At 20 weeks, the baby is often about 10 inches (25 cm) long from head to heel and weighs about 10 ounces (300 g), roughly the size of a banana. This is the halfway point, when the brain and organs keep developing quickly.
20 weeks pregnant is about 4.5 months. You are in month 5 of pregnancy and the second trimester.
Your baby at 20 weeks
Halfway Through Pregnancy, About the Size of a Banana
Week 20 is the halfway point of pregnancy. Your baby is growing quickly, and the brain is forming millions of nerve cells (neurons) that connect with one another.
What is happening this week
At 20 weeks, the baby is often about 10 inches (25 cm) long from head to heel and weighs about 10 ounces (300 g). Growth is very active at this stage, and the brain and organs continue to mature.
- Your baby's length is often measured from head to heel on ultrasound, and size estimates are approximate.
- The brain is forming millions of neurons, which keep building new connections.
- An anatomy ultrasound is often scheduled between about 18 and 22 weeks to check the baby's organs and structures.
How the halfway point may feel
By 20 weeks, the belly is usually clearly rounded. Some people feel more energetic, while others still notice heartburn, shortness of breath with activity, or back discomfort. Many providers suggest small meals, good posture, and regular movement to help with these symptoms. Ask your provider which options are safe for you.
Your body at 20 weeks
Sleep Position and Comfort
Why sleep habits change
By week 20 (about 5 months), your baby and your uterus are growing quickly. Your body's center of gravity shifts, so sleep positions that felt comfortable before may feel less comfortable now. This is a normal change.
Sleeping on your back: What to know
Guidance from ACOG (American College of Obstetricians and Gynecologists) suggests that after about 20 weeks of pregnancy, it may be better to avoid sleeping on your back. In this position, your growing uterus may press on the inferior vena cava, a large vein that returns blood to your heart.
How to find a comfortable position
Many providers recommend sleeping on your side during the second and third trimesters, and the left side is often suggested. Side sleeping may help support blood flow to the placenta and baby, though more research is still being done. Ask your provider what is best for you.
- Use a pregnancy pillow or a regular pillow to support your belly.
- Place a pillow between your knees to ease pressure on your hips and lower back.
- If you feel short of breath, try raising your head slightly with extra pillows.
When to call your doctor or midwife
Common symptoms at 20 weeks
Heartburn and a sour taste can show up as the growing uterus presses on your stomach. Smaller meals, staying upright after eating, and extra pillows when you sleep may help.
Sudden leg cramps, often at night, are common in pregnancy. Gently stretching your calf before bed and staying hydrated may ease them.
Sharp or pulling pain on the sides of your lower belly can happen as the ligaments supporting the uterus stretch. Changing positions slowly and resting can help.
As your belly grows, your posture and balance shift, which can strain your back. Supportive shoes, a pillow behind your lower back when sitting, and gentle stretching often help.
Many people notice a stuffy or nosebleed-prone nose during pregnancy because of extra blood flow and swelling in the nasal passages. A saline spray or a humidifier may bring some relief.
Many people start to feel the baby move around this time, though it can feel like gas bubbles or light flutters at first. Movements usually become stronger and easier to notice over the coming weeks.
Your week 20 checklist
Tests and appointments
- Anatomy ultrasound. This detailed ultrasound is often offered between about 18 and 22 weeks to check the baby's growth and the development of major organs and body structures.
Questions about week 20
How many months is 20 weeks pregnant?
20 weeks pregnant is about 4.5 months. You are in month 5 of pregnancy and the second trimester.
What trimester is 20 weeks?
Week 20 is in the second trimester. The first trimester runs through week 13, the second from week 14 to 27 and the third from week 28 until birth.
What is happening with the baby at 20 weeks?
At 20 weeks, the baby is often about 10 inches (25 cm) long from head to heel and weighs about 10 ounces (300 g), roughly the size of a banana. This is the halfway point, when the brain and organs keep developing quickly.
Is it safe to sleep on my back at 20 weeks?
Many providers, including ACOG, suggest avoiding back-sleeping after about 20 weeks. Lying on your back may press on major blood vessels and affect blood flow. Side-sleeping, often the left side, is commonly recommended. If you wake up on your back, you can simply roll back onto your side.
When will I start feeling the baby move?
Many people first feel movement between about 16 and 25 weeks, and first-time parents often notice it later. Early movements can feel like flutters, bubbles, or tapping. If you have not felt movement by your provider's expected time, mention it at your next visit.
What size is the baby at 20 weeks?
At 20 weeks, the baby is often about 10 inches long from head to heel and weighs about 10 ounces, roughly the size of a banana. Every baby grows at their own pace, so your provider will track growth at your appointments.
Safe or not?
Guides for this stage
Learn more
- NIH: Pregnancy (NICHD)
- CDC: Pregnancy
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