First trimester test

The fetus develops within which cavity?

the amniotic cavity, providing protection and support. From about 5 weeks on.

When does the embryonic heart begin to beat?

Day 35, when embryo 5mm or greater in length.

Which lab value confirms and monitors early pregnancy and doubles every 48 hours in a normal gestation?

Human chorionic gonadotropin (hCG)

What does hCG stand for?

Human Chorionic Gonadotropin

When does the amniotic cavity and the chorionic membranes fuse?

Around 14-16 weeks

What is the main job of hCG

to maintain the corpus luteum and support early pregnancy.

Functions of secondary yolk sac in embryonic development

Provides nutrients to developing embryo

Hematopoiesis

Development of embryonic, forms gut

The first site of formation of red blood cells that will nourish the embryo is the

Secondary yolk sac

are gestational age and menstrual age different?

These are interchangeable

How is Gestational (menstrual age) calculated?

Conceptual age+ 2 weeks.

On an early transvaginal ultrasound, the endometrium appears thick and echogenic with a small fluid collection surrounded by a bright rim. What does this represent?

Decidual sign

The bright echogenic rim seen surrounding an early intrauterine gestational sac on ultrasound represents which layer of decidua?

Decidua capularis

The portion of the decidua located between the implanted conceptus and the uterine wall that later forms the maternal part of the placenta is called the:

A. Decidua capsularis
B. Decidua parietalis
C. Decidua basalis
D. Chorion laeve
E. Trophoblastic shell

C. Decidua basalis

Which sonographic feature confirms a true intrauterine pregnancy and is formed by the interface between the decidua capsularis and decidua parietalis?

A. Decidual sign
B. Double decidual sac sign
C. Chorionic ring sign
D. Subchorionic bleed
E. Yolk sac

B. Double decidual sac sign

Which statement is true about the decidual layers?

A. The decidua basalis covers the outer surface of the gestational sac.
B. The decidua capsularis forms the maternal portion of the placenta.
C. The decidua parietalis lies between the embryo and the uterine wall.
D. The decidua basalis lies beneath the implanted embryo and becomes the maternal placenta.
E. The decidua capsularis lines the rest of the uterus away from the embryo.

D. The decidua basalis lies beneath the implanted embryo and becomes the maternal part of the placenta.

The portion of the endometrium that covers the surface of the implanted blastocyst and separates it from the uterine cavity is known as:

A. Decidua parietalis
B. Decidua basalis
C. Decidua capsularis
D. Chorion frondosum
E. Chorion laeve

C. Decidua capsularis

Which combination of decidual layers produces the double decidual sac sign seen on early transvaginal ultrasound?

A. Decidua basalis and capsularis
B. Decidua basalis and parietalis
C. Decidua capsularis and parietalis
D. Decidua parietalis and basalis
E. Decidua basalis and chorion frondosum

A. Decidua basalis and capsularis

A gestational sac measuring 27 mm with no visible embryo or yolk sac is most consistent with:
A. Threatened abortion
B. Early intrauterine pregnancy
C. Anembryonic (blighted-ovum) pregnancy
D. Pseudogestational sac
E. Molar pregnancy

C. Anembryonic (blighted-ovum) pregnancy

Which of the following findings is most characteristic of a pseudogestational sac rather than a true intrauterine gestation?

A. Double decidual sac sign
B. Eccentric placement within the endometrium
C. Thick trophoblastic rim
D. Central location with homogeneous echoes
E. Presence of a yolk sac

B. Eccentric placement within the endometrium

A gestational sac showing growth < 0.6 mm per day on serial ultrasounds most likely represents:
A. Normal early pregnancy
B. Non-viable pregnancy
C. Gestational trophoblastic disease
D. Multiple gestation
E. Subchorionic hemorrhage

B. Non-viable pregnancy

A centrally located endometrial fluid collection with no double decidual sac sign and no yolk sac is most consistent with:
A. Early normal intrauterine gestation
B. Pseudogestational sac associated with ectopic pregnancy
C. Anembryonic pregnancy
D. Subchorionic hemorrhage
E. Hydropic placenta

B. Pseudogestational sac associated with ectopic pregnancy

Which feature differentiates a failed intrauterine pregnancy from a pseudogestational sac?
A. Central location in uterine cavity
B. Lack of yolk sac
C. Poor decidual reaction
D. Eccentric position within endometrium with double decidual sac sign
E. Absence of chorionic villi

C. Poor decidual reaction

A gestational sac with a thin trophoblastic rim, absent double decidual sac sign, and discrepancy between sac size and hCG level represents:
A. Normal 5-week IUP
B. Threatened abortion
C. Non-viable pregnancy
D. Twin pregnancy
E. Subchorionic bleed

C. Non-viable pregnancy

What is the embryonic age

the true age of the embryo starting from day of fertilization

usually 2 weeks younger than the gestation age. 

The blastocyst typically enters the uterine cavity approximately how many days after fertilization?

4-5 days after fertilization

The anechoic center of the gestational sac represents which of the following?

The fluid in the Chorionic cavity (gestational sac cavity)

What does the decidua parietalis do?

Lines the rest of the uterus, not including the space of implantation

Parietalis and capsularis fuse by 14-16 weeks. 

When does hCG levels plateau and decline?

Plateaus at 10 weeks

Declines at around 16 weeks of gestation. After first trimester is over.

Weeks that the amnion and chorion fuse

at approximately 14-16 weeks of gestation.

The heart beats at how many days

usually between day 35. Embryo is 5mm or greater in length

MSD what size is abnormal to not see the yolk sac?

MSD greater or equal to 8mm

MSD what size is abnormal to not see the embryo

MSD equal or greater to 25mm.