The third trimester begins at 28 weeks and brings a noticeable shift in pregnancy. Your baby is growing rapidly, appointments become more focused on birth and wellbeing, and symptoms such as breathlessness, pelvic pressure, heartburn and disturbed sleep can become more obvious. For many parents, weeks 28-40 of pregnancy feel both exciting and demanding because the due date is close enough to plan for, but still unpredictable. This guide explains what typically happens during the final stretch, what your maternity team may check, and which changes deserve prompt attention.
Weeks 28 to 32: growth, movement and closer monitoring
Week 28
At 28 weeks, you are officially in the third trimester. Your baby continues adding body fat and developing the brain, lungs and nervous system. Movements should be familiar by now, although the type of movement may change as space becomes tighter. There is no universal daily kick number; the important thing is knowing your baby’s usual pattern and seeking help if that pattern changes.
In NHS care, the 28-week appointment commonly includes blood pressure and urine checks, measurement of your bump, discussion of movements, and blood tests to check areas such as iron levels and blood group antibodies. If you are rhesus D negative and not already sensitised, anti-D prophylaxis may also be offered.
Weeks 29 to 30
As the uterus rises, you may notice more heartburn, shortness of breath or difficulty finding a comfortable sleeping position. Braxton Hicks tightenings can also become more noticeable. These are usually irregular and do not steadily become longer, stronger and closer together in the way established labour contractions do.
A practical tip is to notice patterns rather than trying to “test” your baby at a fixed time. If your baby normally becomes active after dinner and is suddenly much quieter, contact your maternity unit rather than waiting until the next morning.
Weeks 31 to 32
If this is your first pregnancy, you may be offered an additional appointment around 31 weeks. Birth preferences, mental wellbeing, blood pressure, urine, bump measurement and fetal movement are common topics. It is also sensible to know how to reach your maternity triage or assessment unit outside normal clinic hours.
Weeks 33 to 36: turning preparation into a practical plan
Weeks 33 to 34
Third trimester symptoms often intensify during these weeks. Backache, pelvic discomfort, swollen feet, reflux and interrupted sleep are common, although symptoms vary widely. Gentle activity, regular meals, good hydration and resting when needed can help, but new or severe symptoms should not be dismissed as “just pregnancy.”
The 34-week appointment usually revisits birth preparation and routine wellbeing checks. This is a useful point to decide how you will get to your chosen birth setting, who will be with you, where your maternity notes are kept, and who can help at home after the birth.
Weeks 35 to 36
Around 36 weeks, your midwife or doctor may feel your abdomen to assess your baby’s position. If breech presentation is suspected, an ultrasound may be offered to confirm it and your maternity team can discuss the available options. You may also feel more pressure low in the pelvis as the baby settles lower, although this does not reliably predict when labour will begin.
Weeks 37 to 40: term pregnancy and waiting for labour
Weeks 37 to 38
From 37 weeks, labour is no longer considered preterm. Appointments continue to check blood pressure, urine, bump growth, movements and the baby’s position. Around 38 weeks, your team may also discuss what happens if pregnancy continues beyond 40 weeks.
Weeks 39 to 40
At 39 and 40 weeks, there is no reliable home method for predicting the exact day labour will start. The baby should still move in their usual pattern right up to and during labour. Movements should not simply fade because there is “less room.” A change in movement is a reason to contact maternity services promptly.
A hospital bag checklist, birth preparation checklist and clear guide to the stages of labour can be useful next reads. Keep essentials ready, but avoid treating the due date as a deadline; many healthy pregnancies continue beyond it, with follow-up and options discussed individually.
Do you need a growth scan in the third trimester?
A common misconception is that everyone routinely has a growth scan in the third trimester. In uncomplicated singleton pregnancies, NICE does not recommend routine ultrasound scans after 28 weeks. Instead, bump size is commonly measured at antenatal appointments after 24 weeks. If the measurement suggests your baby may be smaller or larger than expected, or if there are other clinical concerns, an ultrasound for growth and wellbeing may be offered.
A growth scan third trimester appointment may assess fetal measurements, estimated size, fluid and other aspects of wellbeing depending on the reason for referral. Some pregnancies are monitored with regular scans because of maternal health conditions, previous pregnancy history or identified growth risks. Your own schedule may therefore look different from someone else’s.
Signs of labour and when to seek help
Possible signs of labour include regular contractions or tightenings, a mucus “show,” backache, increased pressure and your waters breaking. Early labour can last for hours, so maternity teams give individual advice based on contraction pattern, previous births and your clinical history.
Contact your midwife or maternity unit urgently if your waters break, you have vaginal bleeding, your baby is moving less than usual, or you think labour may be starting before 37 weeks. NHS guidance also advises urgent contact for unusually frequent contractions or contractions lasting longer than expected. If you are unsure, call for advice rather than trying to diagnose the situation yourself.
FAQ
When does the third trimester start?
The third trimester starts at 28 weeks of pregnancy and continues until birth. A due date at 40 weeks is an estimate, not a guarantee that labour will happen on that day.
What are the most common third trimester symptoms?
Common third trimester symptoms include tiredness, heartburn, backache, pelvic pressure, Braxton Hicks tightenings, sleep disruption, breathlessness and more frequent urination. Sudden, severe or worrying symptoms should be discussed with your maternity team.
Should baby movements decrease near the due date?
No. The character of movements may feel different as your baby grows, but you should continue to feel movement in your baby’s usual pattern up to and during labour. Contact maternity services immediately if movements reduce, stop or noticeably change.
What happens if I reach 40 weeks without labour?
Your maternity team will discuss ongoing monitoring and the choices available if pregnancy continues beyond 40 weeks. NHS antenatal care includes further review around 41 weeks, with next steps based on your circumstances and preferences.
The final stretch
The third trimester is less about counting down to one exact date and more about watching patterns: your baby’s movements, your own symptoms, and the progression of antenatal checks. Use the final weeks to prepare practically, understand the signs of labour and keep your maternity contact details close. If something feels unusually different or worrying, seek professional advice promptly rather than waiting for the next scheduled appointment.
