Chapter 6: Conception and Fetal Development NCLEX

D

(Down syndrome is an intellectual disability caused by aneuploidy. Aneuploidy is a condition characterized by the presence or absence of an extra chromosome. Therefore the presence of extra chromosome 21 causes Down syndrome in the newborn. The deficiency of folic acid results in neural tube defects in the newborn. X-linked recessive gene disorder results from the presence of a defective gene on the X-chromosome of a carrier mother. Down syndrome is not caused by inheritance of an autosomal recessive gene. It occurs because of the defect in the chromosomal count in an individual.)

The nurse is interacting with the parents of a newborn who is diagnosed with Down syndrome. What explanation should the nurse provide to the parents about the genetic disorder? Down syndrome is caused by:

A. A decreased intake of folic acid."

B. An X-linked recessive gene issue."

C. An autosomal recessive gene."

D. The presence of an extra chromosome."

B

(The sperm remains viable in the female reproductive system for 3 to 5 days after sexual intercourse. Within this time a sperm fuses with an ova to form a zygote. The sperm is no longer viable after 5 days. Therefore they do not remain viable after 4 to 8, and 5 to 9 days after intercourse.)

What is the duration for which the sperm remains viable in the female reproductive system?

A. 2 to 4 days after intercourse

B. 3 to 5 days after intercourse

C. 4 to 8 days after intercourse

D. 5 to 9 days after intercourse

C

(The detection of the presence of pulmonary surfactants (surface-active phospholipids) in amniotic fluid has been used to determine fetal lung maturity, or the ability of the lungs to function after birth. This occurs at approximately 35 weeks of gestation. The presence of surface-active phospholipids is not an indication of Down syndrome. This result reveals the fetal lungs are mature and in no way indicates risk for preterm labor. Meconium should not be present in the amniotic fluid.)

A woman at 35 weeks of gestation has had an amniocentesis. The results reveal that surface-active phospholipids are present in the amniotic fluid. The nurse is aware that this finding indicates:

A. The fetus is at risk for Down syndrome.

B. The woman is at high risk for developing preterm labor.

C. Lung maturity.

D. Meconium is present in the amniotic fluid.

A

(The risk for Down syndrome increases in the fetus as the age of the pregnant mother gets older. Because the patient is older than 35 years of age, the fetus is at an increased risk for having Down syndrome. The development of sickle cell anemia is not related to the age of the mother. It is caused by inheriting the defective genes from the parents. Neural tube defect in the fetus results from insufficient intake of folic acid during pregnancy. HD is an autosomal dominant disorder caused by a mutation on the normal gene and is not related to the age of the patient.)

The nurse is assessing a 40-year-old patient who is 12 weeks pregnant. What should the nurse anticipate based on the patient's age?

A. The fetus is at a risk for Down syndrome.

B. The patient is at a risk for sickle cell anemia.

C. The fetus is at a risk for neural tube defects.

D. The patient is at a risk for Huntington's disease (HD).

B

(The gestation period of a fetus is 266 days from the date of conception and 280 days from the last menstrual period. Calculating the gestational period after conception from June 20, the expected date of delivery is March 13, 2013. March 27, 2013, is the expected date of delivery if June 20, 2012, is the first day of the last menstrual period. February 13 and 27 are not the expected date of delivery unless the baby is a preterm infant.)

What is the expected delivery date of a patient whose conception is reported on June 20, 2012?

A. March 13, 2013

B. March 27, 2013

C. February 13, 2013

D. February 27, 2013

C

(Religion does not play a major role in the fetal development. Therefore it is not required to ask whether the patient follows Christianity. Before conducting prenatal testing, the nurse should assess the socioeconomic status of the patient's family. It helps to know the factors that may affect fetal growth and development. Therefore the nurse should ask questions to obtain the information regarding the socioeconomic status of the patient. The nurse should ask about the partner's age to assess the risk for genetic disorders such as Down syndrome. Asking whether the patient regularly drinks alcohol helps assess the risk for fetal alcohol spectrum disorder. Asking about the profession of the patient's partner provides the clue for the risk for carcinogenesis.)

The nurse is teaching a student nurse about questions that can be asked of the patient before undergoing prenatal testing. The nurse then asked the student to write the set of questions on a piece of paper. Which question written by the student nurse indicates the need for further teaching?

A. "What is the age of your partner?"

B. "Do you smoke or drink regularly?"

C. "Do you believe in Christianity?"

D. "What is your partner's profession?

C

(Karyotyping provides genetic information, such as gender and chromosomal structure. The lecithin/sphingomyelin ratio, not karyotyping, reveals lung maturity. Although karyotyping can detect genetic anomalies, the range of normal is nondescriptive. Although karyotyping can detect genetic anomalies, not all such anomalies display obvious physical deformities. The term deformities is a nondescriptive word. Furthermore, physical anomalies may be present that are not detected by genetic studies (e.g., cardiac malformations).)

A couple has been counseled for genetic anomalies. They ask, "What is karyotyping?" The nurse's best response is:

A. "Karyotyping will reveal if the baby's lungs are mature."

B. "Karyotyping will reveal if your baby will develop normally."

C. "Karyotyping will provide information about the gender of the baby, and the number and structure of the chromosomes."

D. "Karyotyping will detect any physical deformities the baby has.

B

(Ultrasound scan or fetal ultrasound is the technique used for visualizing the fetus and the internal structures for prenatal analysis. In this technique, high-frequency sound waves produce the image of the fetus without harming the fetal internal organs. Therefore this technique is used to identify the presence of twins in the patient's womb. Human placental lactogen changes the metabolism of the mother and supplies energy to the fetus. Cytogenetic testing helps find the genetic abnormalities and that caused by changes in the chromosomes. Amniotic fluid protects the fetus from injuries. These tests do not help determine the presence of twins in the patient's womb.)

The nurse is reviewing the diagnostic test results with a pregnant patient and informs the patient that she is going to have twins. Based on which diagnostic test did the nurse make such a conclusion?

A. Human placental lactogen

B. Ultrasound results

C. Cytogenetic testing

D. Amniotic fluid levels

B

(Ultrasound testing is performed using high-frequency sound waves to obtain an image of the fetus. This technique is painless and a needle is not inserted in the womb. If the patient asks about the insertion of a needle in ultrasound, it implies that the patient did not understand about the technique and requires further teaching. A needle is used for an amniocentesis. These sound waves do not harm the fetus, and their frequency can be adjusted. This technique helps to identify the fetal abnormalities, because it shows the image of the fetus.)

Before conducting the ultrasound scan, the nurse instructs the pregnant patient on the procedure. Which statement made by the patient indicates the need for further teaching?

A. "The sound waves are not harmful to the fetus at all."

B. "A needle is inserted in the abdomen during the scan."

C. "The frequency of the sound produced can be adjusted."

D. "Fetal anomalies can be identified by ultrasound scan."

A

(Pregnant women often experience hypotension when they lie on their back (in the supine position). The blood that is trying to return to the right atrium is diminished because the uterus is compressing the vena cava. Therefore the nurse should have the patient to lie on either side to rest. This will reduce the uterine pressure on the right atrium and helps in optimal circulation. Aerobic exercise will not be helpful in reducing the pressure caused by uterine compression. Making the patient stand up and take deep breaths will worsen the symptoms of hypotension. Making the patient lie in the supine position will further increase the uterine compression and hypotension.)

The blood pressure of a pregnant patient becomes low when the patient lies on the back. What would be the best nursing intervention to maintain normal blood pressure in the patient?

A. Position the patient to lie on the left side and rest.

B. Suggest that the patient perform aerobic exercises daily.

C. Have the patient stand up and take a deep breath.

D. Tell the patient to lie straight facing up and take frequent rest periods.

C

(Two milestones that occur at 20 weeks are the appearance of the vernix caseosa and lanugo. The primary lung and urethral buds appear at 6 weeks of gestation. The vagina is open or the testes are in position for descent into the scrotum at 16 weeks. The appearance of smooth skin occurs at 28 weeks, and subcutaneous fat begins to collect at 30 to 31 weeks.)

The student nurse is giving a presentation about milestones in embryonic development. Which information should the student include?

A. At 8 weeks of gestation, primary lung and urethral buds appear.

B. At 12 weeks of gestation, the vagina is open or the testes are in position for descent into the scrotum.

C. At 20 weeks of gestation, the vernix caseosa and lanugo appear.

D. At 24 weeks of gestation, the skin is smooth, and subcutaneous fat is beginning to collect.

C

(The fetal heart starts beating by the end of the fifth week. Two arteries carry blood from the embryo to the chorionic villi, and one vein returns the blood to the embryo. Deoxygenated blood leaves the fetus through the umbilical arteries and enters the placenta, where it is oxygenated. Oxygenated blood leaves the placenta through the umbilical vein, which enters the fetus via the umbilical cord. It is rare for there to be one vein and one artery. Approximately 1% of umbilical cords contain only two vessels: one artery and one vein. This occurrence is sometimes associated with congenital malformations. Therefore the presence of two veins and one artery and two veins and two arteries is inappropriate.)

How many veins and arteries are present between the maternal and the fetal circulatory system by the fifth week of pregnancy?

A. One vein and one artery

B. Two veins and one artery

C. One vein and two arteries

D. Two veins and two arteries

B

(Genetic testing of the couple may determine whether the parents of the newborn are carriers for the mutation. Phenylketonuria can be seen in the newborn only if both parents are carriers for the disorder. Fetal sonography is a technique of imaging the fetus in the uterus using high-frequency sound waves. Chorionic villus sampling is a prenatal diagnostic technique to determine chromosomal disorders in the fetus. Maternal serum sampling is carried out on the mother through a blood test to screen the high risk of carrying a fetus with neural tube defects or genetic abnormalities.)

The genetic screening of a newborn is indicative of phenylketonuria. The nurse learns that the couple has no history of genetic disorders in the past three generations. What other tests does the nurse suggest to the couple to determine the reason for the genetic disorder?

A. Sonography of the fetus

B. Genetic test of the couple

C. Chorionic villus sampling

D. Maternal serum screening

A

(Patients with uncontrolled diabetes are at a higher risk for complications associated with pregnancy. If the pregnant mother develops uncontrolled hyperglycemia, this may produce hyperglycemia in the fetus. This in turn stimulates fetal hyperinsulinemia and islet cell hyperplasia. Hyperinsulinemia prevents fetal lung maturation and places the neonate at an increased risk for respiratory distress. African-American patients have an increased chance of having dizygotic twins. They are not associated with an increased risk for pregnancy-related complications. Patients within the age-group of 30 to 33 years are not at risk for complications associated with pregnancy. Alcohol consumption during pregnancy leads to respiratory complications and fetal alcohol syndrome. However, patients with a history of alcohol consumption do not usually have pregnancy-related complications.)

The nurse is assessing a group of pregnant women at a community health center. Which patients would be at highest risk for pregnancy-related complications? The patient:

A. With uncontrolled diabetes mellitus.

B. Who is of African-American descent.

C. Who is between 30 and 33 years old.

D. With history of alcohol consumption.

B

(Fetuses respond to sound by 24 weeks. The fetus can be soothed by the sound of the mother's voice. Although stating that many pregnant women imagine what their baby is like is accurate, it is not the most appropriate response. The mother should be instructed that her fetus can hear at 24 weeks and can respond to the sound of her voice. Stating that if the woman thinks that her baby hears will help them bond gives the impression that her baby cannot hear her. It also belittles the mother's interpretation of her fetus's behaviors.)

A woman is 8 months pregnant. She tells the nurse that she knows her baby listens to her, but her husband thinks she is imagining things. Which response by the nurse is most appropriate?

A. "Many pregnant women imagine what their baby is like."

B. "A baby in utero does respond to the mother's voice."

C. "You'll need to ask the doctor if the baby can hear yet."

D. "Thinking that your baby hears will help you bond with the baby."

D

(Karyotyping is the estimation of the number, size, and forms of chromosomes for detecting chromosomal abnormalities like trisomy. These are the major causes for frequent miscarriage, stillbirths, and other gynecologic disorders. Blood sample is the preferred sample for determining chromosome abnormalities. Nucleated and replicating cells such as white blood cells are extracted from the blood sample and chosen for karyotyping. Urine, saliva, and muscle samples are not used for analyzing chromosome number, because they do not undergo rapid division to form new cells.)

A patient who has experienced frequent miscarriages is referred for chromosomal analysis. Which sample should the nurse obtain to conduct karyotyping for the patient?

A. Urine

B. Saliva

C. Muscle

D. Blood

B

(Aneuploidy is an abnormality of number that also is the leading genetic cause of cognitive impairment. Chromosomal abnormalities occur in less than 1% of newborns. Down syndrome is the most common form of trisomal abnormality, an abnormality of chromosome number (47 chromosomes). Unbalanced translocation is an abnormality of chromosome structure that often has serious clinical effects.)

With regard to abnormalities of chromosomes, nurses should be aware that:

A. They occur in approximately 10% of newborns.

B. Abnormalities of number are a major cause of pregnancy loss.

C. Down syndrome is a result of an abnormal chromosomal structure.

D. Unbalanced translocation results in a mild abnormality that the child will outgrow.

A

(Fetal movements are generally observed between 16 to 20 weeks of gestation. As the patient is in the 8th week of gestation, she will be able to notice fetal movements in another 8 to 12 weeks. By this time the arms and legs of the fetus will be completely developed. All the other options, which are below 16 weeks of gestation are incorrect as the arms and legs of the fetus are not well developed. Therefore, the patient cannot feel the fetal movements after 6 to 8 weeks, 4 to 6 weeks, or 2 to 4 weeks from then.)

A patient who is 8 weeks pregnant wants to know when she can feel the fetal movements in the womb. What is the best nursing response? "You will have to wait for another:

A. 8 to 12 weeks."

B. 6 to 8 weeks."

C. 4 to 6 weeks."

D. 2 to 4 weeks."

10, 9, 40, 280

(Pregnancy lasts approximately 10 lunar months, 9 calendar months, 40 weeks, 280 days. Length of pregnancy is computed from the first day of the last menstrual period (LMP) until the day of birth.)

List the time span in lunar months, calendar months, weeks, and days that indicates the appropriate length for a normal pregnancy. Record your response as whole numbers separated by commas (ex. 2, 4, 6, 8). _______________

A

(Scalp hair appears after week 16 of pregnancy, along with eyes, ears, and the nose. However, it is still in the developmental stages and is observed upon gross examination of the fetus. Sweat glands are formed at the twenty-fourth week of pregnancy. Nasal cartilage is observed after 40 weeks of pregnancy. Sebaceous glands are formed after 20 weeks of pregnancy.)

A patient in the eighteenth week of pregnancy visits a clinic to know about the development of the fetus. The patient says to the nurse, "I am excited, and I want to know what has developed in my child so far." What information should the nurse be able to tell to the patient about the fetus? The fetus has:

A. "Hair on the scalp."

B. "Some sweat glands."

C. "Nasal cartilage."

D. "Sebaceous glands."

B

(Decisions about genetic testing are shaped by socioeconomic status and the ability to pay for the testing. Some types of genetic testing are expensive and are not covered by insurance benefits. Anxiety and altered family relationships, high false positives, and ethnic and socioeconomic disparity are factors that may be difficulties associated with genetic testing, but they are not risks associated with testing.)

In presenting to obstetric nurses interested in genetics, the genetic nurse identifies the primary risk(s) associated with genetic testing as:

a. Anxiety and altered family relationships.

b. Denial of insurance benefits.

c. High false positives associated with genetic testing.

d. Ethnic and socioeconomic disparity associated with genetic testing.

B

(The couple already has a child with a genetic disease; therefore they will be given a recurrence risk test. If a couple has not yet had children but are known to be at risk for having children with a genetic disease, they are given an occurrence risk test. This couple already has a child with a genetic disorder. Predictive testing is used to clarify the genetic status of an asymptomatic family member. Predisposition testing differs from presymptomatic testing in that a positive result does not indicate 100% risk of a condition developing.)

A man's wife is pregnant for the third time. One child was born with cystic fibrosis, and the other child is healthy. The man wonders what the chance is that this child will have cystic fibrosis. This type of testing is known as:

a. Occurrence risk.

b. Recurrence risk.

c. Predictive testing.

d. Predisposition testing.

B

(This mother likely will experience a disruption in the family process related to the birth of a baby with an inherited disorder. Women commonly experience body image disturbances in the postpartum period, but this is unrelated to giving birth to a child with Down syndrome. The mother likely will have a mix of emotions that may include anxiety, guilt, and denial, but this is not the most essential nursing diagnosis for this family. Risk for injury is not an applicable nursing diagnosis.)

You are a maternal-newborn nurse caring for a mother who just delivered a baby born with Down syndrome. What nursing diagnosis would be the most essential in caring for the mother of this infant?

a. Disturbed body image

b. Interrupted family processes

c. Anxiety

d. Risk for injury

C

(Karyotyping provides genetic information such as gender and chromosome structure. The L/S, not karyotyping, reveals lung maturity. Although karyotyping can detect genetic anomalies, the range of normal is nondescriptive. Although karyotyping can detect genetic anomalies, not all such anomalies display obvious physical deformities. The term deformities is a nondescriptive word. Furthermore, physical anomalies may be present that are not detected by genetic studies (e.g., cardiac malformations).)

A couple has been counseled for genetic anomalies. They ask you, "What is karyotyping?" Your best response is:

a. "Karyotyping will reveal if the baby's lungs are mature."

b. "Karyotyping will reveal if your baby will develop normally."

c. "Karyotyping will provide information about the gender of the baby and the number and structure of the chromosomes."

d. "Karyotyping will detect any physical deformities the baby has."

C

(Nurses should be prepared to help with a variety of stress reactions from a couple facing the possibility of a genetic disorder. Although anyone may have a genetic disorder, certain disorders appear more often in certain ethnic and racial groups. Genetic health care is highly individualized because treatments are based on the phenotypic responses of the individual. Individual nurses at any facility can take a genetic history, although larger facilities may have better support services.)

In practical terms regarding genetic health care, nurses should be aware that:

a. Genetic disorders affect equally people of all socioeconomic backgrounds, races, and ethnic groups.

b. Genetic health care is more concerned with populations than individuals.

c. The most important of all nursing functions is providing emotional support to the family during counseling.

d. Taking genetic histories is the province of large universities and medical centers.

A

(Maternal serum screening identifies the risk for the neural tube defect and the specific chromosome abnormality involved in Down syndrome. Carriers of some diseases such as sickle cell disease do not display symptoms. Predisposition testing determines susceptibility such as for breast cancer; presymptomatic testing indicates that, if the gene is present, symptoms are certain to appear.)

With regard to prenatal genetic testing, nurses should be aware that:

a. Maternal serum screening can determine whether a pregnant woman is at risk of carrying a fetus with Down syndrome.

b. Carrier screening tests look for gene mutations of people already showing symptoms of a disease.

c. Predisposition testing predicts with near certainty that symptoms will appear.

d. Presymptomatic testing is used to predict the likelihood of breast cancer.

B

(Aneuploidy is an abnormality of number that also is the leading genetic cause of mental retardation. Chromosome abnormalities occur in fewer than 1% of newborns. Down syndrome is the most common form of trisomal abnormality, an abnormality of chromosome number (47 chromosomes). Unbalanced translocation is an abnormality of chromosome structure that often has serious clinical effects.)

With regard to chromosome abnormalities, nurses should be aware that:

a. They occur in approximately 10% of newborns.

b. Abnormalities of number are the leading cause of pregnancy loss.

c. Down syndrome is a result of an abnormal chromosome structure.

d. Unbalanced translocation results in a mild abnormality that the child will outgrow.

C

(The cardiovascular system is the first organ system to function in the developing human. Blood vessel and blood formation begins in the third week, and the heart is developmentally complete in the fifth week. "We don't really know when such defects occur" is an inaccurate statement. Regardless of the cause, the heart is vulnerable during its period of development, the third to fifth weeks. "They usually occur in the first 2 weeks of development" is an inaccurate statement.)

A woman's cousin gave birth to an infant with a congenital heart anomaly. The woman asks the nurse when such anomalies occur during development. Which response by the nurse is most accurate?

a. "We don't really know when such defects occur."

b. "It depends on what caused the defect."

c. "They occur between the third and fifth weeks of development."

d. "They usually occur in the first 2 weeks of development."

C

("Babies respond to sound starting at about 24 weeks of gestation" is an accurate statement. "That must have been a coincidence; babies can't respond like that"

is inaccurate. Fetuses respond to sound by 24 weeks. Acoustic stimulations can evoke a fetal heart rate response. There is no such thing as an aural reflex. The statement, "Let me know if it happens again; we need to report that to your midwife" is not appropriate; it gives the impression that something is wrong.)

A pregnant woman at 25 weeks' gestation tells the nurse that she dropped a pan last week and her baby jumped at the noise. Which response by the nurse is most accurate?

a. "That must have been a coincidence; babies can't respond like that."

b. "The fetus is demonstrating the aural reflex."

c. "Babies respond to sound starting at about 24 weeks of gestation."

d. "Let me know if it happens again; we need to report that to your midwife."

C

(These are all milestones in human development that occur at approximately 28 weeks.)

At approximately _____ weeks of gestation, lecithin is forming on the alveolar surfaces, the eyelids open, and the fetus measures approximately 27 cm crown to rump and weighs approximately 1110 g.

a. 20

b. 24

c. 28

d. 30

A

(As the fetus nears term, fetal waste products accumulate in the intestines as dark green-to-black, tarry meconium.)

The nurse caring for the laboring woman should know that meconium is produced by:

a. Fetal intestines.

b. Fetal kidneys.

c. Amniotic fluid.

d. The placenta.

A

("Your baby's umbilical cord is surrounded by connective tissue called Wharton jelly, which prevents compression of the blood vessels and ensures continued nourishment of your baby" is the most appropriate response. "Your baby's umbilical floats around in blood anyway" is inaccurate. "You don't need to worry about things like that" is not appropriate response. It negates the client's need for teaching and discounts her feelings. The placenta does not protect the umbilical cord. The cord is protected by the surrounding Wharton jelly.)

A woman asks the nurse, "What protects my baby's umbilical cord from being squashed while the baby's inside of me?" The nurse's best response is:

a. "Your baby's umbilical cord is surrounded by connective tissue called Wharton jelly, which prevents compression of the blood vessels and ensures continued nourishment of your baby."

b. "Your baby's umbilical floats around in blood anyway."

c. "You don't need to worry about things like that."

d. "The umbilical cord is a group of blood vessels that are very well protected by the placenta."

D

(Chorionic villi are fingerlike projections that develop out of the trophoblast and extend into the blood-filled spaces of the endometrium. The villi obtain oxygen and nutrients from the maternal bloodstream and dispose of carbon dioxide and waste products into the maternal blood. The decidua basalis is the portion of the decidua (endometrium) under the blastocyst where the villi attach. The blastocyst is the embryonic development stage after the morula. Implantation occurs at this stage. The germ layer is a layer of the blastocyst.)

The _____ is/are responsible for oxygen and carbon dioxide transport to and from the maternal bloodstream.

a. Decidua basalis

b. Blastocyst

c. Germ layer

d. Chorionic villi

D

(During the third trimester the only Ig that crosses the placenta, IgG, provides passive acquired immunity to specific bacterial toxins. The fetus produces IgM by the end of the first trimester. IgAs are not produced by the baby. By the third trimester the fetus has IgG and IgM. Breastfeeding supplies the baby with IgA. "Your baby does not have any antibodies to fight infection" is not an accurate statement.)

A woman who is 8 months pregnant asks the nurse, "Does my baby have any antibodies to fight infection?" The most appropriate response by the nurse is:

a. "Your baby has all the immune globulins (Ig) necessary: IgG, IgM, and IgA."

b. "Your baby won't receive any antibodies until he is born and you breastfeed him."

c. "Your baby does not have any antibodies to fight infection."

d. "Your baby has IgG and IgM."

C

(A ratio of 2:1 indicates a two-to-one ratio of L/S, an indicator of lung maturity. Ratios of 1.4:1, 1.8:1, and 1:1 indicate immaturity of the fetal lungs.)

The measurement of lecithin in relation to sphingomyelin (L/S ratio) is used to determine fetal lung maturity. Which ratio reflects maturity of the lungs?

a. 1.4:1

b. 1.8:1

c. 2:1

d. 1:1

C

(The placenta functions by supplying oxygen and excreting carbon dioxide to the maternal bloodstream. The fetal lungs do not function for respiratory gas exchange in utero. The baby does not simply absorb oxygen from a woman's blood system. Blood and gas transport occur through the placenta. The placenta delivers oxygen-rich blood through the umbilical vein and not the artery.)

Sally comes in for her first prenatal examination. This is her first child. She asks you (the nurse), "How does my baby get air inside my uterus?" The correct response is:

a. "The baby's lungs work in utero to exchange oxygen and carbon dioxide."

b. "The baby absorbs oxygen from your blood system."

c. "The placenta provides oxygen to the baby and excretes carbon dioxide into your bloodstream."

d. "The placenta delivers oxygen-rich blood through the umbilical artery to the baby's abdomen."

D

(After implantation, the endometrium is called the decidua. Ova are considered fertile for about 24 hours after ovulation. Sperm remain viable in the woman's reproductive system for an average of 2 to 3 days. Penetration of the ovum by the sperm is called fertilization. Conception occurs when the zygote, the first cell of the new individual, is formed.)

The most basic information a maternity nurse should have concerning conception is that:

a. Ova are considered fertile 48 to 72 hours after ovulation.

b. Sperm remain viable in the woman's reproductive system for an average of 12 to 24 hours.

c. Conception is achieved when a sperm successfully penetrates the membrane surrounding the ovum.

d. Implantation in the endometrium occurs 6 to 10 days after conception.

A

(Amniotic fluid serves as a source of oral fluid, a repository for waste from the fetus, and also cushions the fetus and helps maintain a constant body temperature. The volume of amniotic fluid changes constantly. Too little amniotic fluid (oligohydramnios) is associated with renal abnormalities. Too much amniotic fluid (hydramnios) is associated with gastrointestinal and other abnormalities.)

A maternity nurse should be aware of which fact about the amniotic fluid?

a. It serves as a source of oral fluid and a repository for waste from the fetus.

b. The volume remains about the same throughout the term of a healthy pregnancy.

c. A volume of less than 300 ml is associated with gastrointestinal malformations.

d. A volume of more than 2 L is associated with fetal renal abnormalities.

B

(The placenta produces four hormones necessary to maintain the pregnancy. The placenta widens until week 20 and continues to grow thicker. Toxic substances such as nicotine and carbon monoxide readily cross the placenta into the fetus. Optimal circulation occurs when the woman is lying on her side.)

With regard to the structure and function of the placenta, the maternity nurse should be aware that:

a. As the placenta widens, it gradually thins to allow easier passage of air and nutrients.

b. As one of its early functions, the placenta acts as an endocrine gland.

c. The placenta is able to keep out most potentially toxic substances such as cigarette smoke to which the mother is exposed.

d. Optimal blood circulation is achieved through the placenta when the woman is lying on her back or standing.

C

(A reduction in placental blood flow stresses the fetus, increases blood levels of corticosteroids, and thus accelerates lung maturity. Development of the respiratory system begins during the embryonic phase and continues into childhood. The infant's lungs are mature when the L/S ratio is 2:1, at about 35 weeks. Lung movements have been seen on ultrasound scans at 11 weeks.)

With regard to the development of the respiratory system, maternity nurses should be aware that:

a. The respiratory system does not begin developing until after the embryonic stage.

b. The infant's lungs are considered mature when the lecithin/sphingomyelin (L/S) ratio is 1:1, at about 32 weeks.

c. Maternal hypertension can reduce maternal-placental blood flow, accelerating lung maturity.

d. Fetal respiratory movements are not visible on ultrasound scans until at least 16 weeks.

A

(If the parents-to-be are older and have taken fertility drugs, they would be very interested to know about twinning and other multiple births. Conjoined twins are monozygotic; they are from a single fertilized ovum in which division occurred very late. Identical twins show no racial or ethnic preference; fraternal twins are more common among African-American women. Fraternal twins can be different genders or the same gender. Identical twins are the same gender.)

Many parents-to-be have questions about multiple births. Maternity nurses should be able to tell them that:

a. Twinning and other multiple births are increasing because of the use of fertility drugs and delayed childbearing.

b. Dizygotic twins (two fertilized ova) have the potential to be conjoined twins.

c. Identical twins are more common in Caucasian families.

d. Fraternal twins are same gender, usually male.

A

(Optimal circulation is achieved when the woman is lying at rest on her side. Decreased uterine circulation may lead to intrauterine growth restriction. Previously it was believed that the left lateral position promoted maternal cardiac output, thereby enhancing blood flow to the fetus. However, it is now known that either side-lying position enhances uteroplacental blood flow. If a woman lies on her back with the pressure of the uterus compressing the vena cava, blood return to the right atrium will be diminished. Although this position is recommended and ideal for later in pregnancy, the woman must still maintain a lateral tilt to the pelvis to avoid compression of the vena cava. Many women will find this position uncomfortable as pregnancy advances. Side-lying is the ideal position to promote blood flow to the fetus.)

The nurse caring for a pregnant client knows that her health teaching regarding fetal circulation has been effective when the client reports that she has been sleeping:

a. In a side-lying position.

b. On her back with a pillow under her knees.

c. With the head of the bed elevated.

d. On her abdomen.