Placental Disorders Flashcards
A 31 yo patient, G1 P0 LMP 8 weeks ago presents with painless vaginal bleeding. This is a desired pregnancy. The patient is diagnosed with a threatened abortion. On ultrasound, a hypoechoic crescent-shaped area is noted between the chorion and myometrium.
Subchorionic hematoma
-MC sonographic anomaly in 1st trimester
-~40% of pregnancies
-May represent a partial detachment of the chorion from the uterine wall
-hyperechoic crescent-shaped area between the myometrium and chorion
-May result in abruptio placentae, especially if hematoma is located retroplacentally
-RF: Assisted reproductive technology
-Associated with:
-Spontaneous abortion
-Preterm prelabor rupture of membranes
-Unclear whether its presence is a risk factor for pregnancy loss, though retroplacental hematoma seems to be more commonly associated
-no known management except watchful waiting
A 38 yo G6 P3023 at 31 weeks EGA who has not had any prenatal care awakens in the morning and notes profuse bright red vaginal bleeding not associated with any pain. Upon arrival in the ED, the patient is hypotensive and tachycardic, with fetal heart rate of 185 bpm.
Placenta previa
-After emergent evaluation and institution of fluid resuscitation, you perform an ultrasound of the pelvis, and discover a placenta previa. The fetus has a heart rate of 194 bpm. There are no contractions noted on tocodynamometry. The patient stops bleeding spontaneously. A CBC reveals a hematocrit of 32%. The patient is admitted for further evaluation.
Pathophysiology and etiology of placenta previa and risk factors
-placenta attaches to endometrial cavity -> placenta covers or partially covers the internal os
-Assoc with prior hx of uterine surgery, likely due to implantation of blastocysts in the scar and its vicinity
-Bleeding may be due to atrophic and/or inflammatory changes of the placenta
-RF:
-AMA
-Infertility tx
-Multifetal gestation
-Multiparity
-Prior hx of uterine surgery, including C-section
-incidence- 0.5%-1.3% of all pregnancies
-assoc with an increased risk of the following during pregnancy:
-C-section
-Cesarean hysterectomy
-Prematurity
-Intrauterine growth restriction
-Placenta accreta spectrum
Placenta previa types
-Complete previa: placenta completely covers internal os
-Low-lying placenta: edge of placenta is located within 2-3 cm of internal os
Etiology of hemorrhage from placenta previa
-3rd trimester bleeding may result from development of the lower uterine segment at this time -> leading to changes in the placental attachment
-may cause painless, bright red 3rd trimester bleeding
S&S of placenta previa
-Painless bright red third trimester vaginal bleeding
-May be profound or relatively mild
-Contractions may occur after bleeding due to uterine irritability from hematometra
-prenatal dx:
-Usually made antenatally via transvaginal U/S
-Many resolve by 20 weeks -> if pt has sono evidence of previa at 20 weeks -> it will not resolve
Maternal complications of placenta previa
-Maternal hemorrhage
-0.03% of U.S. pts will die of hemorrhage or disseminated intravascular coagulopathy
-Abruptio placentae
Common complications of placenta previa of the parturient
-antepartum bleeding
-need for hysterectomy
-need for transfusion
-septicemia
-thrombophlebitis
-endometritis
Common fetal complications of placenta previa
-Congenital abnormalities
-Intrauterine growth restriction
-Preterm delivery
-Complications of prematurity
-Fetal anemia and Rh alloimmunization -Low birth weight
-Neonatal mortality up to 1.2% in U.S. neonates
-NICU admission
Management of uncomplicated placenta previa
-Counsel pt about:
-Need! for C-section
-Possible need for Caesarean hysterectomy
-Avoid all intense exercise -> Light is okay
-Abstinence for all sexual activity (alone or with someone else), though evidence for need to do so is conflicted
-Need to notify clinician of any vaginal bleeding
-Deliver between 36-37 weeks, 6 days EGA
Symptomatic previa: management
-perform gentle, careful speculum examination
-!!!!!!!Do NOT ever perform bimanual examination
-Establish large bore IV and administer isotonic fluids
-Perform U/S to determine if the patient has placenta previa
- Workup and management:
-CBC
-Type and screen or crossmatch, depending on severity of bleeding
-History and physical exam
-Electronic fetal monitoring
-Admit for at least 24 hours to L&D all pts with hx of previa with bleeding
-Treat contractions with tocolytics (terbutaline, nifedipine, magnesium sulfate)
-Administer betamethasone to enhance fetal lung maturity
-Most bleeding will stop spontaneously
-In stable pts with prior hx of bleeding:
-Amniocentesis at 36 weeks to determine fetal lung maturity
-Sphingomyelin and lecithin will be elevated if lungs are mature
-If there is maturity, proceed to C-section
-If not, repeat amnio and proceed as above
-unstable with acute bleed that cant be controlled:
-Resuscitate with IV fluids and blood products
-Determine if fetus is alive
-C-section after
resuscitation/stabilization
-Be aggressive with blood products for both pt and neonate
-May require Caesarean hysterectomy
Management of low lying placenta without other risk factors
Deliver between 38 wks and 38 wks, 6 days
A 36 yo G5 P4004, s/p Caesarean section x 4, at 34 weeks EGA was diagnosed in 2nd trimester with placenta previa. The patient was scheduled for elective Caesarean section at 36 weeks, but hemorrhaged last night and is now in the OR undergoing an emergency quinternary Caesarean section.
The placenta has grown through the endometrium and part of the myometrium and cannot be removed.
The surgical team proceeds to Caesarean hysterectomy.
Estimated blood loss is 5,000 cc.
The patient has received 8 units of packed RBCs, 6 units of fresh frozen plasma, and 1 6-pack of platelets. The patient is admitted to the critical care OB unit for observation and management of maternal hemorrhage secondary to placenta increta.
Placenta accreta spectrum
-Placental invasion extending:
-Through the endometrium (accreta), OR
into or through the myometrium (increta), OR
-Into or through the serosa or beyond (percreta)
-RFs:
-80% of cases- placenta accreta spectrum coexists with placenta previa
-risk is greatly increased in pts who have a hx of prior C-section
-(DONT KNOW PIC)
Epidemiology and pathophysiology of placenta accreta spectrum
-1 in 500 of all pregnancies
-1 in 4000 pregnancies in 1970s due to lower C/S rate
-In most cases, due to defect in endometrium and myometrium due to the presence of a uterine scar
-However, 3% in pts w/o any prior hx of uterine instrumentation
-50% of patients will require intensive care
-Maternal mortality rate as high as 7%
Risk of placenta accreta spectrum in currently pregnant patients with coexisting previa per number of prior Caesarean sections
Placental lakes and bridging vessels seen on ultrasound in patient with placenta accreta spectrum
Diagnosis and immediate management of asymptomatic placenta accreta spectrum
-Transvaginal ultrasound
-Multiple vascular lacunae, increased placental vascularity, and abnormalities of the interface between bladder and uterine serosa suggest accreta
-MRI may be useful, but may not be better than transvaginal ultrasound
-With patients diagnosed asymptomatically, transfer care to tertiary care center
-Also, assess for risk based on history of prior Caesarean section and on history of coexisting placenta previa
Management of placenta accreta spectrum
-Perform scheduled C-section and hysterectomy prior to onset of labor at ~34 wks-35 wks, 6 days
-At time of C-section -> CLOSE uterine incision and do NOT attempt to remove placenta -> proceed w/ hysterectomy -> reduces risk of hemorrhage
-No need for amniocentesis to determine fetal lung maturity because results will not change management
-Assemble care team:
-Surgeons -> obstetricians, urologists, trauma surgeons, pelvic reconstructive surgeons, and gynecologic oncologists
-Maternal-fetal medicine specialists
Interventional radiologists
-Obstetric anesthesiologists
-Critical care obstetricians and intensivists
-Neonatologists
-Notify blood bank of pt
-Consider iron supplementation to reduce risk of anemia during pregnancy
-Consider admission in pts with coexisting placenta previa with hx of 3rd trimester bleeding, depending on where the pt lives relative to tertiary care hospital
-In intraoperative period -> consider use of tranexamic acid, recombinant activated
-Factor VIIa, and/or fibrinogen transfusion in addition to blood products
A 43 yo G3 P1011 at 35 week EGA presents to Labor and Delivery, stating that they fell on the ice 2 hours ago, landing on the abdomen.
The patient noted dark red vaginal bleeding with clots beginning about 30 minutes ago, and has had decreased fetal movement since that time.
On exam, maternal vital signs are: BP, 96/60 mm Hg; HR, 105 bpm
The fetal heart rate is 180 bpm with minimal variability and occasional late decelerations
On vaginal exam, there are large clots in the vaginal vault. The cervical exam is: 2 cm dilated, 60% effaced, vertex -2 station
Ultrasound reveals a retroplacental clot
The patient is admitted to Labor and Delivery
Kept NPO
Lactated Ringer’s solution with dextrose 5% IV at 125 cc/hr
Continuous fetal monitoring
Abruptio placentae epidemiology
-A portion or all of placenta separates from uterine attachment prematurely
-BEFORE delivery and after 20 weeks EGA
-MCC of vaginal bleeding after 20 weeks
-approx 1% of U.S. pregnancies
-Fetal mortality=10%
Risk factors for abruptio placentae
-Prior history of abruptio placentae
-AMA
-IVF
Thrombophilia
-Hypertensive disorders of pregnancy
-Placenta praevia
-Smoking
-Amphetamines
-Trauma
-Multiple gestation
-Black and brown patients
Abruptio placentae
-Uncertain pathophys -> believed to be due to abnormal trophoblastic invasion leading to hemorrhage from the spiral arteries
-80% occur before labor begins
-Classic presentation:
-Tetanic uterine contractions with dark red blood with clots
-However, <40% of patients with abruptio placentae have both pain and bleeding at dx
-Dx made definitively after delivery by pathological exam of placenta
-Retroplacental clot on U/S suggests abruption but cannot confirm dx
-U/S has low sensitivity but high specificity for dx when findings are present with high positive predictive value, but low negative predictive value
Maternal morbidity from abruptio placentae
-Hemorrhage
-Sepsis
-Acute kidney injury
-Pulmonary edema
-Acute MI
-Cardiomyopathy
-DIC
-Increased risk of transfusion
-Increased risk of hysterectomy
Neonatal morbidity of abruptio placentae
-Consequences of prematurity
-Hypoxia
-Asphyxia
-Intrauterine growth restriction
-Congenital anomalies
Abruptio placentae: grading
-Grade 1 (40% of all abruptions):
-Normal maternal BP, nl FHR; mild vaginal bleeding; uterine irritability and tenderness
-Grade 2 (45%)
-Vaginal bleeding, uterine contractions, no signs of maternal shock; + fetal distress
-Grade 3 (15%)
-Evident or concealed severe bleeding, persistent abdominal pain, maternal shock, fetal distress or death
Management of abruptio placentae
-CBC
-Type and screen or crossmatch, if indicated
-Coagulation profile, including fibrinogen
-Large bore IV and isotonic fluids
-U/S
-Electronic fetal monitoring
-Consider delivery and best route of delivery:
-C/S if fetus is alive
-Vaginal delivery if fetal demise
-20-30% fetal mortality
Abruptio placentae; retroplacental clot
-if you see the clot it means you prob have it
-if you dont see it doesnt mean you dont have it
Prevention of abruptio placentae in patients with pre-eclampsia
May use aspirin ≥100 mg PO daily at or before 16 weeks EGA
Not significantly reduced when begun after 16 weeks, or at a dose ≤100 mg daily
Which of the following placental disorders is present in approx 40% of all pregnancies
-placenta previa
-abruptio placentae
-subchorionic hematoma!!!!
-placenta accreta spectrum
