Four weeks pregnant

What is happening and what to do

Even though the changes to your body at four-weeks pregnant may be subtle, a lot has happened to result in a positive pregnancy test, and a lot more is soon on it’s way. If you are lucky enough to have the news about being pregnant this early on, it may be fun to start to learn about what is happening inside your body and how you can begin to prepare for what is on the way.

Young couple, positive pregnancy test

First, let’s take a look at what has happened so far.

Two weeks pregnant:

While the actual fertilization has yet to take place, there is a lot going on in your body at two weeks pregnant to prepare your body for what is going to happen. Remember, the beginning of your pregnancy is dated to the first or second week after your last menstrual cycle, not the date of fertilization. So while this week will technically find you “two weeks pregnant,” you won’t be able to test positive for pregnancy yet. What has happened is that your body is preparing for ovulation. This means that your body is already producing extra hormones. At two weeks pregnant you have begun to produce FSH (follicle stimulating hormone) and LH (lutenizing hormone); the combination of which encourages healthy follicles. As the follicles grow they will produce estrogen, which further prepares the uterus to accept its new tenant.

Three weeks pregnant:

Your body will be experiencing changes beyond hormone production once you are three weeks pregnant. While the embryo is only the size of a vanilla seed, it does exist at this point. And while it is small, it is capable, multiplying its cells and moving toward the uterus to signal an official fertization. This process may take five or six days, but you are pregnant.

One thing is for sure: at three weeks pregnancy, your body has started to produce the “pregnancy hormone,” hCG. This is the hormone detected when you receive a positive pregnancy test result. Though your body begins to produce the hormone only ten days after you become pregnant, many women will not discover they are pregnant until later, as this is also the hormone that signals your body to stop releasing eggs and thus stops your period, which is often the first indication of pregnancy.

hCG also increases the production of other hormones such as estrogen and progesterone. These hormonal increases can lead to some physical symptoms including nausea and light abdominal pressure, with more symptoms to follow.

Four weeks pregnant: what’s happening 

At four weeks pregnant you may begin to experience physical symptoms and signs of early pregnancy. You can learn all about these symptoms here: Early Signs of Pregnancy. Remember, every pregnancy is different and you may experience none of these symptoms, or you may notice changes to your body that aren’t on the list.

The vanilla bean-sized cell sack has made its way to the wall of the uterus to begin receiving nourishment from your body. When this occurs it will begin to grow the placenta and amniotic sac. Even if you aren’t feeling changes in your body, they are happening!

What is happening with the baby

At four weeks pregnant, the little one is still an embryo, not yet formed into a fetus. However, although just the size of a poppyseed, a lot has already happened. The first developments are the initial growth of the baby’s heart and nervous system. This growth is due to the development of blood vessels connecting you to the fetus. Over the next few weeks, these blood vessels will grow into a string that will become the umbilical cord.

As mentioned, the placenta will also start to show up as you progress into your pregnancy, but right now the baby-to-be is receiving nourishment from a tiny sack surrounding the embryo.

What should I do at four weeks pregnant? 

Although the main thing that needs to happen right now is to give the embryo time to develop into a fetus, there are some important preparations that you can begin taking. Here are some things that you can do if you know you are pregnant at four weeks:

  • Whether you are ready to begin celebrating or still adjusting to the idea of parenthood, this is a great time to ease into the reality of what lies ahead. If you are nervous, remember, you’ve got eight more months ahead to fully prepare.
  • It is a good time to tell your partner, and many couples choose to keep the news to themselves until the end of the first trimester (12-13 weeks). Every couple is different and this will be a good thing to discuss together.
  • Changes are happening and your body is starting to work hard! The first trimester is when you may want to begin taking a prenatal vitamin.
  • If you have not decided on an OBGYN yet, you will want to begin your research now. Do keep in mind that your doctor may not have you come in for your initial appointment closer to the 8-week mark.
  • Start making those lifestyle adjustments that are going to help ensure a healthy pregnancy and baby. It’s time to stop smoking, cut way back on alcohol consumption or stop completely, and increase your sleep. These good habits will go a long way to support your body over the next nine months.

For further reading:

Expert tips: Preparing for your birth

Becoming parents: Our story

Are you ready to dive into your pregnancy? Take an early look at our providers page, join our network, and start building your baby community.