downs syndrome is caused by

HESI LPN

HESI Maternal Newborn

1. What causes Down's syndrome?

A. Alcohol abuse by the mother at the time of conception.
B. Sex-linked chromosomal abnormalities.
C. An extra chromosome on the 21st pair.
D. Drug abuse by the mother during pregnancy.

Correct answer: C

Rationale: Down's syndrome, also known as trisomy 21, is caused by the presence of an extra chromosome on the 21st pair. Choice A is incorrect as alcohol abuse is not the cause of Down's syndrome. Choice B is incorrect because Down's syndrome is not related to sex-linked chromosomal abnormalities. Choice D is also incorrect as drug abuse by the mother during pregnancy is not the cause of Down's syndrome.

2. The healthcare provider is preparing to administer phytonadione (vitamin K) to a newborn. Which statement made by the parents indicates understanding why the healthcare provider is administering this medication?

A. Improve insufficient dietary intake
B. Stimulate the immune system
C. Help an immature liver
D. Prevent hemorrhagic disorders

Correct answer: D

Rationale: The correct answer is D because phytonadione (vitamin K) is administered to newborns to prevent hemorrhagic disease due to their low levels of vitamin K, which is essential for blood clotting. Choice A is incorrect as vitamin K administration is not related to improving dietary intake. Choice B is incorrect as vitamin K doesn't stimulate the immune system. Choice C is incorrect as vitamin K is not given to help an immature liver, but rather to prevent hemorrhagic disorders.

3. A primigravida at 36 weeks gestation who is RH-negative experienced abdominal trauma in a motor vehicle collision. Which assessment finding is most important for the nurse to report to the healthcare provider?

A. Fetal heart rate at 162 beats per minute
B. Mild contractions every 10 minutes
C. Trace of protein in the urine
D. Positive fetal hemoglobin testing

Correct answer: D

Rationale: The correct answer is 'Positive fetal hemoglobin testing' (D). Positive fetal hemoglobin testing (Kleihauer-Betke test) indicates fetal-maternal hemorrhage, which is critical in an RH-negative mother due to the risk of isoimmunization. This condition can lead to sensitization of the mother's immune system against fetal blood cells, potentially causing hemolytic disease of the newborn in subsequent pregnancies. Reporting this finding promptly is crucial for appropriate management and interventions. Choices A, B, and C are not as critical in this scenario. While monitoring fetal heart rate and contractions is important, the detection of fetal-maternal hemorrhage takes precedence due to the serious implications it poses for the current and future pregnancies of an RH-negative mother.

4. Which of the following statements is true of menstruation?

A. During this time, the endometrium is shed.
B. During this time, an unfertilized egg is discharged.
C. During this time, a female can engage in sexual activity with her partner.
D. During this time, a fertilized egg implants in the uterine lining.

Correct answer: B

Rationale: The correct statement regarding menstruation is that during this time, an unfertilized egg is discharged along with the shedding of the uterine lining. Choice A is incorrect because the endometrium is shed during menstruation. Choice C is incorrect as menstruation does not prevent a female from engaging in sexual activity with her partner. Choice D is incorrect as a fertilized egg does not undergo mitosis during menstruation but rather implants in the uterine lining for further development.

5. During a prenatal visit, for which of the following clients should the nurse auscultate the fetal heart rate?

A. A client who has an ultrasound confirming a molar pregnancy
B. A client who has a crown-rump length corresponding to 7 weeks gestation
C. A client who has a positive urine pregnancy test 1 week after missed menses
D. A client who has felt quickening for the first time

Correct answer: D

Rationale: The correct answer is D because feeling quickening typically occurs around 18-20 weeks of gestation, indicating fetal movement. This is an appropriate time to auscultate the fetal heart rate. Choice A is incorrect because a molar pregnancy is not a viable pregnancy, and auscultating the fetal heart rate in this case is not applicable. Choice B is incorrect because a crown-rump length of 7 weeks gestation is too early for fetal heart rate auscultation. Choice C is incorrect because a positive urine pregnancy test alone does not indicate the appropriate timing for fetal heart rate auscultation.