Patients may present to the emergency department physician with symptoms of vaginal bleeding and abdominal pain with or without a diagnosis of pregnancy. The laboratory provides valuable information, including qualitative and quantitative hCG results that are a vital component in helping to diagnose and manage abnormal early pregnancies.
fetus, such as chromosomal abnormalities incompatible with life.9 Miscarriage can also result from hormonal fluctuations, including inadequate levels of progesterone or estrogens that are necessary for maintenance of the uterine lining. A sudden drop in progesterone levels will cause the endometrium to slough, evacuating the embryo and causing menstruation to begin. This may happen early before pregnancy is suspected and, if it occurs repeatedly, may be the cause of infertility.1,10
Trophoblastic neoplasm results in a tumor growth in the uterus rather than a fetus. This type of neoplasm, or new and abnormal growth, results from an intrauterine or ectopic pregnancy and is quite rare, particularly in the malignant forms. There are several types, including hydatiform mole, invasive hydatiform mole, and chori-ocarcinoma. In hydatiform mole, the pregnancy becomes nonviable and the chori-onic villi grow abnormally, resulting in edema and grapelike clusters of watery sacs in the uterus that are visible by ultrasound. Invasive hydatiform mole is similar to hydatiform mole but the chorionic villi grow to invade the uterine smooth muscles. Choriocarcinoma, also called metastatic trophoblastic disease, is a malignancy in which the chorionic villi not only invade the uterus but spread to surrounding organs. The latter is a carcinoma arising from the trophoblast. In contrast, hydat-iform mole is a benign growth of the trophoblast.2 Quantitative levels of hCG, which are very high in these neoplasms, are helpful in monitoring treatment and progression of neoplastic disease since levels correlate with the amount of tumor present. For example, a patient with hCG of 400,000 IU/L or higher would be expected to have a poor prognosis even with treatment. Within 24 hours of successful removal of the tumor, the hCG level should drop by half considering halflife and correlation with amount of tumor.11
Multiple fetuses in the pregnancy, including twins, will also affect the quantity of hormone detected in urine and serum. With a twin pregnancy, the level of hCG in the mother's serum is close to double the range for a single-fetus pregnancy. This is important to consider when correlating hCG levels with early abnormal pregnancies and with midterm diagnostic procedures that include hCG. The use of hCG and other maternal serum tests for fetal assessment are discussed later in this chapter. Detecting twins or higher order multiple pregnancies relies on using ultrasound techniques, illustrating the need for several diagnostic tools for management of pregnancy by health-care providers.1
Case Scenario 12-1 Pregnancy Testing: Yes or No? Follow-Up
Ms. Garcia left her urine specimen in the physician's office laboratory for a pregnancy test. The laboratory staff performed a qualitative pregnancy test with her urine sample with a positive result. The history and physical
Case Scenario 12-1 Pregnancy Testing: Yes or No? (continued)
examination correlated with these results, and Ms. Garcia was found to be 5 weeks pregnant based on her last menstrual period.
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