Pregnancy Week 5

Your baby is still an embryo and is only around 1–2mm long, about the size of a sesame seed, or small enough to sit on the tip of a pen. It may be tiny, but this is a surprisingly busy stage of development.

The early structure (called the 'neural tube') that will become your baby’s brain and spinal cord is starting to take shape. The head and tail ends of the embryo can now be identified, giving it a slightly curved, tadpole-like appearance.

Your baby’s heart and blood vessels are also beginning to form. The heart is not fully developed yet, but this early cardiovascular system will soon become one of the first systems in the body to start working.

At this stage, development is guided by the genetic instructions in each cell, with cells moving into place to begin forming different parts of the body. It is a carefully coordinated process, supported by the placenta and the early structures that are developing around the embryo.

An early ultrasound may be able to detect signs of a pregnancy, such as a gestational sac, but it may still be too early to see much detail.  In the UK, the first dating scan is usually offered later, between around 8 and 14 weeks.

At 5 weeks pregnant, many people are only just realising they might be pregnant. Your period may be late, a pregnancy test may now be positive, and early pregnancy hormones are rising quickly.

You might start to notice symptoms such as:

Some people feel very pregnant at 5 weeks, while others feel almost no different. Both can be completely normal.

Your body is also beginning the early work of supporting the placenta, which will eventually help provide your baby with oxygen and nutrients and remove waste products.

You should seek medical advice if you have vaginal bleeding, strong or worsening abdominal pain, pain on one side, shoulder tip pain, dizziness, fainting, or symptoms that worry you. Light spotting can happen in early pregnancy, but bleeding and pain should be checked so a doctor, midwife or early pregnancy unit can advise you.

Week 5 can be an emotional one. You may have just had a positive pregnancy test, or you may still be waiting to feel sure. You might feel excited, anxious, overwhelmed, protective, detached, or all of those things in the same afternoon.

It is also common to feel cautious at this stage. Many people choose to keep the news private until later in the first trimester, while others want support from a partner, close friend or family member straight away. There is no single right time to tell people - it depends on what would feel most supportive for you.

If you are feeling worried, try not to sit with it alone. You can speak to your GP, midwife, local early pregnancy service, or someone you trust. The NHS notes that anxiety and stress in pregnancy are common, and support is available if you need it.

Week 5 is a good time to move from “is this real?” into a few gentle next steps. If you have not already, contact your GP surgery or self-refer to your local maternity service and ask what happens next.

Practical next steps:

Try not to chase a perfect pregnancy diet this week. Early nausea, tiredness and appetite changes can make food feel unpredictable, so regular, manageable meals are a better goal than perfection.