At 27 weeks pregnant, your baby is about the size of a cauliflower, and can now open and blink their eyes for the first time. It's the final week of the second trimester — next week marks the start of the third and final stretch of pregnancy.

If your dates feel confusing, remember that gestational age counts from the first day of your last period (LMP), not from conception — so "27 weeks pregnant" usually means about 25 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 26 weeks pregnant first.

Diagram comparing a cauliflower to a 27 week fetus, showing eyes opening and blinking for the first time — At 27 weeks, your baby is about the size of a cauliflower, and can open and blink their eyes for the first time.

Key takeaways

Baby is about the size of a cauliflower (roughly 36.6 cm, head to heel) and weighs around 875 grams.
Eyes can now open and blink for the first time.
This is the final week of the second trimester — the third trimester begins next week.

What "27 Weeks Pregnant" Actually Means

Using standard gestational dating, week 27 starts about 25 weeks after ovulation, closing out the second trimester. In fetal-age terms (counting from conception rather than your last period), this is closer to "25 weeks post-conception."

Trimester boundaries vary slightly depending on the source, but this guide uses the common convention of weeks 1–13 for the first trimester, 14–27 for the second, and 28–40 for the third — which makes week 27 the last week of the second trimester before the home stretch begins.

Baby Size at 27 Weeks

At 27 weeks, your baby is about the size of a cauliflower — roughly 36.6 centimeters long, measured head to heel, and weighing around 875 grams. (Source: Baby Your Baby, Utah Department of Health)

Eyes Opening for the First Time

This week, your baby can open and blink their eyes for the first time. (Source: Cleveland Clinic) Eyelids have been fused shut since around the middle of the second trimester, protecting the eyes as they finished developing — now they're able to separate and function, even though there's not much to see in the dim, fluid-filled environment of the uterus.

Your baby's eyes will keep developing sensitivity to light over the coming weeks, and some studies suggest babies at this stage can perceive brightness changes, like a flashlight held against the belly, even with eyes closed.

What You Might Notice at 27 Weeks Pregnant

Week 27 tends to bring a mix of anticipation for the third trimester and familiar late-second-trimester symptoms. Here's what commonly shows up:

Braxton Hicks contractions, appearing as occasional, painless tightening in the belly.

Backaches, as your center of gravity continues shifting forward.

Swelling in the feet and ankles, especially by the end of the day.

Shortness of breath, as the uterus continues pressing up against the diaphragm.

Trouble sleeping, as the belly grows large enough to limit comfortable positions.

Restless legs, which some people notice more often in the evening.

Increased fatigue, as your body works harder to support the growing pregnancy.

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

Eyes can open and blink for the first time.
This is the final week of the second trimester, with the third trimester starting next week.
Shortness of breath may increase as the uterus presses on the diaphragm.
Braxton Hicks contractions may become more frequent.
Fatigue often increases as your body works harder to support the pregnancy.

Tips for Week 27

Rest when you can, and don't hesitate to ask for help as fatigue increases.

Sit and stand up slowly if shortness of breath or lightheadedness shows up.

Try a pregnancy pillow or extra support if getting comfortable at night is a struggle.

Stretch before bed if restless legs are bothering you.

Start thinking ahead to third-trimester logistics — birth classes, a hospital bag, or a birth plan, if you haven't already.

Keep taking your prenatal vitamin — steady nutrition continues to matter through the rest of pregnancy.

Tips for Partners

Take on more of the physical chores as fatigue and a growing belly make some tasks harder.
Start talking through third-trimester logistics together, like birth classes or hospital bag prep.
Watch for signs of shortness of breath, and encourage rest breaks during activity.
Mark the shift into the third trimester — it's a meaningful milestone worth acknowledging together.

FAQ

How big is my baby at 27 weeks pregnant? About the size of a cauliflower — roughly 36.6 centimeters long, measured head to heel, and weighing around 875 grams.

Can my baby actually see anything at 27 weeks? Eyes can open and blink, but there's little to see in the dim, fluid-filled uterus — some studies suggest babies can perceive brightness changes even with eyes closed.

Is 27 weeks the start of the third trimester? Using the common convention this guide follows (weeks 1–13, 14–27, 28–40), week 27 is the last week of the second trimester, with the third trimester starting at week 28.

Why does trimester timing vary between sources? Trimester boundaries aren't strictly standardized, so different sources sometimes draw the line a week or two differently — the underlying development timeline is the same either way.

What symptoms are normal at 27 weeks pregnant? Braxton Hicks contractions, backaches, swelling, shortness of breath, trouble sleeping, restless legs, and fatigue are all common at this stage.

Should I start preparing for the third trimester now? It's a reasonable time to start thinking about birth classes, a hospital bag, or a birth plan, though there's no need to rush — you'll have several more weeks.

When is my next prenatal appointment likely to be? Many providers switch to appointments every two weeks starting around the third trimester, though your provider will confirm your specific schedule.

Pregnancy Checklist at Week 27

Keep taking a prenatal vitamin daily
Rest when you can as fatigue increases
Try a pregnancy pillow if nighttime comfort is a struggle
Stretch before bed if restless legs are bothering you
Sit and stand up slowly if shortness of breath occurs
Start thinking about birth classes or a hospital bag
Note any severe cramping, heavy bleeding, or reduced movement and call your provider if it occurs

Related guides

26 Weeks Pregnant: Symptoms, Baby Size & What to Expect — what happened the week before, as melanin and surfactant production began
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 27 closes out the second trimester with a sweet milestone — your baby's eyes opening and blinking for the first time — just before the third trimester begins.