4 Weeks Pregnant: What to Expect in the First Trimester

Pregnancy can often come with a whirlwind of emotions and questions, especially in the earliest weeks. If you’re four weeks pregnant or expecting soon, you may be full of anticipation over what comes next! While each pregnancy is unique and individualized, there are certain things to expect during the first trimester that most all moms-to-be experience. We’ll explore these expectations so that you can have an idea of what to expect as your little one grows inside of you.

Related Link: Discover Your Baby's Gender with These Predictive Methods

The Mother’s 4 Week Pregnancy

The development of your baby up to the fourth week of pregnancy is truly remarkable. The blastocyst is now a developing embryo that is making its way toward maturity. You can rest assured that your body is preparing for childbirth, even though you may not yet feel pregnant yet.  The placenta is currently developing within your uterus. Also developing is the neural tube, which becomes the brain and spinal cord of your baby. Women should be aware that the onset of pregnancy symptoms and signs vary between women.Those who are unfamiliar with pregnancy may wonder how far along they are at 4 weeks.

The Baby’s Development at 4 Weeks

Even though there isn't much to see on an ultrasound of a 4-week-old baby, a lot is happening there. The fertilized egg has successfully implanted in your uterus and is rapidly expanding. The blastocyst, a cluster of cells, is dividing this week to form the placenta and the embryo from which you will deliver your baby. The gestational sac, which is so small it is barely visible on an ultrasound, conceals the chromosomal blueprints for your baby's nose, toes, and pretty much everything else.

The Mother’s Development at 4 Weeks

man embracing pregnant woman

Many of the earliest pregnancy symptoms can mimic those of the menstrual cycle, making it difficult to distinguish between the two. 

No Symptoms?

Do you not yet have any symptoms? Most pregnant women don't start showing symptoms until the second half of the first trimester. However, changes are taking place! As the body works hard to start the process of fetal development, the first trimester of pregnancy is marked by a surge in hormones. Here are some of the earliest pregnancy symptoms that you might notice around week four.

Mild Cramps

Normal early pregnancy cramping may be mild. The body undergoes internal changes in preparation for the nine-month gestation period. These minor aches should only last for a few days.

Absent Period

The absence of your period may be the first sign of pregnancy and the reason you decide to take a pregnancy test.

Sore Breasts

Before nausea, vomiting, and extreme fatigue, sore or swollen breasts are common. 


It's normal to bleed a little bit when an embryo attaches to the uterine wall (called implantation bleeding) in about 30 percent of pregnancies. The bleeding is usually a different color than a period, like light pink or dark brown.


Due to the physiological changes that occur to support the growing baby, it is normal for a pregnant woman to feel tired, if not exhausted.

Period Signs

Many have trouble figuring out if they are pregnant early on because the early signs are so similar to those of PMS. PMS can cause irritability, depression, anxiety, fatigue, breast tenderness, and bloating. Morning sickness and vomiting are common during pregnancy, but they usually stop after three months.

Related Link: Exciting Gender Reveal Ideas for Your Pregnancy

Emotional Support

During pregnancy, one's feelings may swing wildly. You may have a wide range of emotions, including joy, relief, and even fear and panic, in response to your pregnancy. Having someone there to lean on is crucial at this time. Your partner, loved ones, friends, and a prenatal support group are all possible resources. Seek assistance when you feel you can't handle things alone.


You should put your health first during pregnancy for both you and the baby. This involves maintaining a healthy lifestyle by exercising regularly and eating well (with your doctor's approval). Consider thinking about prenatal yoga, meditation, or acupuncture as self-care methods. Taking care of yourself during pregnancy is vital for the health of you and your unborn child.

Looking for advice about childcare? Read more on 123 Baby Box today!

What to Expect in Upcoming Weeks

couple holding each other while watching the sunset

Prenatal Care:

After confirming your pregnancy, it’s important to schedule your first prenatal appointment with your healthcare provider. Your provider will review your medical history, conduct a physical exam, and order necessary tests during this appointment. They will also discuss your prenatal care plan, including your diet and any necessary medications or supplements.

Preparing for Parenthood:

Although your baby is only the size of a poppy seed at week 4, it’s never too early to begin preparing for their arrival. Researching prenatal classes, reading parenting books or blogs, and talking to experienced parents can help you feel more confident and prepared for parenthood. Additionally, begin thinking about your birth plan, including your preferred birthing location, pain management options, and support person(s) during labor.

Have any questions about how to take care of your baby? Check out 123 Baby Box!

Understanding Your 4 Week Pregnancy

Ladies and gentlemen, start your engines! You're about to embark on an extraordinary journey. At four weeks pregnant, you've just crossed the starting line, and the wild, exhilarating ride of pregnancy is just getting underway.

It's common to feel a mix of adrenaline and butterflies swirling inside you during these early weeks, like you're strapped into the front seat of a roller coaster just as it starts its climb. Excitement and anxiety are two sides of the same coin, a coin you'll flip many times during this first trimester.

Being in the know is like having a roadmap for this thrilling journey. Understanding what twists and turns to expect during this time can make all the difference in your ride, helping you transition from merely enduring the trip to actually savoring each moment.

Now is not the time to take pit stops on self-care lightly! Health is your fuel, your turbo boost in this grand race. In these early stages, it's even more crucial to prioritize your well-being. It's like ensuring your vehicle is in top shape before hitting the road – vital for both the journey and the destination.

On this race track called pregnancy, there's no such thing as asking for directions too often. A medical expert is your GPS, your guide on this twisting, turning road. Don't hesitate to seek their help. They're there to navigate you through this thrilling race, ensuring you're ready for the victory lap – holding your newborn baby in your arms!

So, buckle up, rev your engines, and enjoy every high-speed twist, every breathtaking turn. You're four weeks pregnant, and the grand adventure is just getting started!

Related Link: 12 Top Tips for Newborn Photography

What to read next

123 Baby Box sources ideas for their blog content from a variety of channels including feedback from subscribers, trending topics in baby care, and insights from industry experts. They aim to cover topics that are both informative and relevant to the needs and interests of parents and caregivers.

The writing process at 123 Baby Box typically involves several steps. First, they outline key points to cover in the article based on thorough research.

123 Baby Box publishes new content on their blog on a weekly basis. This regular schedule helps keep their audience engaged and informed about the latest in baby care, product recommendations, and parenting tips.

The blog posts for 123 Baby Box are typically written by content writers who specialize in parenting, child development, and health. These writers often have backgrounds in journalism, education, or healthcare, providing them with the expertise necessary to produce reliable and valuable content for parents.

123 Baby Box writers put in a lot of time researching and fact checking each article.

123 Baby Box is a subscription service that provides monthly boxes filled with products tailored for babies and toddlers.

Baby Box Subscription

Monthly subscription box for babies aged 0-3 years - delivering unique, fun products

star star star star star
(5.0 rating)
take baby quiz