DueDate.Baby

5 Weeks Pregnant: Baby Size, Symptoms and UK Milestones

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

At 5 weeks pregnant, use this UK guide to understand baby size, common symptoms, likely NHS timing, and the practical dates to keep on your radar.

5 weeks pregnant at a glance

  • You are in the first trimester.
  • Your baby is roughly the size of a sesame seed.
  • You should have your first midwife appointment (booking appointment) booked for between weeks 8 and 12.
  • Every pregnancy is different, so don't worry if your experience varies slightly.

You are 5 weeks pregnant and in your first trimester. Your baby is about the size of a sesame seed. This week's key development: The Heart Stirs. NHS note: You should have your first midwife appointment (booking appointment) booked for between weeks 8 and 12.

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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Baby's Development

Your baby is about the size of a sesame seed.

The Heart Stirs — Your baby's heart is beginning to form and may even start beating by the end of this week. The neural tube, which becomes the brain and spinal cord, is closing.

Illustration of a sesame seed, showing the approximate size of the baby at week 5
Sesame seed
Approx. 0.2cm

Your Symptoms

  • Frequent urination
  • Morning sickness may start
  • Food aversions
  • Exhaustion

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

You should have your first midwife appointment (booking appointment) booked for between weeks 8 and 12.

Practical Advice for Week 5

Nutrition

  • Folic acid and vitamin D — every single day.
  • If nausea is starting, try bland foods like crackers or toast before getting out of bed.
  • Ginger tea or ginger biscuits can help settle your stomach.
  • Eat protein-rich snacks (nuts, cheese, yoghurt) to stabilise blood sugar.

Exercise

  • Continue exercising as normal, adjusting intensity if you feel unwell.
  • Walking is the most accessible and effective exercise throughout pregnancy.
  • Start incorporating gentle stretches for your back and hips.
  • If you're too nauseous to exercise, don't force it — rest is productive too.

Wellbeing

  • Morning sickness can strike at any time of day — don't be surprised by 3pm nausea.
  • Sleep when you can. Early pregnancy exhaustion is profound.
  • Acupressure wristbands may help with nausea — they're available from most chemists.
  • It's normal to feel anxious before your first midwife appointment.

Preparation

  • Book your first midwife (booking) appointment for between weeks 8 and 12.
  • Start a list of questions you want to ask your midwife.
  • Research your screening test options — your midwife will discuss these at the booking appointment.
  • Check your dental health — NHS dental care is free during pregnancy and for 12 months after.

Tip of the Week

Stay hydrated and eat small, frequent meals if you're feeling nauseous.

Frequently Asked Questions for Week 5

How many months is 5 weeks pregnant?
At 5 weeks pregnant, you are roughly 1 months pregnant. Remember that pregnancy is typically measured in weeks rather than months for clinical accuracy.
What size is the baby at 5 weeks?
At 5 weeks, your baby is roughly the size of a sesame seed (about 0.2cm). Your baby's heart is beginning to form and may even start beating by the end of this week. The neural tube, which becomes the brain and spinal cord, is closing.
What are the common symptoms at 5 weeks pregnant?
Common symptoms at this stage include frequent urination, morning sickness may start, food aversions, exhaustion. Remember that every pregnancy is unique, and it's normal to experience different symptoms.
Is 5 weeks in the first trimester?
Yes, 5 weeks falls within the first trimester.
Are there any NHS appointments at 5 weeks?
You should have your first midwife appointment (booking appointment) booked for between weeks 8 and 12.

Tools & Calculators

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

Sources and further reading

Checked for UK week 5 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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NHS Resources

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All Weeks

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