The nurse is assessing the knowledge of new parents with a child born with maple syrup urine disease (MSUD). This is an autosomal recessive inherited disorder, which means that:

Correct Answer: A

Rationale: In this question, the correct answer is A) Both genes of a pair must be abnormal for the disorder to be expressed. This is because maple syrup urine disease (MSUD) is an autosomal recessive inherited disorder. This means that two copies of the abnormal gene, one from each parent, are needed for the disorder to manifest in the child. Option B) Only one copy of the abnormal gene is required for the disorder to be expressed is incorrect because MSUD is recessive, not dominant. If only one copy of the gene was needed, it would be a dominant disorder. Option C) The disorder occurs in males and heterozygous females is incorrect because MSUD is an autosomal recessive disorder, meaning it can affect both males and females equally if they inherit two copies of the abnormal gene. Option D) The disorder is carried on the X chromosome is incorrect because MSUD is an autosomal recessive disorder, not linked to the sex chromosomes. Educationally, understanding the principles of autosomal recessive inheritance is crucial for healthcare professionals working with families affected by genetic disorders. By grasping concepts like these, nurses can provide accurate information and support to families dealing with inherited conditions like MSUD.

Correct Answer: B

Rationale: In addressing the question on chromosome abnormalities in fetal development, it is crucial for nurses to understand that option B, "Abnormalities of number are the leading cause of pregnancy loss," is the correct choice. This option is accurate because aneuploidy, which refers to abnormalities in the number of chromosomes, is indeed the primary cause of pregnancy loss, as these abnormalities often result in non-viable embryos. Options A, C, and D are incorrect for several reasons. Option A stating that chromosome abnormalities occur in approximately 10% of newborns is incorrect, as the actual incidence is much lower. Down syndrome, as mentioned in option C, is caused by an extra copy of chromosome 21, a numerical abnormality, not a structural one. Option D is incorrect because unbalanced translocations can lead to significant abnormalities that a child may not necessarily outgrow. Educationally, understanding chromosome abnormalities is vital for nurses caring for pregnant women and infants. Recognizing the impact of aneuploidy on pregnancy outcomes can help nurses provide appropriate support and guidance to families facing such challenges. By knowing the correct information regarding chromosome abnormalities, nurses can offer comprehensive care and accurate information to patients, enhancing their ability to provide quality care throughout the prenatal and postnatal periods.

Correct Answer: A

Rationale: In fetal development, meconium is the first stool passed by a newborn and is typically a greenish-black, tarry substance. The correct answer is A) Fetal intestines. Meconium is formed in the fetal intestines as a result of the fetus swallowing and processing amniotic fluid. It accumulates in the intestines throughout gestation and is usually passed after birth. Option B) Fetal kidneys is incorrect because meconium is not produced by the kidneys. The kidneys are responsible for filtering waste from the blood to form urine. Option C) Amniotic fluid is incorrect because meconium is not produced by the amniotic fluid itself. While the fetus swallows amniotic fluid, meconium is formed in the intestines. Option D) The placenta is incorrect because meconium is not produced by the placenta. The placenta is an organ that provides oxygen and nutrients to the fetus and removes waste products. Understanding the origin of meconium is crucial for nurses caring for laboring women as the presence of meconium-stained amniotic fluid can indicate fetal distress and may require additional monitoring or interventions during labor and delivery. Being knowledgeable about fetal development helps healthcare providers provide optimal care for both the mother and the baby.

Correct Answer: C

Rationale: The correct answer is C) 2:01. The L/S ratio, which stands for lecithin to sphingomyelin ratio, is an important marker used to assess fetal lung maturity. In the amniotic fluid, the presence of lecithin, a phospholipid produced by type II pneumocytes in the fetal lung, increases as the fetus matures. Sphingomyelin, another phospholipid, remains relatively constant. A ratio of 2:1 or higher indicates mature fetal lungs where surfactant production is sufficient to support gas exchange after birth. Thus, a higher L/S ratio reflects a lower risk of respiratory distress syndrome in the newborn. Now, let's analyze why the other options are incorrect: A) 1.4:1 - This ratio is lower than the ideal 2:1 ratio, indicating insufficient lung maturity. B) 1.8:1 - While closer to the ideal ratio, this value still falls short of the 2:1 benchmark for optimal lung maturity. D) 1:1 - This ratio suggests immature lungs with a higher risk of respiratory distress syndrome due to inadequate surfactant production. Understanding the L/S ratio is crucial for obstetricians, neonatologists, and other healthcare professionals involved in managing pregnancies and newborn care. It helps in predicting and preparing for potential respiratory complications in preterm infants. By grasping the significance of this ratio, healthcare providers can make informed decisions regarding the timing and management of deliveries to optimize neonatal outcomes.

Correct Answer: B

Rationale: The correct answer is B) As one of its early functions, the placenta acts as an endocrine gland. This is because the placenta plays a crucial role in producing hormones that support the pregnancy by sustaining the uterine environment and supporting fetal development. Option A is incorrect because the placenta does not widen and thin to allow the passage of air and nutrients; its structure remains constant throughout pregnancy. Option C is incorrect because while the placenta acts as a barrier, it is not completely impermeable, and some harmful substances can pass through. Option D is incorrect because optimal blood circulation through the placenta is achieved when the woman is lying on her side rather than on her back or standing. Educationally, understanding the functions of the placenta is essential for maternity nurses to provide optimal care for pregnant women and their babies. Knowing how the placenta functions as an endocrine gland helps nurses monitor maternal and fetal well-being during pregnancy and identify any potential issues that may arise. This knowledge is crucial for promoting healthy pregnancy outcomes and providing comprehensive prenatal care.