Week 4 of pregnancy (Days 28-34)

Your baby is no longer a zygote or a single cell. The cells have multiplied rapidly and now the embryo is taking shape. There is not yet a clear sac on 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.

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  • 9

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

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  • 13

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

    How many weeks pregnant?

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1st Trimester

 

 

 
  • 14

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

    How many weeks pregnant?

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  • 22

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

    How many weeks pregnant?

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  • 28

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

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2nd Trimester

 

 

 
  • 29

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

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  • 36

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

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  • 40

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

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3rd Trimester

 

 

 

Ultrasound image of thickened endeometium and possible tiny gestational sac at 4 weeks.

Week 4 of pregnancy is usually when the mother begins to notice symptoms. It is also the week in which most pregnancy tests take place as women wait for their period due date or realise they are slightly late. It’s an important week in your pregnancy, as it may be the one when you have your pregnancy confirmed by a doctor, making the expectant bundle of joy a reality.

Telling Friends and Family

Many people wait until the second trimester to tell friends and family as this is when the risks of miscarriage reduce. Of course, the decision is entirely up to you. Some women feel that even if the worst does happen, they’d be glad their family knew, as they’d be able to offer the support that’s obviously needed at such a trying time.

Your Baby

Your baby is no longer a zygote or a single cell. The cells have multiplied rapidly and now the embryo is taking shape. The baby is actually no bigger than a mustard seed but there is a lot going on in there, as the three layers of cells have important functions crucial to the baby’s body and brain development. Early facial features such as nostrils are developing and retinas are formed and in week 4 the first part of the eyes to develop.

Implantation is still taking place during this week, but the placenta and umbilical cord are forming and the placenta is attaching itself to the uterus lining.

The Science Bit

Known as a blastocyst your mustard seen now has three cell layers. The top layer of cells forms the neural tube from which the brain, spinal cord and nervous system will be formed. The middle layer of cells holds the beginnings of the heart and circulatory system. The heart starts to beat during this week and the heart rate will quicken and become more regular over the next couple of weeks. The third layer of cells contains what will later become the lungs, intestines and urinary system.

Your Body and Symptoms

By now you maybe noticing subtle changes as your body prepares for supporting another life. Your breasts may feel tender, as they store fat ready for breast feeding. You may also notice small lumps which are perfectly normal and known as Montgomery’s Tubercles. These secrete a fluid that prepares the nipples for breast feeding.

If you do feel uncomfortable invest in a good sports bra. Choose cotton to ensure you wear a breathable fabric. It may also be an idea to have your breasts measured again, you may need to do this at different stages throughout the pregnancy to ensure you wear the correct sized bra.

As the pregnancy hormone, HCG increases, you may also notice an increased urge to urinate. This is good, as it shows the pregnancy hormone is encouraging your kidneys to work at their maximum efficiency. It is important to stay hydrated and to not compensate for the extra bathroom trips by decreasing your water intake. The reduction of diuretics however, such as coffee and some herbal teas, may help with the frequency.

Your Care on the NHS

If you’ve confirmed your pregnancy with a home pregnancy test it is now time to schedule an appointment with the doctor. Although your GP has little to do at this stage in your pregnancy he/she will refer you to the relevant antenatal clinics to ensure you have access to the NHS services available.

Private Care Available

If you are concerned about the health of your baby or have previously had a triploidy pregnancy you may be impatient for a blood test to rule out certain life restricting conditions such as Down’s syndrome. This test can now be performed much earlier than it was previously however, you must still be patient as it is not available until you reach week 9 of your pregnancy.

 

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