is the single most appropriate preconception intervention?

Answer: D. Folic acid 400 micrograms daily

Preconception care for the low-risk woman

For a healthy woman with no NTD risk factors, the single evidence-based preconception intervention with the clearest fetal benefit is folic acid 400 micrograms daily, started before conception and continued to 12 weeks, to reduce the risk of neural tube defects.

What else belongs in preconception care

• Lifestyle: smoking cessation, alcohol avoidance, healthy weight.
• Rubella immunity check and vaccination if needed (avoid pregnancy for the advised interval afterwards).
• Optimisation of any chronic disease and review of teratogenic drugs.
• In selected communities: thalassaemia carrier screening; screening for type 2 diabetes where indicated.

Why not the other tests routinely

An OGTT, aneuploidy screening and iron supplementation are not blanket preconception interventions for a low-risk, asymptomatic woman; they are reserved for specific indications or for screening during pregnancy. The principle of a screening test is that it should target an important condition for which an early intervention makes a difference.