What’s Really Going On at 4 Weeks Pregnant?

second week of pregnancy header

In terms of pregnancy, things aren’t always how they appear. 

When you think about being 4 weeks pregnant, for example, you probably assume that you’re one month down (eight left to go) and that a lot of growth and development will have already happened.

On the contrary, the 4th week could be considered the true beginning of your gestational journey.

Since being one week pregnant is essentially a fancy way of saying, “you had your period,” and being “two weeks pregnant” is merely the waiting period between Aunt Flo and ovulation, you can count 4 weeks as the moment when your embryo is finally starting to develop.

I know, I know, I know – pregnancy timelines are weird.

From unusual early pregnancy signs to the completion of the dreaded two week wait, being 4 weeks pregnant comes with a wide range of exciting, strange, and sometimes unpleasant side effects!

This site contains affiliate links, meaning that we earn a small commission for purchases made through our site. We only recommend products we personally use, love, or have thoroughly vetted.

What’s Happening in Your Body at 4 Weeks Pregnant?

Let’s get straight to the point: even though your “baby” (it’s an embryo at this point) is the size of a poppy seed, there’s a whole lot of changes taking place inside your body.

At 4 weeks pregnant, your embryo will have finished its journey down through your fallopian tubes and began burrowing into your uterine lining for implantation.

Once this stage is complete, your beautiful ball of cells will split into two smaller groups of cells during a process called cell division.

One of these cellular groups will become your bouncing bundle of joy. The other will become your placenta.

While your placenta is getting ready to support your little one throughout pregnancy, your baby is having a developmental upgrade of his or her own.

During this period, your amniotic sac (aka the bag of waters that will eventually break!) and yolk sac are also forming around the embryo.

As if those weren’t big enough changes, your embryo itself will now have three distinct cellular layers, which will eventually become your baby’s various body parts and organs. These include:

  • Endoderm (Inner) Layer: Baby’s digestive system, lungs, and liver.
  • Mesoderm (Middle) Layer: Baby’s heart, muscles, kidneys, bones, and sex organs.
  • Ectoderm (Outer) Layer: Baby’s outer skin, hair, eyes, and nervous system

Last but certainly not least, your body will begin producing human chorionic gonadotropin – also known as HCG, the pregnancy hormone. 

Understanding Your HCG Levels

HCG is one of the most vital elements in early pregnancy, as it signals your body to continue producing crucial hormones, like progesterone and estrogen, that help support your embryo through its development.

One of the other great things about HCG is the fact that doctors can use it to tell you whether or not you’re actually pregnant!

Let’s face it, at this early stage, you’re not going to experience significant morning sickness or a developing baby bump. That’s why at 4 weeks pregnant, HCG levels play such an important role. 

Doctors use blood tests to check for HCG in a woman’s system. This is especially true in cases where the individual has undergone some type of female infertility treatment.

Not only will the presence of HCG alert your doctor that conception has occurred, but they can continue to analyze your levels to ensure they’re increasing day by day.

Increasing HCG levels help signify the viability of your pregnancy and show that development is taking place.

4 weeks pregnant
Are you wondering how accurate that pregnancy test is at 4 weeks pregnant? Keep reading to find out!

How Accurate are Pregnancy Tests?

Before you rush out to the local drug store to fill a basket with pregnancy tests, there’s something else you should know about the 4th week of pregnancy:

There’s a good chance any over-the-counter stick pregnancy test you take won’t be accurate at 4 weeks pregnant.

This early on, it would be difficult to get a good reading on a regular pregnancy test.

If you’d really like to know whether those TTC tips you’ve been using have worked, your best bet is to make an appointment with your physician.

Early Pregnancy Symptoms During Week 4

After my embryo transfer, I convinced myself that any strange sensation or minor pain happening inside my body was a sure sign the process was successful.

While yes, I did later find out I was pregnant, it’s hard to prove that any of those weird early pregnancy symptoms I swore I experienced were conception-induced.

When we’re hoping to get pregnant, it’s no wonder we start looking for signs in every ache and pain. Unfortunately, when it comes to pregnancy symptoms during week 4, most women are experiencing a whole lot of nothing.

That’s not to say, that side effects are impossible. Many women have noticed changes, such as:

Early pregnancy symptoms

Is Spotting at 4 Weeks Pregnant Something to Be Concerned About?

Blood and pregnancy don’t really go hand-in-hand.

It’s no wonder that many people who experience spotting at 4 weeks pregnant might worry it’s an early sign of a miscarriage. That early, you might even be confused about whether this is a miscarriage or your period.

While miscarriage is undoubtedly an unfortunate possibility, spotting isn’t always something to concern yourself with.

In fact, one of the successful implantation symptoms many women experience is light bleeding, known as implantation bleeding.

If you’re worried about the amount of blood you’re seeing, or you feel that you might have experienced a missed miscarriage, be sure to set up an appointment with your doctor as soon as possible.

Your Poppy Seed-Sized Baby: What Will an Ultrasound Show?

When something is only the size of a poppy seed, about 1mm long, you probably wouldn’t expect much to show up during an ultrasound–and you’d be correct!

Normally, a woman wouldn’t have her first maternal ultrasound until she is at least six weeks along. Let’s say for the sake of discussion, however, that her doctor decides to give one a try during her 4th week of pregnancy.

Would they be able to see ANYTHING?

The answer is yes! 

Around the middle of the 4th week of pregnancy, ultrasound technology can usually pick up your little one’s gestational sac

While it’s not the most thrilling thing to gaze upon, at least it’s physical proof of the changes happening inside your body.

If you do go for an ultrasound in early pregnancy, be prepared to have a transvaginal ultrasound. During the first several weeks of pregnancy, abdominal ultrasounds aren’t strong enough.

So, if your ultrasound tech whips out something that looks like it could’ve come from your local sex shop, don’t be alarmed! You’re about to have a transvaginal ultrasound.

a mother and father holding their hands in front of her pregnant stomach, in the shape of a heart

Is Anything Different When You’re 4 Weeks Pregnant with Twins?

At this early stage of pregnancy, being 4 weeks pregnant with twins isn’t much different than a singleton pregnancy.

The most unusual variations are that two gestational sacs will appear during any early transvaginal ultrasounds, and most twin pregnancies will result in two separate placentas. 

In rare cases, twins might share a placenta. These are known as monochorionic twins.

The Turning Point in the Your Next Chapter – Things Are About to Get Real

Being 4 weeks pregnant is the jumping-off point for every beautiful and unusual thing your body will begin to experience throughout the remaining 36 weeks (give or take) of pregnancy.

It’s a moment when things move beyond a possibility and begin turning into your new reality. From rising HCG levels to placenta development, the 4th week of pregnancy will set the foundation for everything else that’s about to begin…

If you’re already a mom, did you know or sense you were expecting at 4 weeks pregnant?

Leave a Reply

Your email address will not be published. Required fields are marked *