Baby is about the size ofNot conceived yet
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Week 1 of 40, first trimester39 weeks to go
Your baby at 1 week
Week 1 begins on the first day of your last period. You are not actually pregnant yet. Doctors count pregnancy from this date because it is easier to know than the day you conceived, so your due date is set 40 weeks from now.
During this week your body is getting ready to release an egg. Several small follicles in your ovaries start to grow, and one will usually become the egg released at ovulation.
Your body at 1 week
You have your period as your uterus sheds its lining. Hormones then start to build a new lining, ready for a fertilised egg.
Your checklist this week
- Start taking 400 micrograms of folic acid every day, ideally from at least one month before you conceive.
- Write down the first day of this period: you will need it to work out your due date.
- Ask your doctor about any medicines you take regularly.
- Stop smoking and avoid alcohol if you are trying to conceive.
Not sure which week you are in?
Use our Due Date Calculator or Pregnancy Week Calculator to find out exactly how far along you are.