13 Weeks Pregnant: Baby Size, Symptoms and Start of the Second Trimester

At 13 weeks pregnant, your baby is about the size of a peach and you are officially entering the second trimester. If you are searching for 13 weeks pregnant baby size or 13 weeks pregnant symptoms, this week marks a meaningful transition.

Development continues rapidly, and the most delicate stage of organ formation is now complete. The highest-risk period of early pregnancy has passed.

For many women, nausea begins improving and energy slowly returns.

Let’s look at what happens at 13 weeks pregnant.

At a Glance:
13 Weeks Pregnant
  • Baby size: About the size of a peach, around 7 to 8 cm long
  • Trimester: Second trimester begins
  • Key hormonal shift: hCG stabilizing, progesterone remains elevated
  • Common symptoms: Improving nausea, fatigue easing, round ligament discomfort, increased appetite
  • Doctor visit: Routine prenatal care continues
  • Emotional theme: Relief and renewed steadiness as the second trimester begins.

At 13 weeks pregnant, your baby measures about 7 to 8 cm from crown to rump.

Here is what is happening:

  • Vocal cords are forming
  • Fingerprints continue forming and becoming more defined
  • The intestines have returned to the abdomen and continue developing
  • Bones continue hardening
  • The baby can make more coordinated movements
  • Facial muscles are developing
  • The head is becoming more proportional to the body

Although you cannot feel it yet, movement inside the uterus is becoming more fluid and purposeful.

Growth now accelerates throughout the second trimester.

What Is Happening in Your Body at 13 Weeks Pregnant

13 weeks pregnant symptoms often shift as you enter the second trimester.

You may notice:

  • Nausea improving
  • Energy gradually increasing
  • Increased appetite
  • Mild round ligament pain
  • Visible belly growth
  • Headaches or dizziness

Your uterus has expanded significantly and is rising higher in your abdomen. Blood volume continues increasing to support the placenta and growing fetus.

Many women describe this as the beginning of a more stable phase of pregnancy, though every experience is different.

Emotional and Nervous System Changes

Entering the second trimester can feel like a quiet exhale.

You may feel:

  • Relief
  • Growing confidence
  • Increased excitement
  • Lingering protectiveness

For weeks, your nervous system has been in early pregnancy vigilance mode. As risk decreases and symptoms improve, emotional steadiness may grow.

It does not mean anxiety disappears.

It means your body is recalibrating.

3 Focus Areas This Week

1. Rebuild Energy Gradually

If energy improves, increase activity slowly rather than all at once.

2. Support Muscles and Ligaments

Gentle stretching can help ease round ligament discomfort.

3. Reinforce Emotional Steadiness

Relief is natural. So is caution. Allow both.

Weekly Calm Practice

Sit comfortably.

Place one hand on your belly.

Say silently:

“I am entering the second trimester.”

Pause.

Then say:

“My body has carried me here.”

Allow your shoulders to soften.

This is a transition. You are allowed to feel it.

Looking Ahead to 14 Weeks Pregnant

At 14 weeks pregnant, the second trimester continues. Energy often improves further. Movement becomes stronger, though most women feel it later.

Growth remains steady.

Frequently Asked Questions

13 Weeks Pregnant: Baby Size, Symptoms and Start of the Second Trimester

Is 13 weeks pregnant considered second trimester?
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Yes. The second trimester typically begins at 13 weeks.

Can you feel the baby at 13 weeks?
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Most women feel movement between 16 and 20 weeks.

Is nausea gone at 13 weeks?
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For many women, nausea improves around this time, though it can continue for some.

Why am I having round ligament pain?
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As the uterus grows, supporting ligaments stretch, causing brief sharp discomfort.

At 13 weeks pregnant, you cross an important threshold.

The first trimester is complete. Growth continues. Energy may begin returning.

Relief may be rising.

Move into this next phase with steadiness.

Written by Irin Rubin

Founder of MamaZen

Disclaimer

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider with questions about your pregnancy.