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      20 Weeks Pregnant: Pregnancy Symptoms & Baby Development

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      20 Weeks Pregnant: Pregnancy Symptoms & Baby Development

      Read time: 4 minutes


      20 weeks pregnant is how many months?


      Month 5 (Trimester 2)


      Baby development at 20 weeks

      This week, we start separating the girls from the boys.


      Exercise and health

      Staying fit and healthy supports a fit and healthy baby.


      Diet & nutrition

      Make sure you keep your iron levels up.

      Baby development at 20 weeks

      Foetus Pregnancy Week 20

      What does my baby look like? What size is my baby?

      At 20 weeks pregnant your baby will be roughly 16cm from head to bottom (the size of a banana), and will weigh around 300g1. Their heartbeat is strong enough to be detected easily. 

      Your baby is now covered in a layer of white, creamy ‘vernix’, a substance that’s thought to protect their delicate skin2. Later on, the slipperiness of vernix will help your baby make its way down the birth canal.

      If you’re having a baby girl, her uterus will be developing1, and her ovaries will already have seven million primitive eggs in them3. When she’s born, she’ll be carrying two million eggs3. If you’re having a baby boy, then this is the week when the testes start lowering from his abdomen3.

      The development of your baby’s nerve cells is slowing, but more complex connections are forming - so much so that your baby can enjoy a satisfying stretch4.

      Your anomaly scan

      Between weeks 18-20 of your pregnancy, you’ll be scheduled for an anomaly scan to ensure your baby is developing properly, and discuss next steps if there are any suspected issues. It’s no reason to worry.

      Pregnancy at 20 weeks (second trimester)

      What’s happening in my body?

      Your placenta continues delivering nutrients to, and removing waste from, your baby, but your baby will soon become larger than your placenta. Your placenta continues growing, too, trebling in size by birth3. Because of its important role, the sonographer will also examine your placenta during your scan.

      You may also start experiencing Braxton-Hicks contractions, or ‘false labour pains’5. Even as early as week 20 your body starts preparations for birth. The contractions are unpredictable, and not everyone will experience them. They can be caused by being too active, having a full bladder, or, conversely, dehydration. (See? Unpredictable.) The contractions are normally mild (you may not even notice some), vary in intensity and duration, and aren’t usually a cause for concern.

      If you experience pain during these contractions, have regular, strong contractions every five minutes, or vaginal bleeding then you should contact your doctor or midwife.


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      Pregnancy symptoms at 20 weeks

      Pregnant woman with glass of water

      Blame your hormones. Again. Thankfully, pregnant women receive free dental care which continues for the first year of your baby’s life6. Ask your midwife for a maternity exemption certificate.

      As your belly grows, you may see the appearance of stretch marks on your stomach or breasts7. They usually become much less noticeable after birth. Don’t waste money on ‘miracle creams’ - simple moisturiser is enough.

      Frequent trips to the bathroom are one of the most common symptoms of early pregnancy, as your growing uterus begins to put pressure on your bladder.

      The pregnancy hormone progesterone slows down your digestion which can lead to bloating and excess gas8.

      Pains on the side of your belly are caused by your expanding womb (and also referred to as ‘round ligament pains’)2.

      Focus on Iron

      Iron is a key nutrient throughout pregnancy, and an important part of a balanced diet. The recommended daily intake for every woman, whether pregnant or not, is 14.8mg each day9. Your blood cells need iron to carry oxygen around your body10 and to your baby. Iron also contributes to your baby’s normal cognitive function11.

      Iron deficiency can cause anaemia, so your iron levels, haemoglobin levels and red blood cell count will be regularly checked while you’re pregnant.

      Many women have lower haemoglobin levels during pregnancy, but iron supplements are only prescribed if they’re very low12.

      Broccoli 2

      Foods rich in iron

      • Lean meat (always ensure it’s well cooked) 
      • Oily fish, such as sardines
      • Dark green veg, including broccoli, watercress, spinach and kale
      • Cashew nuts
      • Pulses, chickpeas, beans and lentils
      • Whole grains, including wholemeal bread, and iron-fortified breakfast cereals
      • Dried fruits, such as apricots, prunes and raisins
      • Eggs



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      Vitamin C can help improve iron uptake - but some ingredients and compounds can inhibit your ability to absorb iron. For instance, tea and coffee contain phenolic compounds (natural chemicals that create flavour and ‘mouthfeel’) which are known to inhibit iron absorption13.

      Wholegrains were also thought to prevent mineral absorption due to phytates. However cooking, boiling, soaking or germinating whole grains makes phytic acid inactive, allowing you to absorb iron and other minerals, and benefit from wholegrain fibre14.

      Exercise at 20 weeks

      Moderate exercise is good for both you and your baby as long as you’re both healthy. Even if you’ve not exercised before, you can still start now, but go gently and choose low-impact exercises.

      You may need to slow down as your pregnancy progresses or if your maternity team advises you to. If you’re unable to chat without becoming breathless while exercising, you’re likely exercising too much. If in doubt, talk to your midwife.

      Active For 2 Swimming


      This is a perfect exercise for pregnancy, and walking at a quick pace is good for your heart. You should aim for three to five walks of 30 minutes each week15.


      This can help stretch and strengthen muscles, reduce pregnancy pains (especially lower back pain) and lower your blood pressure. Don’t try complex poses, especially twists, and avoid ‘Bikram hot yoga’15.


      This is great exercise that lets you build strength and aerobic stamina at the same time. You can swim three to five times a week, up to 30 minutes at a time15.

      Start with a low level of effort, and work up to 30 minutes of exercise three to five times a week. Always take a few moments to warm up before exercising, and take time to cool down with stretches and slow, deep breaths afterwords.

      1. Murkoff H, Mazel S. What to Expect When You’re Expecting. 4th ed. London: Simon & Schuster Ltd, 2009.
      2. NHS UK. Week 20 – your second trimester. [ONLINE] Available at: [Accessed December 2019]
      3. 20 weeks pregnant: advice, symptoms and what to expect. [ONLINE] Available at:
      4. Deans A. Your New Pregnancy Bible, The experts’ guide to pregnancy and early parenthood. 4th ed. London: Carroll & Brown Publishers Limited, 2013.
      5. Braxton Hicks. [ONLINE] Available at: Page last reviewed: July 3rd 2019. Next review date: July 3rd 2022.
      6. NHS UK. Start4life. Week 13 - your second trimester [Online] Available at: [Accessed December 2019]
      7. NHS UK. Start4life. Week 17 - your second trimester [Online] Available at: [Accessed December 2019]
      8. NHS Start 4 Life. 1st trimester, week 10 [Online]. Available at: [Acessed December 2019]
      9. Department of Health. Report on Health and Social Subjects 41. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. TSO: London, 1991.
      10. European Union. Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children’s development and health OJ L 136 2012;1
      11. European Union. Commission Regulation (EU) No 957/2010 of 22 October 2010 on the authorisation and refusal of authorisation of certain health claims made on foods and referring to the reduction of disease risk and to children’s development and health. OJ L 279 2010;13-7.
      12. NHS UK. Vitamins, supplements and nutrition in pregnancy. [Online] Available at: [Accessed December 2019]
      13. Mascitelli L, Goldstein M, Inhibition of iron absorption by polyphenols as an anti-cancer mechanism, QJM: An International Journal of Medicine, Volume 104, Issue 5, May 2011, Pages 459–461, [Accessed December 2019]
      14. Brune M, Rossander L, Hallberg L. Department of Medicine II, University of Göteborg, Sweden. Iron absorption and phenolic compounds: importance of different phenolic structures.
      15. Healthline. What Exercises Are Safe in the Second Trimester? [Online] Available at: [Accessed December 2019]

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