After having unprotected sex, there is a greater chance of becoming pregnant. For some women, pregnancy symptoms appear earlier than for others, namely in the first weeks after having sexual intercourse. During the third week of pregnancy, the fertilized egg implants itself in the uterus, and toward the end of this third week, some pregnant women begin to experience normal mid-cycle symptoms. Some pregnant women may have a “feeling” that they are pregnant as their baby transforms into an actual embryo.

Missed Menstrual Period

By the end of the fourth week of pregnancy, women miss a period if pregnant. If the woman has regular menstrual cycle, this can be one of the first symptoms of pregnancy. The average duration of a menstrual cycle is 28 days; therefore, four weeks after having sexual intercourse, a woman should have already had her menstrual period. For those who do not have regular menstrual cycles, however, this may be normal. Use of a pregnancy test kit may help determine pregnancy in this case.

Fuller Breasts

Breasts provide one of the symptoms of pregnancy. A pregnant woman experiences hormonal changes as early as two weeks after conception, which can make her breasts tender, sore, fuller and heavier. These symptoms appear as the mammary glands prepare to produce milk. Some women, however, experience tenderness and soreness normally prior to their menstrual period; therefore, this can be misleading.

Fatigue

For a woman who rarely experiences unexplained tiredness, she may experience fatigue during the fourth week of pregnancy. During pregnancy, the hormone called progesterone becomes elevated. While progesterone level soars, there is also increased blood production, lower blood sugar levels and lower blood pressure that can all drain the pregnant woman’s energy resulting in fatigue.

Spotting and Cramping

There are occasions when pregnant women may experience vaginal bleeding in small amounts, also known as spotting accompanied by cramping. These symptoms sometimes appear when the fertilized egg attaches to the uterus, which happens during the second week after fertilization. Not to be confused with the blood spotting and cramping that happens prior to a normal menstruation, the blood usually appears a little bit lighter in color in comparison. The abdominal cramping, however, is very similar to the one experienced during a normal menstrual period.

Morning Sickness

Nausea, whether accompanied by vomiting or not, can happen to pregnant women as early as two weeks after conception. Known as morning sickness, this symptom can occur any time of day or night. During pregnancy, the estrogen level rises rapidly that can cause the stomach to empty more slowly, causing nausea and vomiting. In addition, a heightened sense of smell while pregnant can cause nausea in early pregnancy; therefore, odors such as strong perfume, cigarette smoke and food cooking may cause this symptom.