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What gonadotropin produced by the anterior pituitary gland initiates the development of follicle within the ovary?
As the dominant follicle develops, what hormone does it secrete?
Estrogen (by theca interna cells of Graafian follicle)
What hormone influences final stages of follicles development, & peaks causing ovulation?
When does menstrual age begin?
first day of LMP
When does fetal age begin?
begins at conception (2 weeks less than menstrual)
Alternative names for fetal age?
Conceptual age or Embryologic Age
Importance of Menstrual Age?
- schedule procedures
- Interpretation of expanded maternal serum alpha-fetoprotein screen
- plan/guess delivery within 38-42 weeks
- evaluate growth
What is the triple-marker?
another name for Maternal alpha-fetoprotein
Where/When does fertilization occur?
- 24 to 36 hours after ovulation
- Ampullary portion of fallopian tube
What is the outer layer of the ovum?
What is a fertilized egg called?
What are gametes?
What is a morula
mitosis to 16-cells
What comprises a blastocyst?
trophoblast cells + inner cell mass
When do blastocysts occur?
day 7 after fertilization
When will a blastocyst implant in the UT?
7-9 days after fertilization
What determines a positive pregnancy?
trophoblast produces hCG
When would a trophoblast produce hCG?
GA around 3 weeks (days 20-21)
During embryonic development, what are the 3 germ cell layers called of the trilaminar disk?
What do the endoderm, mesoderm, and ectoderm form?
form into all the major organs
What is the first organ to function during embryonic development?
heart (day 36)
- 1 endometrium
- 2 uterine endometrium epithelium
- 3 inner cell mass
- 4 trophoblast
- 5 blastocyst cavity
- 6 lumen of uterus
- 7 endometrial stroma with blood vessels and glands
- 8 syncytiotrophoblast
- 9 cytotrophoblast
- 10 inner cell mass (future embryo)
- 11 lumen of uterus
How many days does it take the zygote to reach the uterus after fertilization?
When would you use the term embryo?
up to 9 weeks
When would you use the term fetus?
after 9 weeks
When does the primary yolk sac cease to function?
around 23 days
Which yolk sac is seen during ultrasound?
the secondary yolk sac
What does the secondary yolk sac do?
provides blood/nutrients to developing embryo
When does the secondary yolk sac form?
27-28 days after MA
What is the approximate measurement of the gestational sac when the secondary yolk sac forms?
What hormone do trophoblasts produce? Why?
produces hCG to extend the life of the corpus luteum
What produces proteolytic enzymes?
What is the function of the proteolytic enzymes?
erode the endometrial mucosa and maternal capillaries
Def. the cellular and vascular changes occurring in the endometrium at the time of implantation
3 layers of the decidual reaction
- decidual basalis
- decidual casularis
- decidual parietalis (vera)
Define decidual basalis
where the embryo is implanted into the endometrium (maternal portion of the placenta)
Define decidual casularis
thin portion of endometrium that covers the gestational sac
Define decidual parietalis (vera)
remaining endometrium unoccupied by the implantation that surrounds the rest of the uterine cavity (besides the implantation site)
- 1 chorion laeve
- 2 decidual capsularis
- 3 amniotic cavity
- 4 chorionic cavity
- 5 decidual parietalis
- 6 decidual basalis
- 7 yolk sac
- 1 decidual parietalis (vera)
- 2 decidual basalis
- 3 decidual capsularis
What will the embryo appear as on week 5 sonographically?
grain of rice
What 2 things develop during week 5?
- 2 cardiac tubes
When is the embryonic period?
What is the most critical time of embryonic development when all the internal and external structures are present and congenital malformations can originate?
What has developed at the end of week 6?
- brain has 3 segments
- primitive gut has formed
What is the sonographic appearance of an embryo that is 8 weeks old?
What has developed at week 8?
- heart has adult form
- midgut herniates
- metanephros (primitive kidneys) ascend from pelvis
What has developed at 10 weeks?
- major organ systems established
- embryo (maybe fetus) demonstrates human features
When will the amniotic cavity fuse with the chorion?
12-17 weeks after last menstrual period
What has developed by week 11?
- primitive kidneys reach adult position
- limbs have fingers and toes
- head (large) is disportionate to body
What happens at week 12?
midgut retracts into abdomen
small GS within an echogenic endometrium with focal thickening at implantation site characterizes what?
When can hCG be detected?
3 weeks after LMP
What is a Qualitative hCG?
pregnant (yes or no)
What is a Quantitative hCG?
how much Glycoprotein is in the blood (suggests age)
What does hCG stand for?
Human Chorionic Gonadotropin
Def. refers to the level at which a gestational sac should be visible with regards to hCG
What is the discriminatory level for a TV exam?
What is the discriminatory level for a TA exam?
The symptoms below are associated with what?
gestational trophoblastic disease (molar pregnancy)
high hCG levels
The symptoms below are associated with what?
Describe the normal sonographic gestational sac appearance
- located within the fundus or midportion of the UT
- small, round/ovoid, anechoic, fluid-filled
- enclosed by hyperechoic walls
What is the first structure seen within the gestational sac?
Where does the yolk sac lie?
lies between the amniotic and chorionic cavities
For TA exams, what MSD measurement of the gestational sac will the yolk sac be visible? (both early and always)
For TV exams, what MSD measurement of the gestational sac will the yolk sac be visible?
What is the normal diameter of the yolk sac at 5-10 weeks?
What are the functions of the yolk sac?
- provides nutrients to embryo
- development of the embryonic endoderm (forms primitive gut)
When does the double-bleb sign occur?
What is the double-bleb sign?
it's when the amniotic and yolk sac approximately the same size
What the 2 fetal membranes?
What becomes the covering of the umbilical cord?
When does the amnion fuse with the chorion?
between 12-16 weeks
The Amnion is not vascular and develops from what?
This structure surrounds the gestational sac and merges with the edge of the placenta.
Which gender provides the structures below?
inner cell membrane
Which gender provides the structures below?
gestational sac (chorion)
5 functions of the amniotic cavity
- symmetrical growth
- Prevents adhesions in the fetal membrane
- Cushions embryo
- maintain temperature
- Allow movement = muscle tone
What areas produce amniotic fluid?
- chorion frondosum
- chorionic membrane
- amniotic membrane
- urinary tract
What is primarily responsible for amniotic fluid production?
In the 2nd/3rd trimester amniotic fluid is regulated by what?
fetal urination, swallowing, and fluid exchanges in lungs, membranes, and cord
What is the sonographic appearance of amniotic fluid?
anechoic with or without free-floating particles
Def. not enough amniotic fluid
Def. too much amniotic fluid
What is associated with oligohydramnios?
What is associated with polyhydromnios?
maternal complications, trisomy, GI obstruction
What is the sonographic appearance of chorionic fluid?
more echogenic than amniotic fluid
Def. Embryonic tissue lining the exterior of the gestational sac
What is the purpose of the chorionic cavity?
to invade the decidua and establish nutrition for the embryo
Define Chorionic Villi
finger-like projections that project outward from the walls of the blastocyst into the decidua
Define chorionic frondosum
portion of the chorion located at the implantation site which later contributes to the formation of the placenta
Define chorionic laeve
thinly stretched chorion frondosum that didn't proliferate
A heart rate will be visible on a TV exam when the CRL measures what?
What is the normal heart rate at 6 weeks?
What is the normal heart rate at 9 weeks?
What is the normal heart rate between 10 and 24 weeks?
When does the umbilical cord form?
end of 6th week
What is contained in the umbilical cord?
- 2 arteries
- 1 vein
- Yolk stalk
What umbilical structure is associated with bladder development?
What umbilical structure connects the primitive gut to the yolk sac?
Def. gelatinous substance within the umbilical cord
How is the gestational sac measured?
Where do you measure the gestational sac?
at the fluid-tissue interface
How accurate is the gestational sac measurement for determing embryonic age?
accurate to within one week
When would you stop measuring the gestational sac for embryonic age?
when the embryo is visible
Which transducer is most accurate for measuring structures during early OB?
high frequency transvaginal probes
A gestational sac measuring MSD = 2mm corresponds to what age?
A gestational sac measuring MSD = 5mm corresponds to what age?
At what age will the yolk sac appear?
At what age will the embryo and yolk sac be visible?
What is the most accurate of all fetal measurements?
crown rump length
How many CRL should be taken?
3 for accuracy and averaging
When the fetal pole is visible how quickly does it grow?
1-2 mm per day
How is gestational age calculated from CRL?
CRL (mm) + 42 = GA (days)
When are CRL no longer necessary?
after the 12th week
Why are CRL measurements less accurate after the 12th week?
due to curling
When do the lateral ventricles appear?
When does the choriod plexus appear?
Sonographic appearance of lateral ventricles?
Sonographic appearance of choroid plexus?
Choroid Plexus / Lateral Ventricles
Def. failure of the fetal gut to return after it herniates
Def. Absence of cranial vault/cerebral hemispheres
Def. Lucency at the back of
Def. termination of the pregnancy prior to 20 weeks
Spontaneous Abortion will occur approximately _____ weeks after embryonic demise.
What percentage of pregnancies end in spontaneous abortion?
75% of spontaneous abortions occur before _____ weeks.
What are some causes of Spontaneous Abortion?
unknown, endocrine factors, failure or corpus luteum, interruption of embryonic development, chromosomal anomalies
Spontaneous Abortion begins with ________ into the decidual basalis, followed by _______ and ________ around the implantation site causing the embryo to die.
What will the uterus and cervix do after a spontaneous abortion?
uterus contracts, cervix dilates, and pregnancy is expelled
What happens during a complete abortion?
- Evacuation of ALL products of conception
- Rapid decline in hCG levels
- Vaginal bleeding with clots and tissue
- Very painful cramping
- Pregnancy symptoms disappear
- Cessation of pain and bleeding after conceptus is passed
- Sonographic appearance- thin endometrium, empty uterus
What happens during an incomplete abortion?
- Partial evacuation of products of conception
- Slow fall or plateau of hCG levels
- Moderate cramping
- Persistent bleeding
- Sonographic appearance- presence of complex echoes in endometrial cavity, retained products of conception
What happens during a missed abortion?
- Presence of embryo/GS in uterus but no cardiac activity
- hCG levels less than expected for dates
- Loss of pregnancy symptoms
- Brownish bleeding ordischarge without heavy bleeding or cramping
- Sonographic appearance- no cardiac motion, no fetal motion, size < dates, hypoechoic embryo
Def. Condition in which the pregnancy appears normal but clinical signs such a bleeding or cramping suggest pregnancy is in jeopardy
What happens during an inevitable abortion?
- SAB is imminent when any of 2 or more of the following clinical signs are noted:
- Moderate effacement of the cervix (shortening)
- Cervical dilatation > 3cm
- Rupture of membranes (little or no AFV)
- Bleeding for more than 7 days
- Persistent cramping
- Sonographic appearance- GS seen in the cervix or LUS, cervical dilatation
Def. gestational sac seen in uterus but embryo failed to develop or died at a stage before it was visible
What was an anembryonic pregnancy formerly called?
What is the sonographic appearance of an anembryonic pregnancy?
large gestational sac with no amnion, yolk sac, embryo
What risks are associated with a large yolk sac?
increase risk for spontaneous abortion and embryonic demise
What is the max diameter of the yolk sac at 10 weeks gestation age?
What risks are associated with abnormally shaped or calcified yolk sacs?
A CRL of 5-9 mm with a heart rate of < 100 BPM or a CRL of 10-15 mm with a HR of < 115 BPM indicates
What is the most common reason for bleeding during the first trimester?
Def. an accumulation of blood beneath the chorion
What is the sonographic appearance of an acute chorionic hemorrhage?
- hyperechoic to isoechoic relative to placenta
- 1-2 weeks sonolucent
What is the most important criteria for subchorionic hemorrhage?
- size of the bleed
- should decrease with follow-up scans
Describe an early pregnancy failure.
- Pregnancy shows sonographic evidence of cessation of growth & development & clinical findings are supportive
- Large empty GS
- GS & Yolk sac only
- No CA & smaller than normal or appropriately sized embryo
- Remnants of a sac
What is the name for a surgical abortion?
suction dilation and curettage (D&C)
What pills cause a medical bortionl?
- mifepristone (600mg)
- 2 days later misoprostol (400 µg)
91% of expectant miscarriages occur after ____ days.
What is the leading cause of pregnancy related deaths during the first trimester?
Ectopic pregnancy is the cause of ____% of all pregnancy related deaths.
What has caused ectopic pregnancies to increase of the past 10 years?
What are the symptoms of ectopic pregnancy?
- + pregnancy test and empty uterus
- adnexal mass
- vaginal bleeding
- lower abdominal pain
- cramping on one side of the pelvis
- sharp, stabbing pain in the pelvis, abdomen, or even shoulder or neck
What are the risk factors for ectopic pregnancy?
- Pelvic inflammatory disease (PID) -- 6 to 10 times higher than in women with no previous history of PID.
- Previous ectopic pregnancy
- IUD's -- 16% of pregnancies in women using progesterone containing IUD's were ectopics.
- Tubal ligation
- (sterilization) -- After non-laparoscopic tubal ligation, about 12% of
- pregnancies are ectopic; after laparoscopic tubal coagulation, about 51% of pregnancies are ectopic.
- Previous tubal surgery
- Fertility treatment with ovulation induction or ovarian stimulation
- In vitro fertilization (IVF) -- About 2 to 5% of clinical pregnancies resulting from IVF are ectopic. The figure is higher for women with a history of previous ectopic pregnancy or tubal infertility.
- Some studies have suggested that tubal pregnancies are more likely in African American women.
What poplulation is at most risk for an ectopic pregnancy?
- Varies patient population & inherent risk factors
- All patients of reproductive age
- Coexistent intrauterine & ectopic
- IVF & ovulation induction
- 1 in 2000 pregnancies
What is the ring of fire sign?
a tubal pregnancy with peripheral hypervascularity surrounding the extrauterine gestational sac
What should you demonstrate if there is a live embryo in the adnexa
show cardiac acitivity in M-mode, color, and power dopplar
Empty uterus and adnexal mass
hCG >1500 mIU/ml
Free fluid in pelvis
Look for decidual reaction and “ring of fire” around ectopic
Sonographic pitfalls “pseudogestational sac”-fluid in the endometrial canal
Mimics normal GS
Look for decidual reaction
Resection of diseased tube
Early diagnosis w/ TV = more conservative
Goal is to find early before rupture
Cell growth inhibitor
Spectrum of pathologies resulting from the excessive proliferation of trophoblastic tissue
Paternal genomes control the proliferation of trophoblastic tissue, maternal genomes control growth of the embryo
GTD is caused from excessive paternal genomes
Mole with coexisting normal fetus
Gestational Trophoblastic Disease
GTD clinical signs
- Grossly elevated hCG levels >100,000 mIU/ml
- Hyperemesis gravidarum (severe morning sickness)
- Rapid enlargement of the uterus
- Vaginal bleeding
- Theca lutein cysts
- Early onset of preeclampsia (htn, edema, proteinuria)
Most common form of GTD
1:1500 USA; 1:82
Risk factors include:
< 20 yrs and >40 yrs
Low economic status
Diets deficient in protein and folic acid
1: Duplicated male chromosomes and normal ovum
2: Normal male chromosomes and empty ovum
Complete Molar Pregnancy
Single set of unpaired chromosomes
Hydropic chorionic villi enveloped by hyperplastic atypical trophoblasts
No embryo or fetal tissue is present
Multiple scattered cystic spaces filling a thickened endometrial cavity- “cluster of grapes”
Uterus larger than dates
Enlarged ovaries from theca lutein cysts
Complete molar pregnancy
2 normal sperm fertilize the same normal ovum
2 types of chorionic villi
Hydropic swelling (trophoblastic hyperplasia)
Growth-restricted fetus with anomalies
Large placental size with cystic spaces
Trophoblastic proliferation not as severe
Less severe than complete
Sonographic appearance is similar to a missed or incomplete abortion
Partial Molar Pregnancy
partial mole first trimester
Therapy for molar pregnancy
- Uterine evacuation
- Monitor serum hCG-should fall over 10-12 weeks
- Avoid pregnancy for 1 yr.
2 conceptions occur as in twinning, but one develops into a mole and the other a normal fetus
Cases have been reported of normal going to term, but itis very risky. Mom has to be monitored closely for hemorrhage, severe HTN, or toxicity
Maternal risks are significant and termination is given as an option; Risk for future molar pregnancy or PTN increases
Mole with coexisting normal fetus
2 types of Persistent trophoblastic disease
- Invasive mole
Persistent trophoblastic disease
- PTN can follow normal pregnancy, SAB, ectopic pregnancy, or GTD
- Severe cases of GTD are at the highest risk for PTN
AKA Chorioadenoma destruens Most common form of PTN (80-95%)Trophoblastic tissue that penetrates the myometrium and/or adjacent structures. May penetrate the uterine wall and cause uterine rupture and hemoperitoneum Considered a malignant, non-metastatic form of GTDDiffuse echogenic material with cystic spaces filling the endometrial cavity and extending into myometrium (“more mole than uterus”)
very rare1:30,000 pregnancy; 1:40 molar pregnanciesVascular invasion, hemorrhage, and necrosis of the myometrium are commonTumor composed of syncytiotrophoblastic and cytotrophoblastic cellsConsidered the malignant, metastatic form of GTDCan metastasize to the lung, brain, liver, bone, GI tract, or skin
No embryo or fetal tissue present
Mass with complex, marked vascularity
Treatment for PTN
- Treatments performed as needed based on severity of disease
If abnormality is suspected in 1st trimester follow-up is recommended or genetic testing: by testing what?
- Serum alpha-fetoprotein
What is the major advantage of screening anomalies in the 1st trimester?
maternal reassurance and/or counseling for parents of structurally abnormal fetuses
Def. performed from 15 wksAmniotic fluid is drawn ransabdominally under U/S guidance to avoid fetus, placenta, and umbilical cord
List the Genetic Testing options
- MSAFP- can detect
- ONTD’s-open neural tube defects
- Trisomy 13, 18, 21
- Abdominal wall defects
- Chorionic Villus Sampling – performed 9-12 weeks gestation
- U/S guidance transcervically or transabdominally
- Trophoblastic cells are obtained and can reveal karyotype, chromosomal abnormalities,
- Termination can be performed earlier if elected
- Amniocentesis – performed from 15 wks
- Amniotic fluid is drawn transabdominally under U/S guidance to avoid fetus, placenta, and umbilical cord
What type of US scans are the most accurate for assessment of fetal anatomy
TV and TA sonograms are used for the most accurate assessment of fetal anatomy
When do most congenital anomalies occur?
Most originate in embryonic period
When are most congenital anomalies diagnosed?
Most anomalies are diagnosed in the 2nd trimester due to fetal immaturity affecting visualization
List some congenital anomalies
- Fetal face
- Fetal neck
- CV system
- GI tract
- Genitourinary System
- MS system
Def. exaggerated, hyperextension of the neck, open spinal defects, occipital encephalocele
Def. protrusion of the brain through a bony defect in the skull
Def. absence of the brain and cranial vault, base of skull and face are present along with some brain tissue
Def. partial or complete absence of the cranium, bony structures absent
Def. lack of closure of the spinal column, bulging of spine or meninges into a sac; prognosis depends on severity
Def. cystic dilatation of the 4th ventricle and abnormal configuration of the cerebellum
Def. 3 levels of severity, absence of brain tissue in varying degrees; no cerebral hemispheres or ventricles
Def. hydrocephaly, dilatation of the ventricles without enlargement of the cranium; increased amount of CSF
Def. herniation of the abdominal contents into the umbilical cord; often associated with other congenital anomalies
Def. open defect in the anterior abdominal wall; organs are not covered by a membrane, they are seen “floating” in the amniotic fluid; not associated with other congenital anomalies
Def. One of the most common abnormalities seen in the 1st trimesterSingle or multiple cystic areas, of lymphatic origin, within the soft tissue surrounding the neckAssociated with chromosomal abnormalities such as Turner’s and Down syndromes