4 Weeks Pregnant

4 Weeks Pregnant Baby Size

At four weeks, you’re officially pregnant and might even experience a few common early pregnancy symptoms, such as implantation bleeding, bloating, nausea, or fatigue. It’s also possible you won’t notice anything just yet, which is totally normal! Keep reading to learn about what happens at 4 weeks pregnant, including signs and symptoms, your baby’s development, and what you might want to ask your healthcare provider.

Highlights at 4 Weeks Pregnant

Here are a few important points to consider and highlights to look forward to during your fourth week of pregnancy:

  • You’re at the very beginning of your pregnancy journey, but a lot is happening! The fertilized egg implants itself into your uterus and starts to rapidly divide its cells, all part of the process of developing your baby’s arms, legs, brains, muscles, etc.

  • Your baby is teensy tiny, about the size of a poppy seed at 0.04 inches long.

  • It’s possible not to notice any symptoms at 4 weeks pregnant, but if you do, you’ll likely experience common things like bloating, breast tenderness, fatigue, or spotting—all exciting signs that you’re pregnant!

  • Get ready to focus on you and your developing baby by adopting a healthy lifestyle, which can include ditching any bad habits and seeking out ways to reduce stress, such as with yoga or meditation.

Confirming Your Pregnancy at 4 Weeks

If you've just found out you’re pregnant, congratulations! Perhaps you received this exciting news after missing your period, which might make you wonder if you can get a positive pregnancy test at 4 weeks?

At 4 weeks pregnant, a home pregnancy test could show a positive result if you have high enough levels of the pregnancy hormone hCG (human chorionic gonadotropin), which is present in your urine about 10 days after conception. If your hCG levels are still too low to detect, you might see a false negative test when just 4 weeks pregnant. For the most accurate results, it’s best to wait until after you’ve missed your period to take a pregnancy test —when your hCG levels will be higher—and confirm your pregnancy with your healthcare provider.

When is my due date if I'm 4 weeks pregnant? After confirming your pregnancy, the first question on your mind might be when to expect your little one’s arrival! Your healthcare provider can confirm that exciting date, but in the meantime, try our Due Date Calculator.

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How Many Months Is 4 Weeks Pregnant?

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

Are you asking yourself, “If I'm four weeks pregnant, when did I conceive?” This is another common question that your healthcare provider can help you answer. Pregnancy is measured as 280 days or 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.

4 Weeks Pregnant: Your Baby's Development

While you’ve been adjusting to being pregnant, the new life inside you has been busy. Here’s what’s going on inside your uterus at 4 weeks pregnant:

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

  • 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, connecting your body’s systems to that of the baby, forming and attaching to the uterine wall where the egg implanted.

  • The umbilical cord will eventually come out of one side of the placenta, and the amniotic fluid, which will cushion your baby throughout your pregnancy, is already forming inside a surrounding membrane, or yolk sac.

During the upcoming weeks, your little one will also start forming a neural tube, which is the main building block for the brain and spine. All the activity at 4 weeks pregnant sets your baby up to start all this important development.

How Big Is a Baby at 4 Weeks Pregnant?

At 4 weeks pregnant, your baby is very tiny, as the newly implanted embryo is only about 0.04 inches long. For comparison, this is just about the size of a poppy seed!

Your Baby: What Does 4 Weeks Pregnant Look Like?

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 to get a glimpse of what’s happening in your belly:

Your Body at 4 Weeks Pregnant

A few pregnancy symptoms may appear at 4 weeks pregnant, though it’s completely normal if you’re experiencing no symptoms at all—or, at least, haven’t noticed them. Generally, pregnancy symptoms will be minor at 4 weeks pregnant, so you might feel some cramping and see a little bit of spotting, both of which can happen as the fertilized egg implants itself in your uterus.

As mentioned above, your body is now starting to make the pregnancy hormone hCG, which tells your ovaries to stop releasing an egg each month, thus stopping your monthly period. HCG also increases the production of other hormones, such as estrogen and progesterone, so even at 4 weeks pregnant, you could experience some of those hormone-related symptoms. Keep reading to learn the most common signs that you’re pregnant during this exciting week.

4 Weeks Pregnant: Your Symptoms

Every pregnancy is unique, and what you experience during this pregnancy may be different than what you experienced during a previous pregnancy. To help you feel more prepared for whatever may come, look at this list of possible symptoms of pregnancy at four weeks:

  • Bloated stomach. Your body is preparing itself to house a rapidly growing baby for the next several months. At 4 weeks pregnant, you might experience a bit of bloating and cramping particularly in your abdomen, as your uterine lining is getting a bit thicker, and the swelling means your womb is taking up more space than usual.

  • Light bleeding or spotting. Some women have some spotting at 4 weeks pregnant, which is called implantation bleeding and shouldn’t be heavy like a period. If you see a lot of blood, if the spotting lasts longer than two days, or if you have any concerns, consult your healthcare provider right away.

  • Moodiness. Other symptoms you might notice at 4 weeks pregnant include mood swings. Triggered by increasing hormone levels, these extreme emotions and wild shifts may be the strongest in the first and the third trimesters. Relaxation exercises, massage, sleep, and following a balanced diet are some of the easiest ways 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. If it’s affecting you, consider yourself in good company: some level of morning sickness impacts approximately 85 percent of women who are pregnant. The good news is that this unpleasant symptom often subsides during the second trimester.

  • Light-colored discharge. When you’re 4 weeks pregnant, increased vaginal discharge is a normal symptom. It should be sticky, clear, or white. If you notice a bad odor or have a sore or itchy vaginal area, consult your healthcare provider.

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

Less Common Pregnancy Symptoms at 4 Weeks

Listed above are common signs of pregnancy during the first couple of months, but many wonder about typical symptoms, like trouble sleeping or food cravings. These are less common during early pregnancy, so if you’re 4 weeks pregnant and hungry all the time (or craving strange food combinations) or can’t sleep, it’s best to consult your healthcare provider.

Symptoms at 4 weeks pregnant shouldn’t be severe or cause a lot of pain, so other symptoms not to ignore include feeling pelvic pain, pain in your ovary, lower back pain, or pain on your side (right or left), or experiencing diarrhea or feeling more constipated than usual. 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 healthcare provider right away.

How Big Is a Pregnant Belly at 4 Weeks?

Everyone and every pregnancy is unique, but it’s safe to say that you probably won’t see any difference in your pregnant belly’s size at 4 weeks. Remember, your little one is only the size of a poppy seed! Still, slight bloating around your abdomen may accompany your pregnancy at four weeks, so you might notice what appears to be a small belly. Just know that, typically, a baby bump doesn’t usually show until around weeks 12 to 16, when your uterus starts to move outside your pelvis 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.

4 Weeks Pregnant: Things to Consider

It’s still early in your pregnancy journey, but there are plenty of important things to consider. From adapting your lifestyle to writing down milestones, check out our list below.

  • Start a healthy eating plan if you haven’t already. Make sure you're including iron-rich foods like spinach and cereals to prevent anemia, as well as calcium from milk, cheese, yogurt, tofu, or orange juice to help your growing baby build strong bones.

  • Stop unhealthy habits right away. 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 secondhand smoke. Research shows exposure can increase the risk of complications such as low birth weight, miscarriage, and ectopic pregnancy.

  • 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 haven't been exercising before, consult your healthcare about what type of exercise or program would be best for you. Labor 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.

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

  • Research the type of healthcare provider you'd like to work with during your pregnancy.

  • 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 color and hair color.

4 Weeks Pregnant: Questions for Your Healthcare Provider

Even if you’ve just found out you’re pregnant, you may already have questions that you'd like to put to your healthcare provider. 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 checkups and tests be, and how are these scheduled?


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.