The 5th week of pregnancy

Now, with the absence of your monthly period (menses), you know for sure: you are pregnant! A pregnancy test will confirm this.

Couple celebrating pregnancy news with friends

To calculate the weeks of pregnancy (your baby’s gestational age) and the due date of your baby, the date of the first day of your last monthly period is used.

Over the next weeks and months you will become familiar with new terms such as:

  • Gestation - this is another way to say pregnancy and is used to describe how many weeks old your baby is.
  • Embryo - this is your baby from the first days of pregnancy until the 12th week
  • Fetus - this is your baby from the 12th week to term (40 weeks)

You are now in the 5th week of pregnancy and your embryo is 21 days old.

What to expect from the 5th week of pregnancy

Early signs are likely to go unnoticed when you are 5 weeks pregnant. You may experience unexplained tiredness, tender breasts, emotional changes, and morning sickness to be more noticeable over the next few weeks.

The tiredness is often unexpected, but when you think how your body is changing, preparing the womb, (uterus), establishing the complex, amazing structure of the placenta, and developing a baby; all whilst you are going about your everyday tasks of working, etc., it is understandable you may be more tired. Rest and put your feet up when you can!

Emotionally you may be elated with the news that you are pregnant and having a baby. Even if this was what you planned, it is natural for you to be a little anxious and apprehensive, considering the changes you will make in pregnancy and how your life will adapt as your baby arrives.

If pregnancy was not on the agenda, and this has taken you by surprise, it is important for you to seek support. It may be financial, work, family, relationship factors that contributes to the worry; talking about it may help you get the help and advice you need for a stress-free pregnancy.

Your baby in the 5th week of pregnancy

The embryo is now three weeks old. From the 22nd day of life, the embryo’s primitive brain and neural stem (spinal cord) are developing.1

Your embryo is about 2 mm in length and is the size of an orange seed. * From this point on, the embryo takes on an elongated shape and looks like a small tadpole.

Now it is likely that you have confirmed you are pregnant. Congratulations!

Next steps

  • Arrange an appointment with your doctor to make plans for your care.
  • Discuss with your doctor what supplements you need to take, such as folic acid.2
  • Discuss with your midwife what you should and shouldn’t eat and drink.
  • It is recommended that you avoid alcohol, smoking and certain foods that may harm your baby’s development.
  • Continue to exercise as normal
  • Carry on working, you may feel it’s a little early to share your exciting news with others.
  • If you work in a high-risk environment, you should discuss your pregnancy with your employer to ensure you and your baby are safe and not in any potential harm.

Note: *The length and weight data are average values that cannot be applied to individual cases. Every baby develops individually.


1 Moore KL et al., editors. The developing human: Clinically oriented embryology. Eleventh edition. Edinburgh: Elsevier; 2020.

2 World Health Organization (WHO). Integrated Management of pregnancy and birth: Standards for Maternal and Neonatal Care. Geneva, Switzerland; 2007 [cited 2021 Nov 16]

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