33 Weeks Pregnant: Baby Development, Symptoms & What to Expect
📊 Quick facts about week 33
💡 Key Takeaways for Week 33
- Rapid brain development: Your baby's brain is growing quickly, forming billions of neural connections that will continue to develop after birth
- Lung maturation continues: The lungs are producing surfactant, a substance that helps them inflate properly after birth
- Bones hardening: Your baby's bones are becoming firmer, though the skull remains soft and flexible for delivery
- Monitor fetal movements: Count kick counts daily - you should feel at least 10 movements within 2 hours
- Braxton Hicks are normal: Practice contractions help your uterus prepare for labor, but call your provider if they become regular
- Prepare for birth: Now is a good time to pack your hospital bag and finalize your birth plan
- Rest when possible: Fatigue is common as your body works hard to support your growing baby
How Is My Baby Developing at 33 Weeks?
At 33 weeks, your baby weighs approximately 4.4 pounds (2 kg) and measures 17.2 inches (43.7 cm). The brain is developing rapidly, the lungs are maturing, and your baby can now distinguish between light and dark. The bones are hardening, though the skull remains flexible for delivery.
Week 33 marks an exciting time in your baby's development as the final preparations for life outside the womb intensify. Your baby has grown from a tiny cluster of cells to a nearly fully-formed human being, now weighing about as much as a small pineapple. The rapid weight gain that characterizes the third trimester continues, with your baby adding approximately half a pound each week as fat accumulates beneath the skin.
The fat layer serves multiple crucial functions beyond simply making your baby look plump and adorable. This subcutaneous fat provides essential insulation that will help regulate body temperature after birth, a function previously performed entirely by your body. The fat also serves as an energy reserve, which is vital since newborns need to maintain their blood sugar levels independently once the umbilical cord is cut.
Your baby's brain is undergoing remarkable development during this period. Billions of neurons are forming connections at an astonishing rate, creating the neural pathways that will govern everything from basic reflexes to complex thoughts. The brain's characteristic wrinkled appearance, called gyri and sulci, is becoming more pronounced as the brain continues to grow and fold to fit within the skull. This rapid brain development means your baby is now capable of regulating their own body temperature to some degree and can coordinate breathing movements with swallowing.
The lungs continue their critical maturation process during week 33. The alveoli, the tiny air sacs where oxygen exchange occurs, are increasing in number, and the lungs are producing more surfactant. Surfactant is a lipid-protein substance that prevents the alveoli from collapsing when your baby takes their first breaths. While babies born at 33 weeks may still need some respiratory support, their lung development is significantly more advanced than just a few weeks earlier.
Sensory Development at 33 Weeks
Your baby's senses are becoming increasingly sophisticated. The eyes, which have been opening and closing for several weeks now, can detect changes in light. When bright light shines on your belly, your baby may respond by moving or turning their head. The pupils can now dilate and constrict in response to light, a reflex that will be fully functional at birth.
Hearing is well-developed at this stage. Your baby can recognize your voice and may respond to familiar sounds with increased movement. Research suggests that babies can remember and recognize music and voices they heard frequently in the womb after they are born. Many parents enjoy talking, reading, or playing music for their babies during this time, creating early bonds through these auditory experiences.
Skeletal Changes
Your baby's skeleton is undergoing important changes during week 33. The bones are becoming harder as calcium is deposited into them, though this process will continue well into childhood. However, the bones of the skull remain soft and somewhat pliable. This flexibility is essential because it allows the skull bones to overlap slightly during birth, enabling your baby's head to pass through the birth canal more easily. You may notice a soft spot, called the fontanelle, on your newborn's head - this is where the skull bones haven't yet fused and is completely normal.
What Symptoms Are Normal at 33 Weeks Pregnant?
Common symptoms at 33 weeks include Braxton Hicks contractions, shortness of breath, back pain, frequent urination, swollen feet and ankles, difficulty sleeping, heartburn, and fatigue. These symptoms occur as your body accommodates your growing baby and prepares for childbirth.
The third trimester brings a constellation of symptoms that, while often uncomfortable, are generally signs that your pregnancy is progressing normally. Understanding what to expect can help you distinguish between normal pregnancy changes and symptoms that warrant medical attention.
Your uterus has grown tremendously by week 33, now measuring about 5 inches above your belly button. This growth puts increasing pressure on surrounding organs and structures, contributing to many of the symptoms you may be experiencing. The good news is that as your baby drops lower into your pelvis in the coming weeks (a process called lightening), some of these symptoms, particularly breathlessness, may improve.
Braxton Hicks Contractions
Braxton Hicks contractions, often called practice contractions, typically become more frequent and noticeable during the third trimester. These contractions help tone and prepare your uterus for the work of labor. They usually feel like a tightening or hardening of your abdomen and may be uncomfortable but shouldn't be painful.
Unlike true labor contractions, Braxton Hicks contractions are irregular, don't increase in intensity over time, and typically ease with changes in position or activity. Staying well-hydrated can help reduce their frequency, as dehydration can trigger these contractions. If you experience more than four contractions per hour, or if they become regular, increasingly intense, or painful, contact your healthcare provider as this could indicate preterm labor.
Shortness of Breath
Many pregnant people experience shortness of breath during the third trimester, and week 33 is no exception. This occurs because your expanding uterus pushes upward on your diaphragm, the large muscle that helps you breathe. Additionally, your body requires more oxygen to support your baby's growth and your increased blood volume.
While breathlessness during normal activities is common, sudden or severe shortness of breath, especially if accompanied by chest pain, rapid heartbeat, or fainting, requires immediate medical evaluation as it could indicate a more serious condition.
Sleep Difficulties
Getting comfortable enough to sleep becomes increasingly challenging at 33 weeks. Your growing belly makes it difficult to find a comfortable position, and you may wake frequently to urinate, stretch cramping legs, or adjust your position. Heartburn may worsen when lying down, further disrupting sleep.
Sleeping on your left side is generally recommended during the third trimester, as it improves blood flow to your baby and your kidneys. Using pillows to support your belly, back, and between your knees can help you find a more comfortable position. Some people find specialized pregnancy pillows helpful.
| Symptom | Cause | Management Tips |
|---|---|---|
| Shortness of breath | Uterus pressing on diaphragm | Maintain good posture, sleep propped up |
| Back pain | Shifted center of gravity, hormones loosening ligaments | Good posture, supportive shoes, prenatal massage |
| Frequent urination | Baby pressing on bladder | Limit fluids before bed, empty bladder completely |
| Swollen feet/ankles | Increased blood volume, fluid retention | Elevate feet, reduce sodium, stay hydrated |
| Heartburn | Hormones relaxing esophageal sphincter | Eat smaller meals, avoid lying down after eating |
| Braxton Hicks | Uterus preparing for labor | Change positions, stay hydrated |
Other Common Symptoms
Back pain affects the majority of pregnant people by the third trimester. The weight of your growing belly shifts your center of gravity forward, putting extra strain on your lower back muscles. Additionally, pregnancy hormones cause the ligaments supporting your spine to become more lax in preparation for childbirth, which can contribute to discomfort and instability.
Swelling in the feet and ankles (edema) is extremely common during the third trimester. Your body retains more fluid during pregnancy, and your growing uterus puts pressure on blood vessels, making it harder for blood to return from your legs to your heart. Elevating your feet when possible, avoiding standing for long periods, and reducing sodium intake can help manage mild swelling. However, sudden or severe swelling, especially in your face and hands, can be a sign of preeclampsia and should be reported to your healthcare provider immediately.
Why Are Fetal Movements Important at 33 Weeks?
Monitoring your baby's movements is crucial for assessing their well-being. At 33 weeks, you should feel at least 10 movements within 2 hours when doing kick counts. A significant decrease in movement can indicate that your baby is in distress and requires immediate medical evaluation.
Your baby has been moving throughout your pregnancy, but by week 33, these movements have likely become a familiar and reassuring part of your daily routine. Fetal movement patterns can provide valuable information about your baby's health, which is why healthcare providers recommend monitoring and counting movements regularly during the third trimester.
Every baby has their own unique pattern of activity and rest. By now, you have likely noticed when your baby tends to be most active - perhaps after meals or in the evening when you're resting. Learning your baby's typical pattern is important because a significant change from this pattern can be one of the first signs that something may be wrong.
How to Count Kick Counts
Kick counting is a simple but effective way to monitor your baby's well-being. The American College of Obstetricians and Gynecologists (ACOG) recommends counting fetal movements daily in the third trimester. Here's how to do it effectively:
- Choose a consistent time when your baby is typically active, often after a meal or in the evening
- Get comfortable by lying on your left side or sitting in a supported position
- Note the time when you start counting
- Count every movement - kicks, rolls, jabs, and turns all count as movements
- Record when you reach 10 movements - most healthy babies will move 10 times within 1-2 hours
If you don't feel 10 movements within 2 hours, try eating a snack or drinking something cold and try again. If you still don't feel adequate movement, or if you notice a significant decrease from your baby's normal pattern, contact your healthcare provider immediately. Reduced fetal movement can sometimes indicate that your baby is not getting enough oxygen and may need evaluation.
It's important to remember that as your pregnancy progresses and your baby gets larger, the type of movements may change. Space becomes more limited in the uterus, so you may feel fewer dramatic kicks and more rolling or stretching movements. However, you should still feel regular activity throughout the day.
When Should I Call My Doctor at 33 Weeks Pregnant?
Contact your healthcare provider immediately if you experience: regular contractions (more than 4 per hour), vaginal bleeding, fluid leaking from the vagina, severe headaches or vision changes, decreased fetal movement, severe abdominal pain, or signs of preeclampsia such as sudden swelling or high blood pressure.
While most symptoms during the third trimester are normal parts of pregnancy, certain signs and symptoms require prompt medical attention. Knowing when to call your healthcare provider or go to the hospital can help ensure the safety of both you and your baby.
Signs of Preterm Labor
Preterm labor is labor that begins before 37 weeks of pregnancy. At 33 weeks, while your baby has excellent survival chances, preventing preterm birth when possible gives your baby more time to develop. Signs of preterm labor include:
- Regular contractions (more than 4 per hour) that increase in frequency or intensity
- Lower back pain that is constant or comes and goes rhythmically
- Pelvic pressure that feels like your baby is pushing down
- Abdominal cramps that may feel like menstrual cramps
- Change in vaginal discharge (increase in amount, or if it becomes watery, mucus-like, or bloody)
- You have vaginal bleeding (more than light spotting)
- Fluid is leaking from your vagina (could indicate ruptured membranes)
- You have severe headache, vision changes, or upper abdominal pain (signs of preeclampsia)
- Your baby's movements have significantly decreased
- You have severe abdominal pain
- You feel very unwell or have a high fever
Preeclampsia Warning Signs
Preeclampsia is a serious pregnancy complication characterized by high blood pressure and signs of damage to other organs, usually the kidneys. It typically develops after 20 weeks of pregnancy and can progress rapidly. Warning signs include:
- Severe headaches that don't respond to over-the-counter medication
- Vision changes including blurred vision, seeing spots, or sensitivity to light
- Upper abdominal pain, especially on the right side under the ribs
- Sudden swelling of the face, hands, or feet
- Nausea or vomiting in the second half of pregnancy
- Sudden weight gain (more than 2 pounds in a week)
Preeclampsia can be dangerous for both mother and baby if left untreated. If you experience any of these symptoms, contact your healthcare provider immediately or go to your nearest emergency department.
How Should I Prepare for Birth at 33 Weeks?
At 33 weeks, start preparing by packing your hospital bag, finalizing your birth plan, taking childbirth classes, arranging transportation to the hospital, and setting up the nursery. Practice breathing techniques and discuss pain management options with your healthcare provider.
With only about 7 weeks until your due date, now is an excellent time to focus on practical preparations for your baby's arrival. While it may feel like there's still plenty of time, babies sometimes arrive earlier than expected, and having things ready can provide peace of mind and reduce stress.
Packing Your Hospital Bag
Having a packed hospital bag ready by 33-35 weeks means you won't be scrambling to gather essentials when labor begins. Consider including items for labor (comfortable clothes, lip balm, hair ties), items for after delivery (comfortable going-home outfit, nursing bras, toiletries), items for your baby (going-home outfit, car seat), and items for your support person (change of clothes, snacks, phone charger).
Birth Plan Considerations
A birth plan helps communicate your preferences to your healthcare team. While flexibility is important since birth can be unpredictable, having a plan helps ensure your wishes are known. Topics to consider include:
- Pain management preferences (natural techniques, epidural, other medications)
- Preferred labor positions and freedom of movement
- Who you want present during labor and delivery
- Preferences for interventions like continuous monitoring
- Immediate skin-to-skin contact after birth
- Cord clamping timing preferences
- Feeding preferences (breastfeeding, formula, or combination)
Discuss your birth plan with your healthcare provider at one of your upcoming prenatal appointments. They can provide guidance on what's realistic given your specific situation and help you understand your options.
Childbirth Classes
If you haven't already taken a childbirth class, week 33 is a good time to complete one. These classes typically cover the stages of labor, breathing and relaxation techniques, pain management options, common interventions, and what to expect during delivery. Many hospitals and birthing centers offer classes, and online options are also available.
- Ensure your car seat is properly installed (many fire stations offer free inspections)
- Know the route to your hospital or birthing center and have a backup plan
- Discuss your schedule with your employer if you haven't already
- Set up basic nursery essentials (safe sleep space, diapers, basic clothing)
- Stock up on postpartum supplies for yourself
- Arrange help for the first few weeks after birth if possible
What Happens at Prenatal Appointments Around 33 Weeks?
At 33 weeks, prenatal appointments typically occur every two weeks. Your provider will check your blood pressure, weight, urine, fundal height, and your baby's heart rate. They may discuss birth preferences, signs of preterm labor, and upcoming tests like Group B strep screening.
During the third trimester, prenatal appointments become more frequent to closely monitor both your health and your baby's development. At around 33 weeks, you're likely seeing your healthcare provider every two weeks, with appointments increasing to weekly visits as you approach your due date.
Standard Checks at Each Visit
Your provider will perform several routine assessments at each appointment. Blood pressure monitoring is particularly important during the third trimester to watch for signs of preeclampsia. Urine testing checks for protein (another preeclampsia indicator) and signs of urinary tract infection. Weight monitoring ensures you're gaining weight appropriately for this stage of pregnancy.
Fundal height measurement tracks your baby's growth by measuring from your pubic bone to the top of your uterus. At 33 weeks, this typically measures around 31-35 centimeters. Significant deviations from expected measurements may prompt additional testing to ensure your baby is growing well.
Your provider will also listen to your baby's heart rate using a Doppler device. A normal fetal heart rate is between 110-160 beats per minute. This quick check provides reassurance that your baby is doing well.
Discussions with Your Provider
Your 33-week appointment is a good time to discuss any questions or concerns you have about the remainder of your pregnancy, labor, and delivery. Topics might include your birth plan, pain management options, signs of labor to watch for, and when to go to the hospital.
Upcoming Tests
Between 36 and 37 weeks, you'll likely have a Group B streptococcus (GBS) screening. GBS is a type of bacteria that about 25% of healthy women carry in their vagina or rectum. While it's harmless to adults, it can be passed to babies during delivery and cause serious infections. If you test positive, you'll receive IV antibiotics during labor to protect your baby.
What Should I Eat at 33 Weeks Pregnant?
At 33 weeks, focus on a balanced diet rich in protein, iron, calcium, and omega-3 fatty acids to support your baby's rapid growth. Eat smaller, frequent meals to manage heartburn, stay hydrated with at least 8-10 glasses of water daily, and continue taking your prenatal vitamins.
Good nutrition remains crucial during the third trimester as your baby undergoes rapid growth and development. Your baby is gaining about half a pound per week, and this growth requires adequate nutrients from your diet.
Protein is essential for your baby's tissue growth. Aim for about 75-100 grams daily from sources like lean meats, poultry, fish, eggs, dairy, legumes, and nuts. Iron supports your increased blood volume and helps prevent anemia - good sources include red meat, spinach, beans, and fortified cereals. Pair iron-rich foods with vitamin C (like citrus fruits) to enhance absorption.
Calcium supports your baby's developing bones and teeth. You need about 1,000 mg daily from dairy products, fortified plant milks, leafy greens, and sardines. Omega-3 fatty acids, particularly DHA, support brain and eye development. Good sources include fatty fish (salmon, sardines), walnuts, and flaxseeds.
To manage heartburn, eat smaller, more frequent meals rather than three large ones. Avoid lying down immediately after eating, and limit spicy, fatty, or acidic foods that may worsen symptoms. Staying well-hydrated is important, but try to drink most of your fluids between meals rather than with meals to reduce the feeling of fullness.
How Might I Feel Emotionally at 33 Weeks?
At 33 weeks, it's normal to feel a mix of excitement, anxiety, and emotional ups and downs. You may worry about labor, parenthood, or your baby's health. Physical discomfort can affect mood. Practicing self-care, talking to loved ones, and discussing concerns with your healthcare provider can help.
The final weeks of pregnancy often bring a complex mixture of emotions. It's completely normal to feel excited about meeting your baby while also feeling nervous about labor, delivery, and the changes that parenthood will bring. Hormonal fluctuations, physical discomfort, and sleep deprivation can all contribute to emotional ups and downs during this time.
Many people experience what's sometimes called "nesting instinct" during the third trimester - a strong urge to prepare the home for the baby. While organizing and preparing can be satisfying, try to balance these activities with adequate rest. Ask for help with physical tasks and don't feel pressure to have everything perfect before your baby arrives.
Anxiety about labor and delivery is extremely common. If worries are interfering with your daily life or sleep, talk to your healthcare provider. Childbirth education classes, honest conversations with experienced parents, and discussing your concerns with your provider can all help reduce anxiety.
- Rest when you can - your body is working hard
- Stay connected with your support system
- Practice relaxation techniques like deep breathing or prenatal meditation
- Gentle exercise like walking or prenatal yoga can boost mood
- Don't hesitate to ask for and accept help
- Talk openly with your partner about your feelings and fears
Frequently Asked Questions About 33 Weeks Pregnant
Medical References and Sources
This article is based on current medical research and international guidelines. All claims are supported by scientific evidence from peer-reviewed sources.
- American College of Obstetricians and Gynecologists (ACOG) (2024). "Practice Bulletin: Management of Preterm Labor." ACOG Clinical Guidelines Evidence-based guidelines for preterm labor management. Evidence level: 1A
- World Health Organization (WHO) (2016). "WHO Recommendations on Antenatal Care for a Positive Pregnancy Experience." WHO Guidelines International guidelines for prenatal care.
- National Institute for Health and Care Excellence (NICE) (2021). "Antenatal Care for Uncomplicated Pregnancies." NICE Guidelines Evidence-based recommendations for prenatal care.
- Royal College of Obstetricians and Gynaecologists (RCOG) (2022). "Reduced Fetal Movements: Green-top Guideline No. 57." Guidelines for monitoring and managing reduced fetal movements.
- Cunningham FG, et al. (2022). Williams Obstetrics, 26th Edition. McGraw-Hill Education. Comprehensive obstetrics textbook and clinical reference.
- Moore KL, Persaud TVN (2020). The Developing Human: Clinically Oriented Embryology, 11th Edition. Elsevier. Detailed reference on fetal development.
Evidence grading: This article uses the GRADE framework (Grading of Recommendations Assessment, Development and Evaluation) for evidence-based medicine. Evidence level 1A represents the highest quality of evidence, based on systematic reviews of randomized controlled trials.