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3 Weeks Pregnant: Your Baby, Your Body and What to Do
Conception most likely happens around now, and a tiny ball of cells begins its journey towards the womb.
Before you use this guide: Pregnancy weeks are counted from the first day of your last period. Sizes are rough averages, and healthy babies vary. This is general information, not an individual medical assessment, so please confirm personal health decisions with your doctor or midwife.
What is happening this week
If an egg is fertilised, this is usually the week it happens, in the fallopian tube. The fertilised egg starts dividing within hours and becomes a ball of cells over the next few days.
While it divides, it travels down the tube towards the womb, which takes several days. The inner cells will become the baby and the outer cells will help to form the placenta.
How you may be feeling
You will not feel anything yet, and a pregnancy test will not show a result. Some people notice light cramps or a very slight spotting in the following days, but many notice nothing at all.
Your to-do list for week 3
- Avoid alcohol, smoking and recreational drugs if there is any chance you have conceived.
- Keep taking folic acid and eat a varied diet.
- Wait until the day your period is due, or later, before taking a pregnancy test. Testing earlier can give a false negative.
- Carry on with gentle exercise and rest as normal.
When to ask for help
There is nothing to report this early. If you take prescribed medicines, ask a pharmacist or doctor whether they are safe in pregnancy before you stop or change anything.
For heavy bleeding, severe pain, fluid leaking, a severe headache with vision changes, or a baby who is moving less than usual, do not wait for your next appointment. Contact your midwife, doctor or maternity unit straight away. Our guide to pregnancy warning signs has more detail.
Not sure which week you are in? Use the due-date calculator to estimate your due date and current week.
Useful at this stage: pregnancy test calculator.
Trusted resources to read next
These public health resources provide additional information. Guidance can vary by country, so prioritise advice from your own care team and local health service.
- NHS: Pregnancy — Pregnancy care, common symptoms, screening and complications.
- NHS: Week-by-week pregnancy guide — Pregnancy development and care by week.
This content is for general information only and is not medical advice. Every pregnancy and every baby is different. Always talk to your doctor, midwife or paediatrician about your own situation, and seek urgent care if you are worried.