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      17 weeks pregnant

      17 Weeks Pregnant

      17 weeks pregnant

      All systems go

      Even though you may only feel light flutters within your belly, your baby is becoming active and moving around more. Internally, your baby’s major body systems are becoming established by the time you’re 17 weeks pregnant. Vitamin D still forms a crucial part of your pregnancy diet to support your baby’s bone development.

      Ssw 17 embryo

      Your baby's development at 17 weeks

      Major developments and increased movement in week 17 of pregnancy

      Now weighing roughly 150g (just over 5oz) and measuring around 13cm from crown to rump, your baby’s body is growing bigger and becoming more in proportion with their head. 

      Their hair, eyebrows and eyelashes are growing longer, and they can also open and close their mouth and move their eyes, which are still shut. Although your baby is also putting on a bit of weight, they still don’t have much fat but their special fat-storing ‘adipose tissue’ is beginning to form.

      …they can also open and close their mouth and move their eyes...

      Internally, your baby’s major body systems are becoming established. By the 17th week of pregnancy, their heart may be beating around 140–150 bpm – much faster than the average resting adult, whose bpm ranges from 60–100. Their respiratory system is developing too, and their chest will rise and fall as they start practising how to breathe.

      The future benefits of vitamin D for your baby

      Vitamin D forms an important part of a healthy pregnancy diet. It regulates the levels of calcium and phosphate in your body and supports the growth and development of your baby’s bones. Vitamin D is especially important for normal bone development, as a deficiency can cause your baby’s bones to soften, which can lead to rickets, in extreme cases. Furthermore, the vitamin D you consume during your pregnancy will also help build up your baby’s personal store, which they will rely on in the first few months of life.

      It’s recommended that you get 10 micrograms of vitamin D each day during pregnancy.

      The most efficient way to get vitamin D is through exposure to the UVB rays in sunlight. However, in Ireland we only get around 6 months of effective sunlight each year during the summer. This means that getting enough vitamin D through skin exposure to sun alone may not be enough to support your baby during pregnancy.

      You can increase your vitamin D intake by making sure you eat certain foods, but the best way to make sure you’re getting enough is to take it as a supplement. It’s recommended that you get 10 micrograms of vitamin D each day during pregnancy.


      Make sure your pregnancy supplement includes vitamin D and if not, buy a separate one.

      You can also add some of the following vitamin D-rich foods to your shopping list:

      • Oily fish, including herring, mackerel, sardines, salmon or trout: it’s recommended that you limit your intake to two portions per week due to the toxins they may contain
      • Eggs – the yolk contains the vitamin D
      • Fortified foods – some brands of milk, margarines, low-fat spreads and some breakfast cereals have added vitamin D

      Your baby, this week

      Discover the science behind your baby's developments, week-by-week

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      Questions about feeding and nutrition?

      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.

      Your baby, this week

      Discover the science behind your baby's developments, week-by-week

      Join now for free

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