Week 17 of pregnancy (Days 119-125)

Your baby and the umbilical cord are experiencing a growth spurt this week. Your baby's sex can now be accurately detected on an ultrasound scan.

Trimester Chart
A Guide to each week of your pregnancy, with details on your baby’s growth, your body and symptoms to look out for.
  • 4

    Your baby is no longer a zygote or a single cell. The cells have multiplied rapidly and now the embryo is taking shape.

    Select from the circles below and Read our guide from experts...

  • 9

    From week 9 you can have Non-Invasive Prenatal Screening, to assess your risk of Down's Syndrome and other conditions.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

  • 13

    This week marks the end of the first trimester, and the risk of miscarrage reduces dramatically.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

1st Trimester

 

 

 
  • 14

    Your baby now measures around 8cm, from crown to rump and weighs around 40g.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

  • 22

    Your growing baby now measures 28cm from crown to heel and weighs approximately 350g.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

  • 28

    Your growing baby now measures 38cm from crown to heel and weighs approximately 1kg.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

2nd Trimester

 

 

 
  • 29

    Your growing baby now measures 39cm from crown to heel and weighs approximately 1.1kg.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

  • 36

    Your growing baby now measures up to 47.5cm from crown to heel and weighs approximately 2.7kg.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

  • 40

    Your baby is now considered full term and will not normally gain much weight at this point.

    How many weeks pregnant?

    Select from the circles below and Read our guide from experts...

3rd Trimester

 

 

 

Ultrasound image of fetus at 17 weeks gestation.

Baby

The fetus now typically measures between 11.4cm and 12.7cm long (from crown to rump) and weighs around 100g. This increase in length and weight is larger than in previous weeks due to a growth spurt that is well underway. This growth spurt not only applies to the fetus, but also to the umbilical cord, which is thickening and growing stronger too. As well as a growth spurt, the fetus also experiences an energy burst – becoming more active over the coming weeks. This week could be the time that you feel the first movements of the fetus, although many women, particularly if it is their first pregnancy, do not feel fetal movement at this stage.

The skeleton, which is largely formed of cartilage at the moment, will start to harden during the course of this week and myelin (a protective coating) is forming around the spinal cord. Body fat is also beginning to develop. This will eventually help to maintain a constant body temperature. The brain now controls heart rate, irregular heartbeats are now rare and heart rate is usually between 140 and 150 beats per minute – twice the rate of an adult female.

You

You may find that your weight gain is now sufficientto affect your centre of gravity – making you feel off-balance. If you are struggling with your balance, it may be a good idea to avoid wearing high-heeled shoes. It is also around this time that many women begin to need to wear maternity clothes.

Although an increased need to urinate is a perfectly normal part of pregnancy, caused by a combination of increased hormone levels and the physical effects of the uterus pressing down on the bladder, you should look out for additional urine-related symptoms such as a burning sensation during urination. This could be an indicator that you have cystitis or a urinary tract infection (UTI). If you have any concerns, you should seek the advice of a health care professional.

You may also continue to, or start to experience a thin, milky vaginal discharge called leukorrhea. This is both normal and functional as it helps to keep the birth canal free from infection. You may be experiencing occasional dizziness or faintness. There are many possible causes for this, including hormonal increases and fatigue, however headaches and dizziness may also be the result of dehydration. Drinking plenty of fluids and avoiding diuretics such as caffeine can help with this.

Due to a combination of increased levels of progesterone causing blood vessels to dilate and a higher metabolic rate causing more body heat to be generated, many women suffer from hot flushes during pregnancy. Avoiding triggers such as alcohol, spicy foods and coffee may help to reduce hot flushes.

Symptoms to watch out for

Vaginal bleeding is not normal at this stage. Some mild abdominal pain and backache is normal. Vaginal discharge should be of consistent milky colour and volume. If it should be pink or more voluminous you should see a medical professional. This is particularly true if you have had a previous late miscarriage, operation on your cervix or short cervix. This is also important if you are carrying more than one baby.

What is routinely offered in the NHS.

The midwife will be able to provide you with advice. The NHS will not routinely be able to offer you an ultrasound scan at this time.

What other care is available

General midwifery and medical advice is available in private clinics for which you do not require a referral letter. An ultrasound scan, called a reassurance scan at this stage can check the size and normality of the baby. It can also determine the sex of the baby quite accurately. If you are concerned about your cervix becoming short or have other concerns about your cervix then an ultrasound scan of your cervix can be reassuring. This gives a better assessment when performed through the vagina (you can request a female sonographer).

Scans and Packages

Longer Appointments - Time to discuss choices with our expert staff

Read Our Reviews    

Thank you to all our patients for considering coming to our clinic. We aim to meet the highest standards.

Clinic Locations

Visit our clinic in Central London and Cheshire

THE BIRTH COMPANY - LONDON

137 Harley Street, London W1G 6BF
Nearest Underground Tube Stations

Baker Street
Regent’s Park
Great Portland Street

THE BIRTH COMPANY - CHESHIRE

Festival Hall, Talbot Road, Alderley Edge SK9 7HR
Nearest Overground Train Station

Alderley Edge