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Signs of Pregnancy

Signs of Pregnancy Overview

Pregnancy occurs when an egg is fertilized by a sperm, grows inside a woman's uterus (womb), and develops into a baby. In humans, this process takes about 264 days from the date of fertilization of the egg, but the obstetrician will date the pregnancy from the first day of the last menstrual period (280 days 40 weeks).

The doctor will use certain terms when discussing a pregnancy. Some of the following definitions are useful:

  • Intra-uterine pregnancy: A normal pregnancy occurs when a fertilized egg is implanted in the uterus (womb) and an embryo grows.
  • Embryo: The term used for the developing fertilized egg during the first 9 weeks of pregnancy.
  • Fetus: The term used for the developing embryo after 9 weeks of gestation.
  • Beta human chorionic gonadotropin (also called beta-hCG): This hormone is secreted by the placenta and can be measured to determine the presence and progression of the pregnancy. Urine or blood can be tested for its presence, and it is the hormone involved in the performance of a home pregnancy test. A positive result means a woman is pregnant; however, this test result can stay positive for several weeks after delivering a baby or following a spontaneous miscarriage.
  • Trimester: The duration of an individual pregnancy is divided into three periods called trimesters (approximately three months in duration). Each trimester is characterized by specific events and developmental markers. For instance, the first trimester includes the differentiation of the different organ systems.
  • Estimated date of delivery (EDD): The delivery date is estimated by counting forward 280 days from the first day of the woman's last period. It is also called the estimated date of confinement (EDC).

A pregnant woman and her doctor will monitor the pregnancy to exclude or prevent certain pregnancy conditions. The physician will also treat non pregnancy-related medical conditions in such a way as to promote the appropriate physical and neurological development of the fetus. Conditions of particular importance include:

  • High-risk pregnancy: If a woman is considered  prone to certain complications during pregnancy, she will be classified as high risk. Examples include pregnancies in women with diabetes and/or high blood pressure. Age-related complications can occur in women such as teenagers, women who are over the age of 35, or those who have been treated for infertility and have pregnancies resulting from the use of assisted reproductive technology.
  • Ectopic pregnancy: This is a pregnancy in which the egg implants somewhere other than the uterus. This complication can be life-threatening. Ectopic pregnancy must be diagnosed early to avoid damage to the Fallopian tubes and to prevent serious maternal illness or death. It is also called tubal pregnancy (if the egg implants in the Fallopian tubes) or extra-uterine pregnancy.
  • Cervical incompetence: This is a condition in which the cervix begins to open (widen) and/or efface (thin) without contractions before the pregnancy has reached term. Cervical incompetence can be a cause of mid-pregnancy miscarriage.
  • Preterm Labor: In this condition, the uterus begins to contract before the baby has reached full-term.
  • Preeclampsia/eclampsia: Preeclampsia is a systemic disease that can affect various organ systems. Vascular effects cause the blood pressure to rise in a pregnant woman. The condition may cause kidney damaged, generalized swelling, hyperactive reflexes, as well as deleterious abnormalities in blood chemistry and nerve reflexes. If left untreated, preeclampsia can proceed to eclampsia, a serious condition which may result in seizures, coma, and even death.
  • Multiple Gestation (e.g. twins, triplets): Preterm births are twice as likely in twin pregnancies than in singleton pregnancies. The percentage of preterm birth is even greater for triplet pregnancies and higher order pregnancies. Preeclampsia is also seen three to five times more frequently with multiple gestation.

Pregnancy Causes

Pregnancy occurs with the fertilization of a woman's egg by a man's sperm. Fertility drugs may improve a woman's odds of achieving a pregnancy.

Medically Reviewed by a Doctor on 2/16/2016

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Woman having pregnancy test

Pregnancy Test

Positive Home Pregnancy Test

For most home pregnancy tests, you either hold a test strip in your urine stream as you urinate into the toilet or you collect your urine in a clean cup and dip your test strip into the cup. The test usually takes only a few minutes.

  • Some tests are able to detect low levels of hCG, indicating pregnancy. For the most reliable results, test 1-2 weeks after you have missed your period.
  • You can improve your chances for an accurate result by using your first morning urine for the test.
  • If you think you are pregnant, but your first test was negative, you can take the test again after several days.
  • The home pregnancy test and the urine pregnancy test used by your health-care professional are similar. Both can detect hCG, but your provider is probably more experienced in running the test.

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