Whether a woman is hoping to get pregnant, trying to avoid pregnancy, or simply trying to keep track of what is going on with her body, few things are more confusing than beginning to experience symptoms of pregnancy and then getting a period a few days later. False signs of pregnancy can be frustrating--and further confusing matters, the early signs of pregnancy include many symptoms common to other conditions as well.
The classic signs of early pregnancy all share the function of indicating that a woman's body is preparing itself for the rigors of housing a developing baby for the next nine months. Early changes, according to Heidi Murkoff and Sharon Mazel in their book, "What to Expect When You're Expecting," include breast tenderness, fatigue, spotting and moodiness. While nausea is common in early pregnancy, it typically doesn't arrive until approximately the sixth week of pregnancy, by which time women know they're pregnant. Many of these early symptoms are due to high levels of the hormone progesterone.
The hormone progesterone is also responsible for the symptoms of an approaching period. Many women notice that in the week before they menstruate, they feel moody, bloated and tired and have tender breasts. As such, it can be very difficult to tell the difference between symptoms of early pregnancy and those of imminent menstruation. Light periods can resemble implantation spotting, making it difficult to determine whether a woman is pregnant or menstruating, according to Dr. Miriam Stoppard in her book, "Conception, Pregnancy and Birth."
The most common time for false signs of pregnancy is during the week just prior to an expected period and during the week in which a period is scheduled to arrive. Murkoff and Mazel explain that period symptoms and early pregnancy symptoms both tend to arrive approximately one week after ovulation. Further, if a woman's period is late, her premenstrual, pregnancy-like symptoms tend to last longer than they otherwise would, providing further false evidence of pregnancy.
One possible mechanism for avoiding being fooled by false signs of pregnancy is to take a home pregnancy test on the first day of a missed period. While the test can't keep a woman from wondering whether she's pregnant during the week before her period, it can at least provide answers before too much time passes. In "What You Forgot to Ask Your Obstetrician," Dr. Raymond Poliakin recommends testing a second time a week later if signs of pregnancy persist despite a negative test.
Unfortunately, explains Dr. Stoppard, it's possible for a test to show a positive result and then for a woman to get her period a few days later. This is called a chemical pregnancy, and it's an indication that a fertilized egg failed to implant correctly. Chemical pregnancies are very common, and most women don't even know they've had them, but for early test users, they can represent yet another false sign of pregnancy. Dr. Stoppard notes that chemical pregnancies are not true miscarriages, and that the period following one will be relatively normal, if slightly heavy.