The nurse is preparing a patient in her second trimester for a three-dimensional ultrasound ...

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Rationale 1: Not all fetal anomalies are detectable by ultrasound.
Rationale 2: Nuchal translucency measurements are screening, not diagnostic, for trisomies 13, 18, and 21.
Rationale 3: Ultrasounds provide a very clear photo-like image of the fetus, often providing parents the opportunity to identify a familial characteristic such as nose shape.
Rationale 4: Transvaginal ultrasound is used to measure the cervical length as a screening for risk for preterm labor. However, a normal-length cervix does not preclude preterm birth.