5 weeks pregnant: Pregnancy Symptoms & Baby Development
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Month 2 (Trimester 1)
At 5 weeks pregnant, even though it’s very early in your pregnancy, exciting developments are happening. From the growth of your baby’s vital organs to the formation of the umbilical cord, your baby is growing rapidly. Your body is going through some big changes too, even if you’re not aware of them yet.
This week might be the week that you miss a period and begin to suspect that you’re pregnant (this may not be the case if your periods aren’t particularly regular). Here we’re looking at some of the early pregnancy symptoms at 5 weeks pregnant, as well as your baby’s growth and development and the importance of a healthy pregnancy diet.
Your baby’s development at 5 weeks pregnant
Even though it’s still very early in your pregnancy, your baby’s nervous system is already starting to develop, and the foundations are laid for the growth and development of your baby’s vital organs. This includes their heart1, which will have already started to beat by the end of your fourth week of pregnancy2.
The outer cells of the embryo have developed into the ‘neural tube’, and this will become your baby’s spinal cord and brain. To support the growth of your baby’s brain and spinal cord, it’s important that you’re taking 400 mcg of folic acid every day. This is to help prevent defects in the neural tube that can cause spina bifida1.
There are already a number of blood vessels in place that are helping your baby’s blood to circulate. Some of these blood vessels will become the umbilical cord that will keep you and your baby connected throughout your pregnancy1.
How big is my baby at 5 weeks pregnant, and what do they look like?
At 5 weeks pregnant, your baby is approximately 2 mm long and about the size of a sesame seed3.
Whilst they wouldn’t yet be visible if you went for an ultrasound scan, your baby’s facial features are already starting to form. Their tiny eyes and nose are in place, but they’ll stay closed until you’re around 28 weeks pregnant3.
Pregnancy at 5 weeks (first trimester): what changes are happening in your body?
Your pregnancy won’t be visible to the outside world just yet, but you may now know that you’ve got a little one on the way. If you’ve missed a period - the biggest and most reliable indicator yet that you might be pregnant.
If this is the case, it’s a good idea to take a pregnancy test. The test works by detecting the pregnancy hormone hCG (human chorionic gonadotrophin), which is usually present in your body by about 6 days after your egg has been fertilised4. Whilst it’s not possible for a pregnancy test to show a false positive, it is possible to get a false negative. This can happen if you take the test too early or if you don’t follow the instructions properly, so be sure to follow guidance on the pack very carefully4.
Your body is now very busy supporting the growth of the placenta - a vital organ during pregnancy. The placenta will provide your baby with the nutrients and oxygen they need, as well as removing the waste products that they produce3.
Early pregnancy symptoms at 5 weeks
At 5 weeks pregnant, any symptoms you have may vary between being subtle, noticeable and non-existent - no one pregnancy is the same. Below we’re exploring some of the more common symptoms of pregnancy at 5 weeks pregnant, and what you might expect as your pregnancy progresses.
Sore and tender breasts are a common early pregnancy symptom. Your breasts might be larger, with the veins more visible. Your nipples may be standing out more and becoming darker5.
Breast tenderness is also a sign that your period is due, which is why at 5 weeks pregnant, some women are still unaware that they’re expecting a baby. If you’re unsure, it’s a good idea to take a pregnancy test.
If you’re feeling exhausted at 5 weeks pregnant, you’re certainly not alone. The hormonal changes you’re going through can leave you feeling very tired during your first trimester5. Listen to your body and take any opportunity to get the rest that you need, when you need it.
Nausea and vomiting, more commonly known as morning sickness, is a very well-known symptom of pregnancy - despite the name, it can occur at any time of the day and night.
Morning sickness can be very unpleasant, but the good news is that symptoms usually ease anywhere between weeks 16 and 20 of your pregnancy6.
Once again, it’s those pregnancy hormones that are thought to be responsible for morning sickness, and you’re more likely to experience it if6:
- You’ve done so in a previous pregnancy
- You’re having twins or other multiple birth
- This is your first pregnancy
During your pregnancy, your body produces a number of hormones. One of these is progesterone, a female hormone that helps the muscles in your uterus to relax and expand as your baby grows. At the same time, it can also relax the muscles in your digestive system, resulting in excess wind7.
It’s very common to experience some mild cramping at 5 weeks pregnant. This can be caused by a number of things, for example8:
- Your tummy ligaments stretching as your baby grows
- Constipation (another common pregnancy symptom)
- Trapped wind and bloating
In most cases, mild cramping is nothing to be concerned about. However, always seek advice from a healthcare professional if the cramps become more frequent, are accompanied by spotting, bleeding or unusual discharge, or back pain8, just to be on the safe side.
Just like cramping, light bleeding and spotting (often at the time when your period would have been due) is a common pregnancy symptom. This early on in your pregnancy, it’s usually the result of the embryo implanting into the lining of your womb9, something referred to as ‘implantation bleeding’.
From early pregnancy right up until your due date, it’s not unusual to find yourself needing to go for a wee more often. The reason for this in early pregnancy is thought to be caused by the increased level of the pregnancy hormone hCG10. As your pregnancy progresses, and your baby gets bigger, more frequent urination is likely to be due to the fact that your baby is pressing on your bladder.
Pregnancy hormones - specifically progesterone and oestrogen - may play a part in the emotional ups and downs you feel during your pregnancy11. Whilst pregnancy can be a time of happiness and excitement, it’s also a time filled with questions, and it’s not uncommon to have a level of anxiety as you get ready to embark on your parenting journey.
If you’re worried about your mood swings, remember that you’re not alone and that you can always speak to your doctor, midwife or other healthcare professional for advice. You should also seek medical advice if you experience low moods frequently, have negative thoughts, or start to feel negative and hopeless12. You can find more information on this here.
Focus on: folic acid in pregnancy
Reviewed by Bahee van de Bor
From the moment you discover that you’re pregnant (and before this if you’ve actively been trying to have a baby), you’re advised to take a daily 400 mcg supplement of folic acid13.
The naturally occurring food source of folic acid is called folate, and it can be found in14:
- Green leafy vegetables
- Oranges and berries
- Beans
- Brown Bread
- Beetroot
However, because your need for folic acid is so high during the first trimester of pregnancy, it’s difficult to get enough from food sources alone. This is why a supplement is recommended.
Check that your prenatal multivitamin contains the recommended 400mcg of folic acid that you need. If you find out you’re pregnant and haven’t been taking folic acid supplements or a prenatal multivitamin containing folic acid, don’t worry. Simply start taking them straight away and carry on until you reach 12 weeks.
The science behind Folic Acid
Folic acid is a vital nutrient that supports the development of your baby’s neural tube, which will become your baby’s spine and nervous system15. Taking 400 mcg of folic acid as a supplement is the best way to reduce the risk of neural tube defects, such as spina bifida15.
Why do some pregnant women take a higher dose of folic acid?
If your risk of having a baby with spina bifida is higher than normal, you’ll be advised to take a daily dose of 5 mg of folic acid. This is higher than usual, and it will need to be prescribed by a doctor. You may be advised to take an increased dose if13:
- You have had a previous pregnancy affected by spina bifida.
- You or your partner have spina bifida.
- You’re taking certain medications for epilepsy.
- You have coeliac disease or diabetes.
- Your BMI is 30 or more.
- You have sickle-cell anaemia or thalassaemia; the higher dose of folic acid will also help to prevent and treat anaemia if you are in this situation.
- You’ve had bariatric surgery.
Do not take vitamin supplements that have vitamin A (retinol) in when you are pregnant as high levels can cause harm to your baby16.
How much weight should I gain in pregnancy?
Knowing how much weight you’ll gain in pregnancy isn’t an exact science. It varies from woman to woman, and depends on a number of factors, for example, your pre-pregnancy weight.
Most women gain between 10kg and 12.5kg (22–28lb) while pregnant, some of which is the weight of the growing baby17. Learn everything you need to know about weight gain in pregnancy.
5 weeks pregnant: next steps
If you haven’t been to see your GP or midwife yet, you should arrange your appointment (you might hear this referred to as your booking appointment). That way, you can start your antenatal care, get an idea of your due date, and get ready to schedule your first ultrasound scan.
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- NHS. You and your baby at 5 weeks pregnant [online] 2021. Available at https://www.nhs.uk/pregnancy/week-by-week/1-to-12/5-weeks/. [Accessed January 2024]
- Valenti O, Di Prima FA, Renda E, Faraci M, Hyseni E, De Domenico R, Monte S, Giorgio E. Fetal cardiac function during the first trimester of pregnancy. J Prenat Med. 2011 Jul;5(3):59-62. PMID: 22439077; PMCID: PMC3279166.
- NHS Start for Life. Pregnancy week 5 [online]. Available at https://www.nhs.uk/start-for-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-5/#look-like. [Accessed January 2024]
- NHS. Doing a pregnancy test [online 2022]. Available at https://www.nhs.uk/pregnancy/trying-for-a-baby/doing-a-pregnancy-test/. [Accessed January 2024]
- NHS. Signs and symptoms of pregnancy [online] 2022. Available at https://www.nhs.uk/pregnancy/trying-for-a-baby/signs-and-symptoms-of-pregnancy/#:~:text=Sore%20breasts%20in%20early%20pregnancy,may%20darken%20and%20stand%20out. [Accessed January 2024]
- NHS. Vomiting and morning sickness [online] 2021. Available at https://www.nhs.uk/pregnancy/related-conditions/common-symptoms/vomiting-and-morning-sickness/. [Accessed January 2024]
- NHS Start for Life. Pregnancy week 10 [online]. Available at https://www.nhs.uk/start-for-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-10/. [Accessed January 2024]
- NHS. Stomach pain in pregnancy [online] 2021. Available at https://www.nhs.uk/pregnancy/related-conditions/common-symptoms/stomach-pain/#:~:text=Stomach%20(abdominal)%20pains%20or%20cramps,a%20poo%20or%20pass%20wind. [Accessed January 2024]
- NHS. Vaginal bleeding [online] 2021. Available at https://www.nhs.uk/pregnancy/related-conditions/common-symptoms/vaginal-bleeding/. [Accessed January 2024]
- Katharine L. Cheung, Richard A. Lafayette. Renal Physiology of Pregnancy, Advances in Chronic Kidney Disease, Volume 20, Issue 3, 2013, Pages 209-214, ISSN 1548-559. Available at https://doi.org/10.1053/j.ackd.2013.01.012.
- Tommy's. Emotional changes in pregnancy [online] 2018. Available at https://www.tommys.org/pregnancy-information/im-pregnant/mental-wellbeing/emotional-changes-pregnancy. [Accessed January 2024]
- NHS. Depression in pregnancy [online] 2021. Available at https://www.nhs.uk/pregnancy/keeping-well/depression/#:~:text=Some%20mood%20changes%20are%20normal,a%20lot%20of%20the%20time. [Accessed January 2024]
- NHS. Vitamins, minerals and nutrition in pregnancy [online] 2023. Available at https://www.nhs.uk/pregnancy/keeping-well/vitamins-supplements-and-nutrition/#:~:text=But%20when%20you're%20pregnant,you're%2012%20weeks%20pregnant. [Accessed January 2024]
- British Nutrition Foundation. Nutrition during pregnancy [online] 2015. Available at https://www.nutrition.org.uk/life-stages/pregnancy/healthy-eating-during-pregnancy/nutrition-during-pregnancy/#:~:text=You%20should%20also%20try%20to,12th%20week%20of%20your%20pregnancy. [Accessed January 2024]
- NHS. You and your baby at 5 weeks pregnant [online] 2021. Available at https://www.nhs.uk/pregnancy/week-by-week/1-to-12/5-weeks/. [Accessed January 2024]
- BDA. Pregnancy and diet. [Online]. 2020. Available at https://www.bda.uk.com/resource/pregnancy-diet.html [Accessed April 2024]
- NHS. Weight gain in pregnancy [online] 2020. Available at https://www.nhs.uk/pregnancy/related-conditions/common-symptoms/weight-gain/ [Accessed January 2024]
Last reviewed: January 2024