4 Weeks Pregnant

Your baby is the size of a

Poppy seed

If you’ve reached four weeks, you’re officially pregnant! It’s possible to experience no pregnancy symptoms at 4 weeks, however, a few common symptoms to look out for include a spot of implantation bleeding, tender breasts, morning sickness, bloating or fatigue. Keep reading to learn all about the signs and symptoms of pregnancy at 4 weeks, your baby’s development, and some important things to consider.

Highlights at 4 Weeks Pregnant

Before we get into all the details, here are a few important highlights to look forward to at 4 weeks pregnant :

  • This may be the beginning of your pregnancy journey, but there’s a lot happening! Implantation takes place, which means the fertilised egg implants itself into your uterus and the cells start to rapidly divide – it’s all part of the development process for your baby.

  • Your baby is teeny tiny, about the size of a poppy seed at 2 millimetres long.

  • It’s possible to have no symptoms at 4 weeks pregnant, but if you do, some common symptoms are bloating, breast tenderness, fatigue or spotting – all exciting signs that you’re pregnant!

  • It’s time to adopt a healthy lifestyle (if you haven’t already) to support your baby’s development and your own health. Think about ditching any bad habits and seeking out ways to reduce stress, such as yoga or meditation.

Confirming Your Pregnancy at 4 Weeks

Have you just received the exciting news that you’re pregnant? Congratulations! Perhaps you’ve just missed your period, which might make you wonder if you can get a positive pregnancy test at 4 weeks pregnant?

A home pregnancy test can show a positive result at 4 weeks pregnant depending on your levels of the pregnancy hormone hCG (human chorionic gonadotropin), which is present in your urine when you’re pregnant and increases as the pregnancy develops. If your hCG levels are still too low to detect, you might see a false negative test when just 4 weeks pregnant. It’s best to wait until after you’ve missed your period to take a pregnancy test – your hCG levels will be higher at this time, and then you can confirm it with your GP.

After confirming your pregnancy, you might be wondering when your due date will be! Your GP can confirm that exciting date, but in the meantime, try our Due Date Calculator.


How Many Months Is 4 Weeks Pregnant?

Your GP will usually refer to your pregnancy in terms of weeks, but it’s also common to hear a reference to months. Usually, the first four weeks are considered the first month of pregnancy (though this can vary, as the weeks of pregnancy don't fit evenly into months). So, at 4 weeks pregnant, you’re likely in your first month of pregnancy, even if you haven’t noticed any belly bump or symptoms!

If you’re wondering when you conceived, this is a common question that your GP can help you answer. Pregnancy is measured as an average of 40 weeks, beginning with the date you started your last period. If you have an average 28-day cycle, you probably conceived during the second or third week of your pregnancy.

Your Baby's Development at 4 Weeks Pregnant

There’s a lot going on during these early stages of pregnancy – your little one is busy – even if you can’t notice it. Check out what’s happening inside your belly at 4 weeks pregnant:

  • Implantation. The fertilised egg implants itself into the side of your uterus.

  • Cells divide. The egg rapidly divides into layers of cells, some of which become the embryo. The cell layers will start to grow into different parts of your little one's body, such as the nervous system, skeleton, muscles, organs and skin.

  • The placenta begins to form. The placenta connects your body’s systems to that of the baby, forming and attaching to the uterine wall where the egg implanted. But for now, it’s a tiny yolk sac that provides nourishment and will later develop into the placenta.

In the upcoming weeks, your little one will also start forming the main building block for the brain and spine – the neural tube. All the activity at 4 weeks pregnant sets your baby up on the road to development.

Your Baby’s Size at 4 Weeks Pregnant

At 4 weeks pregnant, your baby is very tiny, about the size of a poppy seed. Your newly implanted embryo is only about 2 millimetres long.

What Does Your Baby Look Like at 4 Weeks Pregnant?

So, if the embryo is just a poppy seed, what does that look like at 4 weeks pregnant? For a sneak peek, look at this illustration of the gestational sac at 4 weeks pregnant to get a glimpse of what’s happening in your belly:

Your Body at 4 Weeks Pregnant

At 4 weeks pregnant, you may or may not experience some pregnancy symptoms – or, perhaps you haven’t noticed them. It’s usual for pregnancy symptoms to be minor at 4 weeks pregnant, so you might feel mild cramping and see a little bit of spotting, both of which can happen during implantation.

As mentioned above, during pregnancy, your body starts to make the pregnancy hormone hCG, which tells your ovaries to stop releasing an egg each month. This is what causes your monthly periods to stop. HCG also increases the production of other hormones, such as oestrogen and progesterone, so even at 4 weeks pregnant, you could experience some of those hormone-related symptoms. Keep reading to learn the most common pregnancy signs during this exciting week.

Your Symptoms at 4 Weeks Pregnant

Every pregnancy is unique, and what you experience during this pregnancy may be different than what you experienced during a previous pregnancy. To help prepare you for whatever may come, check out the possible pregnancy symptoms you may feel at 4 weeks:

  • Bloated stomach. As your body prepares itself for a growing baby, at 4 weeks pregnant, you might experience some bloating and mild cramping particularly in your abdomen. This happens as implantation takes place, and your uterine lining is getting a bit thicker. Changes in your hormones may also slow down your gut, causing constipation and bloating.

  • Light bleeding or spotting. Spotting may occur at 4 weeks pregnant, also known as implantation bleeding, but it shouldn’t be heavy like a period. If you see a lot of blood, the spotting lasts longer than two days, or if you have any concerns, consult your GP right away.

  • Moodiness. Mood swings are another symptom you may experience at 4 weeks pregnant. Triggered by increasing hormone levels, these extreme emotions and wild shifts may be the strongest in the first and the third trimesters. Try relaxation exercises, massage, sleep and a balanced diet to help yourself feel better.

  • Breast tenderness. Just like your abdomen, your breasts are starting to prepare for the important job of nourishing a new arrival. The number of milk glands increases, and the fat layer also thickens, causing your breasts to become enlarged.

  • Morning sickness. You may or may not have morning sickness at 4 weeks pregnant, as this condition varies from one person to the next, with some feeling only mild nausea and others vomiting. And despite the name, morning sickness can occur at any time of the day.

  • Light-coloured discharge. When you’re 4 weeks into your pregnancy, increased vaginal discharge is a normal symptom. It should be sticky, clear, or white. If you notice a bad odour or have a sore or itchy vaginal area, consult your GP.

  • Fatigue. Don’t be surprised if you feel fatigued even at 4 weeks pregnant! Your body is busy working hard to support your little one, and your hormone levels are changing, which can tire you out.

Less Common Pregnancy Symptoms at 4 Weeks

Symptoms at 4 weeks pregnant aren’t severe and shouldn’t cause a lot of pain, so if you feel pelvic pain, pain in your ovary, lower back pain or pain in your side (right or left), it’s advised to contact your GP for advice. There’s a lot going on during pregnancy and hormones can trigger many different feelings, but if you’re in pain or experience anything unusual, consult your GP right away.

What Size is a Pregnant Belly at 4 Weeks?

Everyone and every pregnancy is unique, but it’s safe to say that your little one is still too tiny for you to see any difference in your pregnant belly’s size at 4 weeks. Still, slight bloating around your abdomen may give you a small belly at 4 weeks pregnant. Just know that, typically, a baby bump doesn’t show until around weeks 12 to 16, when your uterus starts to move outside your pelvic area.

What Does 4 Weeks Pregnant Look Like?

To get a better idea of what your belly might look like around 4 weeks pregnant, when you’re in your first month of pregnancy, check out the image below.


Pregnancy Symptoms
What to Do About Back Pain During Pregnancy

Things to Consider at 4 Weeks Pregnant

Even if you’ve just found out you’re pregnant, there are still plenty of important things to consider at 4 weeks pregnant. From adapting your lifestyle to writing down milestones, check out our list below.

  • Start a healthy eating plan. Maybe you’ve already adopted a healthy diet, but if not, make sure you're including iron-rich foods like spinach and cereals to prevent anaemia, calcium to help your growing baby build strong bones, as well as plenty of fruit, vegetables, protein-rich foods, and wholegrain/ high fibre starchy foods.

  • Quit unhealthy habits. Quit smoking and replace alcohol with water and other healthy beverages to help prevent preterm birth and other birth defects. It’s also important to avoid second-hand smoke. Research shows the toxins and chemicals in cigarettes can affect your baby’s development. You can talk to your GP or midwife for support when quitting.

  • Try to relax and keep your stress level low. You can do this with lifestyle changes, meditation and exercise. Most likely, you can continue exercising throughout pregnancy, as long as there are no complications. If you don’t usually exercise, consult your GP about the best types of exercise for you. Labour and delivery are hard work, and the fitter you are, the better off you’ll be.

  • Begin taking prenatal vitamins every day to support your health and help the new life inside you develop! Look for a vitamin that contains at least 400 micrograms (mcg) of folic acid, an important nutrient that’s proven to reduce the likelihood of birth defects. Vitamin D is also recommended for healthy bones and muscles, especially during the winter months when sunlight is limited.

  • Download our Pregnancy Guide for even more information to help support you through the coming months, including tips on nutrition, prenatal visits and more.

  • Familiarise yourself with the maternity care options available. Most women in the UK get their maternity care free through the NHS, but there are private options available.

  • Start collecting memories, such as with a photo book, pregnancy book or journal. Some things to include could be pictures of your bump week to week, special dates like when you found out you were pregnant, a letter to your child or even predictions about eye colour and hair colour.

Tip for Partners

If you've just found out that you and your partner are having a baby, it’s time to celebrate! Spend some time together as a couple and treat your pregnant partner to a day out or a date night. Keep in mind that your partner might be experiencing some pregnancy symptoms right now, so be supportive if they decide on an early night.


Questions for Your Doctor at 4 Weeks Pregnant

It’s still early on in your pregnancy, but you may already have questions for your GP. Some common questions at 4 weeks pregnant include:

  • Are there any specific tests needed based on my ethnicity or medical history?

  • Can I safely continue taking certain medications now that I'm pregnant?

  • When will the routine pregnancy check-ups and ultrasounds be, how are these scheduled, and can I have a scan at 4 weeks pregnant?


It’s quite possible to feel no pregnancy symptoms at 4 weeks, but if you do experience some of those common signs, you could feel tired, bloated, moody and/or a little nauseated.

4 Weeks Pregnant: Your Checklist

Yes, it’s early, but it’s also an exciting moment! As you anticipate your new pregnancy, consider the following to-dos:

□ Schedule a pregnancy confirmation appointment, if needed.

□ Though it’s common to wait until after your first trimester to make the big announcement (as that’s when the risk of miscarriage is much lower), you might want to share the good news with your partner or a close family member to have a little support from the start.

□ Think about what lifestyle changes you may need to make (like adjusting your diet, for example), and plan how you will implement them.

How We Wrote This Article The information in this article is based on the expert advice found in trusted medical and government sources, such as the National Health Service (NHS). You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.

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