The third trimester runs from week 28 until your baby is born, usually around week 40. This is the finishing stage: your baby gains most of its birth weight, practises breathing and swallowing, and settles into position for birth, while your body prepares for labour. Appointments become more frequent and the weeks often feel slower as tiredness returns. This third trimester week by week guide explains what changes, what is checked and how to prepare.
The growth foundations were laid in the second trimester weeks 14 to 27; now the emphasis shifts from forming new structures to maturing, fattening and getting ready for life outside the womb.
Weeks 28 to 31: Rapid Weight Gain Begins
At week 28 your baby weighs around 1 kilogram and can blink, dream and move its eyes. Through weeks 29 to 31 the baby gains weight quickly, the lungs and digestive system continue to mature, and the bones harden further, although the skull stays soft and flexible to ease the journey through the birth canal.
Movements change character during this stage. With less spare room, big kicks give way to rolls, stretches and pushes that can visibly move your whole bump. Hiccups are common and feel like small rhythmic pulses. Your appointments typically move to every two or three weeks, with blood pressure, urine and bump measurement at each visit, plus a blood test to check for anaemia around week 28.
Weeks 32 to 35: Settling Into Position
By week 32 most babies are lying head-down, which is the ideal position for birth, though many turn later. The baby practises breathing movements more regularly, swallows amniotic fluid and continues to store fat, becoming rounder and stronger each week. By week 35 the baby typically weighs around 2.4 kilograms and measures about 46 centimetres from head to heel.
For you, this stage often brings the return of fatigue, along with breathlessness as the womb presses up against the diaphragm. Heartburn, backache and needing the toilet frequently are all common. Many women notice Braxton Hicks tightenings, where the bump goes hard for a few seconds; these practice contractions are usually irregular and ease with rest or a change of position. If tightenings become regular, stronger and closer together, that is different, and our guide to the signs of labour explains how to tell the difference.
Weeks 36 to 38: Full Term Approaches
Around week 36 your midwife or doctor will usually check the baby’s position by feeling your bump, and growth scans may be offered if measurements raise questions. The baby’s head may engage, dropping lower into the pelvis, which can make breathing easier but walking and pelvic pressure heavier. This is sometimes called lightening.
Babies born from week 37 onwards are considered early term, and from week 39 full term. The final weeks are mostly about lung maturity, brain development and laying down the fat and iron stores the baby needs after birth. This is a sensible window to finish practical preparations: wash the baby clothes, install the car seat, and pack using a hospital bag checklist so you are not scrambling when labour starts.
Weeks 39 to 40 and Beyond: The Waiting Game
By your due date only a small minority of babies have actually arrived on that exact day; most are born in the two weeks either side. Your baby is now typically around 3 to 3.5 kilograms and about 50 centimetres long, though healthy birth weights vary widely. Movements should continue right up to and during labour, even if they feel like slower rolls rather than kicks.
If you pass your due date, appointments usually include an offer of a membrane sweep after week 40, and induction is commonly discussed for around week 41 if labour has not started. Remembering that a due date is an estimate built on averages, not a deadline your baby must meet, can take some of the pressure off the waiting.
Common Third Trimester Discomforts
Late pregnancy is physically demanding, and most women experience several of the following:
- Backache and pelvic girdle pain when walking or turning in bed
- Swollen hands, feet and ankles, especially in warm weather
- Restless sleep and vivid dreams
- Heartburn and indigestion after even small meals
- Breathlessness when climbing stairs or lying flat
- Itchy skin across the stretched bump
- Carpal tunnel tingling or numbness in the hands
- Leaking a little colostrum from the breasts
Some symptoms should always be checked promptly rather than put down to late pregnancy: a severe headache that does not ease, vision changes, sudden swelling of the face or hands, pain just under the ribs, persistent itching particularly on the hands and feet, or any clear reduction in your baby’s movements. Our round-up of common pregnancy discomforts and simple ways to ease them covers the everyday side in more depth.
Preparing for Birth
These weeks are the time to think through your preferences for labour. Many women write a short birth plan covering pain relief options, who will be with them, and preferences for the first hour after birth. It is a preferences document, not a contract, and plans often change on the day. Antenatal classes, whether local or online, can help you and your partner know what to expect from each stage of labour.
At home, small preparations make the first days easier: meals in the freezer, feeding supplies if you plan to use them, nappies and wipes stocked, and a simple plan for who helps in week one. Rest matters too. Maternity leave often starts in this window, and using it to nap and pace yourself is not indulgence; it is preparation for broken nights ahead.
Sleeping and Staying Comfortable
Sleeping on your side is recommended in late pregnancy, and many women find a pillow between the knees, one under the bump and one behind the back makes a workable nest. Getting up in stages, rolling onto your side and pushing up with your arms, protects your back and abdominal muscles. Short daytime rests are worthwhile if nights are broken.
Appointments and Checks in the Final Weeks
Antenatal care steps up in this trimester. Appointments are commonly every two weeks from around week 28 to 36, then weekly until the birth, although patterns vary. At each one your blood pressure and urine are checked, because rising blood pressure and protein in the urine can be early signs of pre-eclampsia. Your bump is measured to track growth, and the baby’s heartbeat is listened to.
Your midwife will also feel for the baby’s position. If the baby seems to be breech, bottom-down, after about week 36, options are usually discussed, which may include a procedure to try to turn the baby, or planning the type of birth. Blood tests may be repeated to check your iron levels, and whooping cough and flu vaccinations are often offered during pregnancy to pass protection to the baby. Keep your notes with you at all times in these weeks; if you need care away from home, they tell any clinician your full story at a glance.
Your Birth Partner and Practical Support
Deciding who will be with you in labour is worth doing early in this trimester. A good birth partner knows your preferences, can speak up for you when you are focused on contractions, and understands that their job includes drinks, encouragement and calm company as much as anything dramatic. Many hospitals and birth centres allow one or two partners; check the local arrangements so there are no surprises.
Practical support planning matters just as much. Arrange how you will get to hospital or the birth centre at 3 a.m., including a backup driver. If you have older children or pets, line up who will look after them at short notice, and give those people a key and clear instructions in advance. Agree who will field messages after the birth so you are not managing a phone while feeding a newborn.
Partners and family can also prepare for the weeks after birth, when help with cooking, laundry and night-time settling is worth more than any gift. Having honest conversations now, about what you will and will not need, prevents misunderstandings when everyone is tired and emotional later.
Feeding Plans and the First Days After Birth
It helps to think a little about feeding before the baby arrives, because the first days are emotional and tiring, and decisions feel harder then. If you plan to breastfeed, antenatal classes and a conversation with your midwife about how feeding gets established, and where to get help at 2 a.m., are genuinely useful. If you plan to formula feed, or to combine both, having bottles, sterilising equipment and formula at home removes a midnight shopping problem.
Also expect the first week to be a blur of feeding, nappy changes, broken sleep and visitors. Babies typically lose a little weight in the first days and regain it over the following week or two, feeding frequently around the clock. Midwife visits in the first days check feeding, weight, jaundice and your own recovery, whether you gave birth vaginally or by caesarean. Knowing this pattern in advance makes the intensity feel normal rather than alarming.
Finally, accept that preparation has a limit. You can pack the bag, freeze the meals and read the guides, and the birth will still be its own unpredictable event. That is normal, and the professionals around you are there precisely for the parts no plan can cover.
This article is general information only, not medical advice, so please check any personal questions or worries with your doctor or midwife.
Conclusion
Weeks 28 to 40 are about finishing touches: your baby gains weight, matures and settles head-down, while you balance discomfort, preparation and waiting. Keep every appointment, watch your baby’s movement pattern, finish the practical jobs early, and rest without guilt. When labour begins, you will be as ready as anyone can be, and the first week with your newborn, covered in our newborn guides, is just around the corner.
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