Chapter 10 Fetal Development and Genetics

Prenatal testing is used to assess for genetic risks and to identify genetic disorders. In explaining to a couple about an elevated alpha-fetoprotein screening test result, the nurse would discuss the need for: A) Special care needed for a Down syndrome infant B) A more specific determination of the acid-base status C) Further, more definitive evaluations to conclude anything D) Immediate termination of the pregnancy based on results

Ans: C Feedback: Increased maternal serum alpha fetoprotein levels may indicate a neural tube defect, Turner syndrome, tetralogy of Fallot, multiple gestation, omphalocele, gastroschisis, or hydrocephaly. Therefore, additional information and more specific determinations need to be done before any conclusion can be made. Down syndrome is associated with decreased maternal serum alpha fetoprotein levels. This type of testing provides no information about the acid-base status of the fetus. Immediate termination is not warranted; more information is needed.

After teaching a pregnant woman about the hormones produced by the placenta, the nurse determines that the teaching was successful when the woman identifies which hormone produced as being the basis for pregnancy tests? A) Human placental lactogen (hPL) B) Estrogen (estriol) C) Progesterone (progestin) D) Human chorionic gonadotropin (hCG)

Ans: D Feedback: The placenta produces hCG, which is the basis for pregnancy tests. This hormone preserves the corpus luteum and its progesterone production so that the endometrial lining is maintained. Human placental lactogen modulates fetal and maternal metabolism and participates in the development of the breasts for lactation. Estrogen causes enlargement of the woman's breasts, uterus, and external genitalia and stimulates myometrial contractility. Progesterone maintains the endometrium.

A woman just delivered a healthy term newborn. Upon assessing the umbilical cord, the nurse would identify which of the following as normal? (Select all that apply.) A) One vein B) Two veins C) One artery D) Two arteries E) One ligament F) Two ligaments

Ans: A, D Feedback: The normal umbilical cord contains one large vein and two small arteries.

Assessment of a pregnant woman reveals oligohydramnios. The nurse would be alert for the development of which of the following? A) Maternal diabetes B) Placental insufficiency C) Neural tube defects D) Fetal gastrointestinal malformations

Ans: B Feedback: A deficiency of amniotic fluid, oligohydramnios, is associated with uteroplacental insufficiency and fetal renal abnormalities. Excess amniotic fluid is associated with maternal diabetes, neural tube defects, and malformations of the gastrointestinal tract and central nervous system.

When describing genetic disorders to a group of childbearing couples, the nurse would identify which as an example of an autosomal dominant inheritance disorder? A) Huntington's disease B) Sickle cell disease C) Phenylketonuria D) Cystic fibrosis

Ans: A Feedback: Huntington's disease is an example of an autosomal dominant inheritance disorder. Sickle cell disease, phenylketonuria, and cystic fibrosis are examples of autosomal recessive inheritance disorders.

After teaching a group of students about fetal development, the instructor determines that the teaching was successful when the students identify which of the following as providing the barrier to other sperm after fertilization? A) Zona pellucida B) Zygote C) Cleavage D) Morula

Ans: A Feedback: The zona pellucida is the clear protein layer that acts as a barrier to other sperm once one sperm enters the ovum for fertilization. The zygote refers to the union of the nuclei of the ovum and sperm resulting in the diploid number of chromosomes. Cleavage is another term for mitosis. The morula is the result of four cleavages leading to 16 cells that appear as a solid ball of cells. The morula reaches the uterine cavity about 72 hours after fertilization.

A group of students are reviewing information about genetic inheritance. The students demonstrate understanding of the information when they identify which of the following as an example of an autosomal recessive disorder? (Select all that apply.) A) Cystic fibrosis B) Phenylketonuria C) Tay-Sachs disease D) Polycystic kidney disease E) Achondroplasia

Ans: A, B, C Feedback: Examples of autosomal recessive disorders include cystic fibrosis, phenylketonuria, and Tay-Sachs disease. Polycystic kidney disease and achondroplasia are examples of autosomal dominant diseases.

A nurse is discussing fetal development with a pregnant woman. The woman is 12 weeks pregnant and asks, "What's happening with my baby?" Which of the following would the nurse integrate into the response? (Select all that apply.) A) Continued sexual differentiation B) Eyebrows forming C) Startle reflex present D) Digestive system becoming active E) Lanugo present on the head

Ans: A, D Feedback: At 12 weeks, sexual differentiation continues and the digestive system shows activity. Eyebrows form and startle reflex is present between weeks 21 and 24. Lanugo on the head appears about weeks 13-16.

A pregnant woman undergoes maternal serum alpha-fetoprotein (MSAFP) testing at 16 to 18 weeks' gestation. Which of the following would the nurse suspect if the woman's level is decreased? A) Down syndrome B) Sickle-cell anemia C) Cardiac defects D) Open neural tube defect

Ans: A Feedback: Decreased levels might indicate Down syndrome or trisomy 18. Sickle cell anemia may be identified by chorionic villus sampling. MSAFP levels would be increased with cardiac defects, such as tetralogy of Fallot. A triple marker test would be used to determine an open neural tube defect.

A nurse is describing advances in genetics to a group of students. Which of the following would the nurse least likely include? A) Genetic diagnosis is now available as early as the second trimester. B) Genetic testing can identify presymptomatic conditions in children. C) Gene therapy can be used to repair missing genes with normal ones. D) Genetic agents may be used in the future to replace drugs.

Ans: A Feedback: Genetic diagnosis is now possible very early in pregnancy (see Evidence-Based Practice 10.1). Genetic testing can now identify presymptomatic conditions in children and adults. Gene therapy can be used to replace or repair defective or missing genes with normal ones. Gene therapy has been used for a variety of disorders, including cystic fibrosis, melanoma, diabetes, HIV, and hepatitis (Tamura, Kamuma, Nakazato, et al. 2010). The potential exists for creation of increased intelligence and size through genetic intervention. Recent research using gene therapy shows promise for the generation of insulin-producing cells to cure diabetes (Calne, Gan, & Lee 2010). In the future, genetic agents may replace drugs, general surgery may be replaced by gene surgery, and genetic intervention may replace radiation.

After teaching a group of students about fetal development, the instructor determines that the teaching was successful when the students identify which of the following as essential for fetal lung development? A) Umbilical cord B) Amniotic fluid C) Placenta D) Trophoblasts

Ans: B Feedback: Amniotic fluid is essential for fetal growth and development, especially fetal lung development. The umbilical cord is the lifeline from the mother to the growing embryo. The placenta serves as the interface between the mother and developing fetus. It secretes hormones and supplies the fetus with nutrients and oxygen needed for growth. The trophoblasts differentiate into all the cells that form that placenta.

After the nurse describes fetal circulation to a pregnant woman, the woman asks why her fetus has a different circulation pattern than hers. In planning a response, the nurse integrates understanding of which of the following? A) Fetal blood is thicker than that of adults and needs different pathways. B) Fetal circulation carries highly oxygenated blood to vital areas first. C) Fetal blood has a higher oxygen saturation and circulates more slowly. D) Fetal heart rates are rapid and circulation time is double that of adults.

Ans: B Feedback: Fetal circulation functions to carry highly oxygenated blood to vital areas first while shunting it away from less vital ones. Fetal blood is not thicker than that of adults. Large volumes of oxygenated blood are not needed because the placenta essentially takes over the functions of the lung and liver during fetal life. Although fetal heart rates normally range from 120 to 160 beats per minute, circulation time is not doubled.

A woman is scheduled to undergo fetal nuchal translucency testing. Which of the following would the nurse include when describing this test? A) "A needle will be inserted directly into the fetus's umbilical vessel." B) "You'll have an intravaginal ultrasound to measure fluid in the fetus." C) "The doctor will take a sample of fluid from your bag of waters." D) "A small piece of tissue from the fetal part of the placenta is taken."

Ans: B Feedback: Fetal nuchal translucency testing involves an intravaginal ultrasound that measures fluid collection in the subcutaneous space between the skin and cervical spine of the fetus. Insertion of a needle into the fetus's umbilical vessel describes percutaneous umbilical blood sampling. Taking a sample of fluid from the amniotic sac (bag of waters) describes an amniocentesis. Obtaining a small tissue specimen from the fetal part of the placenta describes chorionic villus sampling.

A nursing instructor is preparing a teaching plan for a group of nursing students about the potential for misuse of genetic discoveries and advances. Which the following would the instructor most likely include? A) Gene replacement therapy for defective genes B) Individual risk profiling and confidentiality C) Greater emphasis on the causes of diseases D) Slower diagnosis of specific diseases

Ans: B Feedback: Individual risk profiling based on an individual's genetic makeup can raise issues related to privacy and confidentiality. Gene replacement therapy for defective genes and a greater emphasis on looking at the causes of disease are considered benefits associated with genetic advances. Rapid, more specific diagnosis of diseases would be possible.

A nurse is teaching a class on X-linked recessive disorders. Which of the following statements would the nurse most likely include? A) Males are typically carriers of the disorders. B) No male-to-male transmission occurs. C) Daughters are more commonly affected with the disorder. D) Both sons and daughters have a 50% risk of the disorder.

Ans: B Feedback: Most X-linked disorders demonstrate a recessive pattern of inheritance. Males are more affected than females. A male has only one X chromosome and all the genes on his X chromosome will be expressed, whereas a female will usually need both X chromosomes to carry the disease. There is no male-to-male transmission (since no X chromosome from the male is transmitted to male offspring), but any man who is affected will have carrier daughters. If a woman is a carrier, there is a 50% chance that her sons will be affected and a 50% chance that her daughters will be carriers.

The nurse is developing a presentation for a community group of young adults discussing fetal development and pregnancy. The nurse would identify that the sex of offspring is determined at the time of: A) Meiosis B) Fertilization C) Formation of morula D) Oogenesis

Ans: B Feedback: Sex determination occurs at the time of fertilization. Meiosis refers to cell division resulting in the formation of an ovum or sperm with half the number of chromosomes. The morula develops after a series of four cleavages following the formation of the zygote. Oogenesis refers to the development of a mature ovum, which has half the number of chromosomes.

When describing the structures involved in fetal circulation, the nursing instructor describes which structure as the opening between the right and left atrium? A) Ductus venosus B) Foramen ovale C) Ductus arteriosus D) Umbilical artery

Ans: B Feedback: The foramen ovale is the opening between the right and left atrium. The ductus venosus connects the umbilical vein to the inferior vena cava. The ductus arteriosus connects the main pulmonary artery to the aorta. The umbilical artery carries blood to the placenta.

During a prenatal class for a group of new mothers, the nurse is describing the hormones produced by the placenta. Which of the following would the nurse include? (Select all that apply.) A) Prolactin B) Estriol C) Relaxin D) Progestin E) Human chorionic somatomammotropin

Ans: B, C, D, E Feedback: Estriol, relaxin, progestin, and human chorionic somatomammotropin are secreted by the placenta. Prolactin is secreted after delivery for breast-feeding.

A nurse is assessing a child with Klinefelter's syndrome. Which of the following would the nurse expect to assess? (Select all that apply.) A) Gross mental retardation B) Long arms C) Profuse body hair D) Gynecomastia E) Enlarged testicles

Ans: B, D Feedback: Manifestations of Klinefelter's syndrome include mild mental retardation, small testicles, infertility, long arms and legs, gynecomastia, scant facial and body hair, and decreased libido.

After teaching a class on the stages of fetal development, the instructor determines that the teaching was successful when the students identify which of the following as a stage? (Select all that apply.) A) Placental B) Preembryonic C) Umbilical D) Embryonic E) Fetal

Ans: B, D, E Feedback: The three stages of fetal development are the preembryonic, embryonic, and fetal stage. Placental and umbilical are not stages of fetal development.

When describing amniotic fluid to a pregnant woman, the nurse would include which of the following? A) "This fluid acts as transport mechanism for oxygen and nutrients." B) "The fluid is mostly protein to provide nourishment to your baby." C) "This fluid acts as a cushion to help to protect your baby from injury." D) "The amount of fluid remains fairly constant throughout the pregnancy."

Ans: C Feedback: Amniotic fluid protects the floating embryo and cushions the fetus from trauma. The placenta acts as a transport mechanism for oxygen and nutrients. Amniotic fluid is primarily water with some organic matter. Throughout pregnancy, amniotic fluid volume fluctuates.

While talking with a pregnant woman who has undergone genetic testing, the woman informs the nurse that her baby will be born with Down syndrome. The nurse understands that Down syndrome is an example of: A) Multifactorial inheritance B) X-linked recessive inheritance C) Trisomy numeric abnormality D) Chromosomal deletion

Ans: C Feedback: Down syndrome is an example of a chromosomal abnormality involving the number of chromosomes (trisomy numeric abnormality), in particular chromosome 21, in which the individual has three copies of that chromosome. Multifactorial inheritance gives rise to disorders such as cleft lip, congenital heart disease, neural tube defects, and pyloric stenosis. X-linked recessive inheritance is associated with disorders such as hemophilia. Chromosomal deletion is involved with disorders such as cri du chat syndrome.

A couple comes to the clinic for preconception counseling and care. As part of the visit, the nurse teaches the couple about fertilization and initial development, stating that the zygote formed by the union of the ovum and sperm consists of how many chromosomes? A) 22 B) 23 C) 44 D) 46

Ans: D Feedback: With fertilization, the ovum, containing 23 chromosomes, and the sperm, containing 23 chromosomes, join, forming a zygote with a diploid number or 46 chromosomes.