1st TrimesterMonth 1Week 3 of 40
3 Weeks Pregnant
— How Many Months Is It?
3w
Equivalent to
Month 1
1st Trimester
🌱
Baby is the size of a
Vanilla Seed
0.2 mm
🌱Fetal Development Milestones — Week 3
The embryo is forming the neural tube — the foundational structure for your baby's brain and spinal cord.
Pregnancy timeline progress8%
Week 1Week 3Week 40
Calculate Your Exact Due Date
Enter your last period date for an instant gestational calculation
212835
Enter your date to calculate gestational age.
Based on ACOG guidelines and Naegele's Rule for informational purposes only. Consult your OB-GYN.
Adjacent Pregnancy Weeks
Frequently Asked Questions — Week 3
3 weeks pregnant equals Month 1 of gestation in the 1st Trimester. Because calendar months vary between 28 and 31 days while weeks are exactly 7 days, clinical tracking in weeks provides the most accurate timeline.
The embryo is forming the neural tube — the foundational structure for your baby's brain and spinal cord.
Use the calculator above: enter the first day of your last period (LMP) and the tool will calculate your exact estimated due date using Naegele\'s Rule (LMP + 280 days).