Week three is the first week you are physically pregnant, as fertilization takes place at the end of week two/beginning of week three.
If fertilization has occurred, you are now the proud owner of a zygote, which starts off as a single cell. The zygote usually contains 46 chromosomes, 23 from both partners. Your baby’s sex as well as its other traits are decided by this point. The zygote travels toward the uterus, dividing and growing rapidly to form a blastocyst—a cluster of 70 to 100 cells that, all together, are about the size of a pin.
Your Week 3 Ultrasound
Week three is a bit early to be having an ultrasound—there’s still not much to see. At this point, your baby would likely appear as a tiny, tiny dot adrift in your uterus on an ultrasound.
Changes in You
At week three, you will most likely not be able to notice any changes in your body unless you are specifically looking for them. However, some women do start to experience some side effects of pregnancy early; you may notice swollen or tender breasts, increased fatigue, heightened sense of smell, nausea/queasiness, a higher basal temperature, and bleeding or spotting. You may be able to detect your pregnancy on a home pregnancy test; it simply depends on how your body is reacting.
What You Should Be Doing
Starting at week three, your baby takes in everything that you take in, so now is the time to make healthy lifestyle changes if you have not already done so. Exercise is healthy throughout pregnancy for most women; you may want to take up yoga to help strengthen and tone your body, getting it ready for childbirth. You want to stay clear of pesticides and other dangerous substances, stop smoking and stop imbibing alcohol and caffeine. Some studies have shown that occasionally drinking red wine is healthy during pregnancy, but there is by no means universal agreement on the subject. Ultimately, it’ll just be your personal choice. Also, if you must undergo any medical procedures, such as an x-ray, inform the doctor that you may be pregnant, as some may be harmful during the early stages of development.
The End of Week 3
If you don’t already know you’re pregnant, then you should be starting to expect the arrival of your period within a few days. A missed period is, for many women, the first sign that they are pregnant—and they’re already four weeks in!