Week 27 of Pregnancy: Your Baby Is the Size of a Cabbage

TL;DR

• Your baby is about 36.6 cm — the size of a cabbage.
• Baby now has regular sleep and wake cycles you may be able to notice.
• Your glucose screening test typically happens around this week.
• The third trimester begins next week — you're almost there.

Your Baby This Week

At 36.6 cm, your baby is the size of a cabbage and has settled into something that looks a lot more like a real schedule. Your baby now has regular sleep and wake cycles — periods of activity followed by periods of rest. You might notice that your baby tends to be active at certain times of day (often when you're trying to sleep, naturally) and quieter at others.

During active periods, your baby is busy. They're kicking, stretching, rolling, and practicing breathing movements. During sleep periods, they're truly resting — brain activity shifts to more organized patterns that resemble the sleep stages seen in newborns.

Your baby's brain is developing rapidly. The characteristic wrinkles and folds of the brain surface — called sulci and gyri — are forming, dramatically increasing the brain's surface area and its capacity for processing information. The brain will continue this rapid development throughout the third trimester and well into the first years of life.

The lungs continue to mature, producing increasing amounts of surfactant. While they're not yet ready for independent breathing, they're getting closer every day. Your baby is also putting on weight steadily, and that baby fat is helping to round out the wrinkled skin.

Your Body This Week

The glucose screening test typically happens between weeks 24 and 28, so if you haven't had it yet, it's likely coming soon. This test screens for gestational diabetes by measuring how your body processes sugar. You'll drink a sweet glucose solution and have your blood drawn an hour later. If results are elevated, a three-hour glucose tolerance test may follow.

Gestational diabetes affects about 6-9% of pregnancies. If diagnosed, it's manageable through dietary changes, blood sugar monitoring, and sometimes medication. The most important thing is catching it, which is exactly what the screening does.

You might be feeling more tired as the second trimester draws to a close. The boundless energy of weeks 14-20 may be fading, replaced by the fatigue of carrying a bigger baby and the physical demands of a changing body. Rest when you can — the third trimester will ask even more of you.

Sleep disturbances are common at this stage. Between the frequent bathroom trips, heartburn, baby's active schedule, and difficulty getting comfortable, a solid night's sleep is getting harder to come by. A consistent bedtime routine, a supportive pillow arrangement, and keeping the bedroom cool can all help.

You may also notice that you're more forgetful or scattered than usual. This is normal — your brain is literally rewiring to prepare for parenthood, and the combination of hormones, sleep deprivation, and emotional processing can affect short-term memory and focus.

Common Questions at Week 27

What if I fail the glucose test?

First, an elevated screening result doesn't mean you have gestational diabetes — it means you need the follow-up three-hour test for a definitive diagnosis. Many people who have elevated initial results pass the longer test. If you are diagnosed, your provider will create a management plan. Gestational diabetes is common, treatable, and usually resolves after birth.

How should I prepare for the third trimester?

The third trimester brings more frequent prenatal visits (every two weeks, then weekly as you approach your due date), the start of formal kick counting, and practical preparations like packing a hospital bag, installing the car seat, and finalizing your birth preferences. Take things one step at a time.

When should I start my birth plan?

Now is a great time to start thinking about your birth preferences. Consider pain management options, who you want in the room, your feelings about interventions, and what matters most to you during labor and delivery. Your provider can discuss your options and help you understand what to expect at your chosen birth location.

Is it normal for baby to have hiccups every day?

Yes. Frequent hiccups are completely normal and are a sign that your baby's diaphragm is developing. Some babies hiccup multiple times a day. While the rhythmic jolting can be surprising (or even annoying), it's harmless and usually decreases as your baby gets bigger.

This Week's Tip

Your glucose screening test typically happens around this week — and while the sweet drink isn't anyone's favorite, the test itself is quick and important. If you're nervous about it, know that most people pass without issue. Some tips: don't eat a sugary breakfast before the test (even though you don't need to fast), bring something to read during the waiting period, and try to stay relaxed. This is one of the many ways your provider monitors your health and your baby's health, and early detection of gestational diabetes makes a real difference in outcomes.

Milestone: Third Trimester Begins

Week 27 marks the doorstep of the third trimester — the final stretch. As you cross from the second trimester into the third, the focus shifts from development to growth and preparation. Your baby will gain significant weight over the next 13 weeks, and your body will make its final preparations for birth. The third trimester brings more prenatal visits, stronger kicks, and the growing anticipation of meeting your baby. You've come so far. The finish line is in sight.

Sources

• American College of Obstetricians and Gynecologists (ACOG). How Your Fetus Grows During Pregnancy.
• Mayo Clinic. Fetal Development: The 2nd Trimester.

Related Articles

• Week 26 of Pregnancy
• Week 28 of Pregnancy
• Second Trimester: The Complete Guide
• Third Trimester: The Complete Guide