Week 4 Pregnancy
You are 4 weeks pregnant and in your first trimester. Your baby is about the size of a poppy seed. This week's key development: Hello, Little One. NHS note: Contact your GP or local maternity service to register your pregnancy and book your 'booking' appointment.
Baby's Development
Your baby is about the size of a poppy seed.
Hello, Little One — Implantation is complete and your body is producing hCG, the hormone a home pregnancy test can now detect. Tiny layers of cells are already differentiating into what will become your baby's brain, spine, and heart.
Your Symptoms
- Missed period
- Tender breasts
- Fatigue
- Mild nausea
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
Contact your GP or local maternity service to register your pregnancy and book your 'booking' appointment.
Practical Advice for Week 4
Nutrition
- Continue folic acid and vitamin D daily.
- Eat wholegrain carbohydrates for sustained energy — brown rice, oats, wholemeal bread.
- Stay hydrated, especially if you're experiencing early nausea.
- Avoid soft cheeses with white rinds (brie, camembert) and blue cheeses.
Exercise
- You can safely continue most exercises, including running and gym classes.
- Listen to your body — if something feels wrong, stop and rest.
- Pelvic tilts can help strengthen your core for the months ahead.
- Avoid hot yoga or exercising in extreme heat.
Wellbeing
- Fatigue is very real right now — your body is building a placenta. Rest guilt-free.
- It's okay to feel overwhelmed, excited, scared, or all three at once.
- Talk to your partner about when and how you'd like to share the news.
- If morning sickness hits, know that it usually peaks around weeks 8–10 and then eases.
Preparation
- Contact your GP or self-refer to your local maternity service to register your pregnancy.
- Your booking appointment should be scheduled between weeks 8 and 12.
- Find out about the free NHS Maternity Exemption Certificate (MatEx) for prescriptions and dental care.
- Download your hospital trust's app or online portal if they have one.
Tip of the Week
A positive home pregnancy test is very reliable. You don't usually need a GP to confirm it.
Track Your Due Date
Keep track of your pregnancy milestones, NHS scans, and countdown to your due date.
Go to TrackerNHS Resources
Find trusted information on financial support, antenatal classes, and local maternity services.
View ResourcesLoading guide...