Week 1: The countdown begins
You’re 1 week pregnant — about 39 weeks to go. Your baby is roughly the size of a fresh start.
Size of
a fresh start
Length
—
Weight
—
Your baby this week
You are not actually pregnant yet — week 1 is your period. Because due dates are counted from the first day of your last menstrual period, the calendar starts now even though conception is still a couple of weeks away.
Your body & how you might feel
Your body is shedding the previous cycle’s lining and preparing a fresh one. It is the ideal moment to begin a prenatal vitamin with folic acid, which supports healthy neural-tube development before you even conceive.
Common symptoms at week 1
- Menstrual bleeding
- Mild cramps
- A normal pre-conception cycle
This week’s tip: Start a daily prenatal with at least 400 mcg of folic acid now — the earliest weeks of development matter most.
A gentle reminder: This is an estimate, not medical advice. Dates and figures are general guidance — every pregnancy is different. Your healthcare provider’s assessment, especially from an early ultrasound, always takes priority. Always speak with your provider about your pregnancy.
Week 1 FAQs
How big is the baby at 1 weeks?
At 1 weeks pregnant, your baby is roughly the size of a fresh start. These are typical averages — every baby grows at its own pace.
How many months is 1 weeks pregnant?
1 weeks pregnant is less than 1 month, in the first trimester, with about 39 weeks to go until your due date.
What are common symptoms at 1 weeks?
Common experiences around week 1 include menstrual bleeding, mild cramps, a normal pre-conception cycle. Symptoms vary widely — contact your provider if anything worries you.