DueDate.Baby

1 Weeks Pregnant: Baby Size, Symptoms and UK Milestones

First Trimester
Guide reviewed: July 2026Reviewed against cited UK guidance

At 1 weeks pregnant, use this UK guide to understand baby size, common symptoms, likely NHS timing, and the practical dates to keep on your radar.

1 weeks pregnant at a glance

  • You are in the first trimester.
  • Conception is happening or preparing to happen.
  • No appointments yet, but it's a good time to start taking folic acid and vitamin D.
  • Every pregnancy is different, so don't worry if your experience varies slightly.

You are 1 weeks pregnant and in your first trimester. This week's key development: It Begins.

This page is for general pregnancy planning and date guidance only. It is not medical advice, diagnosis, or treatment. Pregnancy dates are estimates and can change after a scan or advice from your midwife, GP, or maternity team.

If you have symptoms, concerns, or questions about your pregnancy, speak to your midwife, GP, or maternity team. For urgent help, use NHS 111; call 999 in an emergency. Read how we source and review content in our editorial policy.

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Week 2

Baby's Development

Your baby is about the size of not here yet.

It Begins — Pregnancy is counted from the first day of your last period. Your body is quietly preparing, shedding its lining and building fresh, ready to receive new life. Conception hasn't happened yet, but the journey has already started.

Your Symptoms

  • Menstrual bleeding
  • Cramping
  • Mood swings
  • Fatigue

Every pregnancy is different. You may experience all, some, or none of these symptoms — and that's completely normal. If anything concerns you, speak to your midwife.

NHS Appointments

No appointments yet, but it's a good time to start taking folic acid and vitamin D.

Practical Advice for Week 1

Nutrition

  • Start taking 400mcg folic acid daily — this is the single most important supplement right now.
  • Take 10mcg vitamin D daily, as recommended by the NHS for all UK adults.
  • Eat plenty of leafy greens, beans, and fortified cereals for natural folate.
  • Stay well hydrated — aim for 6–8 glasses of fluid per day.

Exercise

  • Continue your normal exercise routine — there's no need to change anything yet.
  • Walking, swimming, and cycling are all excellent choices.
  • Start practising pelvic floor exercises (Kegels) to build a strong foundation.
  • Aim for 150 minutes of moderate activity per week, as the NHS recommends.

Wellbeing

  • If you're trying to conceive, try to reduce stress where you can — it genuinely helps.
  • Talk to your partner about how you're both feeling about this journey.
  • Get into a good sleep routine — aim for 7–9 hours per night.
  • Consider cutting back on caffeine to under 200mg per day (about 2 cups of coffee).

Preparation

  • Start taking folic acid and vitamin D if you haven't already.
  • Book a GP appointment or contact your local maternity service to discuss your plans.
  • Review any medications with your GP to check they're safe for pregnancy.
  • Check that you're up to date with vaccinations, especially rubella.

Tip of the Week

Start taking 400mcg of folic acid daily to help your baby's neural tube develop correctly.

Frequently Asked Questions for Week 1

How many months is 1 weeks pregnant?
At 1 weeks pregnant, you are roughly in your first month pregnant. Remember that pregnancy is typically measured in weeks rather than months for clinical accuracy.
What size is the baby at 1 weeks?
At 1 weeks, your baby is roughly the size of not here yet. Pregnancy is counted from the first day of your last period. Your body is quietly preparing, shedding its lining and building fresh, ready to receive new life. Conception hasn't happened yet, but the journey has already started.
What are the common symptoms at 1 weeks pregnant?
Common symptoms at this stage include menstrual bleeding, cramping, mood swings, fatigue. Remember that every pregnancy is unique, and it's normal to experience different symptoms.
Is 1 weeks in the first trimester?
Yes, 1 weeks falls within the first trimester.
Are there any NHS appointments at 1 weeks?
No appointments yet, but it's a good time to start taking folic acid and vitamin D.

Tools & Calculators

Due Date Calculator UKPregnancy Week CalculatorTimeline by Due DateHow Many Weeks Am I?

Sources and further reading

Checked for UK week 1 pregnancy information guidance in July 2026.

How we review content

We prioritise official NHS and GOV.UK guidance, then relevant professional-body information where needed.

Source links are checked on the review date shown above. Your midwife, GP, maternity team, fertility clinic, or employer can give advice that is more specific to your circumstances.

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Week 2

Track Your Due Date

Keep track of your pregnancy milestones, NHS scans, and countdown to your due date.

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NHS Resources

Find trusted information on financial support, antenatal classes, and local maternity services.

View Resources

All Weeks

Browse the complete week-by-week pregnancy guide from conception to birth.

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