13 Weeks Pregnant
You’re 13 weeks pregnant — in the first trimester, and 27 weeks to go until your due date. Your baby is about the size of a lemon this week.
★ Last week of the first trimester.
How big is your baby at 13 weeks?
Size of a
lemon
Length
~7.4 cm
Weight
~23 g
Last week your baby was about the size of a lime; this week it's grown to roughly a lemon.
Sizes are averages from standard fetal-growth references. Every baby grows at its own pace — your provider tracks yours at scans.
Baby development at week 13
The final week of the first trimester. The fetus now has tiny, unique fingerprints, and vocal cords are forming. The intestines, which had been developing in the umbilical cord, move into the abdomen. The head is becoming more proportional to the body, and bones in the arms and legs continue to harden. About the size of a lemon.
Your body at 13 weeks
Common symptoms many people notice around week 13 include:
- Energy often improving as the second trimester approaches
- Nausea fading for most
- Possible increase in libido
- A more visible bump
Symptoms vary enormously from person to person and pregnancy to pregnancy. Not having a symptom on this list is just as normal as having it.
Tips for week 13
- Enjoy the 'honeymoon' second trimester many are about to enter
- Start thinking about maternity clothes as your bump grows
- Keep up balanced meals and hydration
What trimester is 13 weeks?
Week 13 falls in the first trimester. As a quick map: the first trimester runs weeks 1–13, the second covers weeks 14–27, and the third is week 28 through birth (a due date is set at 40 weeks). Want your own dates? Our Pregnancy Due Date Calculator shows your due date and exactly how far along you are today.
The first trimester (weeks 1–13) is when the baby's major organs and body systems form, and when pregnancy symptoms like nausea and fatigue are usually strongest. It's also when most prenatal care begins — the dating scan, early bloodwork, and (if you choose) genetic screening all happen in this window.
Frequently asked questions
- How many months is 13 weeks pregnant?
- 13 weeks pregnant is about 3 months. Pregnancy months don't divide evenly into 4-week blocks, so week-to-month conversions are approximate — most providers track pregnancy by week, not month.
- How big is the baby at 13 weeks?
- At 13 weeks, the baby is about the size of a lemon, roughly 7.4 cm and around 23 g. These are averages — healthy babies vary, and your provider tracks your baby's own growth curve at scans.
- What trimester is 13 weeks?
- Week 13 is in the first trimester. The first trimester is weeks 1–13, the second is weeks 14–27, and the third is weeks 28 to birth (around week 40).