What to Expect in the Third Trimester: Physical and Emotional Changes

The third trimester of pregnancy spans weeks 28 to 40 - or until delivery. It is simultaneously the most physically demanding and emotionally charged stage of pregnancy. Your body is preparing for one of the most significant events of your life, and your baby is making its final developmental push before birth.

During these final weeks, your baby gains more than half of its total birth weight, its organs reach full maturity, its senses sharpen, and it typically settles into a head-down position ready for delivery. For you, this trimester brings intensifying physical symptoms - including back pain, heartburn, shortness of breath, Braxton Hicks contractions, swelling, and disturbed sleep - alongside powerful emotions ranging from excitement and anticipation to anxiety and the strong nesting urge to prepare your home.

This is also the time to finalise your birth plan, attend prenatal check-ups that become more frequent, pack your hospital bag, and ensure you and your family are ready for your baby's arrival. At Nanavati Max Super Speciality Hospital our obstetric team support you through every week of this final stage.

Your Baby's Development in the Third Trimester

During the third trimester, your baby undergoes the most dramatic growth of the entire pregnancy. Here is what is happening week by week at key milestones: 

Week 28: The baby's eyelids can partially open and close, and the central nervous system can now regulate body temperature. The brain is developing rapidly, with billions of neurons forming.

Weeks 29-32: The baby can kick, stretch, and make grasping movements. Bones are hardening (though the skull remains flexible to help with delivery). Fat is beginning to accumulate under the skin, giving the baby a rounder, plumper appearance. By 32 weeks, fingernails reach the fingertips.

Weeks 33-36: The baby's pupils can now respond to light. Most lanugo (fine body hair) sheds, though vernix caseosa (a waxy protective coating) remains on the skin. The baby's sucking reflex is developed. Lung maturity continues to improve significantly during these weeks.

Week 36: Most babies settle into a head-down (vertex) position in preparation for birth - a process called engagement or 'lightening'. If the baby is in a breech (bottom-down) or transverse position, your obstetrician will discuss options, which may include an External Cephalic Version (ECV) procedure or a planned caesarean section. 

Weeks 37-40: The baby is considered full-term from week 39. At birth, an average baby weighs between 2.7 kg and 4 kg (6-9 pounds) and measures 48-53 cm (19-21 inches) in length. The baby gains more than half of its total body weight during the third trimester alone.

Throughout these weeks, your baby's senses are maturing too - it can hear your voice clearly, respond to light through your abdomen, and even taste the amniotic fluid. Research suggests newborns recognise their mother's voice from sounds heard in the womb.

Physical Changes in Third Trimester Pregnancy

Body and Weight Changes

Many women gain around 5 to 6 kg during the last trimester, although this can vary depending on pre-pregnancy weight, overall health, and pregnancy needs. This weight supports your growing baby, the placenta, amniotic fluid, and the extra blood your body needs during pregnancy.

Stretch marks on the belly, breasts, or thighs are common and usually fade with time. Mild swelling in the feet and hands may also appear as your body holds more fluid. Some women notice skin changes, such as itchiness or slightly darker patches. Using a gentle moisturiser and drinking enough water can bring some comfort.

Sudden or severe swelling, especially of the face or hands, should be reported to your doctor.

Changes in Mobility and Posture

As your belly grows, your balance naturally changes. You may walk more slowly, and your back, hips, or legs may feel sore because they are working harder. Back pain and pelvic pressure are also common in these weeks.

Gentle stretches, flat supportive footwear, or a pillow behind your back can ease daily discomfort. If sleeping feels difficult, placing a cushion between your knees or using a pregnancy pillow may help you rest better.

Digestive and Sleep Changes

Your growing uterus puts pressure on the stomach and intestines, which can lead to heartburn, bloating, or constipation. Eating small, frequent meals and avoiding very spicy or oily food may offer relief. Simple home-cooked dishes like moong dal, boiled vegetables, or plain rice are often easier to digest.

Sleep may also feel disturbed during these weeks. You may wake up frequently due to discomfort or the need to use the bathroom. Sleeping on your side can improve comfort. A warm bath, light reading, or gentle massage may also help you relax before bed.

Preparing for Labour Physically

Braxton Hicks contractions are common in the third trimester. They feel like mild tightening in the stomach and usually ease with rest, hydration, or a change in position.

As your due date nears, your body may show signs of preparation. You may feel the baby settle lower in your pelvis or notice slightly more discharge. Your doctor will explain which signs are typical and when you should seek guidance.

Varicose Veins, Spider Veins, and Haemorrhoids

Increased blood volume during the third trimester can cause veins to swell and become more visible. You may notice:

• Spider veins: small reddish-purple veins appearing on the face, neck, or arms - usually harmless and fade after delivery
• Varicose veins: swollen, sometimes aching veins on the legs - aggravated by prolonged standing or sitting with legs crossed
• Haemorrhoids: varicose veins in the rectal area, which can cause itching, pain, or mild bleeding - very common in late pregnancy

Frequent Urination and Urinary Leakage

As the baby moves deeper into the pelvis and puts increasing pressure on the bladder, frequent trips to the bathroom are expected. Many women also notice urinary leakage - a few drops of urine when laughing, coughing, sneezing, or lifting. This is a normal result of the physical pressure on pelvic floor muscles.

Kegel exercises - repeatedly contracting and releasing the pelvic floor muscles - can help strengthen these muscles and reduce leakage. Panty liners may offer comfort for day-to-day management. If you notice a continuous trickle or sudden gush of clear fluid, contact your doctor promptly - it may be amniotic fluid (waters breaking) rather than urine.

Emotional and Mental Changes in Third Trimester Pregnancy

Mood Swings and Anxiety

Hormonal changes, tiredness, and thoughts about childbirth can bring mixed emotions. You may feel excited at one moment and a little worried the next, and that is normal. Many women experience mood swings or self-doubt during these weeks. Concerns about labour, work, or upcoming responsibilities can all play on your mind.

Coping Strategies for Emotional Wellbeing

Small habits can help you feel calmer. Deep breathing, short walks, gentle yoga, or calming music may ease stress. Sharing your feelings with your partner or someone close can also bring comfort.

Some women also find prenatal support groups or speaking with a counsellor helpful during this stage. Reaching out for support is a healthy way to manage emotional changes.

Health Check-ups and Monitoring

During the third trimester, check-ups become more frequent. These visits help track your baby's growth and position, your weight, blood pressure, and any early signs of concern. You may also be advised to take or repeat tests for anaemia, gestational diabetes, infections, or other pregnancy-related concerns depending on your health and previous reports.

Around 36 to 38 weeks, a Group B Streptococcus test may be advised depending on your doctor’s recommendation and local protocol to support safe delivery planning.

Monitoring your baby's movement is also essential. Notice your baby’s usual pattern of kicks, rolls, and movements. If your baby seems less active than before, contact your doctor promptly. Reaching out early brings reassurance and helps protect your wellbeing.

Preparing for Delivery

This is a good time to discuss your delivery plan. Talking about your preferences for vaginal birth, planned caesarean birth, or pain relief options can help you feel more prepared and avoid last-minute confusion.

Keep your hospital bag ready with essentials like ID, insurance papers, medical records, comfortable clothes, toiletries, maternity pads, and baby clothes. Snacks and a water bottle can also be helpful if allowed by your care team.

Choosing a paediatrician before delivery offers peace of mind. Meeting them during the third trimester allows you to ask questions and feel more confident about your baby's care.

The Nesting Instinct

Many women in the third trimester experience a sudden and powerful urge to clean, organise, decorate, and prepare their home before the baby arrives - this is known as the nesting instinct. It often comes with a burst of energy that can feel surprising after weeks of fatigue. Nesting can be a healthy, productive way to channel anticipation and prepare practically for your baby's arrival.

Channel it wisely: while nesting energy can be useful for tasks like setting up the nursery, washing baby clothes, or organising your home, avoid overexerting yourself or taking on physically demanding activities. Delegate heavy lifting and climbing to others.

Health Check-ups and Monitoring

During the third trimester, check-ups become more frequent. These visits help track your baby's growth and position, your weight, blood pressure, and any early signs of concern. You may also be advised to take or repeat tests for anaemia, gestational diabetes, infections, or other pregnancy-related concerns depending on your health and previous reports.

Around 36 to 38 weeks, a Group B Streptococcus test may be advised depending on your doctor’s recommendation and local protocol to support safe delivery planning.

Monitoring your baby's movement is also essential. Notice your baby’s usual pattern of kicks, rolls, and movements. If your baby seems less active than before, contact your doctor promptly. Reaching out early brings reassurance and helps protect your wellbeing.

Preparing for Delivery

This is a good time to discuss your delivery plan. Talking about your preferences for vaginal birth, planned caesarean birth, or pain relief options can help you feel more prepared and avoid last-minute confusion.

Keep your hospital bag ready with essentials like ID, insurance papers, medical records, comfortable clothes, toiletries, maternity pads, and baby clothes. Snacks and a water bottle can also be helpful if allowed by your care team.

Choosing a paediatrician before delivery offers peace of mind. Meeting them during the third trimester allows you to ask questions and feel more confident about your baby's care.

Third Trimester Complications to Be Aware Of

While most third trimester pregnancies progress normally, some complications can arise. Your obstetrician monitors for these during prenatal visits. Common third trimester complications include:

• Preeclampsia: a condition causing high blood pressure, protein in the urine, and sometimes severe headaches, vision changes, or facial swelling. Can develop after 20 weeks and requires prompt medical management.
• Gestational diabetes: elevated blood sugar during pregnancy that increases risks for both mother and baby. Usually managed through diet, monitoring, and sometimes medication.
• Preterm labour: labour beginning before 37 weeks. Signs include regular painful contractions, lower back pain, pelvic pressure, or vaginal discharge changes. Seek immediate care if these occur before 37 weeks.
• Premature Rupture of Membranes (PROM): waters breaking before labour begins, which can lead to infection or preterm birth. Contact your doctor immediately if you notice a gush or steady trickle of clear fluid from your vagina.
• Breech presentation: baby positioned bottom- or feet-first instead of head-down after week 36. Options include an External Cephalic Version (ECV) procedure to turn the baby, or a planned caesarean section.
• Intrauterine Growth Restriction (IUGR): when the baby is estimated to be below the 10th percentile for its gestational age. Usually detected on ultrasound and requires closer monitoring.

When to Contact Your Doctor Immediately

Seek medical advice promptly if you experience:

• Reduced or absent baby movements
• Vaginal bleeding
• Leakage of fluid from the vagina
• Severe abdominal pain
• Regular painful contractions before 37 weeks
• Severe headache or vision changes
• Sudden swelling of the face, hands, or feet
• Fever or chills
• Severe breathlessness
• Persistent vomiting
• Chest pain or fainting

Conclusion

The third trimester of pregnancy is a time of extraordinary change - for both you and your baby. While the physical demands intensify and emotions run high, it is also the most exciting phase: your baby is putting on final weight, developing its senses, and preparing to enter the world.

Managing the third trimester well means staying consistent with prenatal appointments (every 2 weeks until week 36, then weekly), receiving your Tdap and flu vaccines, learning to recognise the signs of labour, understanding what complications to watch for, and building a support system around you for the weeks ahead. The nesting instinct, the vivid dreams, the breathlessness, the Braxton Hicks - all of it is part of your body's remarkable preparation for birth.

At Nanavati Max Super Speciality Hospital, Dr Gayatri Deshpande and our multidisciplinary maternal health team walk alongside you through every week of this final trimester - from prenatal monitoring and complication management, to birth planning, labour support, and postnatal care. If you have any questions, concerns, or symptoms during this phase, do not hesitate to reach out. You are not alone in this.

Frequently Asked Questions

1. What is considered normal weight gain in the third trimester?

Many women gain around 5 to 6 kg during this stage, although this varies depending on their pre-pregnancy weight, health, and pregnancy needs.

2. How can I ease back pain during the third trimester?

Gentle stretches, supportive footwear, warm compresses, side sleeping, and pillow support may offer relief. If the pain is severe or persistent, consult your doctor.

3. Are mood swings normal at this stage?

Yes. Hormonal changes, tiredness, physical discomfort, and thoughts about childbirth can cause emotional shifts during the third trimester.

4. When should I contact my doctor about unusual symptoms?

Seek help for severe pain, heavy swelling, bleeding, fever, fluid leakage, severe headache, vision changes, or reduced baby movement.

5. What signs indicate labour is approaching?

Signs may include stronger and more regular contractions, the baby dropping lower, increased vaginal discharge, a mucus plug, or water breaking. Contact your doctor if you are unsure whether labour has started.

6. What complications can happen in the third trimester?

The most common third trimester complications include preeclampsia (high blood pressure with protein in the urine), gestational diabetes (high blood sugar), preterm labour (labour before 37 weeks), premature rupture of membranes (waters breaking before labour), breech presentation (baby positioned bottom-first after 36 weeks), and intrauterine growth restriction (baby measuring small for gestational age). 

7. What is the nesting instinct and is it normal?

Yes, the nesting instinct is entirely normal. It is a strong, often sudden urge to clean, organise, and prepare your home for the baby's arrival. It typically occurs in the third trimester and can come with a burst of energy that feels surprising after weeks of fatigue. It is thought to be driven by hormonal changes and the instinctive preparation for parenthood. Nesting is healthy and productive - use it to set up the nursery, wash baby clothes, and organise your home. Just avoid overexerting yourself or doing heavy lifting.