One common early sign of pregnancy is a metallic taste in the mouth. Some women feel as though they're chewing on aluminum foil, while to others, it seems that they have a penny tucked in their cheek. The exact reason for this metallic taste isn't known, but like many symptoms of early pregnancy, it's attributed largely to hormones.
One of the benefits of a metallic taste in the mouth is that it can alert a woman to her pregnancy long before she tests positive on a home pregnancy test. While levels of human chorionic gonadotropin, or hCG, generally don't rise high enough to be detected in urine by home pregnancy tests until at least the first day of a missed period, pregnancy hormones start changing a woman's body as soon as she conceives. In their book "What To Expect When You're Expecting," Heidi Murkoff and Sharon Mazel note that many women taste metal within a few days of conception.
There don't seem to be clear reasons for the metallic taste some women experience during pregnancy. Dr. Raymond Poliakin, in his book "What You Didn't Think To Ask Your Obstetrician," notes that many women have a sharper sense of smell during pregnancy than they usually do, and that this may partially explain the metallic taste. Women who have more morning sickness may also taste metal more frequently than those who are largely unaffected by early pregnancy hormones.
Many women are not bothered by the taste in their mouth, though some find it mildly disturbing or off-putting. Women who are particularly sensitive to odors and flavors in early pregnancy may have more morning sickness than those who aren't as sensitive, and may find it more difficult to eat. In their book "You: Having A Baby," Drs. Michael Roizen and Mehmet Oz explain that proper nutrition is important during pregnancy, so excessive nausea may make it difficult for women to eat balanced diets.
Most women notice a metallic taste, if they experience one at all, any time from a few days to a few weeks after conception. Like many hormone-related symptoms of pregnancy, metallic tastes typically fade or disappear by the end of the first trimester, though some women may have them throughout pregnancy. Dr. Poliakin notes that as long as the taste doesn't greatly interfere with eating and doesn't cause excessive nausea, it's normal and harmless.
Murkoff and Mazel recommend that those with strongly unpleasant metallic tastes in the mouth--and those with any sort of morning sickness, regardless of other circumstances--try ginger during pregnancy. The chemical responsible for the flavor of ginger relieves nausea and fills the nostrils with a strong odor that helps block reception of other, more unpleasant tastes and smells. Ginger ale, ginger tea, and ginger-flavored foods may all help pregnant women to get some relief from early pregnancy flavor-related discomforts.