01-03 Weeks Pregnant Baby Size

Pregnancy is an exciting time in your life, and you may be eagerly watching for those very early signs in weeks 1, 2, or 3. But, did you know that you’re not actually pregnant during these first couple of weeks? We know it’s a little confusing, but it’s also why you might not notice any pregnancy symptoms early on! Keep reading to better understand what’s going on in that body of yours during the first three weeks of pregnancy.

Your First Three Weeks of Pregnancy

Here’s the thing: Because of the way pregnancy is usually measured, you’re not actually pregnant during the first two weeks or so of your pregnancy. Healthcare providers calculate the length of an average pregnancy as 40 weeks, starting from the first day of your last menstrual period—this is known as the LMP dating method. So, when you’re 1 week pregnant, you’ve only just started your period. At two weeks pregnant, you’re ovulating. And since ovulation happens about 14 days after the start of your period (assuming you have a 28-day cycle) you can’t really become pregnant until week 3 at the earliest. It can be mind-boggling—we get it. But, for the sake of calculation, and what you and your healthcare provider will consider as 1 and 2 weeks pregnant, you’re not actually pregnant! But although at 1, 2, or 3 weeks pregnant you may not notice any of those very early signs of pregnancy, there may be a lot happening on the inside.

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Will You Notice Early Signs and Symptoms When You're 1 Week Pregnant or 2 Weeks Pregnant?

Your journey through pregnancy has officially begun, but as mentioned above, you’re not actually pregnant yet. Remember that healthcare providers calculate your pregnancy as 40 weeks, or 280 days, from the start of your last period. So, if you have a typical 28-day menstrual cycle, the first two weeks are mainly just Aunt Flo doing her thing.

But after two weeks, other things start to happen.

  • One of your ovaries will release an egg around 14 days after the first day of your last period.

  • The egg will travel down one of the fallopian tubes where it may unite with sperm.

It’s worth noting that sperm can live inside your body for up to five days, and your egg has a lifespan of up to one day. This means your window of fertility (when you should have sex if you’re trying to get pregnant) is about five days before you ovulate to one day after. What this all means is that you won’t feel any of those very early signs of pregnancy in weeks 1, 2, or possibly even 3. If you have yet to conceive, then it makes sense that you wouldn’t notice anything!

What Are the Signs and Symptoms When You're 3 Weeks Pregnant?

When you’re 1 week “pregnant,” you haven’t conceived yet, and so there’s not much going on. That can change by the time you’re three weeks pregnant. Your belly can be a hive of activity, though you may not be able to tell.

  • If the sperm and egg find each other, they’ll join up in a fallopian tube to create a single cell called a zygote in a process called fertilization.

  • The zygote carries chromosomes from the mother and father and sets the first building blocks of your future baby’s genetic makeup.

  • The zygote then moves down the fallopian tube and toward the uterus as it starts dividing into a larger group of cells.

Although there’s more activity in your third week of pregnancy, will you feel anything? Probably not. However, read on to learn a bit more about those typical early symptoms of pregnancy and when you might notice them.

Will You Notice Any Pregnancy Symptoms During Weeks 1, 2, or 3?

During weeks one, two, or three, you may not even suspect you’re pregnant and you might not notice any pregnancy symptoms at all, as it’s still very early. Don’t worry—this is common (and you might not have even conceived until 3 weeks pregnant). Missing a period is often the first clue that you may be pregnant, and around the time you miss a period—or a little later—you may start noticing those very early pregnancy symptoms. One common early pregnancy symptom is implantation bleeding, which is light spotting that occurs when the tiny ball of cells (now known not as a zygote, but as a blastocyst) attaches to the uterine lining. Not everyone experiences it, but this light bleeding is normal and can sometimes be mistaken for menstrual blood. It usually happens 10 to 14 days after conception. Other signs of pregnancy in the first month can include

Morning sickness is another common symptom of early pregnancy, but it usually crops up between weeks 4 and 9. Now that you know these early signs of pregnancy, take our quiz to test your knowledge!

When Can You Confirm Your Pregnancy?

If you think you might be pregnant because you missed your period or are experiencing some of the early symptoms of pregnancy listed above, you can take a home pregnancy test. These tests can confirm a pregnancy by checking your urine for the presence of a hormone called hCG.

If you think you may be pregnant, but the test says otherwise, test again after a few more days or speak to your healthcare provider. You can also ask your provider to confirm your pregnancy with a blood test. Think you might be pregnant? Take our Am I Pregnant quiz. It won’t tell you for sure, but it’s all good fun!

How to Determine Your Due Date

When you find out you’re pregnant, you’re probably wondering when you’ll meet your new baby! For an estimate, try our Due Date Calculator, where you can simply enter the first day of your last menstrual period (LMP) or the date of conception.

Healthcare providers use the LMP method to determine your estimated due date. Due dates are typically calculated as 280 days (or 40 weeks) starting from the first day of your last menstrual period. Remember, when generating a due date this way, you aren’t technically pregnant during the first couple of weeks of pregnancy. And, again, this is why you probably won’t feel those highly anticipated very early signs of pregnancy in weeks 1, 2, or 3. But once you start to notice them—and take a pregnancy test or confirm you’re pregnant with your healthcare provider—you can calculate your due date!

How Far Along Am I?

Knowing how far along you are in pregnancy is helpful for both you and your healthcare provider. Your provider will use this information to check on your baby’s growth and development, keep an eye on your health, and schedule tests and exams. The weeks of pregnancy can be grouped into three trimesters:

Check out the illustration below to see how far along you are in your pregnancy:

What Precautions Should You Take During Early Pregnancy?

Even if you haven’t spotted any signs of pregnancy very early on, you’ll want to do everything you can to stay healthy and safe. In fact, it’s always wise to take some precautions as soon as you start trying to conceive or learn that you’re pregnant. Even simple adjustments can help support you as you start your pregnancy! Though you’ll want to consult your healthcare provider to determine what’s best for you, some worthwhile lifestyle changes and precautions include

When you start trying for a baby or learn that you’re pregnant, folic acid is essential, as it’s a B vitamin that helps reduce the risk of certain birth defects that affect the baby’s brain and spine. Your healthcare provider can recommend a prenatal vitamin that contains at least 400 micrograms of folic acid. Pre-pregnancy is also a great time to eliminate some less healthy habits, including

  • smoking

  • exposure to secondhand smoke

  • drinking alcohol.

In addition, your provider may recommend limiting your daily consumption of caffeine. Talk with your healthcare provider about the best ways to stay healthy and safe when you’re pregnant. For more general advice, download our pregnancy guide!

The Bottom Line

Although you might be eager to feel those very typical signs of pregnancy early on, you probably won’t notice them when you’re only 1, 2, or 3 weeks pregnant. Since your healthcare provider will calculate your 40-week pregnancy from the first day of your last menstrual cycle, chances are you won’t even conceive in those initial weeks! However, your body is still doing important work, laying the first building blocks of your baby’s life! Perhaps you’re at the start of a wonderful journey without even realizing it. And within the first month, you may or may not experience some typical symptoms of pregnancy, such as a missed period, implantation bleeding, fatigue, and bloating. If you’re interested in what happens in the remaining weeks of pregnancy, check out our pregnancy calendar.