Fundal height measurement
Measured from symphysis pubis to superior aspect of uterine fundus.
- -16-34 weeks- cm measurement= ga in weeks
- i.e. 18 weeks= 18 cm
- -20 weeks closer to fundus
- -Max height at 36 weeks
Normal gestation is how long
280 days or 40 weeks from LNMP (first day)
Calculate due date by adding 9 months and 7 days to the 1st day of the last period.
When is hCG first secreted?
1st secreted by the chorion of the blastocyst by 14 days post fertilization.
At what beta hCG level should we see a gestational sac? (1st IRP)
At what beta hCG level should we see the yolk sac? (1st IRP)
At what beta hCG level should we see a live embryo? (1st IRP)
Low hCG levels associated with?
- Ectopic pregnancy
- Spontaneous abortion
High hCG levels are associated with?
- Multiple gestations
- Hydatidiform mole (low MSAFP)
Between 11 and 13 weeks ga
87% sensitive for detection of T21
3 blood tests- MSAFP, estriol, Beta hCG
Performed between 14 and 19 weeks ga
- Used to identify risk for
- -chromosomal abnormalities (70% sensitive for T21)
- -birth defects(open NTD)
- Produced in fetal liverNormal levels in both maternal and fetal serum
- Open NTD> *spina bifida, anencephaly*
- Underestimation of GA
- Multiple gestation
- Threatened abortion
- Congenital nephrosis
- Duodenal atresia
- Sacrococcygeal teretoma
- Long standing fetal death
- T13, T18
- Hydatidiform mole
- Risk for:
- -Growth restriction
- -Fetal death
- -Anomalies- T21
- -Post maturity
- -Rh immunization
Triple screen (MSAFP, Beta hCG, and Estriol) with the addition of inhibin A
Inhibin A is produced in fetus and placenta and has an abnormal increase with T21 (86% detection)
Cell free fetal DNA
- Indicates if at risk of having a fetus with T21, T18, T13
- Blood sample taken at 10 weeks LNMP
- Extremely sensitive for detection of downs and T18 (98%)
- Slightly less sensitive for T13(65%)
- Chorionic villi retrieved from chorion frondosum
- Performed between 10 and 14 weeks
- Most done transcervical
- Risk of abortion... slightly higher than amnio
- Usually performed between 15 and 17 weeks
- Provides kayotype
the birth process
Thinning of cx
delivery that occurs prior to 20 weeks ga
Subcutaneous scalp edema
Method to remove products of conception
Can detect spina bifida
A disorder with one defective gene is considered what?
Polyhydramnios (3rd trimester value)
Oligohydramnios (2nd vs 3rd trimester)
Thick placenta is associated with:
- Maternal diabetes
- Eyrithroblastosis fetalis
- Nonimmune hydrops
Causes of postpartum hemmorhage
- #1>> uterine atony (inability to contract)
- multiple gestation
- long labor
Molar pregnancy that is invasive but does not metastisize
Drug used to combat RH immunization
When should the uterus return to pregravid size?
4 weeks postpartum
Maternal HTN is associated with?
- Thin placenta
- Fetal demise
- Advanced placental age
Term for after birth
Cystic hygroma is associated with what chromosomal abnormality?
Caudal regression syndrome
Associated with maternal diabetes
Midline anechoic brain lesion with color
Vein of galen anyeurism
Causes of oligohydramnios
- Fetal demise
- Bilateral renal agenisis
Long bone least affected by IUGR
Gestational sac measurements are accurate in estimating ga with in what margin?
What does the placenta form from?
Chorion and the decidua
- @ term rarely exceeds 4cm
- thickness= ga +/- 10mm
Smoking causes what type of change to placenta
Causes it to age faster
Stage 3 placenta should not be seen until when?
- 35 to 37 weeks
- Diabetics may be 0 ot 1 at term
Cerebellar measurements loose accuracy when?
- Normally 70-85%
- bpd/ofd X 100
- Low CI = dolichocephally
- High CI = brachycephally
- AKA omphalomesenteric duct
- Connects yolk sac to embryo once they diverge from one another
Gestational sac should take up half the uterine cavity when?
~8 weeks ga
1st sight at which fluid will collect if there is an obstruction of CSF?
Lateral ventricular atria
Best view of the diaphragm
Coronal or parasagital
Bladder in male fetus' are sometimes enlarged bc of what?
Coronal view of the fetal bladder will consistently demonstrate what other anatomy?
Largest normal measurement of the yolksac
Double bleb sign
Amnion and yolk sac
Amount of fluid needed for amnio
20-30mL (no amnio prior to 15 weeks)
- More comprehensive karyotyping than amniocentesis
- Sensitive for mosacism
- Needle inserted 2-3cm from insertion into placenta
- Blood obtained from umb vein
- Can cause hematoma
- Puncturing artery can cause bradycardia
Fetal lung maturity
- L/S ratio
- Flourescence Polarization ( currently most widely used) elevated surfactanct to albumin ratio indicates lung maturity
List the three potential spaces of the female pelvis.
- Space of Rezius (prevesical or retropubic space)
- Anterior cul-de-sac (uterovesical pouch)
- Posterior cul-de-sac (pouch of Douglas, rectouterine space)
Describe the location of the Space of Retzius.
Space anterior to the bladder (between the transversalis fasica and the umbilical prevesical fascia)
Describe the location of the Anterior cul-de-sac.
- Posterior to the urinary bladder
- Anterior to the uterine body and fundus
Describe the perimetrium.
Outter layer of the uterine tissue
Describe the location of the Posterior cul-de-sac aka the Pouch of Douglas.
- Retrouterine space
- Posterior to uterus and upper 1/3 of vagina
- Anterior to rectum
List the tissue layer of the uterus.
Describe the myometrium
Middle, smooth muscle layer of the uterine tissue
Describe the endometrium
- Inner mucous later of the uterine tissue
- Line uterine cavity and is shed during menstration
List and describe the anatomic divisions of the uterus.
- Fundus: superior portion above entrance of fallopian tubes
- Body: Mid portion/ corpus
- Isthmus: narrow lower uterine segment
- Cervix: inferior portion
Normal measurement and location of the fallopian tubes
- 7-12cm in length
- 3mm in diameter
- Extends from uterine fundus to ovaries
List and describe the divisions of the fallopian tubes.
- Isthmic: longest thinnest section
- Ampullary: usual site of fertilization; common site of ectopic pregnancy
- Infundibulum: largest section
- Fimbria: fingerlike ends
Describe the vascular supply of the uterus.
Aorta > common iliac arteries > internal iliacs > anterior trunk > R & L uterine arteries
Describe the vascular supple of the ovaries
- Aorta > L & R ovarian arteries
- IVC > R ovarian vein
- IVC > L renal vein > L ovarian vein
List & decribe the tissue layers of the ovaries
- Cortex: outer portion containing follicles
- Medulla: inner portion containing blood vessels connective tissue and smooth muscle
Describe the typical uterine position when the bladder is empty.
Anteverted: tilts anteriorly
List the most consistent landmarks for identification of the ovaries
- Internal iliac arteries which lay posterior to the uterus
The ovaries are located in the fossa of __________.
Describe the sonographic pattern and normal measurement range of the endometrial cavity during the early proliferative phase of the normal menstrual cycle.
- end of menses
- Thin, hyperechoic line
Describe the sonographic pattern and normal measurement range of the endometrial cavity during the proliferative phase of the normal menstrual cycle.
- 8mm thick
- Hypoechoic junctional zone deep to endometrium
Describe the sonographic pattern and normal measurement range of the endometrial cavity during the periovulatory phase of the normal menstrual cycle.
- Striated (triple layer sign)
- Hyperechoic lines surrounding 2 hypoechoic layers
- Signifies time when endometrium is receptive to implantation
Describe the sonographic pattern and normal measurement range of the endometrial cavity during the secretory phase of the normal menstrual cycle.
- Hyperechoic & thick
- Right before period starts
Describe the hormonal control of the menstrual cycle
- FHS stimulates follicle to develop.
- Estrogen increases & LH surges
- Progesterone increases and builds up endometrium
- Once the progesterone drops the endometrium is shed
- 2 Phases: proliferative and secratory
List the terms and stages of development of a corpus luteum for a cycle not ending in pregnancy.
Develops @ site of ovulation and degenerates once body realizes there is no pregnancy (lack of Beta hCG
Fetal landmarks identifiable on ultrasound at week 4.
gestational sac ~2-3mm
Fetal landmarks identifiable on ultrasound at week 5.
yolk sac, fetal heart beat (end of 5th week), earliest sign of the morrow reflex, MSD = 5mm, double bleb sign (5 to 7 weeks)
Fetal landmarks identifiable on ultrasound at week 7
crown-rump length is obtainable ~8mm, rapid head growth, corpus leutem reaches max size
Fetal landmarks identifiable on ultrasound at week 8.
- limb buds, head, ventricles in brain, mid gut herniates into base of umbilical cord, earliest date to see fluid in stomach
- CRL = 23mm (weight = 1 gram)
Fetal landmarks identifiable on ultrasound at week 9.
choroid plexus, brain
Fetal landmarks identifiable on ultrasound at 10
stomach week 10 ~2-3cm, midgut returns
Fetal landmarks identifiable on ultrasound at week 12.
hands/fingers, bladder, mid gut retracts from herniation
Fetal landmarks identifiable on ultrasound at week 14.
CRL ~8.5cm, sex recognition possible, kidneys visable
Embryo should be seen when gestational sac measures what?
Yolk sac should not be seen when gestational sac measures what?
What is the double sac sign?
- Hyperechoic: decidua perietalis
- Hypoechoic: unoccupied lumen
- Hyperechoic: decidua capsularus
List the progression of embryological development
Gamete > zygote > blastomere > morula > blastocyst > throphoblast & inner cell mass
A male or female reproductive cell (sperm, egg) capable of entering into a union with another in process of fertilization. (23 chromosomes each)
Organism produced by union of 2 gametes. (46 chromosomes)
The progressively smaller cells formed by cleavage of fertilized ovum
Berrylike solid mass of cells which reaches uterine cavity ~3-4 days after fertilization
Central fluid cavity forms and by 7th day, cells differentiate into outer layer (trophoblast) and inner cluster of cells (inner cell mass)
Becomes chorionic membrane and fetal contribution to placenta
- Spontaneous abortion
- Expulsion (live or stillborn) of products of conception before 20th completed week of gestation with out deliberate interference
- Therapeutic abortion
- Interruption of pregnancy for legally acceptable, medically approved indications
- Stillborn (born dead)
- Fetus, irrespective of its gestational age, that after complete expulsion from the mother shows no evidence of life
death of liveborn infant within first month of life (28 days or less)
Describe the routine gestational dating parameters used during the first trimester pregnancy.
- 6-12 weeks = crown-rump length
- before 6 weeks = Mean Sac Diameter (MSD)
Cardiac activity should be present when CRL is what?
When is the rhombencephalon visualized?
Normal midgut herniation should meaure
- If more than 7mm consider omphalocele
- Should not see herniation when CRL 45mm or more
Bradycardia in 1st trimester
90 and below
- AKA blighted ovum
- Demise occurs early in pregnancy
- Embryo has been reabsorbed or development ceased before formation of embryonic disc
- lack of cardiac activity
- dilated cx >3cm
- low position of embryo/fetus
- irregular gs
- AKA heterotropic pregnancy
- IUP with coexisting ectopic
Ectopic beta hCG level
Subnormal rise in beta hCG levels (below 66%) is seen in 85% of ectopics.
Transabdominally- looks like normal early IUP without cresent sign
Sonographic indicators of ectopic
- 100%- extrauterine embryo with cardiac activity
- 100%- adnexal mass containing yolk sac or nonliving embryo
- 95%- "tubal" or "adnexal ring" surrounding a fluid collection
- 92% complex or solid adnexal mass- no embryo, yolk sac or tubal ring
- Incidence increases after injury to EC (post D&C, bx, or section) interfering with normal implantation
- Can be fatal due to severe hemmorhage
- ? true cervical ectopic vs abortion in progress
Risk of rupture of an ectopic pregnancy significantly increases at what point?
after 7 weeks LNMP
Hemoperitoneum in the cul de sac is a red flag for what?
Gestational trophoblastic disease
- HX of spontaneous abortion
- Retained products of conception persist and continue to secrete hCG (@ higher levels than in a normal IUP)
- Theca lutein cysts are associated from the ovarian hyperstimulation (multiple and bilateral)
Symptoms of gestational trophoblastic disease
- absence of fetal parts/heart tone
- uterine bleeding in 1st trimester
- High hCG levels
Complete hydatidiform mole
- fertilization of empty ovum
- Sperm duplicates its own chromosomes (46xx)- all paternally derived
- Echogenic mass with hydropic vili filing and expanding EC
- "swiss cheese pattern"
- Bilat theca lutein cysts 20-50% of the time
- Fetal parts identified
- Usually triploidy
- No term cases
- AKA choriocarcinoma destruens
- 12-15% of pts with a molar pregnancy
- invasion of myo/parametrium
- Hypervascularity in myometrium
- Most malignant form of trophoblastic disease
- 50% hx of molar pregnancy
- Mets- lung, brain, liver, bone, GI tract
- indistinguishable from benign mole
Treatment for molar pregnancy
D&C = methotrexate
Abnormal nuchal translucency measurement
Abnormal nuchal translucency increases risk for?
- Aneuploidy (particularyl when sepatated)
Most common feature of T13?
Cystic hygroma is associated with?
2nd most common NTD?
FGR is associated with what chromosomal abnormalities?
T18 and 13
Most single umbilical arteries are ____ sided.
______ anomalies are most common with SUA.
False umbilical knot
Folding of vessels
Lack of Wharton's jelly is seen with:
- Velementous insertion
- Coarctation of the AO
- Intrauterine death
- Preterm delivery
Majority of umbilical cord cysts are:
Paraxial- eccentrically located, vessels not displaced
Multiple cord cysts are associated with:
- Increased nuchal thickness
- Poor outcome
Allantoic cord cyst
- True cyst secondary to patent urachus
- Always near cord insertion
Most common cord tumor
Cord around babies neck
Segment of cord located between fetal presenting part and lower pole of intact membranes
Cord inserts into amniotic membrane instead of placental tissue
Intrahepatic 4VC associated with:
Excelent prognosis and usually isolated finding
Extrahepatic 4VC associated with:
- Almost all cases have SUA
Normal placental thickness = ____ +/- _____
Gestational age in mm +/- 10 mm
Thin placenta is associated with:
- Chromosomal abnormalities
- Preconceptual diabetes
- Sever intrauterine infection
Thick placenta is associated with:
- Gestational maternal diabetes
- Fetal anomalies
- Molar pregnancy
- Edges of placenta not attatched
- Creates a cupped appearance
#1 cause of painless vaginal bleeding
Most common site of abruption is:
At placental margin- subchorionic
Abruption risk factors
Acute abruption w/48 hrs
3-7 day old abruption
1-2 week abruption
2+ week old abruption
Villi grow into myometrium
Villi grow through myometrium
Villi penetrate serosa and may extending into rectum or bladder
Placenta accreta risk factors
- Precious c-section
- Placenta previa
- Submucosal fibroid
- Uterine cornua
Most common benign neoplasm of the placenta
Low risk for preterm labor occurs at a cervical length of:
Greater than or equal to 30mm
Intermediate risk of preterm labor occurs at a cervical length of:
High risk for preterm labor occurs when the cervical length is:
less than 20mm
1st sign of decreased cervical length