• Explore the biophysical, psychosocial, sociodemographic, and environmental aspects of high risk pregnancy. • Examine risk factors identified through history, physical examination, and diagnostic techniques. • Differentiate among diagnostic techniques, including when they are used in pregnancy and for what purposes. • Develop a teaching plan to explain diagnostic techniques and implications of findings to patients and their families. chorionic villus sampling (CVS) Removal of fetal tissue from the placenta for genetic diagnostic studies percutaneous umbilical blood sampling (PUBS) (also called cordocentesis) Procedure during which a fetal umbilical vessel is accessed for blood sampling or for transfusions In the past, risk factors were evaluated only from a medical standpoint; therefore only adverse medical, obstetric, or physiologic conditions were considered to place the woman at risk. Today, a more comprehensive approach to high risk pregnancy is used, and the factors associated with high risk childbearing are grouped into broad categories based on threats to health and pregnancy outcome. Categories of risk are biophysical, psychosocial, sociodemographic, and environmental (Gilbert, E.S., 2007) (Box 19-1). Risk factors are interrelated and cumulative in their effects. Sociodemographic risks arise from the mother and her family. These risks may place the mother and fetus at risk. Examples include lack of prenatal care, low income, marital status, and ethnicity (see Box 19-1). Environmental factors include hazards in the workplace and the woman’s general environment and may include environmental chemicals (e.g., pesticides, lead, mercury), radiation, and pollutants (Silbergeld & Patrick, 2005). The major expected outcome of all antepartum testing is the detection of potential fetal compromise. Ideally, the technique used identifies fetal compromise before intrauterine asphyxia occurs so that the health care provider can take measures to prevent or minimize adverse perinatal outcomes. Antepartum testing is used primarily in patients at risk for disrupted fetal oxygenation. In most cases, monitoring begins by 32 to 34 weeks of gestation and continues regularly until birth. Assessment tests should be selected based on their effectiveness, and the results must be interpreted in light of the complete clinical picture. Box 19-3 lists common maternal and fetal indications for antepartum testing that are supported by currently available evidence (Miller, Miller, & Tucker, 2013). Diagnostic ultrasonography is an important, safe technique in antepartum fetal surveillance. It provides critical information to health care providers regarding fetal activity and gestational age, normal versus abnormal fetal growth curves, visual assistance with which invasive tests may be performed more safely, fetal and placental anatomy, and fetal well-being (Richards, 2007). Ultrasound examination can be performed abdominally or transvaginally during pregnancy. Both methods produce a two- or three-dimensional view from which a pictorial image is obtained (Fig. 19-1, A, B). It is also possible to produce a four-dimensional image. Abdominal ultrasonography is more useful after the first trimester when the pregnant uterus becomes an abdominal organ. During the procedure, the woman usually should have a full bladder to displace the uterus upward to provide a better image of the fetus. Transmission gel or paste is applied to the woman’s abdomen before a transducer is moved over the skin to enhance transmission and reception of the sound waves. She is positioned with small pillows under her head and knees. The display panel is positioned so that the woman or her partner (or both) can observe the images on the screen if they desire. TABLE 19-1 Major Uses of Ultrasonography during Pregnancy
Assessment of High Risk Pregnancy
Assessment of Risk Factors
Antepartum Testing
Biophysical Assessment
Daily Fetal Movement Count
Ultrasonography
Indications for use
FIRST TRIMESTER
SECOND TRIMESTER
THIRD TRIMESTER
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Assessment of High Risk Pregnancy
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