Chapter 45 - The Role of Sonography in Obstetrics

Question 1

bleeding from a normally situated placenta as a result of its complete or partial detachment after the 20th week of gestation

Answer 1

abruptio placentae

Question 2

aspiration of a sample of amniotic fluid through the mother’s abdomen for diagnostic analysis of fetal genetics, maturity, and/or disease

Answer 2

amniocentesis

Question 3

smooth membrane enclosing the fetus and amniotic fluid; it is loosely fused with the outer chorionic membrane except at the placental insertion of the umbilical cord, where the amnion is contiguous with the membranes surrounding the umbilical cord

Answer 3

amnion

Question 4

a neural tube defect where absence of the brain, including the cerebrum, the cerebellum, and basal ganglia, may be present

Answer 4

anencephaly

Question 5

fetal syndromes associated with an abnormal number of chromosomes

Answer 5

aneuploidy

Question 6

the ligatures around the cervix uteri used to treat cervical incompetence during pregnancy

Answer 6

cerclage

Question 7

inferior segment of the uterus, which is normally more than 3.5 cm long during pregnancy, decreasing in length during labor

Answer 7

cervix

Question 8

cellular, outermost extraembryonic membrane, composed of trophoblast lined with mesoderm; the outer chorion (villous chorion) develops villi, which are vascularized by allantoic vessels and give rise to the placenta; the inner chorion (the smooth chorion) is fused with the amnion except at the placental cord insertion

Answer 8

chorion

Question 9

a functional structure within the normal ovary, which is formed from cells lining the graafian follicle after ovulation; the corpus luteum produces estrogen and progesterone and may become enlarged and appear cystic during early pregnancy

Answer 9

corpus luteum

Question 10

vascular structure within the fetal liver that connects the umbilical vein to the inferior vena cava and allows oxygenated blood to bypass the liver and return directly to the heart

Answer 10

ductus venosus

Question 11

developing individual from implantation to the end of the 9th week of gestation

Answer 11

embryo

Question 12

age of embryo stated as time from day of conception

Answer 12

embryonic age (conception age)

Question 13

length of pregnancy defined in the United States as number of weeks from first day of last normal menstrual period (LNMP)

Answer 13

gestational (menstrual) age

Question 14

structure lined by the chorion that normally implants within the uterine decidua and contains the developing embryo

Answer 14

gestational sac

Question 15

total number of pregnancies

Answer 15

gravidity (G)

Question 16

abnormal conception in which there is partial or complete conversion of the chorionic villi

Answer 16

hydatidiform mole

Question 17

a condition in which the cervix dilates silently during the second trimester; without intervention, the membranes bulge through the cervix and rupture, and the fetus drops out, resulting in a premature preterm delivery

Answer 17

incompetent cervix

Question 18

reduced growth rate (symmetrical IUGR) or abnormal growth pattern (asymmetrical IUGR) of the fetus, resulting in a small for gestational age (SGA) infant

Answer 18

intrauterine growth restriction (IUGR)

Question 19

thin expanded lower portion of the uterus that forms in the last trimester of pregnancy

Answer 19

lower uterine segment

Question 20

exceptionally large infant with excessive fat deposition in the subcutaneous tissue; most frequently seen in fetuses of diabetic mothers

Answer 20

macrosomia

Question 21

one of several biochemical tests used to assess fetal risk for aneuploidy or fetal defect; a component of the “quad screen,” the normal value of MSAFP varies with gestational age; assessment of gestational age is essential for accurate interpretation of results

Answer 21

maternal serum alpha-fetoprotein (MSAFP)

Question 22

a collection of fluid that extends behind the fetal neck and along the spine in the first trimester

Answer 22

nuchal translucency

Question 23

reduced amount of amniotic fluid

Answer 23

oligohydramnios

Question 24

number of live births

Answer 24

parity (P)

Question 25

organ of communication in which nutrition and products of metabolism are interchanged between the fetal and maternal blood systems; is formed from the chorion frondosum with a maternal decidual contribution

Answer 25

placenta

Question 26

placental implantation encroaches upon the lower uterine segment; if the placenta presents first in late pregnancy, bleeding is inevitable

Answer 26

placenta previa

Question 27

excessive amount of amniotic fluid

Answer 27

polyhydramnios

Question 28

maternal serum biochemical levels in the second trimester of human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), estriol, and inhibin A

Answer 28

quad screen

Question 29

a 40-week pregnancy is divided into three 13-week periods from the first day of the last normal menstrual period (weeks 1 through 13, first trimester; weeks 14 through 27, second trimester; week 28 to term, third trimester)

Answer 29

trimester

Question 30

connecting lifeline between the fetus and placenta; it contains two umbilical arteries, which carry deoxygenated fetal blood, and one umbilical vein, which carries oxygenated fetal blood encased in Wharton’s jelly

Answer 30

umbilical cord

Question 31

a circular structure within the gestational sac seen sonographically between 4 and 10 weeks’ gestational age; the yolk sac supplies nutrition, facilitates waste removal, and is the origin of early hematopoietic stem cells in the embryo; it lies between the chorion and the amnion

Answer 31

yolk sac

Question 32

products of conception from fertilization through implantation; the zygotic stage of pregnancy lasts for approximately 12 days after conception

Answer 32

zygote