Fatigue and tiredness are symptoms experienced by many women in the early stages of pregnancy. The cause of this fatigue has not been fully determined, but it is believed to be related to rising levels of the hormone progesterone. Fatigue is another symptom that may be experienced early, in the first weeks after conception.Some women may experience feelings of abdominal enlargement or bloating, but there is usually only a small amount of weight gain in the first trimester or pregnancy. In this early stage of pregnancy a weight gain of about one pound per month is typical. Sometimes women also experience mild abdominal cramping during the early weeks of pregnancy, which may be similar to the cramping that occurs prior to or during the menstrual period.

A woman in the early stages of pregnancy may feel she has to urinate frequently, especially at nighttime, and she may leak urine with a cough, sneeze, or laugh. The increased desire to urinate may have both physical and hormonal causes. Once the embryo has implanted in the uterus, it begins to produce the hormone known as human chorionic gonadotrophin (hCG), which is believed to stimulate frequent urination. Another cause of frequent urination that develops later is the pressure exerted by the growing uterus on the bladder.A persistently elevated basal body temperature (the oral temperature measured first thing in the morning, before arising from bed) is another characteristic sign of early pregnancy. An elevation in the basal body temperature occurs shortly after ovulation and persists until the next menstrual period occurs. Persistence of the elevated basal body temperature beyond the time of the expected menstrual period is another sign of early pregnancy.Women may notice a deepening of the color of the area surrounding the nipple, called the areola and/or a dark line going down from the middle of the central abdomen area to the pubic area (known as the linea nigra). Some degree of darkening of the areola persists after pregnancy in many women, but the linea nigra typically disappears in the months following delivery of the baby.Some women may develop a so-called "mask of pregnancy" in the first trimester, referring to a darkening of the skin on the forehead, bridge of the nose, upper lip, or cheekbones. The darkened skin is typically present on both sides of the face. Doctors refer to this condition as melasma or chloasma, and it is more common in darker-skinned women than those with lighter skin. Melasma can also occur in some conditions other than pregnancy. Women who have a family history of melasma are at greater risk of developing this sign of pregnancy.