Welcome to the second trimester, often called the "golden period" of pregnancy. For many people, nausea fades, energy returns, and you start to actually enjoy being pregnant. The fetus is growing rapidly and developing unique features like fingerprints. Use our Due Date Calculator to track your timeline.
Key Takeaways
- At 13 weeks, your baby is about 7 cm long (the size of a peach) and weighs roughly 23 grams
- Unique fingerprints are forming on the fingertips this week
- The kidneys are producing urine, which is released into the amniotic fluid — a normal and healthy process
- Bones are hardening rapidly, especially in the skull and long bones
- You need approximately 340 extra calories per day starting this trimester to support fetal growth
Your Baby This Week
Size: Peach (about 7 cm, or 2.9 inches)
Weight: About 23 grams
- Fingerprints: Unique patterns are forming on the fingertips
- Vocal cords: Continuing to develop
- Intestines: Now fully inside the abdomen and beginning to form villi for nutrient absorption
- Head and body: The body is catching up in size to the proportionally large head
- Kidneys: Producing urine, which is released into the amniotic fluid. This is normal and helps maintain amniotic fluid levels.
- Bones: Rapidly hardening, especially in the skull and long bones
The fetus can squint, frown, and grimace, though these are reflexive movements rather than expressions. Track your baby's growth with our Milestone Tracker.
Your Body
- More energy. Many people feel significantly better starting this week.
- Growing bump. Your clothes are getting tighter. Time for stretchy pants.
- Increased appetite. With nausea fading, food may sound appealing again.
- Reduced urination frequency. The uterus has moved up, relieving pressure on the bladder temporarily.
- Visible veins across the chest and abdomen as blood volume continues to increase.
What to Do This Week
- Increase calorie intake slightly. In the second trimester, you need roughly 340 extra calories per day (about a yogurt, a piece of fruit, and a handful of nuts).
- Start doing pelvic floor exercises. Kegel exercises strengthen the muscles that support the bladder, uterus, and bowels. They help during delivery and recovery.
- Stay active. Walking 30 minutes a day, swimming, or prenatal yoga are all excellent choices. Check out our Exercise During Pregnancy Guide for safe workout ideas as your energy returns.
Common Questions
How much weight should I gain in the second trimester?
The recommended total weight gain depends on your pre-pregnancy BMI. For a normal BMI (18.5 to 24.9), the total recommended gain is 11.5 to 16 kg (25 to 35 pounds) across the entire pregnancy, with most of the gain occurring in the second and third trimesters. Your provider will guide you.
Is it safe to travel in the second trimester?
The second trimester (weeks 13 to 27) is generally the most comfortable time to travel. Most airlines allow pregnant passengers to fly until 36 weeks, though policies vary. Carry your prenatal records, stay hydrated, and walk regularly during flights to reduce the risk of blood clots.
FAQ
What week does the second trimester start?
The second trimester officially begins at week 13 and runs through week 27. It is often called the "golden period" because nausea typically eases, energy returns, and the risk of miscarriage is significantly lower than in the first trimester.
What is happening with the baby at 13 weeks?
At 13 weeks, the fetus is about 7 cm long and weighs around 23 grams. Unique fingerprints are forming, the kidneys are producing urine, bones are hardening, and the intestines are inside the abdomen and developing villi for nutrient absorption. The fetus can squint, frown, and grimace.
How many extra calories do I need in the second trimester?
Roughly 340 extra calories per day during the second trimester. This is about the equivalent of a yogurt, a piece of fruit, and a small handful of nuts. Focus on nutrient-dense foods rather than empty calories.
When do you start showing at 13 weeks?
Many first-time parents start showing between weeks 12 and 16. If you have been pregnant before, relaxed abdominal muscles mean you may show earlier. Factors like body type, uterus position, and whether you are carrying multiples all affect when a bump becomes visible.
Is it safe to do Kegel exercises during pregnancy?
Yes — pelvic floor (Kegel) exercises are recommended during pregnancy. They strengthen the muscles supporting the bladder, uterus, and bowels, can help during delivery, and support faster postpartum recovery.
Related Articles
- Pregnancy Week-by-Week Overview — see the full timeline
- Pregnancy Week 14: Growing Stronger — what comes next
- Fetal Development Trimester Guide, your baby's development
Sources
🔧 Helpful Tools
- Due Date Calculator — Calculate your estimated due date
- Contraction Timer — Track your contractions during labor
- All Baby Tools — Browse all free tools for pregnancy and baby care
