Which of the following findings should a nurse report to the provider for a client who is at 20 weeks of gestation?

Choice A reason: Detecting congenital anomalies at 10 weeks via ultrasound is limited, as major anomalies are better assessed at 18-20 weeks when fetal structures are more developed. Early ultrasound primarily confirms viability and gestational age. While some anomalies may be seen, it is not the primary purpose at this stage, per obstetric imaging protocols.

Choice B reason: An ultrasound at 10 weeks accurately determines gestational age by measuring crown-rump length, enabling calculation of the expected delivery date. This measurement reflects embryonic development and is most precise in the first trimester, aligning with fetal growth patterns and supporting obstetric planning for pregnancy monitoring and delivery timing.

Choice C reason: Assessing amniotic fluid volume at 10 weeks is not the primary focus of ultrasound, as fluid levels are typically evaluated later (second trimester) when oligohydramnios or polyhydramnios become relevant. Early ultrasound prioritizes viability and dating, as amniotic fluid dynamics are less critical at this stage of embryonic development.

Choice D reason: Determining the biological sex of the fetus at 10 weeks is not feasible with standard ultrasound, as genital differentiation is clearer after 12-14 weeks or later. Early ultrasound focuses on gestational age and viability, not sex, which requires advanced imaging or genetic testing, per fetal development and imaging science.

Choice A reason: Critical congenital heart disease (CCHD) screening uses pulse oximetry, not a heel blood sample. Blood sampling is for metabolic screening, not heart defects. Pulse oximetry measures oxygen saturation non-invasively, detecting shunting or cyanotic defects, aligning with CCHD screening’s focus on circulatory assessment.

Choice B reason: CCHD screening is typically performed at 24-48 hours of age, not 6-12 hours, to ensure stable postnatal circulation. Early testing may yield false positives due to transitional physiology. Pulse oximetry at the correct timing accurately detects critical heart defects, per neonatal screening protocols.

Choice C reason: CCHD screening compares oxygen saturation in the upper (right hand) and lower (foot) extremities using pulse oximetry to detect congenital heart defects causing differential cyanosis. A significant difference indicates potential shunting or ductal-dependent lesions, requiring further evaluation, aligning with the physiological basis of CCHD screening.

Choice D reason: CCHD screening results are immediate via pulse oximetry, not delayed 1-2 weeks. Real-time oxygen saturation readings identify potential heart defects, enabling prompt referral for echocardiography. Delayed results apply to metabolic screening, not CCHD, which relies on instant physiological data, per neonatal diagnostic protocols.