Elevated basal body temperature

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.

Changes in nipple color

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.

Melasma (darkening of the skin)

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.