3rd TrimesterMonth 9Week 39 of 40
39 Weeks Pregnant
— How Many Months Is It?
39w
Equivalent to
Month 9
3rd Trimester
🍉
Baby is the size of a
Watermelon
50.7 cm (~20 in) · 3.3 kg
🌱Fetal Development Milestones — Week 39
Brain and lung maturation continues until labor begins naturally.
Pregnancy timeline progress98%
Week 1Week 39Week 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 39
39 weeks pregnant equals Month 9 of gestation in the 3rd 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.
Brain and lung maturation continues until labor begins naturally.
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).