27 Weeks Pregnant

At a Glance: Week 27

Welcome to the threshold of the third trimester. At 27 weeks, your baby is about the size of a head of cauliflower — roughly 36.5 cm (14.4 inches) and weighing approximately 875 grams (1.93 pounds). The most striking milestone this week is the maturation of brain tissue: the cerebral cortex is rapidly developing folds and grooves, and your baby is exhibiting clear sleep-wake cycles, including REM-like sleep.

Some providers consider this the official start of the third trimester, while others mark it at 28 weeks. Either way, you've completed roughly two-thirds of your pregnancy and your baby would have a very good chance of survival (over 90% in well-equipped neonatal centers) if born now, though significant intensive care would be needed.

Your Baby's Development This Week

• Brain: The cerebral cortex is rapidly folding (gyrification). Brain weight roughly triples between weeks 27 and 40. Distinct REM and quiet sleep phases are observable.
• Lungs: Air sacs are now producing more surfactant. Your baby is practicing "breathing" by drawing amniotic fluid into the lungs and pushing it back out — this strengthens respiratory muscles and may trigger hiccups.
• Eyes: Now fully open. Retinas are developing the cells (rods and cones) needed for vision. Pupils can constrict and dilate in response to light.
• Hearing: Your baby distinguishes voices from background noise and can recognize specific patterns of speech. Research published in journals including Proceedings of the National Academy of Sciences shows newborns recognize sounds heard repeatedly during late pregnancy.
• Taste: Taste buds are formed, and flavors from your diet (garlic, vanilla, sweet foods) pass through amniotic fluid. Your baby's preferences are beginning to be shaped.
• Immune system: Maternal IgG antibodies continue crossing the placenta, providing passive immunity for the early newborn period.
• Fat: Subcutaneous fat is being laid down. Skin is becoming less translucent and less wrinkled.

Your Body and Symptoms This Week

At 27 weeks, you're starting to feel many "third trimester" symptoms even if technically still in the second:

• Swelling (edema) in the feet, ankles, and hands
• Leg cramps at night
• Restless legs syndrome in some pregnancies
• Shortness of breath with mild activity
• Frequent urination returning as the uterus presses on the bladder
• Constipation, hemorrhoids, and varicose veins
• Heartburn and indigestion
• Insomnia and vivid dreams
• Braxton Hicks contractions becoming more noticeable
• Mild colostrum leakage
• Stretch marks appearing or expanding
• Backache and pelvic pressure

Nutrition: What to Eat and Avoid This Week

As your baby enters a rapid growth phase, nutritional quality matters more than ever. Continue focusing on:

• Iron (27 mg/day): red meat, lentils, beans, fortified cereals, leafy greens with vitamin C
• Calcium (1,000 mg/day): dairy, fortified plant milks, sardines, tofu, leafy greens
• Vitamin D (600 IU/day): fortified milk, fatty fish, sunlight exposure
• DHA omega-3 (200–300 mg/day): low-mercury fatty fish or algae supplement; critical for late-term brain development
• Choline (450 mg/day): eggs, beans, lean meats — supports memory and brain development
• Fiber (25–30 g/day) and water (2.3–3 L/day): help with constipation, swelling, and circulation
• Protein (75–100 g/day): distribute across meals for steady amino acid availability

Continue avoiding: alcohol entirely, high-mercury fish, raw/undercooked animal products, unpasteurized dairy and juices, processed deli meats unless heated through, raw sprouts, and caffeine over 200 mg per day. If you have gestational diabetes, follow your individualized meal plan strictly.

Movement and Exercise

Movement remains valuable through the third trimester. At 27 weeks, prioritize:

• Walking — still excellent, but on level surfaces and at a sustainable pace
• Swimming — relieves joint and ligament strain dramatically
• Prenatal yoga — emphasizes hip and pelvic opening, breath awareness, and gentle strengthening
• Stationary cycling — low impact and balance-safe
• Pelvic floor exercises (Kegels) — for both birth preparation and postpartum recovery

Avoid: exercises lying flat on the back for prolonged periods, contact sports, scuba diving, hot yoga/saunas, anything with high fall risk, and exercises that cause pelvic pain or breathlessness. Stop and call your provider for contractions, bleeding, fluid leakage, vision changes, dizziness, chest pain, or calf swelling/pain.

Mental and Emotional Wellbeing

Many parents describe week 27 as the moment when birth feels "real." Common emotional patterns include increased dreaming, mild to moderate anxiety about labor, excitement about meeting the baby, and a strong urge to organize and prepare ("nesting").

Protect your sleep aggressively: a cool, dark room, no screens for the last 60 minutes before bed, a side-sleeping setup with a pregnancy pillow, and limited evening fluids. If you snore loudly, gasp, or feel exhausted despite sleeping, ask your provider about screening for pregnancy-induced sleep apnea, which is associated with preeclampsia and gestational diabetes risk.

If you have a partner, this is an important week for explicit conversations: who will handle which baby tasks, expectations for the early weeks (visitors, paid leave, sleep arrangements), and any anxieties either of you carries. Couples counseling — even briefly — can be very useful for preparing relational dynamics. Screen yourself for prenatal depression and anxiety; both are common and treatable.

Common Concerns and When to Call Your Doctor

From 27 weeks onward, preterm-labor awareness becomes important. Call your provider promptly for:

• Regular contractions (more than 4–6 per hour) before 37 weeks
• Low back pain that comes in a rhythmic pattern
• Pelvic pressure that feels like the baby is pushing down
• Menstrual-like cramping
• Vaginal bleeding or pink/brown discharge
• Leaking or gushing fluid
• Severe headache, blurred vision, or upper-right belly pain
• Sudden swelling of the face or hands
• Decreased fetal movement compared to your baby's pattern
• Calf swelling/pain or one-sided leg redness (possible DVT)

Trust your instincts. Providers would rather assess a false alarm than miss something time-sensitive.

Tests and Appointments This Week

If you haven't completed glucose screening yet, this week is the last typical opportunity (24–28 week window). Your provider may also:

• Schedule or administer the Tdap vaccine (recommended at weeks 27–36, CDC)
• Plan for RhoGAM at 28 weeks if you are Rh-negative
• Order a CBC to check for anemia
• Move appointments from every 4 weeks to every 2 weeks at the next visit
• Begin discussing your birth preferences
• Listen to baby's heart rate with Doppler and measure fundal height

Tips for Week 27

• Begin a daily kick-count routine next week (28 weeks). Start noticing patterns now.
• Make a draft hospital-bag checklist. You don't need to pack yet — just know what you'll need.
• Install and inspect your car seat early. Many fire stations or pediatric clinics offer free installation checks.
• Sign up for a breastfeeding class or newborn care class if you haven't yet. Best timing is 27–32 weeks.
• Get the Tdap vaccine if it's offered at your next visit.

Preparing for What's Next

From here, your prenatal calendar accelerates. At 28 weeks, your visits become every two weeks; from 36 weeks, weekly. Group B strep (GBS) testing happens around 36 weeks. Knowing the rhythm helps you plan work and life around it.

In the coming weeks, focus on: finalizing your nursery, completing childbirth class, choosing and meeting your pediatrician, planning for postpartum support (meal trains, household help), and discussing parental leave logistics. Small actions now spare you exhaustion later.

Frequently Asked Questions About Week 27