Week 5 of 40
What's happening with the baby
Around week 5 the embryo is roughly 2mm long (often compared to a sesame seed). The brain and spinal cord are taking shape along the neural tube. A tiny heart is forming and typically begins to beat around now, though you will not hear or feel it yourself yet. The NHS week 5 guide summarises this stage clearly.
Early blood vessels are appearing, and the beginnings of the placenta and umbilical cord are underway. Facial features are only just starting. Pregnancy, Birth and Baby's week 5 page and ACOG's growth FAQ are useful companions if you want more detail.
This is still when major structures are being laid down, which is one reason folic acid and avoiding alcohol and smoking matter so much early on.
What you might notice
Many people first realise they are pregnant around week 5, when a period is late. A home urine test is often reliable from about now. NHS signs of pregnancy and Tommy's week 5 page list the usual early symptoms.
Those can include sore breasts, nausea (at any time of day), strong tiredness, mood swings, new food likes or dislikes, a metallic taste, needing to pee more, mild cramping, or light spotting. You might also have none of these and still be pregnant.
Light spotting can be implantation-related, but ACOG advises getting bleeding checked so someone can advise you. Finding out can bring excitement, worry, or both. Feeling anxious is common; you do not have to sit with it alone. Healthdirect's pregnancy hub is another calm place to start in Australia.
Things worth doing
- Confirm and book in. Share the news with a GP or midwife, or refer yourself to maternity care if that is how services work where you live. The longer first appointment is often between weeks 8 and 12. Ask about dating scans and screening when you are ready. See NHS antenatal care.
- Folic acid and vitamin D. Many expecting parents keep taking folic acid (often 400 mcg daily to week 12) and ask about vitamin D, but if you're unsure what fits your situation, check with your doctor or midwife. The NHS supplements page explains the usual UK advice.
- Review medicines and long-term conditions. Tell your specialist or GP promptly. Do not stop regular medication without advice (NHS medicines guidance).
- Cut down caffeine, skip alcohol, stop smoking if you can, and ask for help if you need it. Avoid secondhand smoke where possible. See NHS stop smoking in pregnancy and alcohol advice.
- Eat normally, not "for two". A varied diet is enough for most people; focus on what you can keep down if nausea has started.
- Unusual cravings for non-food items (dirt, chalk and similar) can relate to iron deficiency. Mention them to a clinician.
For partners this week
Tommy's "getting involved" guide is aimed at partners in these early weeks.
- Help with the first booking call or form, and offer to come to appointments.
- Take symptoms seriously without panicking: support them to call if bleeding or severe pain starts.
- Share the load at home if tiredness or nausea has landed hard.
- Look after your own feelings too. It is fine to want information and reassurance as well.
When to get help
- Bleeding, especially with pain, dizziness or feeling faint
- Severe one-sided abdominal pain (ectopic pregnancy needs urgent care)
- You cannot keep fluids down, or nausea is stopping you functioning
- Fever, painful peeing, or chest pain
- Low mood or anxiety that is hard to manage day to day
If you think you or a partner might have an STI, get checked. Some infections have no obvious symptoms and can affect pregnancy. For bleeding concerns, see NHS and ACOG.