Pregnancy
33 Weeks Pregnant
At 33 weeks pregnant, your baby is the size of a pineapple. Learn about immune system development, increased fatigue, swollen feet, and how to prepare for birth.
Published:
This article is for general information and is not a substitute for professional medical advice. Always consult your pediatrician or doctor about your child.
Sources: WHO, CDC, AAP and NHS guidance. Recommendations differ between countries — for local advice see the NHS or ACOG.
See how we research and review →
At a Glance
- Trimester: Third trimester (weeks 28–40)
- Weeks to go: About 7 weeks until your due date
- Baby size: Pineapple — about 43 cm (17 inches) head-to-heel, around 1.9 kg (4.25 lb)
- Key milestone: Antibodies are now actively transferring from you to the baby — your immune memory is becoming the baby's first defense
At 33 weeks, your baby is sturdy, mostly developed, and laying down the fat and immune protections that will support life after birth. For you, the focus narrows to comfort, sleep, monitoring fetal movement, and getting practical preparations in place. There are still 7 weeks to go on average — but be ready, because a meaningful percentage of babies arrive before their due date.
Your Baby's Development This Week
Week 33 is dominated by immune system development, brain growth, and fat deposition. Most of the visible changes from here are about getting ready for the outside world.
- Immune system: Maternal antibodies (IgG) cross the placenta in large amounts in the final 6–8 weeks. This passive immunity protects your baby for the first months of life until their own immune system matures. This is why vaccinations like Tdap and influenza in pregnancy are so protective for newborns.
- Brain: Continues rapid growth. The brain triples in weight during the third trimester. Neural connections are forming at an extraordinary rate.
- Skull: Bones are firm but still flexible and unfused, allowing the head to mold during birth.
- Skin: Less wrinkled and more pink as fat fills underneath. Vernix (the waxy protective coating) is thick.
- Eyes: Pupils constrict and dilate in response to light. The baby spends about 90% of their time with eyes closed, but increasingly opens them when awake.
- Lungs: Producing surfactant; most babies born this week breathe on their own with some support.
- Sleep–wake cycles: Clearer patterns. You may notice the baby is most active in the evening when you slow down.
- Coordination: Movements are purposeful — the baby can reach for the umbilical cord, suck a thumb, and respond to touch through the abdomen.
Your Body and Symptoms This Week
By 33 weeks, the fundal height is about 13 cm above your navel. The combined demands of carrying a nearly 2 kg baby, plus the placenta, amniotic fluid, and expanded blood volume, mean fatigue and discomfort are at their peak.
- Swollen feet and ankles: Especially by the end of the day.
- Pelvic and pubic pain: From loosened ligaments and the baby's weight.
- Lower back pain: From shifted center of gravity and ligament laxity.
- Difficulty sleeping: Frequent urination, discomfort, vivid dreams.
- Heartburn and indigestion: Often worsening.
- Hemorrhoids: From pelvic vein pressure and constipation.
- Shortness of breath: Until the baby drops.
- Stronger Braxton Hicks: Practice contractions may feel intense at times.
- Forgetfulness, "pregnancy brain": Persistent.
- Increased vaginal discharge: Clear or milky white is normal; report any color change, odor, blood, or watery gush.
- Colostrum leakage: Common.
- Carpal tunnel symptoms: Numbness or tingling in fingers.
Nutrition: What to Eat & Avoid This Week
Your baby is gaining about half a pound per week, much of it as fat. Your nutrient needs remain high, with particular emphasis on iron, calcium, omega-3 DHA, and protein.
Prioritize:
- Iron (27 mg/day): Red meat, lentils, beans, fortified cereals, dark leafy greens; pair with vitamin C.
- Calcium (1000 mg/day): Dairy, fortified plant milks, tofu, sardines, broccoli.
- DHA (200–300 mg/day): Salmon, sardines, anchovies; vegetarian options include algae oil supplements.
- Protein (75 g/day): Eggs, fish, poultry, legumes, dairy.
- Choline (450 mg/day): Eggs, lean meat — critical for fetal brain development.
- Fiber: Whole grains, fruits, vegetables — helps constipation and hemorrhoids.
- Hydration: 8–10 glasses of water; may help with swelling, constipation, and Braxton Hicks frequency.
Avoid: Raw or undercooked fish, meat, and eggs; unpasteurized dairy; deli meats unless heated until steaming; high-mercury fish (swordfish, king mackerel, tilefish, shark); alcohol entirely; caffeine above 200 mg/day; herbal teas not confirmed safe in pregnancy.
Movement & Exercise
Most movement remains safe and beneficial in the absence of complications. At 33 weeks, your priorities shift slightly toward labor preparation and mobility maintenance.
Good choices: Walking, prenatal yoga (especially hip openers), swimming, water aerobics, stationary cycling, pelvic tilts, cat-cow, supported squats, and time on a birth ball (sitting, bouncing gently, hip circles). Daily pelvic floor exercises remain important. Perineal massage from 34 weeks can be discussed with your provider.
Avoid: Contact sports, activities with fall risk, scuba diving, hot yoga or saunas, exercise lying flat on your back for extended periods, deep twists, jumping, and any activity that triggers sharp pelvic or back pain. Stop and call your provider for chest pain, severe shortness of breath at rest, dizziness, bleeding, fluid leakage, or regular contractions.
Mental & Emotional Wellbeing
By 33 weeks, anticipation, anxiety, and impatience often coexist. The reality that a baby will soon be in your arms is concrete. Sleep is fragmented, the body is uncomfortable, and the future is uncertain — all valid reasons for emotional intensity.
What helps:
- Finish childbirth classes; the knowledge directly reduces fear
- Practice breathing, visualization, or hypnobirthing techniques
- Discuss postpartum plans with your partner — sleep schedules, household division of labor, visitor boundaries
- Identify your support network for postpartum: who to call, who to text, who can bring food
- Limit dramatic birth content on social media; choose informational sources over fear-based ones
- Talk openly with your provider about birth fears — many can be addressed with information or planning
If anxiety, sadness, or intrusive thoughts persist or worsen, contact your provider. Perinatal mental health is treatable, and treatment now also protects postpartum recovery.
Common Concerns & When to Call Your Doctor
Call your provider the same day for any of:
- Decreased fetal movement — fewer than 10 movements in 2 hours after eating and resting on your left side
- Regular contractions before 37 weeks (4 or more in 20 minutes)
- Lower back pain that comes in rhythmic waves
- Fluid leakage from the vagina (possible water breaking)
- Vaginal bleeding or blood-tinged mucus before 37 weeks
- Severe headache that does not respond to rest and water
- Vision changes — blurriness, spots, or flashes
- Sudden swelling of the face or hands, or swelling in one leg
- Upper-right abdominal pain
- Severe widespread itching, especially on palms and soles
- Fever above 38°C (100.4°F)
- Painful urination
These can indicate preterm labor, preeclampsia, infection, cholestasis, or other conditions that benefit from early evaluation. Babies born at 33 weeks (late moderately preterm) typically do well with brief NICU support.
Tests & Appointments This Week
A typical 33-week visit includes:
- Blood pressure check
- Urine dipstick for protein and glucose
- Weight
- Fundal height measurement
- Fetal heart rate via Doppler
- Palpation to assess baby's position
- Review of fetal movement
- Conversation about labor signs, birth plan, and hospital bag
- Possible third-trimester labs (CBC, infection screens) if not yet done
GBS testing is typically scheduled at 36–37 weeks. If you have specific risk factors (gestational diabetes, hypertension, growth concerns), you may have additional ultrasounds or non-stress tests.
Tips for Week 33
- Pack your hospital bag now. Keep it by the door or in the car. Include essentials for you, the baby, and your partner.
- Install the car seat. Get it checked by a certified technician (many fire stations and pediatric clinics offer free inspections).
- Finalize childcare logistics for older children or pets. Who is on call when you go to the hospital?
- Discuss your birth preferences. Write down what matters most to you — and what is flexible — and share with your provider.
- Stock up on postpartum supplies. Pads (regular and large), peri bottle, witch hazel pads, comfortable underwear, nursing bras, breast pads if planning to breastfeed.
Preparing for What's Next
In the next 3–4 weeks you will move into "any day now" territory. While most first babies arrive after their due date, about 11% of births in the U.S. are preterm, so being ready by 36 weeks is wise. Consider:
- Pre-register at your birth facility if available
- Know multiple routes to the hospital and the right entrance to use after hours
- Discuss postpartum support — partner leave, family help, meal trains, postpartum doula
- Plan the first 2 weeks at home — minimal visitors, simple meals, skin-to-skin time
- Confirm pediatrician and the newborn's first appointment (usually 24–72 hours after discharge)
- Discuss postpartum mental health plans — what early warning signs to watch for and who to call
- Take final maternity photos if you want them
Frequently Asked Questions
Why are my feet so swollen at 33 weeks pregnant?
Mild swelling (edema) in the feet, ankles, and hands is normal in the third trimester. Your blood volume is about 50% higher, the growing uterus presses on the veins returning blood from your legs, and gravity does the rest. Help with elevating your feet when possible, sleeping on your left side, drinking plenty of water (it actually reduces fluid retention), and avoiding long periods of standing. Call your provider for sudden swelling of the face or hands, swelling of only one leg, or swelling with headache or vision changes — all can signal preeclampsia or a blood clot.
Can my baby still flip to head-down at 33 weeks?
Yes, but the window is closing. About 90% of babies are head-down by 36 weeks. If your baby is still breech at 33 weeks, your provider may suggest spinning techniques (forward leans, Webster chiropractic, swimming) or schedule an external cephalic version (ECV) around 36–37 weeks if needed. Try not to worry — many babies turn on their own in the next few weeks.
Is heightened fatigue normal at 33 weeks?
Yes. Third trimester fatigue rivals first trimester fatigue but for different reasons: disrupted sleep, the metabolic cost of growing a nearly full-size baby, possible anemia, and the physical work of carrying extra weight. Rest is medicine right now. Aim for naps when possible, prioritize protein and iron, and ask your provider to check hemoglobin if fatigue feels disproportionate.
What is the baby's size at 33 weeks?
At 33 weeks, your baby is roughly the size of a pineapple — about 43 cm (17 inches) head-to-heel and weighing around 1.9 kg (4.25 lb). They are gaining roughly half a pound per week now and starting to look chubby as fat fills out under the skin.
How can I tell the difference between Braxton Hicks and real labor at 33 weeks?
Braxton Hicks contractions are irregular, do not get stronger or closer together, often ease with hydration or rest, and usually feel like a tightening across the whole belly. True labor contractions are regular (e.g., every 5–10 minutes), gradually become more intense, last longer, and do not stop with rest. At 33 weeks, any regular pattern of contractions — particularly 4 in 20 minutes — should be reported to your provider immediately, as it could indicate preterm labor.
Is it safe to fly at 33 weeks?
Most airlines allow uncomplicated pregnancies to fly up to 36 weeks, but a few cut off earlier. Always check with your airline and carry a letter from your provider if asked. During flights, walk every hour, do ankle circles, drink water, wear compression socks, and use a seatbelt low on your hips. Do not fly if you have preeclampsia, preterm labor risk, twins, placenta previa, or other complications.
When should I worry about decreased baby movement?
From 28 weeks onward, do daily kick counts. ACOG recommends counting until you feel 10 movements (kicks, rolls, jabs); this typically happens within 30 minutes to 2 hours after eating and resting. Any clear, sustained decrease from your baby's normal pattern — or fewer than 10 movements in 2 hours after eating and resting on your left side — warrants a same-day call to your provider. Do not wait, and do not "stir the baby" with caffeine or sugar before calling.
Why am I having vivid or scary dreams at 33 weeks?
Vivid dreams in pregnancy are very common and intensify in the third trimester. The likely causes are hormonal shifts, fragmented sleep (more time in REM sleep when you wake frequently), and the brain processing significant life changes. Scary or distressing dreams about labor or the baby are common and not predictive of real outcomes. If dreams are extremely disturbing or affecting daytime mood, mention this to your provider.
Should I be doing anything to prepare for breastfeeding at 33 weeks?
Yes — basic preparation now pays off later. Consider taking a breastfeeding class (often offered alongside childbirth class), identifying a lactation consultant in your area in case you need help, learning about feeding cues (rooting, hand-to-mouth, lip-smacking) and good latch basics, and discussing breastfeeding goals with your partner. You generally do not need to do anything to your nipples or "toughen" them — modern guidance discourages this.
Why is my pelvic pain worse this week?
As the baby grows and the hormone relaxin loosens pelvic ligaments, the joints of the pelvis become less stable. Pubic symphysis dysfunction (sharp pain in the front pelvic bone) and sacroiliac joint pain (lower back/buttock) are common. Help with avoiding asymmetric movements (do not put on pants standing on one leg), sleeping with a pillow between your knees, prenatal physical therapy, and a maternity support belt. Severe pain that limits walking deserves a referral to physical therapy.
What tests happen at 33 weeks?
Standard 33-week visits include blood pressure, weight, urine dipstick, fundal height, and fetal heart rate. Some providers do a final blood work check (CBC for anemia, possibly repeat infection screens). GBS testing is typically done at 36–37 weeks. If you have risk factors, a non-stress test or growth ultrasound may be added. Discuss any signs that need urgent care so you know when to call.
Track Your Pregnancy with Whispie
Personalized weekly guidance, kick counters, appointment reminders, and evidence-based support — all in one app.
Weekly parenting tips, no spam
Evidence-based guidance for your child's stage — straight to your inbox.