17 Weeks Pregnant: Pregnancy Symptoms & Baby Development

Pregnant woman feeling sick

Explore pregnancy stages week by week

quick explanation

See how your baby is developing at 17 weeks pregnant. Learn about changes to your body, your baby and important nutrients for week 17 of pregnancy.




reading time



17 weeks pregnant is how many months?

Month 4 (Trimester 2)


Baby development at 17 weeks

This week, your baby should start practicing breathing.


Excercise and fitness

Pregnancy is no excuse to ease off exercise - but keep fit safely.


Diet & nutrition

Stock up on the sunshine vitamin - vitamin D.

Baby development at 17 weeks


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

At 17 weeks your baby should weigh about 150g (just over 5oz)1 and measure around 13cm from crown to rump2. Until now, your baby’s head has been larger in proportion, but now its body is starting to catch up and put on weight. It’s around this time that fat-storing ‘adipose tissue’ is beginning to form3.

Hair, eyebrows and eyelashes are continuing to grow4. The respiratory system is also developing, and your baby will begin practising breathing as its chest rises and falls. By week 17, it’s possible for your baby’s heart rate to beat at around 140–150 bpm2 – much faster than an average resting adult range of 60–100 bpm.

Pregnancy symptoms at 17 weeks

woman resting on a sofa

Along with Vitamin D, you’ll also need plenty of extra iron for your baby. Signs of iron deficiency include feeling tired and out of breath, and looking pale8. Talk to your midwife about taking an iron supplement.

Your body holds more water while you’re pregnant, so if you stand for too long gravity will take a toll and send the water to your ankles, hands and feet. Put your feet up - right up: prop them up so they’re higher than your heart for an hour each day8.

It usually strikes at night, so make sure you turn a light on if you stand up to help clear it. You don’t want to trip and fall. Gentle exercise for your legs, ankles and feet may help prevent cramp8.

With your body pumping more blood, and rampaging hormones, you can feel extremely hot. And not always in the best sense of the word. Wear loose, breathable fabrics and stay hydrated with chilled water8.

Pregnancy hormones, oestrogen and progesterone, soar during pregnancy9, affecting how you’re feeling emotionally. Get plenty of rest and light exercise to keep you feeling like yourself.

The pregnancy hormone progesterone slows down your digestion which can lead to bloating and excess gas10.

Focus on Vitamin D

It’s recommended that you get 10 micrograms of vitamin D each day during pregnancy11. The most efficient way to get vitamin D is through exposure to direct sunlight – UVB rays in particular. However, Britain’s latitude means we only get six months of effective sunlight each year, from April to September. This may explain why a significant number of young women in the UK have low vitamin D, and why sun exposure alone may not be enough to support your baby during pregnancy12.

How to boost your vitamin D intake

Vitamin D is present in certain foods, like eggs and oily fish. But the best way to make sure you’re getting enough is to take it as a 10mcg supplement. Some prenatal multivitamins contain this already, or you can choose to take a separate vitamin D supplement. You can also boost your vitamin D intake by including the following foods in your diet:

  • Oily fish, including herrings, mackerel, sardines, salmon, trout (limit your intake to 2 portions a week).
  • Eggs – the yolk contains the vitamin D.
  • Fortified foods – some brands of milk and breakfast cereals have added vitamin D.

The science behind Vitamin D, Powered by Nutricia

Vitamin D forms an essential part of your healthy pregnancy diet. It plays a vital supporting role in the growth and development of your baby’s bones by regulating the levels of calcium and phosphate in their body13. An adequate supply of vitamin D also reduces your baby’s risk of vitamin D deficiency.

As well as supporting your baby’s bone development during pregnancy, the vitamin D you consume now helps to build up your baby’s personal store, which they will rely on during their first few months of life14.

Headaches in pregnancy

Some women experience headaches in early pregnancy. They usually improve or clear by the fourth month and don’t harm your baby.

Paracetamol is usually safe to take during pregnancy and while breastfeeding, but always at the lowest effective dose, and for the shortest possible time. When used correctly, there are no harmful effects to you or your baby15. Talk to your doctor or midwife for advice on how much paracetamol you should take, and for how long.

Painkillers to avoid

There are some painkillers you should avoid while pregnant or breastfeeding. These include non-steroidal anti-inflammatory drugs like Ibuprofen or Naproxen, and medications containing codeine and other opiates unless specifically directed by a healthcare professional15.

A headache or pre-eclampsia?

If you continue to experience headaches, it could be a sign of pre-eclampsia15. This can affect women around week 20 of their pregnancy or soon after giving birth.

The earlier pre-eclampsia is diagnosed, the better the outlook for you and your baby. Call your doctor, midwife or maternity unit if you develop a severe headache accompanied by:

  • Blurred vision
  • Seeing flashes of light
  • A pain just below your ribs
  • Vomiting
  • Swelling in your face, hands, feet or ankles

Most cases of pre-eclampsia are mild, but if it’s not monitored or treated, it can lead to serious complications.

Your baby's future health begins here

At Aptaclub, we believe that experience helps to build resilience; and that each new encounter, whether in pregnancy or after birth, can shape your baby’s future development. With our scientific expertise and one-to-one round the clock support, we can help you and your baby embrace tomorrow.

mom and baby

Get in touch with our Careline experts

Our nutritionists and feeding advisors are always on hand to talk about feeding your baby. So if you have a question, just get in touch

  1. NHS UK. You and your baby at 17-20 weeks pregnant [Online]. 2013. Available at: www.nhs.uk/conditions/pregnancy-and-baby/pages/pregnancy-weeks-17-18-19-20.aspx Page last reviewed: 17 July 2018. Next review due: 17 July 2021.
  2. Murkoff H, Mazel S. What to Expect When You’re Expecting. 4th ed. London: Simon & Schuster Ltd, 2009.
  3. Curtis GB, Schuler J. Your pregnancy week by week. 7th ed. Cambridge: Fisher books, 2011.
  4. Deans A. Your New Pregnancy Bible, The experts’ guide to pregnancy and early parenthood. 4th ed. London: Carroll & Brown Publishers Limited, 2013.
  5. NHS UK. How do I check my pulse? [Online]. 2013. Available at: www.nhs.uk/chq/Pages/2024.aspx?CategoryID=72 Page last reviewed: 22 February 2018. Next review due: 22 February 2021.
  6. NHS UK. What is the placenta? [Online] Available at: https://www.nhs.uk/common-health-questions/pregnancy/what-is-the-placenta/ Page last reviewed: 3 September 2018. Next review due: 3 September 2021.
  7. NHS UK. Start for Life. Week-by-week Guide to Pregnancy. [Online] Available at: https://www.nhs.uk/start4life/pregnancy/week-by-week/2nd-trimester/week-17/ [Accessed: November 2019]
  8. 10 common pregnancy complaints. [ONLINE] Available at: https://www.tommys.org/pregnancy-information/im-pregnant/early-pregnancy/10-common-pregnancy-complaints Page last reviewed: April 10 2018. Next review due: April 10 2021.
  9. Claudio N. Soares and Brook Zitek. Reproductive hormone sensitivity and risk for depression across the female life cycle: A continuum of vulnerability? 2008. [Online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440795/ [Accessed: November 2019]
  10. NHS Start 4 Life. 1st trimester, week 10 [Online]. Available at: https://www.nhs.uk/start4life/pregnancy/week-by-week/1st-trimester/week-ten/ [Accessed November 2019]
  11. Department of Health. Report on Health and Social Subjects 41. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. London: TSO, 1991.
  12. Department of Health and the Food Standards Agency. National Diet and Nutrition Survey: Headline results from Years 1, 2 and 3 (combined) of the Rolling Programme (2008/2009-2010/11) [Online]. 2012. Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/207708/NDNS-Y3-report_All-TEXT-docs-combined.pdf [Accessed:November 2019]
  13. European Union. Commission Regulation (EC) No 983/2009 of 21 October 2009 on the authorisation and refusal of authorisation of certain health claims made on food and referring to the reduction of disease risk and to children’s development and health. OJ L 277 2009;3-12. [Accessed: November 2019]
  14. NHS UK. Vitamins and nutrition in pregnancy [Online]. 2013. Available at: www.nhs.uk/conditions/pregnancy-and-baby/pages/vitamins-minerals-supplements-pregnant.aspx Page last reviewed: 26 January 2017. Next review due: 26 January 2020.
  15. NHS UK. Can I take paracetamol when I’m pregnant? [Online] Available at: https://www.nhs.uk/common-health-questions/pregnancy/can-i-take-paracetamol-when-i-am-pregnant/ Page last reviewed: 1 June 2018. Next review due: 1 June 2021.

Last reviewed: 18th December 2019

Reviewed by Nutricia’s Medical and Scientific Affairs Team


Share this article