Before you're pregnant: what actually matters

Most preconception advice is a long list of optional improvements. There is one item that is not optional and is genuinely time-sensitive, so it goes first.

Folic acid, and why the timing is the whole point

The neural tube — which becomes the brain and spinal cord — forms in the first few weeks of pregnancy, typically before a woman knows she is pregnant.

That is why 400 micrograms of folic acid daily is recommended for every woman who could become pregnant, not only those actively trying. Starting it when a test turns positive is already late for the thing it prevents.

The CDC estimates that universal use before and during early pregnancy could prevent a substantial share of neural tube defects. Few interventions anywhere in medicine are that cheap and that effective.

If you have had a previous pregnancy affected by a neural tube defect, a much higher dose is recommended — that one is prescribed rather than bought, so ask.

This is the one to start today rather than when you get a positive test. By then the window it protects has already begun.

The rest of the short list

• A preconception appointment — a conversation about your history, your medications and anything chronic
• Check your prescriptions. Some need changing before pregnancy rather than after, and stopping them on your own is the wrong move
• Iron, if your periods are heavy or you've been anaemic before. Starting pregnancy depleted makes the whole year harder
• Vaccinations up to date, some of which are better given before conception
• Dental care, which gets harder to arrange later and matters more in pregnancy than people expect
• Stop smoking, and reduce alcohol — both of you

What matters less than you'd think

Elaborate detox protocols, expensive fertility supplement stacks, and cutting out entire food groups on the internet's advice do not have evidence behind them and can cost a lot.

If you want to spend money on something, spend it on the appointment and on a decent basic prenatal vitamin.

Check what's in the prenatal

They are not equivalent. Look for the folic acid amount, iron, iodine, and vitamin D — and check choline, which many contain little or none of despite mattering for the baby's brain development.

The best prenatal is the one you will actually take every day. If one makes you feel sick, try a different form rather than giving up.

And your husband

Sperm take around three months to develop, so changes he makes now affect what is available in three months' time rather than tomorrow.

Smoking, heavy drinking, heat and some medications all matter. This is a shared project, and framing it that way from the start changes how the rest of it goes.