At 20 weeks pregnant, your baby is about the size of a banana, and you've officially reached the halfway point of a typical 40-week pregnancy. This week often lines up with the anatomy scan — a detailed ultrasound that checks in on your baby's organs, growth, and overall development, and often reveals the sex if you'd like to know.

If your dates feel confusing, remember that gestational age counts from the first day of your last period (LMP), not from conception — so "20 weeks pregnant" usually means about 18 weeks since ovulation. For the full timeline, see our pregnancy week-by-week guide, or find out exactly how your due date is calculated. If you're picking up from last week, catch up on 19 weeks pregnant first.

Diagram comparing a banana to a 20 week fetus, marking the halfway point of pregnancy — At 20 weeks, your baby is about the size of a banana, and you've reached the halfway point of a typical pregnancy.

Key takeaways

Baby is about the size of a banana (roughly 25.6 cm, head to heel) and weighs around 300 to 331 grams.
You've reached the halfway point of a typical 40-week pregnancy.
This week often lines up with the anatomy scan, a detailed ultrasound checking organs, growth, and development.

What "20 Weeks Pregnant" Actually Means

Using standard gestational dating, week 20 starts about 18 weeks after ovulation, and marks the exact halfway point of a typical 40-week pregnancy. In fetal-age terms (counting from conception rather than your last period), this is closer to "18 weeks post-conception."

Reaching the halfway mark is a meaningful checkpoint for a lot of people — you're through the trimester most associated with early symptoms, and the third trimester's heavier physical demands are still a ways off.

Baby Size at 20 Weeks

At 20 weeks, your baby is about the size of a banana — roughly 25.6 to 25.7 centimeters long, measured head to heel, and weighing somewhere around 300 to 331 grams depending on the source. (Source: Cleveland Clinic)

The Halfway-Point Anatomy Scan

ACOG recommends that every pregnancy include a detailed second-trimester ultrasound, typically performed between 18 and 22 weeks — and for a lot of people, that appointment lands right around week 20. During the scan, a sonographer systematically checks your baby's brain, heart, spine, kidneys, stomach, limbs, and the placenta's position, along with estimating growth against your dates.

It's often the appointment where, if you're interested, the sonographer can tell you your baby's sex — though it isn't the primary purpose of the scan, and in rare cases the anatomy isn't positioned clearly enough to tell that day. Elsewhere in development this week, fingernails have grown out to reach the fingertips, and the areas of the brain responsible for the five senses are beginning to take shape.

Why this matters for prenatal care. The anatomy scan is one of the more information-dense appointments of pregnancy — it's worth bringing a list of questions and, if you have a partner or support person, inviting them along. (General guidance — confirm specifics with your provider: ACOG)

Diagram showing an anatomy scan ultrasound view alongside a fetus with fingernails reaching the fingertips at 20 weeks pregnant — The halfway-point anatomy scan checks organs, growth, and placental position, while fingernails reach the fingertips this week.

What You Might Notice at 20 Weeks Pregnant

For many people, week 20 brings a mix of excitement around the anatomy scan and familiar second-trimester changes. Here's what commonly shows up:

Regular movement. By now, many people feel consistent kicks, punches, or rolls throughout the day.

A clearly visible bump. The uterus is now roughly at the level of the belly button, making the bump obvious to those around you.

Braxton Hicks contractions. Some people start noticing occasional, painless tightening in the belly — a preview of practice contractions that can continue on and off for the rest of pregnancy.

Backaches. Mild lower back discomfort often continues as your center of gravity keeps shifting.

Swelling. Some people start noticing mild swelling in the feet or ankles, especially by the end of the day.

Heartburn. As the uterus continues pressing on the stomach, acid reflux can remain a common complaint.

Leg cramps, particularly at night, remain common for some people at this stage.

It's also completely normal to have few or no symptoms yet. Symptom timing and intensity vary widely from person to person and even between pregnancies for the same person.

What's Happening in Your Body

You reach the halfway point of a typical 40-week pregnancy.
The anatomy scan often happens around now, checking organs, growth, and placental position.
Fingernails reach the fingertips, and sensory brain regions begin developing.
Movement becomes more regular and recognizable.
Braxton Hicks contractions may start, appearing as occasional, painless tightening.

Tips for Week 20

Keep taking your prenatal vitamin. Steady nutrition continues to matter as you head into the second half of pregnancy.

Prepare questions for your anatomy scan, and consider bringing a partner or support person if you can.

Elevate your feet if mild swelling shows up by the end of the day.

Stay hydrated and stretch before bed if leg cramps are an issue.

Note any Braxton Hicks contractions, and learn to distinguish them from real labor signs your provider outlines.

Avoid alcohol, tobacco, and unapproved medications. These guidelines continue through the second trimester.

Tips for Partners

Attend the anatomy scan if you can — it's often one of the most memorable appointments of pregnancy, and a good moment to ask questions together.
Help track down-time for swollen feet, like propping up a footrest in the evening.
Learn the difference between Braxton Hicks and real labor signs together, so you both feel prepared later on.
Mark the halfway point — it's a meaningful milestone worth acknowledging together.

FAQ

How big is my baby at 20 weeks pregnant? About the size of a banana — roughly 25.6 to 25.7 centimeters long, measured head to heel, and weighing around 300 to 331 grams.

Is 20 weeks really the halfway point of pregnancy? Yes, for a typical 40-week pregnancy, week 20 marks the exact halfway point.

What does the anatomy scan check for? It systematically evaluates the brain, heart, spine, kidneys, stomach, limbs, and placenta, and estimates your baby's growth against your dates.

Can the anatomy scan tell me my baby's sex? Often, yes, if you're interested — though it isn't the scan's primary purpose, and in rare cases the anatomy isn't positioned clearly enough to tell that day.

What symptoms are normal at 20 weeks pregnant? Regular movement, a clearly visible bump, Braxton Hicks contractions, backaches, swelling, heartburn, and leg cramps are all common at this stage.

What are Braxton Hicks contractions? Occasional, usually painless tightening of the uterus that can start around this stage and continue on and off for the rest of pregnancy. Your provider can help you tell them apart from real labor signs.

When is my next prenatal appointment likely to be? Many providers continue with appointments roughly every four weeks through the rest of the second trimester, though your provider will confirm your specific schedule.

Pregnancy Checklist at Week 20

Keep taking a prenatal vitamin daily
Prepare questions for your anatomy scan
Elevate your feet if mild swelling shows up
Stay hydrated and stretch before bed if leg cramps are an issue
Learn to distinguish Braxton Hicks contractions from real labor signs
Avoid alcohol, tobacco, and check any medications with your provider
Note any severe cramping, heavy bleeding, or reduced movement and call your provider if it occurs

Related guides

19 Weeks Pregnant: Symptoms, Baby Size & What to Expect — what happened the week before, as vernix caseosa began forming
Pregnancy Week by Week: A Complete Guide — see what happens in every week and trimester, from implantation to full term
How Is Your Due Date Actually Calculated? — the exact formula behind your due date, plus a free calculator

Week 20 marks the halfway point of pregnancy, often paired with the anatomy scan — a detailed look at your baby's growth and development, and for many people, the moment they learn the sex.