Pregnancy Week 3


Baby on board! Since your due date is calculated by conception date, or the first day of your last period, you technically are not pregnant in weeks 1-2. But week 3, now that’s where the magic happens!

You probably have no idea that you’re actually pregnant yet, as it’s still a little early to tell at 3 weeks pregnant. You have recently ovulated and fertilization has taken place, but it is not quite yet time to miss a period!


3 weeks pregnant

Baby Growth at 3 Weeks

You wouldn't know it yet, but wow, how your baby is growing! 

The winning sperm met an egg sometime this week in your fallopian tubes, your genetic material combined, baby’s sex is determined, and your single-celled “zygote” started traveling through the fallopian tube. Voila – you made a baby!

The zygote typically has 46 chromosomes – 23 from the biological mother and 23 from the biological father. These chromosomes determine your baby's sex and physical traits.

Your baby is currently a tiny ball of cells that are rapidly dividing. The cells in the middle of the “ball” become the embryo and the cells on the outside of the “ball” become the placenta; the organ that carries oxygen and nutrients to your baby. As cells divide, the zygote becomes a blastocyst over a period of about 5-6 days and will soon be ready for implantation.

Once the blastocyst makes its way to your uterus, it takes an additional 3-5 days for it to implant in the uterine lining, making the total travel time from ovulation to implantation about 8-14 days. This is why you probably have no idea you’re pregnant yet!


Fetal development at 3 weeks pregnant


You & Your Body at 3 Weeks Pregnant

So, what’s going on with you? Eh, probably not too much yet.

While some people have no pregnancy symptoms yet, others may detect some differences. Bloating and mood swings are both common symptoms at this stage. These symptoms are due to an increase in the production of hormones estrogen and progesterone. Some light cramping or spotting is also common. Both of these are signs of implantation, where your little ball of cells settles in the uterine wall, getting nice and cozy for the next 9 months. 

You probably have not missed your next period yet, but you should soon! We can thank hormones for the bloating we think is a baby bump, but your baby is still too small to see.


Typical Symptoms at Pregnancy Week 3

During this week, if you have not noticed any symptoms just yet, that’s okay. Early pregnancy symptoms vary from person to person and you may not start to feel anything until week 5 or 6. Most pregnancy symptoms are caused by the pregnancy hormone hCG, which is probably not present yet, but you’ll get there.

Some symptoms that you may start to experience during week 3: 

  • Fatigue: The start of growing a baby is exhausting. Don’t be surprised if you find yourself a little tired during week 3 and during your first trimester. 
  • Breast changes: You may start to notice some breast changes from hormones changing. This is very common in early pregnancy especially now as your progesterone begins to rise.
  • Cramping: Some light cramping is common during this week as the embryo finds the best spot to implant in your uterine lining. 
  • Implantation bleeding: Once your little bean starts to attach to its new home, you may see a little bit of spotting as it tucks away into your uterine lining. 


Pregnancy Week 3 Tips and Advice 

You may be feeling nervous and anxious this week, especially if you have been trying to conceive for a little while now. You have no idea yet if you’re pregnant, but you’ve done your part and now you’re waiting to see the magic happen!

If you haven’t already, start taking a prenatal vitamin with folic acid or methylated folate; this is super important for baby’s brain development. Also, talk with your doctor to see if there are any added supplements you should include  such as Vitamin D, Fish Oil with DHA, or Iron. 

You’re probably eager to take a pregnancy test, but it still may be too early for it to show positive. The placenta produces the pregnancy hormone hCG once the baby implants. Since the journey to implantation can take a little while, 6-10 days on average, the placenta won’t send out enough of that hormone to trigger a positive pregnancy test. It is recommended to wait at least 12-14 days past ovulation – or after a missed period – before taking a home pregnancy test. 

This is such an exciting journey, and you’re doing great. Next step, is a positive pregnancy test! 



early pregnancy symptoms, fetal development, pregnancy, pregnancy symptoms, pregnancy tips, pregnancy week 3
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