All weeks

First Trimester

Week 1 of pregnancy

Your baby is the size of a poppy seed (it's actually your last period).

Baby at 1 weeks

  • Pregnancy is dated from the first day of your last period — so you're not actually pregnant yet.
  • This week your body is preparing for ovulation in 1-2 weeks.
  • The egg you'll release later this cycle hasn't been fertilised yet.

What you may feel

  • Your period — flow as usual.
  • Cramping or premenstrual symptoms.
  • No pregnancy signs yet.

This week’s checklist

  • Start a folic-acid supplement (400 mcg/day) if not already.
  • Cut alcohol, smoking, and excess caffeine while trying.
  • Track your period start day for accurate due-date dating.

Key milestone

Pregnancy clock starts at LMP — Naegele's rule (LMP + 280 days) gives the EDD.

Doctor / midwife visits

If actively trying: confirm folic acid + pre-pregnancy GP visit if any medical condition.

Top foods this week

Educational only — not medical advice. Always consult your midwife or GP. Sources: NICE NG201 antenatal care, NICE NG207 inducing labour, NHS, RCOG. Read the full medical disclaimer.