Pregnancy Week 29: Managing Back Pain and Your Baby's Busy Movements

Quick answer: At 29 weeks your baby measures about 38.6cm and weighs around 1.15kg, with stronger, more purposeful kicks. Back pain affects up to 50% of pregnant women now, eased by low-impact exercise, good posture, side-sleeping with a pillow between the knees and supportive flat shoes. Ask your midwife for a physiotherapy referral if pain is severe, and contact her immediately about sudden severe swelling.

What parents need to know

Week 29 brings increasing activity from your baby as they settle into more regular patterns of movement. You may also be finding that some of the physical discomforts of the third trimester are becoming more noticeable. Back pain in particular is very common at this stage, and there are practical steps you can take to manage it.

How big is your baby at 29 weeks?

Your baby now measures approximately 38.6cm from crown to heel and weighs around 1.15 kilograms — roughly the weight of a small butternut squash. They're growing quickly and will continue to put on weight steadily over the coming weeks.

What's happening with your baby?

Your baby's muscles and lungs are continuing to mature. They are actively practising breathing by inhaling and exhaling amniotic fluid, which helps the lungs develop the strength and coordination they'll need for breathing air after birth. Your baby's bone marrow is now fully responsible for producing red blood cells. The head is also growing to accommodate the rapidly developing brain. Your baby's kicks, punches, and rolls may feel stronger and more purposeful this week as their muscles grow stronger.

Managing back pain in pregnancy

Back pain affects up to 50% of pregnant women and is one of the most common complaints of the third trimester. It occurs because the growing uterus shifts your centre of gravity forwards, causing you to lean back to compensate and putting strain on the lower back. The hormone relaxin also loosens the ligaments and joints throughout the body, including those in the spine, which can lead to instability and pain.

Practical strategies to help manage back pain include: keeping active with low-impact exercise such as swimming, walking, or antenatal yoga; avoiding standing for long periods and taking regular breaks; using good posture when sitting — a small cushion or rolled towel behind the lower back can help; sleeping on your side with a pillow between your knees; wearing flat, supportive shoes; and lifting carefully by bending at the knees rather than the waist.

Your midwife can refer you to a physiotherapist if your back pain is severe or affecting your daily life. A physiotherapist can provide targeted exercises and treatments to help. Some women also find that a maternity support belt helps reduce discomfort by supporting the bump and taking some of the strain off the lower back.

What's happening in your body?

You may notice that your ankles and feet are swelling, particularly towards the end of the day. Mild swelling (oedema) is very common in the third trimester. Elevating your legs when possible, staying hydrated, and gentle walking can help. However, sudden or severe swelling of the face, hands, or feet can be a sign of pre-eclampsia — contact your midwife immediately if this occurs, especially if accompanied by headaches, visual disturbances, or pain below the ribs.

Your week 29 checklist

This week:

• Try gentle exercise or swimming to help with back pain.
• Ask your midwife for a physiotherapy referral if needed.
• Monitor for any sudden severe swelling.
• Continue tracking your baby's movements.
• Start writing a list of questions for your next antenatal appointment.