Home › Pregnancy week by week › Week 1
1 Week Pregnant: Your Baby, Your Body and What to Do
Pregnancy is counted from the first day of your last period, so this week your body is getting ready rather than pregnant.
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
You are not pregnant yet in week 1. Doctors and midwives count pregnancy from the first day of your last menstrual period, which adds about two weeks to the time since conception. That is why a full-term pregnancy is described as 40 weeks.
During your period the lining of the womb is shed. At the same time, hormones signal several eggs in the ovaries to start maturing. Usually one of them goes on to be released.
How you may be feeling
Your period is the main thing happening. Some people have cramps, tiredness, mood changes or headaches. If you are planning a pregnancy, this is a good moment to look after your general health.
Your to-do list for week 1
- Start taking folic acid if you have not already. Most guidance suggests 400 micrograms a day before conception and until week 12, with a higher dose advised in some situations.
- Note the first day of your period. It helps to date your pregnancy later.
- Cut back on alcohol and stop smoking. Ask for support if you need it.
- Check with a pharmacist or doctor that any regular medicines are safe if you become pregnant.
When to ask for help
If you have a health condition such as diabetes, epilepsy or high blood pressure, or take regular medicines, talk to your doctor before you try to conceive so that any changes can be made safely. Do not stop prescribed medicines on your own.
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: ovulation calculator and period 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.