Chapter 49 - The Early Embryonic Stage of the First Trimester

B

The cavity in which the fetus exists is called the ______________ cavity.

A. Chorionic

B. Amniotic

C. Decidual

D. Embryonic

C

Which one of the following laboratory tests indicates pregnancy when the values are elevated?

A. FSH

B. LH

C. hCG

D. HL

C

Serum maternal hCG levels in a normal intrauterine pregnancy less than 7 weeks should increase by doubling every _______________.

A. 24 hours

B. 48 hours

C. 3.5 days

D. 1 week

D

Which of the following ages refers to the length of time calculated from the first day of the last normal menstrual period to the point at high the pregnancy is being assessed?

A. Gestational

B. Embryonic

C. Menstrual

D. Either gestational or menstrual

D

Which one of the following terms refers to a multiple pregnancy within one chorionic sac?

A. Monoembryonic

B. Dichorionic

C. Diamniotic

D. Monochorionic

C

The interface between the decidua capsularis and echogenic vascular endometrium is which one of the following?

A. Decidua capsularis

B. Decidua basalis

C. Double decidual sign

D. Chorionic cavity

C

The beta hCG levels plateau and subsequently decline, whereas the gestational sac continues to grow after _____________ weeks.

A. 3 to 5

B. 6 to 8

C. 9 to 10

D. 10 to 12

C

The fusion of the chorion and amnion occurs between _____________ weeks.

A. 9 and 10

B. 11 and 12

C. 14 and 15

D. 20 and 21

B

The embryonic heart begins to beat at _________ days.

A. 23

B. 35

C. 43

D. 49

D

With transvaginal ultrasound, an abnormal pregnancy is suspected when visualizing the yolk sac fails with a minimum mean sac diameter (MSD) of _________ mm.

A. 6

B. 8

C. 10

D. 12

D

To calculate the mean sac diameter of a gestational sac, which one of the following formulas should be used?

A. Length x width x height

B. Length + width +height

C. (Length x width x height)/3

D. (Length + width + height)/3

B

Using a transvaginal approach, the first structure visualized within a gestational sac is which one of the following structures?

A. Primary yolk sac

B. Secondary yolk sac

C. Amnion

D. Embryo

C

In the first trimester, herniated bowel will return within the abdominal cavity by the ___________ week.

A. Eighth

B. Tenth

C. Twelfth

D. Fifteenth

B

The diameter of the normal yolk sac should never exceed ___________mm.

A. 4

B. 6

C. 8

D. 10

B

A sonogram at 10 weeks' gestation demonstrates a cystic area within the posterior cranium. This appearance most likely represent which one of the following?

A. Abnormal mesencephalon

B. Normal rhombencephalon

C. Abnormal rhombencephalon

D. Normal prosencephal

A

Transvaginal imaging of the female pelvis uses which of the following planes?

A. Sagittal and coronal

B. Coronal and transverse

C. Sagittal and transverse

D. Sagittal only

C

Typically, the yolk sac resorbs and is no longer visible sonographically by _____________ weeks.

A. 8

B. 10

C. 12

D. 14

C

After fertilization of the ovum, the corpus luteum begins to secrete which of the following hormones?

A. Estrogen only

B. Progesterone only

C. Progesterone with some estrogen

D. Estrogen with some progesterone

C

The blastocyst typically enters the uterus ________ days after fertilization.

A. 1 to 2

B. 2 to 3

C. 4 to 5

D. 7 to 9

D

Implantation into the uterine decidua is completed within ______ days after fertilization.

A. 2

B. 5

C. 10

D. 12

D

In transabdominal scanning, a normal gestational sac can be consistently demonstrated when the beta hCG level is ____________ mega international units per milliliter (mIU/ml).

A. 500

B. 1000

C. 1500

D. 1800

B

The anechoic center of a 5- to 6-week gestational sac represents which of the following?

A. Amniotic cavity

B. Chorionic cavity

C. Decidual reaction

D. Primary yolk sac

B

The villi on the myometrial side of the conceptus is known as which one of the following?

A. Double decidual sign

B. Decidua basalis

C. Decidua capsularis

D. Chorion laeve

B

In early pregnancy, the gestational sac size grows at a rate of _______mm/day.

A. 0.5

B. 1

C. 2

D. 2.5

Amniotic cavity:

Cavity in which the fetus exists; it forms early in gestation and fills with amniotic fluid to protect the fetus

Chorionic cavity:

Surrounds the amniotic cavity; the yolk sac is within the chorionic cavity

Chorionic villi sampling (CVS):

Invasive diagnostic genetic testing that involves sampling zygotic cells from developing placental tissue

Crown-rump length (CRL):

Most accurate measurement of the embryo in the first trimester

Decidua basalis:

The uterine decidual surface on the maternal side of the placenta; the decidual basalis is invaded by trophoblastic cells that form the placenta

Decidua capsularis:

The uterine decidua on the surface of the implantation site; as the pregnancy progresses, the decidua capsularis may shed, causing light early pregnancy bleeding

Diamniotic:

Multiple pregnancy with two amniotic sacs

Dichorionic:

Multiple pregnancy with two chorionic sacs

Double decidual sac sign:

Interface between the decidua capsularis and the echogenic, highly vascular surface on the opposite side of the endometrial cavity

Embryologic age (conceptual age):

Age calculated from when conception occurs

Embryonic period:

Time between 4 and 10 weeks' gestation

Hematopoiesis:

Production and development of blood cells

Human chorionic gonadotropin (hCG):

Hormone secreted by the trophoblastic cells (developing placental cells) of the blastocyst; laboratory test indicates pregnancy when values are elevated

IUP:

Intrauterine pregnancy

Menstrual age (gestational age):

Length of time calculated from the first day of the last normal menstrual period (LMP) to the point at which the pregnancy is being assessed

Monoamniotic:

Multiple pregnancy with one amniotic sac

Monochorionic:

Multiple pregnancy with one chorionic sac

MSD:

Mean sac diameter

Primary yolk sac:

First site of formation of red blood cells that will nourish the embryo

Secondary yolk sac:

Formed at 23 days when the primary yolk sac is pinched off by the extraembryonic coelom

Transvaginal (TV) transducer:

High-frequency transducer that is inserted into the vaginal canal to obtain images of first-trimester pregnancy

Yolk stalk:

The umbilical duct connecting the yolk sac with the embryo

Zygote:

The concept us resulting from the union of male and female gametes; in a normal pregnancy, the zygote travels through the tubes and implants in the uterus

B

Which one of the following statements about the amniotic fluid development is true?

a. the fetal kidneys begin to produce urine in the first trimester

b. in the first trimester, fluid is produced by the placenta

c. the fluid decreases in volume until the 34 weeks gestation

d. the fetus gains two thirds of its weight in during the first two trimesters

A

The chorionic plate is related to which one of the following?

A) fetal surface of the placenta

B) cotyledons and intervillous spaces

C) allantois of the yolk sac

D) maternal surface of the fetus

A

A diamniotic and dichorionic twin pregnancy demonstrated which one of the following sonographic findings?

A) two gestational sacs and two placenta

B) two gestational sacs and one embryo

C) one gestational sac and two placentas

D) two gestational sacs and one placenta

C

The following sonographic findings of increased nuchal thickening, shortened femurs, cardiac anomalies, and pyelectasis may be found in which one of the following?

a. Trisomy 13

b. Trisomy 18

c. Trisomy 21

d. Turner syndrome

C

Which one of the following structures forms early in gestation and surrounds the embryo?

A. Chorionic cavity

B. Chorion frondosum

C. Amniotic cavity

D. Fetal cavity

B

An early noninvasive means of assessing the risk of aneuploidy is which one of the following?

a. Facial analysis

b. Nuchal translucency

c. Fetal position

d. Biophysical profile

C

When measuring the gestational sac, all of the following statements are true except:

a. A distended urinary bladder can compress the sac from round to ovoid.

b. If the sac is round, one diameter should be measured.

c. If the sac is ovoid, measurements cannot be obtained.

d. If the sac is ovoid, the anteroposterior and width is measured to obtain mean diameter.

B

Using a transvaginal approach, the first structure visualized within a gestational sac is which one of the following structures?

a. primary yolk sac

b. secondary yolk sac

c. amnion

d. embryo

C

The chorion around the gestational sac on the opposite side of implantation is chorion _______.

A) frondosum

B) vera

C) laeve

D) capsularis

C

The maternal side of the placenta is decidua _______.

A) parietalis

B) capsularis

C) basalis

D) frondosum

B

Linear acceleration of the embryonic heart rate correlates well with gestational age up to _________________ weeks.

a. 8 menstrual

b. 9 gestational

c. 10 menstrual

d. 12 conception

B

Fusion of the amnion and chorion usually occurs by _______ weeks' gestation.

A) 20

B) 16

C) 12

D) 14

B

The anechoic center of a 5 to 6 week gestation sac represents which one of the following?

a. amniotic cavity

b. chorionic cavity

c. decidual reaction

d. primary yolk sac

A

The cranial bones ossify by ______ weeks of gestation.

a. 12

b. 14

c. 16

d. 18

D

The function of the human chorionic gonadotropin (hCG) is to perform which one of the following?

A) develop Wharton's jelly around the cord

B) produce amniotic fluid

C) stimulate the yolk sac development

D) maintain the corpus luteum in early pregnancy

C

Which one of the following laboratory tests indicates pregnancy when the values are elevated?

a. FSH

b. LH

c. hCG

d. HL

B

The villi on the myometrial side of the conceptus is known as which one of the following?

a. double decidual sign

b. decidua basalis

c. decidua capsularis

d. chorion laeve

B

Early in gestation, the major source of amniotic fluid is produced by which one of the following?

a. Yolk sac

b. Amniotic membranes

c. Yolk stalk

d. Chorionic villi

D

Which of the following ages refers to the length of time calculated from the first day of the last normal menstrual period to the point at which the pregnancy is being assessed?

a. gestational

b. embryonic

c. menstrual

d. either a or c

C

The placenta performs all of the following functions except:

A) protection

B) respiration

C) absorption

D) nutrition

B

The umbilical cord is formed by the fusion of which of the following?

A) Amnion and yolk sac

B) Yolk stalk and allantoic ducts

C) Yolk sac and allantoic ducts

D) Allantoic ducts and chorion

B

In the first trimester, the length of the umbilical cord is approximately the same size as which one of the following?

A) Mean (gestational) sac diameter

B) Crown-rump length

C) Biparietal diameter

D) Femur length

C

The CRL measurement may be used up to the _____ gestational week?

a. 10th

b. 11th

c. 12th

d. 13th

D

The major functioning unit(s) of the placenta is(are) which of the following?

A) cotyledons

B) yolk sac

C) amnion

D) chorionic villi

C

The blastocyst typically enters the uterus ____ days after fertilization?

a. 1 to 2

b. 2 to 3

c. 4 to 5

d. 7 to 9

A

The fetal membranes are comprised of all of the following except the:

A) blastocyst

B) amnion

C) chorion

D) yolk sac

A

By 9 weeks, the yolk sac should measure _____ millimeters (mm) in diameter:

A) less than 5

B) greater than 2

C) less than 2

D) greater than 5

D

When the gestational mean sac diameter (MSD) exceeds _____ millimeters (mm), an embryo with definite cardiac activity should be clearly seen with transvaginal scanning.

a. 7

b. 10

c. 13

d. 16

D

The quadruple screen evaluates all of the following markers except:

a. AFP

b. Human chorionic gonadotropin (hCG)

c. Unconjugated estriol

d. Fetal lung maturity

C

What sonographic finding(s) confirms the presence of a diamniotic pregnancy?

A) two yolk sacs

B) two placentas

C) membrane that separates the fetuses

D) two fetal poles

B

Pregnancy-associated plasma protein A (PAPP-A) levels:

a. Peak from 16 to 20 weeks' gestation.

b. Increase throughout pregnancy.

c. Decline after 24 weeks' gestation.

d. Peak from 15 to 18 weeks' gestation.

D

Which one of the following terms refers to a multiple pregnancy within one chorionic sac?

a. monoembryonic

b. dichorionic

c. diamniotic

d. monochorionic

D

The most accurate measurement of gestational age during the first trimester is which one of the following?

a. mean sac diameter

b. yolk sac diameter

c. biparietal diameter

d. crown-rump length

D

Transvaginally, an embryo w/cardiac activity should be identified when the gestational sac measures ______ mm?

a. 5 to 8

b. 8 to 12

c. 10 to 15

d. 16 to 20

B

Which one of the following is the most frequent sonographic finding in an ectopic pregnancy?

a. extrauterine gestation w/heart motion

b. adnexal mass

c. echogenic free fluid in Morrison's Pouch

d. pseudo gestational sac

D

Which one of the following is the most common pelvic mass seen in a 1st trimester pregnancy?

a. ovarian dermoid

b. ectopic pregnancy

c. fibroid

d. corpus luteum cyst

A

An ovum without an embryo is know as which one of the following?

a. anembryonic pregnancy

b. diamniotic pregnancy

c. ectopic pregnancy

d. pseudogestational sac

B

A congenital fissure that remains open past weeks in the wall of the abdomen just to the right of the umbilical cord is called which one of the following?

a. umbilical hernia

b. gastroschisis

c. omphalocele

d. midgut herniation

D

Cranial anatomy is routinely visualized after how many gestational weeks?

a. 8 to 10

b. 9 to 11

c. 10 to 12

d. 12 to 14

A

A partial absence of the cranium is called which one of the following abnormalities?

a. iniencephaly

b. anencephaly

c. acrania

d. osteogenesis imperfecta

D

Multiple tiny clusters of grape like echoes within the uterine cavity best describes?

a. pseudogestational sacs

b. ectopic pregnancy

c. incomplete abortion

d. gestational trophoblastic disease

B

A hemorrhage located between the gestational sac and the myometrium represents which one of the following conditions?

a. placenta abruption

b. subchorionic hemorrhage

c. placental hematoma

d. placental lake

C

Corpus luteum cysts regress and are typically not seen beyond _______ weeks?

a. 10 to 12

b. 12 to 14

c. 16 to 18

d. 18 to 20

B

An ectopic pregnancy most commonly occurs in which one of the following structures?

a. ovary

b. fallopian tube

c. cornua

d. cervix

C

The increased risk of massive hemorrhage in an ectopic pregnancy is located?

a. within the adnexa

b. within the peritoneum

c. near the uterine cornua

d. within the ovary

D

Findings in an ectopic pregnancy include all of the following except?

a. no evidence of IUP

b. adnexal mass

c. intraperitoneal fluid

d. normal increase in serum beta hCG levels

C

Which one of the following statements about a pseudogestational sac is false?

a. does not contain a yolk sac

b. contains low-level internal echoes

c. is eccentrically located within the endometrium

d. demonstrates a high resistive spectral waveform

A

The best sonographic correlation in the diagnosis of an ectopic pregnancy is the combination of no IUP and which one of the following?

a. adnexal mass

b. complex endometrium

c. ovarian mass

d. anechoic cul de sac fluid

B

An increase risk of a complete hysterectomy is present when an ectopic pregnancy is located in which one of the following structures?

a. peritoneum

b. cervix

c. fallopian tube

d. adnexa

B

The most common cause of vaginal bleeding in the 1st trimester is which one of the following?

a. placenta previa

b. subchorionic hemorrhage

c. ectopic pregnancy

d. missed abortion

A

Embryos w/heart rates below ______ bpm generally have a poor prognosis?

a. 90

b. 100

c. 105

d. 110

A

The fetal urinary bladder becomes sonographically apparent at _______ weeks?

a. 10 to 12

b. 12 to 13

c. 13 to 14

d. 14 to 15

B

The most potentially life-threatening ectopic gestation is which one of the following?

a. cervical

b. interstitial

c. ovarian

d. peritoneal