18 weeks pregnant: baby's development, back pain and antenatal classes

Your baby measures about 14cm this week - roughly the same as a bell pepper!

Your baby’s development this week

Your baby can now make facial expressions, although they can’t control them yet.

Around this week, your baby will become able to hear sounds such as your heart beating, the blood pumping around your body and the noises made by your digestive system.

Soon they will be able to hear sounds outside your body and may jump around to loud noises, such as music.

    Your pregnancy symptoms in week 18

    Back pain and pregnancy

    Pregnancy can put a strain on your joints and affect your posture, as your body learns to cope with the growing weight of your bump. This can sometimes cause back pain. 

    Low-impact exercises, such as swimming, may help. Find more tips for back pain.

    Feeling your baby move

    You might feel the odd movement as your baby practises kicking and flexing their tiny limbs, but don't expect to feel it much at this stage.

    Lots of people don't feel movement for a couple of weeks yet, especially in their first pregnancy. You may not even be sure if it's the baby at first as movements can just feel like a fluttering in your stomach.

    Read more about baby's movements.

    If you have any concerns

    Tell your midwife or doctor if there is anything that you're concerned about. Do not worry if you've talked about it before and don't be concerned about whether you're wasting anyone's time. This is your pregnancy and it's important to trust your own instincts if you feel something isn't right.

    What to do in week 18

    Your next scan

    You’ll have your second scan, known as the fetal anomaly scan between 18 and 21 weeks. This is scan is to check the physical development of your baby.

    In most cases, the scan will show that the baby appears to be developing as expected. But sometimes they may show that you or your baby have an increased chance of health problems, or you may be referred to a fetal medicine specialist for a more detailed ultrasound scan. 

    We are here for you if this happens. You can contact our midwives on 0800 014 7800 or email [email protected].

    The charity Antenatal Results and Choices offers specialised support for anyone facing a suspected or diagnosed fetal anomaly. 

    Read more about pregnancy ultrasound scans.

    How can I find antenatal classes near me?

    Antenatal classes are a great way to prepare for the birth of your baby. And they’re sometimes a good way to meet other expectant families in your area.

    Ask your midwife, health visitor or GP about local classes. Some of these may be offered online. The NHS offers free classes and the National Children’s Charity (NCT) also offers antenatal classes for a fee.

    If my partner smokes, is my baby at risk?

    Secondhand smoke can affect you and the baby during pregnancy and after baby is born.

    No matter how careful anyone you live with thinks they are being, you and your baby can still breathe in the harmful poisons. Opening windows and doors or smoking in another room will not make it safe.

    Ask the people around you to read our information about the effects of secondhand smoke and what support is available to help them quit. 

    Pregnancy clothes

    If you haven't already, you may need to get some maternity clothes. Trousers or skirts that are elasticated or loose around your tummy will be the most comfortable.

    Don't spend a lot on maternity clothes as you won't need them for long. Lots of high street shops have affordable maternity ranges and you can also save money by:

    • borrowing clothes from friends who have recently had babies
    • looking on local forums or online auction sites
    • browsing second-hand shops.

    1.  Regan, Lesley (2019) Your pregnancy week by week. Penguin Random House, London

    2. Sue Macdonald and Gail Johnson Mayes’ Midwifery (Edinburgh: Baillir̈e Tindall Elsevier, 2017) p.531

    3. Clinical Knowledge Summaries (2021) Antenatal care – uncomplicated pregnancy https://cks.nice.org.uk/antenatal-care-uncomplicated-pregnancy#!topicsummary

    4. NHS. Your baby’s movements. https://www.nhs.uk/pregnancy/keeping-well/your-babys-movements/ (Page last reviewed: 12 October 2021 Next review due: 12 October 2024)

    5. NICE (2015). Antenatal care. National Institute for health and care excellence https://www.nice.org.uk/guidance/ng201

    6. NHS. Stop smoking in pregnancy. https://www.nhs.uk/pregnancy/keeping-well/stop-smoking/ (Page last reviewed: 7 November 2019 Next review due: 7 November 2022)

    Review dates
    Reviewed: 11 July 2022
    Next review: 11 July 2025