At three weeks pregnant, you are about one week from your expected period. During week three of pregnancy, your baby is a tiny ball of rapidly dividing cells called a blastocyst. At the end of this week, it will attach to the uterine wall. This will cause a buildup of hCG, the hormone that will detect pregnancy in your urine. It is possible to begin experiencing signs and symptoms at this time, but not all women will experience the same signs and symptoms. Symptoms may also differ from those of a subsequent or prior pregnancy.
Tender or Swollen Breasts
Your breasts may provide one of the first symptoms of pregnancy, reports the Mayo Clinic. Rising hormone levels can cause them to become swollen and tender. It can be similar to the tenderness and swelling that you may experience prior to your menstrual period. You may also notice breast changes at this time. The areola can appear darker in color and larger in size. The appearance of blue veins on breast tissue may become apparent.
Implantation Bleeding and Cramping
Implantation bleeding and cramping may occur during week three of your pregnancy. About six to 12 days after conception, the embryo implants itself into the uterine wall, states the American Pregnancy Association. This may cause vaginal bleeding or spotting and mild uterine cramping. Implantation bleeding is usually lighter in duration, flow and color than a normal menstrual period. Not all women will experience implantation bleeding.
Fatigue can occur at three weeks into your pregnancy. High levels of the hormone progesterone may make you feel more sleepy and fatigued than usual. Make sure to get at least eight hours of sleep nightly and take a midday nap, if possible, to help you feel more refreshed throughout the day.
Some women may experience nausea as early as three weeks into their pregnancy. This is thought to be due to rising levels of the hormone estrogen. Pregnant women also have a heightened sense of smell, so various odors—such as foods cooking, perfume or cigarette smoke—may cause waves of nausea in early pregnancy, states the Mayo Clinic.