Pregnancy Tests And Early Markers Of Problems

Questions that were considered in Case Scenario 12-1 will serve to summarize this portion of the chapter:

1. What is the main urinary marker for pregnancy? Human chorionic gonadot-ropin is the main marker.

2. What is the difference in methodology and clinical value of qualitative and quantitative pregnancy tests? Qualitative tests provide positive or negative hCG results to help determine if the patient is pregnant or not pregnant. These are usually simple immunoassay tests performed on a urine specimen and having one or few steps in analysis. Qualitative tests are less sensitive than a quantitative test but they have the advantages of being faster and easier to perform and, because they do not require an instrument to read the results, they are less expensive. Qualitative testing can generally detect pregnancy within a few days after the first missed menstrual period. A quantitative pregnancy test, which is generally performed using serum, is more sensitive in that hCG can be detected even before the first missed menstrual period (e.g., by day 21 to 27 from the last menstrual period). Quantitative hCG tests are labeled immunoassay methods that require automated instrumentation. This more sensitive testing is useful for detecting pregnancy prior to surgery or other invasive techniques or to measure in a series to monitor for healthy progression of pregnancy or rule out abnormal pregnancy.

3. What other markers are there for pregnancy, and how do they correlate with uncomplicated simple pregnancy? Other hormones are produced during pregnancy, including estriol and hPL, which tend to rise at a predictable rate. Another estrogen, estradiol, is higher in the nonpregnant women, while estriol is the main estrogen found in pregnant women. Additional markers of pregnancy include physical signs of pregnancy and ultrasound imaging of the uterus by 6 weeks of gestation.

4. What early markers are there for problem pregnancies such as ectopic, trophoblastic, or multiple pregnancies or threatened miscarriages?

Quantitative hCG tests are used in conjunction with history, physical examination, and ultrasound for detecting abnormal pregnancy, such as ectopic pregnancy, or miscarriage. There is an exponential increase in hCG early in a normal pregnancy. In ectopic or misplaced pregnancy, the hCG value may continue to increase but not to a level as high as that for a normal pregnancy, while fetal demise and impending miscarriage are indicated by leveling off or falling of hCG levels. Trophoblastic diseases such as hydatiform mole result from the demise of the fetus but with an abnormal growth of remaining trophoblastic cells causing higher than normal levels of hCG. Ultrasound and other imaging techniques will indicate grapelike clusters of watery sacs instead of a fetus. Multiple fetuses, including twins, will result in hCG levels higher than those expected for a single fetus or for the gesta-tional age. Ultrasound can be used to verify the presence of multiple fetuses.

Pregnancy Nutrition

Pregnancy Nutrition

Are You Expecting? Find Out Everything You Need to Know About Pregnancy and Nutrition Without Having to Buy a Dictionary. This book is among the first books to be written with the expertise of a medical expert and from the viewpoint of the average, everyday, ordinary,

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