What Are the First Signs of Pregnancy?

Accurate Diagnosis at the Right Time and Place

If pregnancy occurs, a hormone called HCG is secreted from the pituitary gland, which stimulates the corpus luteum in the ovary to produce progesterone. Progesterone then prepares the uterus to accept the fertilized egg. Four to six weeks after fertilization or the last menstrual period, most of the HCG production is provided by the placenta, whose sole function is to nourish the fetus. HCG is excreted in the urine, and the amount of HCG in the urine can be measured. This laboratory examination is the most commonly used pregnancy test and yields results in four to eight hours. These tests can be performed in a doctor's office, but a positive result requires a very high level of HCG in the urine. Laboratory tests are more sensitive. A positive reaction in one or the other of these tests indicates that you are pregnant, but the reverse is not true. A pregnancy test may yield a negative reaction, especially within the first three to five weeks of fertilization, but you may still be pregnant. Pregnancy tests should be repeated weekly until a positive reaction is obtained, or continued until menstruation, the clearest sign of not being pregnant, occurs. A urine pregnancy test generally does not yield a positive result until two weeks after a missed period, six weeks after the observed period, or four weeks after conception.

Choosing a Doctor

To detect pregnancy immediately after fertilization, a group of researchers at Cornell University in New York have developed a highly sensitive method for early detection of HCG, allowing for positive results within two weeks after fertilization, even before the first missed menstrual period. This method measures HCG levels in the blood. There are also over-the-counter pregnancy tests that measure HCG levels in the urine. These methods make early pregnancy diagnosis even more practical. One of the first visible signs of pregnancy is breast enlargement and darkening of the brown pigment around the nipples. A doctor may look for signs of uterine softening, but this usually doesn't become apparent until six or seven weeks after a missed menstrual period. Nausea, a feeling of fullness, and breast tenderness are often the first symptoms noticed by pregnant women. Persistently high basal body temperature is another sign of pregnancy. If all these symptoms appear and pregnancy is understood early enough, abortion can be performed relatively simply. The earlier the abortion is performed, the fewer the subsequent complications will be.