During implantation, which trophoblast layer remains mitotically active and supplies new cells?
A. Syncytiotrophoblast
B. Hypoblast
C. Cytotrophoblast
D. Epiblast

C. Cytotrophoblast

Which trophoblast layer is multinucleated, erosive, and responsible for invasion into endometrium?
A. Syncytiotrophoblast
B. Cytotrophoblast
C. Amnion
D. Decidual stroma

A. Syncytiotrophoblast

The embryoblast of the blastocyst is the:
A. Outer trophoblast shell
B. Lacunar network
C. Exocoelomic membrane
D. Inner cell mass

D. Inner cell mass

The bilaminar embryonic disc is composed of:
A. Amnion + chorion
B. Epiblast + hypoblast
C. Cytotrophoblast + syncytium
D. Somatic + splanchnic mesoderm

B. Epiblast + hypoblast

“Embryotroph” is best defined as:
A. Maternal nourishing fluid
B. Fetal capillary blood
C. Amniotic fluid only
D. Yolk-derived nutrients

A. Maternal nourishing fluid

Decidual cells near implantation are:
A. Multinucleated trophoblast masses, glycogen-lipid stores
B. Cuboidal hypoblast cells, glycogen-lipid stores
C. Polyhedral CT, glycogen-lipid stores
D. Smooth muscle myocytes, glycogen-lipid stores

C. Polyhedral CT, glycogen-lipid stores

hCG is a:
A. Steroid hormone
B. Glycoprotein hormone
C. Prostaglandin lipid
D. Catecholamine amine

B. Glycoprotein hormone

hCG reaches maternal blood for detection mainly through:
A. Spiral arteries directly
B. Maternal lymphatics
C. Endometrial glands
D. Syncytial lacunae to blood

D. Syncytial lacunae to blood

The corpus luteum is:
A. Exocrine mucus gland
B. Implantation enzyme layer
C. Endocrine estrogen-progesterone tissue
D. Fibrin coagulum plug

C. Endocrine estrogen-progesterone tissue

By the end of week 2, common pregnancy tests detect which syncytiotrophoblast product?
A. Human chorionic gonadotropin
B. Progesterone
C. Early pregnancy factor
D. Human placental lactogen

A. Human chorionic gonadotropin

The epiblast is primarily composed of:
A. Small cuboidal cells
B. Multinucleated invasive cells
C. Polyhedral decidual cells
D. High columnar cells

D. High columnar cells

The hypoblast is primarily composed of:
A. High columnar cells
B. Small cuboidal cells
C. Multinucleated syncytium
D. Mitotic cytotrophoblast

B. Small cuboidal cells

Primordial germ cells originate (per these notes) in the:
A. Primary umbilical vesicle
B. Chorion
C. Prechordal plate
D. Amniotic cavity

A. Primary umbilical vesicle

“Umbilical vesicle” is used instead of “yolk sac” because:
A. It forms placenta directly
B. It becomes umbilical cord
C. Humans lack yolk
D. It produces surfactant

C. Humans lack yolk

The amniotic cavity forms when:
A. Hypoblast cavitates
B. Cytotrophoblast hollows out
C. Lacunae coalesce
D. Amnioblasts split from epiblast

D. Amnioblasts split from epiblast

Extraembryonic mesoderm is the tissue that:
A. Lines only endometrium
B. Surrounds amnion and vesicle
C. Forms embryonic germ layers
D. Replaces zona pellucida

B. Surrounds amnion and vesicle

Oxygen is supplied and wastes removed by which vessels, respectively?
A. Spiral arteries; endometrial veins
B. Endometrial veins; spiral arteries
C. Umbilical arteries; umbilical vein
D. Chorionic villi; fetal veins

A. Spiral arteries; endometrial veins

What forms at the same time as the amniotic cavity?
A. Primary chorionic villi
B. Prechordal plate
C. Secondary umbilical vesicle
D. Bilaminar embryonic disc

D. Bilaminar embryonic disc

A “10-day conceptus” is:
A. Free in uterine cavity
B. Completely embedded endometrium
C. Primary villi already formed
D. Uteroplacental flow established

B. Completely embedded endometrium

Early implantation nutrition reaches the embryonic disc mainly via:
A. Umbilical blood flow
B. Chorionic villus capillaries
C. Embryotroph in syncytial lacunae
D. Amniotic fluid swallowing

C. Embryotroph in syncytial lacunae

The trophoblast is best defined as:
A. Outer blastocyst enzyme-secreting cells
B. Inner cell mass
C. Hypoblast cuboidal sheet
D. Amnioblast lining

A. Outer blastocyst enzyme-secreting cells

Compared with trophoblast expansion, bilaminar disc growth is:
A. Faster than trophoblast
B. Slower than trophoblast
C. Same rate
D. Stops after day 7

B. Slower than trophoblast

The “closing plug” sealing endometrial epithelium is a:
A. Chorionic villus cap
B. Mucus glycoprotein seal
C. Decidual cell cluster
D. Fibrin blood coagulum

A. Chorionic villus cap

Lacunar networks later become the primordia of:
A. Neural tube lumen
B. Amniotic cavity
C. Intervillous space primordia
D. Prechordal plate

C. Intervillous space primordia

Deficient implantation-site vascular development is associated with low:
A. hCG
B. Connexin 43
C. Progesterone receptor
D. Actin myosin

B. Connexin 43

The connecting stalk later becomes the:
A. Umbilical cord
B. Chorionic plate
C. Amniotic fold
D. Vitelline duct

A. Umbilical cord

The secondary umbilical vesicle forms when:
A. Cytotrophoblast invaginates
B. Epiblast undergoes apoptosis
C. Hypoblast endodermal migration
D. Lacunae fuse

C. Hypoblast endodermal migration

Compared with the primary umbilical vesicle, the secondary vesicle is:
A. Larger than primary vesicle
B. Filled with yolk stores
C. Immediately perfused by cord
D. Smaller than primary vesicle

D. Smaller than primary vesicle

The end of the second week is marked by appearance of:
A. Primary chorionic villi appear
B. Definitive germ layers appear
C. Neural folds appear
D. Secondary villi vascularize

A. Primary chorionic villi appear

The closing plug becomes covered around day 12 due to:
A. Estrogen and oxytocin
B. cAMP and progesterone
C. LH and FSH
D. Prolactin and hPL

B. cAMP and progesterone

The extraembryonic coelom splits into:
A. Epiblast and hypoblast
B. Ectoderm and endoderm
C. Somatic and splanchnic mesoderm
D. Amnion and chorion

C. Somatic and splanchnic mesoderm

Extraembryonic somatic mesoderm primarily:
A. Surrounds umbilical vesicle, covers amnion
B. Forms embryonic germ layers, covers amnion
C. Lines embryo proper, covers amnion
D. Lines trophoblast, covers amnion

D. Lines trophoblast, covers amnion

Extraembryonic splanchnic mesoderm primarily:
A. Surrounds umbilical vesicle
B. Covers amnion surface
C. Lines trophoblast
D. Forms neural plate

A. Surrounds umbilical vesicle

The chorion is the outermost membrane forming the fetal placenta part; it is formed by:
A. Splanchnic mesoderm + hypoblast
B. Somatic mesoderm + trophoblast layers
C. Epiblast + amnioblasts
D. Endometrium + decidua

B. Somatic mesoderm + trophoblast layers

Before 20 weeks, expulsion of fetus with retained placenta is:
A. Complete abortion
B. Missed abortion
C. Incomplete abortion
D. Threatened abortion

C. Incomplete abortion

Formation of the extraembryonic coelom occurs alongside formation of the:
A. Secondary umbilical vesicle
B. Prechordal plate
C. Neural tube
D. Primary chorionic villi

A. Secondary umbilical vesicle

Placenta partially/completely covering the internal os (with bleeding risk) is:
A. Abruptio placentae
B. Placenta accreta
C. Cervical ectopic pregnancy
D. Placenta previa

D. Placenta previa

The prechordal plate forms as:
A. Day 12, cytotrophoblast thickening
B. Day 13, syncytium thickening
C. Day 14, hypoblast thickening
D. Day 15, epiblast groove

C. Day 14, hypoblast thickening

The prechordal plate is clinically important because it marks the:
A. Future umbilical ring
B. Future mouth, head organizer
C. Intervillous space boundary
D. Neural crest migration

B. Future mouth, head organizer

Pelvic inflammatory disease (PID) is:
A. Pelvic organ infection/inflammation
B. Physiologic implantation pain
C. Endometrial decidualization only
D. Isolated ovarian torsion

A. Pelvic organ infection/inflammation

PID may include:
A. Orchitis, prostatitis, cystitis
B. Vaginitis, vulvitis, urethritis
C. Appendicitis, ileitis, peritonitis
D. Salpingitis, oophoritis, endometritis, endocervicitis

D. Salpingitis, oophoritis, endometritis, endocervicitis

Abdominal pregnancy (per these notes) begins with implantation in the:
A. Uterine fundus
B. Ampulla or fimbriae
C. Cervical canal
D. Ovary surface

B. Ampulla or fimbriae

After expulsion into the peritoneal cavity, implantation often occurs in the:
A. Rectouterine pouch
B. Vesicouterine pouch
C. Inguinal canal
D. Hepatorenal recess

A. Rectouterine pouch

Early pregnancy evaluation: endovaginal US measures which diameter to assess development/outcome?
A. Biparietal diameter
B. Femur length
C. Chorionic sac diameter
D. Nuchal translucency

C. Chorionic sac diameter

A medically performed termination before 20 weeks is:
A. Threatened abortion
B. Habitual abortion
C. Spontaneous abortion
D. Induced abortion

D. Induced abortion

A “stone fetus” (lithopedion) occurs when an:
A. Tubal conceptus ruptures
B. Abdominal conceptus dies unnoticed
C. Intrauterine fetus post-term calcifies
D. Cervical pregnancy resorbs

B. Abdominal conceptus dies unnoticed

Which embryonic tissue layers are formed from the hypoblast?
A. Ectoderm only
B. Endoderm only
C. None; all from epiblast
D. Mesoderm only

C. None; all from epiblast

In these notes, the hypoblast still contributes by forming:
A. Extraembryonic mesoderm
B. Cytotrophoblast
C. Neural tube
D. Syncytiotrophoblast

A. Extraembryonic mesoderm

Implantation chronology: day 5 is characterized by:
A. Lacunar networks form
B. Closing plug forms
C. Blastocyst adheres
D. Zona pellucida degenerates

D. Zona pellucida degenerates

Implantation chronology: day 6 is characterized by:
A. Trophoblast differentiates
B. Lacunae appear
C. Blastocyst adheres endometrium
D. Primary villi develop

C. Blastocyst adheres endometrium

Implantation chronology: day 7 is characterized by:
A. Syncytium erodes endometrium
B. Trophoblast splits two layers
C. Maternal vessels opened
D. Zona pellucida degenerates

B. Trophoblast splits two layers

Implantation chronology: day 8 is characterized by:
A. Syncytium erodes, embeds blastocyst
B. Blood-filled lacunae appear
C. Closing plug forms
D. Epithelium defect repaired

A. Syncytium erodes, embeds blastocyst

Implantation chronology: day 9 is characterized by:
A. Lacunar networks form
B. Primary villi form
C. Blood-filled lacunae appear
D. Prechordal plate forms

C. Blood-filled lacunae appear

Implantation chronology: day 10 is characterized by:
A. Epithelium defect repaired
B. Maternal vessels eroded
C. Primary villi develop
D. Closing plug forms

D. Closing plug forms

Implantation chronology: day 11 is characterized by:
A. Blood-filled lacunae appear
B. Lacunar networks form
C. Zona pellucida degenerates
D. Prechordal plate forms

B. Lacunar networks form

Implantation chronology: day 12 establishes uteroplacental circulation when:
A. Maternal blood enters lacunae
B. Bilaminar disc forms
C. Primary villi develop
D. Closing plug covered

A. Maternal blood enters lacunae

Implantation chronology: day 13 is characterized by:
A. Primary villi form
B. Lacunar networks form
C. Uteroplacental flow begins
D. Endometrial defect repaired

D. Endometrial defect repaired

Implantation chronology: day 14 is characterized by:
A. Secondary villi vascularize
B. Prechordal plate forms
C. Primary chorionic villi develop
D. Zona reaction occurs

C. Primary chorionic villi develop

Main cause of maternal death in first trimester (per these notes) is:
A. Placenta previa
B. Tubal ectopic pregnancy
C. Preeclampsia
D. Amniotic embolism

B. Tubal ectopic pregnancy

Missed period + abdominal pain + bleeding + peritoneal irritation most suggests:
A. Tubal ectopic pregnancy
B. Complete abortion
C. Placenta previa
D. PID flare

A. Tubal ectopic pregnancy

Right-sided tubal ectopic pain may be confused with:
A. Ovarian torsion
B. Renal colic
C. Appendicitis
D. Cholecystitis

C. Appendicitis

Compared with intrauterine pregnancy, ectopic β-hCG rises at a:
A. Faster rate
B. Same rate
C. Pulsatile rate
D. Slower rate

D. Slower rate

Slower β-hCG rise in ectopic pregnancy can cause:
A. False-negative test
B. False-positive ultrasound
C. Higher progesterone
D. Immediate fetal viability

A. False-negative test

“Abortion” is best defined as:
A. Delivery after 28 weeks
B. Pre-viability conceptus expulsion
C. Failure of fertilization
D. Implantation outside uterus

B. Pre-viability conceptus expulsion

Threatened abortion is:
A. Retained products after expulsion
B. Dead fetus retained
C. Three consecutive losses
D. Bleeding with miscarriage threat

D. Bleeding with miscarriage threat

Spontaneous abortion is best defined (per these notes) as:
A. Loss before 20 weeks
B. Loss after 28 weeks
C. Medically induced loss
D. Placenta covering internal os

A. Loss before 20 weeks

Habitual abortion is:
A. Two consecutive losses
B. Three consecutive losses
C. Any bleeding episode
D. Loss after viability

B. Three consecutive losses

Complete abortion is:
A. Fetus expelled, placenta retained
B. Dead fetus retained
C. All products expelled
D. Medically induced termination

C. All products expelled

Missed abortion is:
A. Bleeding with viable fetus
B. All products expelled
C. Fetus expelled, placenta retained
D. Dead fetus retained

D. Dead fetus retained

The morning-after pill prevents pregnancy mainly by:
A. Blocking fertilization
B. Preventing implantation
C. Killing sperm directly
D. Inducing ovulation

B. Preventing implantation